panopainter/tests/renderer_api/renderer_api_tests.cpp

#include "renderer_api/renderer_api.h"
#include "renderer_api/recording_renderer.h"
#include "renderer_api/shader_catalog.h"
#include "test_harness.h"

#include <array>
#include <cstddef>
#include <string_view>

using pp::foundation::StatusCode;
using pp::renderer::BlitFilter;
using pp::renderer::blit_filter_name;
using pp::renderer::BlendFactor;
using pp::renderer::blend_factor_name;
using pp::renderer::BlendOp;
using pp::renderer::blend_op_name;
using pp::renderer::BlendState;
using pp::renderer::ClearColor;
using pp::renderer::CompareOp;
using pp::renderer::compare_op_name;
using pp::renderer::DepthState;
using pp::renderer::Extent2D;
using pp::renderer::frame_capture_byte_size;
using pp::renderer::ICommandContext;
using pp::renderer::IMesh;
using pp::renderer::IRenderDevice;
using pp::renderer::IRenderTarget;
using pp::renderer::IRenderTrace;
using pp::renderer::IShaderProgram;
using pp::renderer::MeshDesc;
using pp::renderer::PrimitiveTopology;
using pp::renderer::ReadbackRegion;
using pp::renderer::RecordedRenderCommandKind;
using pp::renderer::RecordingMesh;
using pp::renderer::RecordingReadbackBuffer;
using pp::renderer::RecordingRenderDevice;
using pp::renderer::RecordingRenderTarget;
using pp::renderer::RecordingShaderProgram;
using pp::renderer::RecordingTexture2D;
using pp::renderer::SamplerAddressMode;
using pp::renderer::sampler_address_mode_name;
using pp::renderer::SamplerDesc;
using pp::renderer::SamplerFilter;
using pp::renderer::sampler_filter_name;
using pp::renderer::ScissorRect;
using pp::renderer::ShaderProgramDesc;
using pp::renderer::ShaderStageSource;
using pp::renderer::TextureDesc;
using pp::renderer::TextureFormat;
using pp::renderer::Viewport;
using pp::renderer::max_shader_source_bytes;
using pp::renderer::max_texture_dimension;
using pp::renderer::max_texture_slots;
using pp::renderer::panopainter_shader_catalog;
using pp::renderer::primitive_topology_name;
using pp::renderer::readback_byte_size;
using pp::renderer::recorded_render_command_kind_name;
using pp::renderer::ShaderCatalogEntry;
using pp::renderer::texture_byte_size;
using pp::renderer::texture_format_name;
using pp::renderer::validate_extent;
using pp::renderer::validate_blit_descs;
using pp::renderer::validate_blit_filter;
using pp::renderer::validate_blend_factor;
using pp::renderer::validate_blend_op;
using pp::renderer::validate_blend_state;
using pp::renderer::validate_compare_op;
using pp::renderer::validate_depth_state;
using pp::renderer::validate_mesh_desc;
using pp::renderer::validate_readback_region;
using pp::renderer::validate_sampler_address_mode;
using pp::renderer::validate_sampler_desc;
using pp::renderer::validate_sampler_filter;
using pp::renderer::validate_scissor;
using pp::renderer::validate_shader_catalog;
using pp::renderer::validate_shader_program_desc;
using pp::renderer::validate_texture_slot;
using pp::renderer::validate_viewport;

namespace {

class FakeRenderTarget final : public IRenderTarget {
public:
    [[nodiscard]] TextureDesc color_desc() const noexcept override
    {
        return TextureDesc {
            .extent = Extent2D { .width = 64, .height = 32 },
            .format = TextureFormat::rgba8,
            .render_target = true,
        };
    }
};

class FakeShaderProgram final : public IShaderProgram {
public:
    [[nodiscard]] const char* debug_name() const noexcept override
    {
        return "fake-shader";
    }
};

class FakeMesh final : public IMesh {
public:
    [[nodiscard]] MeshDesc desc() const noexcept override
    {
        return MeshDesc { .vertex_count = 3, .index_count = 0, .topology = PrimitiveTopology::triangles };
    }
};

class FakeTexture final : public pp::renderer::ITexture2D {
public:
    [[nodiscard]] TextureDesc desc() const noexcept override
    {
        return TextureDesc {
            .extent = Extent2D { .width = 64, .height = 32 },
            .format = TextureFormat::rgba8,
            .render_target = true,
        };
    }
};

class FakeReadbackBuffer final : public pp::renderer::IReadbackBuffer {
public:
    explicit FakeReadbackBuffer(std::uint64_t size) noexcept
        : size_(size)
    {
    }

    [[nodiscard]] std::uint64_t size_bytes() const noexcept override
    {
        return size_;
    }

private:
    std::uint64_t size_ = 0;
};

class FakeTrace final : public IRenderTrace {
public:
    void marker(const char* component, const char* name) noexcept override
    {
        last_component = component;
        last_name = name;
    }

    const char* last_component = nullptr;
    const char* last_name = nullptr;
};

class FakeCommandContext final : public ICommandContext {
public:
    [[nodiscard]] pp::foundation::Status begin_render_pass(
        IRenderTarget& target,
        ClearColor) noexcept override
    {
        in_render_pass = true;
        return validate_extent(target.color_desc().extent);
    }

    [[nodiscard]] pp::foundation::Status set_viewport(Viewport viewport) noexcept override
    {
        if (!in_render_pass) {
            return pp::foundation::Status::invalid_argument("render pass has not begun");
        }
        return validate_viewport(viewport, Extent2D { .width = 64, .height = 32 });
    }

    [[nodiscard]] pp::foundation::Status set_scissor(ScissorRect scissor) noexcept override
    {
        if (!in_render_pass) {
            return pp::foundation::Status::invalid_argument("render pass has not begun");
        }
        const auto status = validate_scissor(scissor, Extent2D { .width = 64, .height = 32 });
        if (!status.ok()) {
            return status;
        }
        last_scissor = scissor;
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status bind_shader(IShaderProgram& shader) noexcept override
    {
        shader_name = shader.debug_name();
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status set_blend_state(BlendState state) noexcept override
    {
        if (!in_render_pass) {
            return pp::foundation::Status::invalid_argument("render pass has not begun");
        }
        const auto status = validate_blend_state(state);
        if (!status.ok()) {
            return status;
        }
        last_blend_state = state;
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status set_depth_state(DepthState state) noexcept override
    {
        if (!in_render_pass) {
            return pp::foundation::Status::invalid_argument("render pass has not begun");
        }
        const auto status = validate_depth_state(state);
        if (!status.ok()) {
            return status;
        }
        last_depth_state = state;
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status bind_texture(
        std::uint32_t slot,
        pp::renderer::ITexture2D& texture) noexcept override
    {
        if (!in_render_pass) {
            return pp::foundation::Status::invalid_argument("render pass has not begun");
        }
        const auto slot_status = validate_texture_slot(slot);
        if (!slot_status.ok()) {
            return slot_status;
        }
        const auto bytes = texture_byte_size(texture.desc());
        if (!bytes) {
            return bytes.status();
        }
        last_texture_slot = slot;
        last_texture_bytes = bytes.value();
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status bind_sampler(
        std::uint32_t slot,
        SamplerDesc sampler) noexcept override
    {
        if (!in_render_pass) {
            return pp::foundation::Status::invalid_argument("render pass has not begun");
        }
        const auto slot_status = validate_texture_slot(slot);
        if (!slot_status.ok()) {
            return slot_status;
        }
        const auto sampler_status = validate_sampler_desc(sampler);
        if (!sampler_status.ok()) {
            return sampler_status;
        }
        last_sampler_slot = slot;
        last_sampler_desc = sampler;
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status bind_mesh(IMesh& mesh) noexcept override
    {
        return validate_mesh_desc(mesh.desc());
    }

    [[nodiscard]] pp::foundation::Status draw() noexcept override
    {
        return in_render_pass ? pp::foundation::Status::success()
                              : pp::foundation::Status::invalid_argument("render pass has not begun");
    }

    [[nodiscard]] pp::foundation::Status read_texture(
        pp::renderer::ITexture2D& texture,
        ReadbackRegion region,
        pp::renderer::IReadbackBuffer& destination) noexcept override
    {
        const auto bytes = readback_byte_size(texture.desc(), region);
        if (!bytes) {
            return bytes.status();
        }
        if (destination.size_bytes() < bytes.value()) {
            return pp::foundation::Status::out_of_range("readback buffer is too small");
        }
        last_readback_bytes = bytes.value();
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status upload_texture(
        pp::renderer::ITexture2D& texture,
        ReadbackRegion region,
        std::span<const std::byte> rgba_or_channel_bytes) noexcept override
    {
        const auto bytes = readback_byte_size(texture.desc(), region);
        if (!bytes) {
            return bytes.status();
        }
        if (rgba_or_channel_bytes.size() != bytes.value()) {
            return pp::foundation::Status::invalid_argument("texture upload byte size does not match the region");
        }
        last_upload_bytes = bytes.value();
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status capture_frame(
        IRenderTarget& target,
        pp::renderer::IReadbackBuffer& destination) noexcept override
    {
        const auto bytes = frame_capture_byte_size(target.color_desc());
        if (!bytes) {
            return bytes.status();
        }
        if (destination.size_bytes() < bytes.value()) {
            return pp::foundation::Status::out_of_range("frame capture buffer is too small");
        }
        last_capture_bytes = bytes.value();
        return pp::foundation::Status::success();
    }

    [[nodiscard]] pp::foundation::Status blit_render_target(
        IRenderTarget& source,
        ReadbackRegion source_region,
        IRenderTarget& destination,
        ReadbackRegion destination_region,
        BlitFilter filter) noexcept override
    {
        const auto source_desc = source.color_desc();
        const auto destination_desc = destination.color_desc();
        const auto desc_status = validate_blit_descs(source_desc, destination_desc);
        if (!desc_status.ok()) {
            return desc_status;
        }
        const auto filter_status = validate_blit_filter(filter);
        if (!filter_status.ok()) {
            return filter_status;
        }
        const auto source_bytes = readback_byte_size(source_desc, source_region);
        if (!source_bytes) {
            return source_bytes.status();
        }
        const auto destination_bytes = readback_byte_size(destination_desc, destination_region);
        if (!destination_bytes) {
            return destination_bytes.status();
        }

        last_blit_source_bytes = source_bytes.value();
        last_blit_destination_bytes = destination_bytes.value();
        last_blit_filter = filter;
        return pp::foundation::Status::success();
    }

    void end_render_pass() noexcept override
    {
        in_render_pass = false;
    }

    bool in_render_pass = false;
    const char* shader_name = nullptr;
    ScissorRect last_scissor {};
    BlendState last_blend_state {};
    DepthState last_depth_state {};
    std::uint32_t last_texture_slot = 0;
    std::uint64_t last_texture_bytes = 0;
    std::uint32_t last_sampler_slot = 0;
    SamplerDesc last_sampler_desc {};
    std::uint64_t last_upload_bytes = 0;
    std::uint64_t last_readback_bytes = 0;
    std::uint64_t last_capture_bytes = 0;
    std::uint64_t last_blit_source_bytes = 0;
    std::uint64_t last_blit_destination_bytes = 0;
    BlitFilter last_blit_filter = BlitFilter::nearest;
};

class FakeRenderDevice final : public IRenderDevice {
public:
    [[nodiscard]] const char* backend_name() const noexcept override
    {
        return "fake";
    }

    [[nodiscard]] ICommandContext& immediate_context() noexcept override
    {
        return context;
    }

    [[nodiscard]] IRenderTrace* trace() noexcept override
    {
        return &trace_recorder;
    }

    FakeCommandContext context;
    FakeTrace trace_recorder;
};

void computes_texture_sizes(pp::tests::Harness& h)
{
    const auto rgba = texture_byte_size(TextureDesc {
        .extent = Extent2D { .width = 16, .height = 8 },
        .format = TextureFormat::rgba8,
    });
    const auto r8 = texture_byte_size(TextureDesc {
        .extent = Extent2D { .width = 16, .height = 8 },
        .format = TextureFormat::r8,
    });

    PP_EXPECT(h, rgba.ok());
    PP_EXPECT(h, rgba.value() == 512U);
    PP_EXPECT(h, r8.ok());
    PP_EXPECT(h, r8.value() == 128U);
    PP_EXPECT(h, texture_format_name(TextureFormat::depth24_stencil8) == std::string_view("depth24_stencil8"));
}

void rejects_invalid_or_excessive_extents(pp::tests::Harness& h)
{
    const auto zero = validate_extent(Extent2D { .width = 0, .height = 1 });
    const auto huge = validate_extent(Extent2D { .width = max_texture_dimension + 1U, .height = 1 });
    const auto excessive_bytes = texture_byte_size(TextureDesc {
        .extent = Extent2D { .width = max_texture_dimension, .height = max_texture_dimension },
        .format = TextureFormat::rgba8,
    });

    PP_EXPECT(h, !zero.ok());
    PP_EXPECT(h, zero.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !huge.ok());
    PP_EXPECT(h, huge.code == StatusCode::out_of_range);
    PP_EXPECT(h, !excessive_bytes.ok());
    PP_EXPECT(h, excessive_bytes.status().code == StatusCode::out_of_range);
}

void validates_readback_bounds(pp::tests::Harness& h)
{
    const TextureDesc desc {
        .extent = Extent2D { .width = 64, .height = 32 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    };

    PP_EXPECT(h, validate_readback_region(desc, ReadbackRegion { .x = 0, .y = 0, .width = 64, .height = 32 }).ok());
    PP_EXPECT(h, validate_readback_region(desc, ReadbackRegion { .x = 63, .y = 31, .width = 1, .height = 1 }).ok());

    const auto empty = validate_readback_region(desc, ReadbackRegion { .x = 0, .y = 0, .width = 0, .height = 1 });
    const auto origin_outside = validate_readback_region(desc, ReadbackRegion { .x = 65, .y = 0, .width = 1, .height = 1 });
    const auto overrun = validate_readback_region(desc, ReadbackRegion { .x = 63, .y = 31, .width = 2, .height = 1 });

    PP_EXPECT(h, !empty.ok());
    PP_EXPECT(h, empty.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !origin_outside.ok());
    PP_EXPECT(h, origin_outside.code == StatusCode::out_of_range);
    PP_EXPECT(h, !overrun.ok());
    PP_EXPECT(h, overrun.code == StatusCode::out_of_range);
}

void computes_readback_byte_sizes(pp::tests::Harness& h)
{
    const TextureDesc rgba_desc {
        .extent = Extent2D { .width = 64, .height = 32 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    };
    const TextureDesc r8_desc {
        .extent = Extent2D { .width = 64, .height = 32 },
        .format = TextureFormat::r8,
        .render_target = true,
    };

    const auto rgba = readback_byte_size(rgba_desc, ReadbackRegion { .x = 4, .y = 2, .width = 8, .height = 3 });
    const auto r8 = readback_byte_size(r8_desc, ReadbackRegion { .x = 0, .y = 0, .width = 5, .height = 7 });
    const auto overrun = readback_byte_size(rgba_desc, ReadbackRegion { .x = 63, .y = 0, .width = 2, .height = 1 });

    PP_EXPECT(h, rgba.ok());
    PP_EXPECT(h, rgba.value() == 96U);
    PP_EXPECT(h, r8.ok());
    PP_EXPECT(h, r8.value() == 35U);
    PP_EXPECT(h, !overrun.ok());
    PP_EXPECT(h, overrun.status().code == StatusCode::out_of_range);
}

void computes_frame_capture_byte_sizes(pp::tests::Harness& h)
{
    const TextureDesc target_desc {
        .extent = Extent2D { .width = 16, .height = 8 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    };
    const TextureDesc texture_desc {
        .extent = Extent2D { .width = 16, .height = 8 },
        .format = TextureFormat::rgba8,
        .render_target = false,
    };

    const auto capture = frame_capture_byte_size(target_desc);
    const auto non_target = frame_capture_byte_size(texture_desc);

    PP_EXPECT(h, capture.ok());
    PP_EXPECT(h, capture.value() == 512U);
    PP_EXPECT(h, !non_target.ok());
    PP_EXPECT(h, non_target.status().code == StatusCode::invalid_argument);
}

void validates_blit_contract(pp::tests::Harness& h)
{
    const TextureDesc target_desc {
        .extent = Extent2D { .width = 16, .height = 8 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    };
    const TextureDesc r8_target_desc {
        .extent = Extent2D { .width = 16, .height = 8 },
        .format = TextureFormat::r8,
        .render_target = true,
    };
    const TextureDesc texture_desc {
        .extent = Extent2D { .width = 16, .height = 8 },
        .format = TextureFormat::rgba8,
        .render_target = false,
    };

    PP_EXPECT(h, validate_blit_descs(target_desc, target_desc).ok());
    PP_EXPECT(h, validate_blit_filter(BlitFilter::nearest).ok());
    PP_EXPECT(h, validate_blit_filter(BlitFilter::linear).ok());
    PP_EXPECT(h, blit_filter_name(BlitFilter::linear) == std::string_view("linear"));

    const auto non_target = validate_blit_descs(texture_desc, target_desc);
    const auto mismatched_format = validate_blit_descs(target_desc, r8_target_desc);
    const auto bad_filter = validate_blit_filter(static_cast<BlitFilter>(255));

    PP_EXPECT(h, !non_target.ok());
    PP_EXPECT(h, non_target.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !mismatched_format.ok());
    PP_EXPECT(h, mismatched_format.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_filter.ok());
    PP_EXPECT(h, bad_filter.code == StatusCode::invalid_argument);
    PP_EXPECT(h, blit_filter_name(static_cast<BlitFilter>(255)) == std::string_view("unknown"));
}

void validates_blend_contract(pp::tests::Harness& h)
{
    const BlendState alpha_blend {
        .enabled = true,
        .source_color = BlendFactor::source_alpha,
        .destination_color = BlendFactor::one_minus_source_alpha,
        .color_op = BlendOp::add,
        .source_alpha = BlendFactor::one,
        .destination_alpha = BlendFactor::one_minus_source_alpha,
        .alpha_op = BlendOp::add,
    };

    PP_EXPECT(h, validate_blend_state(alpha_blend).ok());
    PP_EXPECT(h, validate_blend_factor(BlendFactor::destination_alpha).ok());
    PP_EXPECT(h, validate_blend_op(BlendOp::reverse_subtract).ok());
    PP_EXPECT(h, blend_factor_name(BlendFactor::one_minus_destination_alpha)
                     == std::string_view("one_minus_destination_alpha"));
    PP_EXPECT(h, blend_op_name(BlendOp::subtract) == std::string_view("subtract"));

    auto bad_source = alpha_blend;
    bad_source.source_color = static_cast<BlendFactor>(255);
    auto bad_op = alpha_blend;
    bad_op.alpha_op = static_cast<BlendOp>(255);

    const auto bad_source_status = validate_blend_state(bad_source);
    const auto bad_op_status = validate_blend_state(bad_op);

    PP_EXPECT(h, !bad_source_status.ok());
    PP_EXPECT(h, bad_source_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_op_status.ok());
    PP_EXPECT(h, bad_op_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, blend_factor_name(static_cast<BlendFactor>(255)) == std::string_view("unknown"));
    PP_EXPECT(h, blend_op_name(static_cast<BlendOp>(255)) == std::string_view("unknown"));
}

void validates_depth_contract(pp::tests::Harness& h)
{
    const DepthState read_write_depth {
        .test_enabled = true,
        .write_enabled = true,
        .compare = CompareOp::less_or_equal,
    };

    PP_EXPECT(h, validate_depth_state(read_write_depth).ok());
    PP_EXPECT(h, validate_compare_op(CompareOp::always).ok());
    PP_EXPECT(h, compare_op_name(CompareOp::greater_or_equal) == std::string_view("greater_or_equal"));

    auto bad_compare = read_write_depth;
    bad_compare.compare = static_cast<CompareOp>(255);
    const auto bad_compare_status = validate_depth_state(bad_compare);

    PP_EXPECT(h, !bad_compare_status.ok());
    PP_EXPECT(h, bad_compare_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, compare_op_name(static_cast<CompareOp>(255)) == std::string_view("unknown"));
}

void validates_sampler_contract(pp::tests::Harness& h)
{
    const SamplerDesc sampler {
        .min_filter = SamplerFilter::linear,
        .mag_filter = SamplerFilter::nearest,
        .mip_filter = SamplerFilter::linear,
        .address_u = SamplerAddressMode::repeat,
        .address_v = SamplerAddressMode::mirrored_repeat,
        .address_w = SamplerAddressMode::clamp_to_border,
    };

    PP_EXPECT(h, validate_sampler_desc(sampler).ok());
    PP_EXPECT(h, validate_sampler_filter(SamplerFilter::nearest).ok());
    PP_EXPECT(h, validate_sampler_address_mode(SamplerAddressMode::clamp_to_border).ok());
    PP_EXPECT(h, sampler_filter_name(SamplerFilter::linear) == std::string_view("linear"));
    PP_EXPECT(h, sampler_address_mode_name(SamplerAddressMode::mirrored_repeat) == std::string_view("mirrored_repeat"));

    auto bad_filter = sampler;
    bad_filter.min_filter = static_cast<SamplerFilter>(255);
    auto bad_address = sampler;
    bad_address.address_w = static_cast<SamplerAddressMode>(255);

    const auto bad_filter_status = validate_sampler_desc(bad_filter);
    const auto bad_address_status = validate_sampler_desc(bad_address);

    PP_EXPECT(h, !bad_filter_status.ok());
    PP_EXPECT(h, bad_filter_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_address_status.ok());
    PP_EXPECT(h, bad_address_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, sampler_filter_name(static_cast<SamplerFilter>(255)) == std::string_view("unknown"));
    PP_EXPECT(h, sampler_address_mode_name(static_cast<SamplerAddressMode>(255)) == std::string_view("unknown"));
}

void validates_viewports_and_mesh_descriptors(pp::tests::Harness& h)
{
    const Extent2D target { .width = 64, .height = 32 };

    PP_EXPECT(h, validate_viewport(
                     Viewport { .x = 0, .y = 0, .width = 64, .height = 32, .min_depth = 0.0F, .max_depth = 1.0F },
                     target)
                     .ok());
    PP_EXPECT(h, validate_scissor(ScissorRect {}, target).ok());
    PP_EXPECT(h, validate_scissor(ScissorRect { .enabled = true, .x = 0, .y = 0, .width = 64, .height = 32 }, target)
                     .ok());
    PP_EXPECT(h, validate_scissor(ScissorRect { .enabled = true, .x = 63, .y = 31, .width = 1, .height = 1 }, target)
                     .ok());
    PP_EXPECT(h, validate_mesh_desc(MeshDesc { .vertex_count = 3, .topology = PrimitiveTopology::triangles }).ok());
    PP_EXPECT(h, primitive_topology_name(PrimitiveTopology::lines) == std::string_view("lines"));

    const auto negative_origin = validate_viewport(Viewport { .x = -1, .y = 0, .width = 1, .height = 1 }, target);
    const auto too_wide = validate_viewport(Viewport { .x = 63, .y = 0, .width = 2, .height = 1 }, target);
    const auto bad_depth = validate_viewport(
        Viewport { .x = 0, .y = 0, .width = 1, .height = 1, .min_depth = 0.75F, .max_depth = 0.25F },
        target);
    const auto empty_mesh = validate_mesh_desc(MeshDesc {});
    const auto negative_scissor = validate_scissor(ScissorRect { .enabled = true, .x = -1, .y = 0, .width = 1, .height = 1 }, target);
    const auto empty_scissor = validate_scissor(ScissorRect { .enabled = true, .x = 0, .y = 0, .width = 0, .height = 1 }, target);
    const auto scissor_overrun = validate_scissor(ScissorRect { .enabled = true, .x = 63, .y = 0, .width = 2, .height = 1 }, target);

    PP_EXPECT(h, !negative_origin.ok());
    PP_EXPECT(h, negative_origin.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !too_wide.ok());
    PP_EXPECT(h, too_wide.code == StatusCode::out_of_range);
    PP_EXPECT(h, !bad_depth.ok());
    PP_EXPECT(h, bad_depth.code == StatusCode::out_of_range);
    PP_EXPECT(h, !empty_mesh.ok());
    PP_EXPECT(h, empty_mesh.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !negative_scissor.ok());
    PP_EXPECT(h, negative_scissor.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !empty_scissor.ok());
    PP_EXPECT(h, empty_scissor.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !scissor_overrun.ok());
    PP_EXPECT(h, scissor_overrun.code == StatusCode::out_of_range);

    PP_EXPECT(h, validate_texture_slot(0).ok());
    PP_EXPECT(h, validate_texture_slot(max_texture_slots - 1U).ok());
    const auto invalid_slot = validate_texture_slot(max_texture_slots);
    PP_EXPECT(h, !invalid_slot.ok());
    PP_EXPECT(h, invalid_slot.code == StatusCode::out_of_range);
}

void validates_shader_program_descriptors(pp::tests::Harness& h)
{
    constexpr char vertex_source[] = "#version 330 core\nvoid main(){}";
    constexpr char fragment_source[] = "#version 330 core\nout vec4 color; void main(){ color = vec4(1); }";

    const ShaderProgramDesc valid {
        .debug_name = "solid-color",
        .vertex = ShaderStageSource {
            .entry_point = "main",
            .source = vertex_source,
            .source_size = sizeof(vertex_source) - 1U,
        },
        .fragment = ShaderStageSource {
            .entry_point = "main",
            .source = fragment_source,
            .source_size = sizeof(fragment_source) - 1U,
        },
    };

    PP_EXPECT(h, validate_shader_program_desc(valid).ok());

    auto missing_name = valid;
    missing_name.debug_name = nullptr;
    auto missing_vertex_entry = valid;
    missing_vertex_entry.vertex.entry_point = "";
    auto missing_fragment_source = valid;
    missing_fragment_source.fragment.source = nullptr;
    auto empty_fragment_source = valid;
    empty_fragment_source.fragment.source_size = 0;
    auto excessive_source = valid;
    excessive_source.vertex.source_size = max_shader_source_bytes + 1U;

    const auto missing_name_status = validate_shader_program_desc(missing_name);
    const auto missing_vertex_entry_status = validate_shader_program_desc(missing_vertex_entry);
    const auto missing_fragment_source_status = validate_shader_program_desc(missing_fragment_source);
    const auto empty_fragment_source_status = validate_shader_program_desc(empty_fragment_source);
    const auto excessive_source_status = validate_shader_program_desc(excessive_source);

    PP_EXPECT(h, !missing_name_status.ok());
    PP_EXPECT(h, missing_name_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !missing_vertex_entry_status.ok());
    PP_EXPECT(h, missing_vertex_entry_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !missing_fragment_source_status.ok());
    PP_EXPECT(h, missing_fragment_source_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !empty_fragment_source_status.ok());
    PP_EXPECT(h, empty_fragment_source_status.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !excessive_source_status.ok());
    PP_EXPECT(h, excessive_source_status.code == StatusCode::out_of_range);
}

void validates_panopainter_shader_catalog(pp::tests::Harness& h)
{
    const auto catalog = panopainter_shader_catalog();

    PP_EXPECT(h, catalog.size() == 25U);
    PP_EXPECT(h, validate_shader_catalog(catalog).ok());
    PP_EXPECT(h, catalog.front().name == std::string_view("texture"));
    PP_EXPECT(h, catalog.front().path == std::string_view("data/shaders/texture.glsl"));
    PP_EXPECT(h, catalog.back().name == std::string_view("bakeuv"));
    PP_EXPECT(h, catalog.back().path == std::string_view("data/shaders/bake-uv.glsl"));

    bool found_stroke = false;
    bool found_brush_stroke = false;
    bool found_equirect = false;
    for (const auto& entry : catalog) {
        found_stroke = found_stroke || std::string_view(entry.name) == "stroke";
        found_brush_stroke = found_brush_stroke || std::string_view(entry.name) == "brush-stroke";
        found_equirect = found_equirect || std::string_view(entry.name) == "equirect";
    }

    PP_EXPECT(h, found_stroke);
    PP_EXPECT(h, found_brush_stroke);
    PP_EXPECT(h, found_equirect);
}

void rejects_invalid_shader_catalogs(pp::tests::Harness& h)
{
    const std::array<ShaderCatalogEntry, 2> duplicated {
        ShaderCatalogEntry { .name = "texture", .path = "data/shaders/texture.glsl" },
        ShaderCatalogEntry { .name = "texture", .path = "data/shaders/texture-alpha.glsl" },
    };
    const std::array<ShaderCatalogEntry, 1> missing_name {
        ShaderCatalogEntry { .name = "", .path = "data/shaders/texture.glsl" },
    };
    const std::array<ShaderCatalogEntry, 1> missing_path {
        ShaderCatalogEntry { .name = "texture", .path = "" },
    };
    const std::array<ShaderCatalogEntry, 1> wrong_extension {
        ShaderCatalogEntry { .name = "texture", .path = "data/shaders/texture.txt" },
    };

    const auto empty = validate_shader_catalog({});
    const auto duplicate = validate_shader_catalog(duplicated);
    const auto no_name = validate_shader_catalog(missing_name);
    const auto no_path = validate_shader_catalog(missing_path);
    const auto bad_extension = validate_shader_catalog(wrong_extension);

    PP_EXPECT(h, !empty.ok());
    PP_EXPECT(h, empty.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !duplicate.ok());
    PP_EXPECT(h, duplicate.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !no_name.ok());
    PP_EXPECT(h, no_name.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !no_path.ok());
    PP_EXPECT(h, no_path.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_extension.ok());
    PP_EXPECT(h, bad_extension.code == StatusCode::invalid_argument);
}

void renderer_interfaces_support_backend_neutral_dispatch(pp::tests::Harness& h)
{
    FakeRenderDevice device;
    FakeRenderTarget target;
    FakeTexture texture;
    FakeReadbackBuffer readback_buffer(64U * 32U * 4U);
    const std::array<std::byte, 80> upload_bytes {};
    FakeShaderProgram shader;
    FakeMesh mesh;

    PP_EXPECT(h, device.backend_name() == std::string_view("fake"));
    device.trace()->marker("renderer", "begin");
    PP_EXPECT(h, device.trace_recorder.last_component == std::string_view("renderer"));
    PP_EXPECT(h, device.trace_recorder.last_name == std::string_view("begin"));

    auto& context = device.immediate_context();
    PP_EXPECT(h, context.begin_render_pass(target, ClearColor { .r = 0.1F, .g = 0.2F, .b = 0.3F, .a = 1.0F }).ok());
    PP_EXPECT(h, context.set_viewport(Viewport { .x = 0, .y = 0, .width = 64, .height = 32 }).ok());
    PP_EXPECT(h, context.set_scissor(ScissorRect { .enabled = true, .x = 4, .y = 5, .width = 16, .height = 8 }).ok());
    PP_EXPECT(h, context.set_blend_state(BlendState {
                     .enabled = true,
                     .source_color = BlendFactor::source_alpha,
                     .destination_color = BlendFactor::one_minus_source_alpha,
                 })
                     .ok());
    PP_EXPECT(h, context.set_depth_state(DepthState {
                     .test_enabled = true,
                     .write_enabled = true,
                     .compare = CompareOp::less_or_equal,
                 })
                     .ok());
    PP_EXPECT(h, context.bind_shader(shader).ok());
    PP_EXPECT(h, context.bind_texture(2, texture).ok());
    PP_EXPECT(h, context.bind_sampler(2, SamplerDesc {
                     .min_filter = SamplerFilter::linear,
                     .mag_filter = SamplerFilter::nearest,
                     .address_u = SamplerAddressMode::repeat,
                 })
                     .ok());
    PP_EXPECT(h, context.bind_mesh(mesh).ok());
    PP_EXPECT(h, context.draw().ok());
    context.end_render_pass();

    const auto draw_after_end = context.draw();
    PP_EXPECT(h, !draw_after_end.ok());
    PP_EXPECT(h, draw_after_end.code == StatusCode::invalid_argument);
    PP_EXPECT(h, context.upload_texture(
                     texture,
                     ReadbackRegion { .x = 2, .y = 3, .width = 4, .height = 5 },
                     upload_bytes)
                     .ok());
    PP_EXPECT(h, context.read_texture(
                     texture,
                     ReadbackRegion { .x = 2, .y = 3, .width = 4, .height = 5 },
                     readback_buffer)
                     .ok());
    PP_EXPECT(h, context.capture_frame(target, readback_buffer).ok());
    PP_EXPECT(h, context.blit_render_target(
                     target,
                     ReadbackRegion { .x = 2, .y = 3, .width = 4, .height = 5 },
                     target,
                     ReadbackRegion { .x = 0, .y = 0, .width = 8, .height = 10 },
                     BlitFilter::linear)
                     .ok());
    PP_EXPECT(h, device.context.shader_name == std::string_view("fake-shader"));
    PP_EXPECT(h, device.context.last_scissor.enabled);
    PP_EXPECT(h, device.context.last_scissor.x == 4);
    PP_EXPECT(h, device.context.last_scissor.height == 8U);
    PP_EXPECT(h, device.context.last_blend_state.enabled);
    PP_EXPECT(h, device.context.last_blend_state.source_color == BlendFactor::source_alpha);
    PP_EXPECT(h, device.context.last_blend_state.destination_color == BlendFactor::one_minus_source_alpha);
    PP_EXPECT(h, device.context.last_depth_state.test_enabled);
    PP_EXPECT(h, device.context.last_depth_state.write_enabled);
    PP_EXPECT(h, device.context.last_depth_state.compare == CompareOp::less_or_equal);
    PP_EXPECT(h, device.context.last_texture_slot == 2U);
    PP_EXPECT(h, device.context.last_texture_bytes == 8192U);
    PP_EXPECT(h, device.context.last_sampler_slot == 2U);
    PP_EXPECT(h, device.context.last_sampler_desc.mag_filter == SamplerFilter::nearest);
    PP_EXPECT(h, device.context.last_sampler_desc.address_u == SamplerAddressMode::repeat);
    PP_EXPECT(h, device.context.last_upload_bytes == 80U);
    PP_EXPECT(h, device.context.last_readback_bytes == 80U);
    PP_EXPECT(h, device.context.last_capture_bytes == 8192U);
    PP_EXPECT(h, device.context.last_blit_source_bytes == 80U);
    PP_EXPECT(h, device.context.last_blit_destination_bytes == 320U);
    PP_EXPECT(h, device.context.last_blit_filter == BlitFilter::linear);
}

void recording_renderer_records_valid_command_sequences(pp::tests::Harness& h)
{
    RecordingRenderDevice device;
    RecordingTexture2D texture(TextureDesc {
        .extent = Extent2D { .width = 64, .height = 32 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    });
    RecordingReadbackBuffer readback_buffer(64U * 32U * 4U);
    const std::array<std::byte, 96> upload_bytes {};
    RecordingRenderTarget target(TextureDesc {
        .extent = Extent2D { .width = 64, .height = 32 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    });
    RecordingRenderTarget blit_target(TextureDesc {
        .extent = Extent2D { .width = 64, .height = 32 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    });
    RecordingShaderProgram shader("recorded-shader");
    RecordingMesh mesh(MeshDesc { .vertex_count = 3, .index_count = 3, .topology = PrimitiveTopology::triangles });

    PP_EXPECT(h, device.backend_name() == std::string_view("recording"));
    device.trace()->marker("renderer", "frame");

    auto& context = device.immediate_context();
    PP_EXPECT(h, context.begin_render_pass(target, ClearColor { .r = 0.2F, .g = 0.3F, .b = 0.4F, .a = 1.0F }).ok());
    PP_EXPECT(h, context.set_viewport(Viewport { .x = 0, .y = 0, .width = 64, .height = 32 }).ok());
    PP_EXPECT(h, context.set_scissor(ScissorRect { .enabled = true, .x = 4, .y = 6, .width = 16, .height = 8 }).ok());
    PP_EXPECT(h, context.set_blend_state(BlendState {
                     .enabled = true,
                     .source_color = BlendFactor::source_alpha,
                     .destination_color = BlendFactor::one_minus_source_alpha,
                     .source_alpha = BlendFactor::one,
                     .destination_alpha = BlendFactor::one_minus_source_alpha,
                 })
                     .ok());
    PP_EXPECT(h, context.set_depth_state(DepthState {
                     .test_enabled = true,
                     .write_enabled = true,
                     .compare = CompareOp::less_or_equal,
                 })
                     .ok());
    PP_EXPECT(h, context.bind_shader(shader).ok());
    PP_EXPECT(h, context.bind_texture(1, texture).ok());
    PP_EXPECT(h, context.bind_sampler(1, SamplerDesc {
                     .min_filter = SamplerFilter::linear,
                     .mag_filter = SamplerFilter::nearest,
                     .address_u = SamplerAddressMode::repeat,
                     .address_v = SamplerAddressMode::clamp_to_edge,
                     .address_w = SamplerAddressMode::clamp_to_border,
                 })
                     .ok());
    PP_EXPECT(h, context.bind_mesh(mesh).ok());
    PP_EXPECT(h, context.draw().ok());
    context.end_render_pass();

    const auto commands = device.commands();
    PP_EXPECT(h, commands.size() == 12U);
    PP_EXPECT(h, commands[0].kind == RecordedRenderCommandKind::trace_marker);
    PP_EXPECT(h, commands[0].component == std::string_view("renderer"));
    PP_EXPECT(h, commands[0].name == std::string_view("frame"));
    PP_EXPECT(h, commands[1].kind == RecordedRenderCommandKind::begin_render_pass);
    PP_EXPECT(h, commands[1].target_desc.extent.width == 64U);
    PP_EXPECT(h, commands[1].clear_color.a == 1.0F);
    PP_EXPECT(h, commands[2].kind == RecordedRenderCommandKind::set_viewport);
    PP_EXPECT(h, commands[2].viewport.height == 32U);
    PP_EXPECT(h, commands[3].kind == RecordedRenderCommandKind::set_scissor);
    PP_EXPECT(h, commands[3].scissor.enabled);
    PP_EXPECT(h, commands[3].scissor.x == 4);
    PP_EXPECT(h, commands[3].scissor.height == 8U);
    PP_EXPECT(h, recorded_render_command_kind_name(commands[3].kind) == std::string_view("set_scissor"));
    PP_EXPECT(h, commands[4].kind == RecordedRenderCommandKind::set_blend_state);
    PP_EXPECT(h, commands[4].blend_state.enabled);
    PP_EXPECT(h, commands[4].blend_state.destination_color == BlendFactor::one_minus_source_alpha);
    PP_EXPECT(h, recorded_render_command_kind_name(commands[4].kind) == std::string_view("set_blend_state"));
    PP_EXPECT(h, commands[5].kind == RecordedRenderCommandKind::set_depth_state);
    PP_EXPECT(h, commands[5].depth_state.test_enabled);
    PP_EXPECT(h, commands[5].depth_state.write_enabled);
    PP_EXPECT(h, commands[5].depth_state.compare == CompareOp::less_or_equal);
    PP_EXPECT(h, recorded_render_command_kind_name(commands[5].kind) == std::string_view("set_depth_state"));
    PP_EXPECT(h, commands[6].kind == RecordedRenderCommandKind::bind_shader);
    PP_EXPECT(h, commands[6].name == std::string_view("recorded-shader"));
    PP_EXPECT(h, commands[7].kind == RecordedRenderCommandKind::bind_texture);
    PP_EXPECT(h, commands[7].texture_slot == 1U);
    PP_EXPECT(h, commands[7].texture_desc.extent.height == 32U);
    PP_EXPECT(h, recorded_render_command_kind_name(commands[7].kind) == std::string_view("bind_texture"));
    PP_EXPECT(h, commands[8].kind == RecordedRenderCommandKind::bind_sampler);
    PP_EXPECT(h, commands[8].sampler_slot == 1U);
    PP_EXPECT(h, commands[8].sampler_desc.mag_filter == SamplerFilter::nearest);
    PP_EXPECT(h, commands[8].sampler_desc.address_w == SamplerAddressMode::clamp_to_border);
    PP_EXPECT(h, recorded_render_command_kind_name(commands[8].kind) == std::string_view("bind_sampler"));
    PP_EXPECT(h, commands[9].kind == RecordedRenderCommandKind::bind_mesh);
    PP_EXPECT(h, commands[9].mesh_desc.vertex_count == 3U);
    PP_EXPECT(h, commands[9].mesh_desc.index_count == 3U);
    PP_EXPECT(h, commands[10].kind == RecordedRenderCommandKind::draw);
    PP_EXPECT(h, commands[10].mesh_desc.vertex_count == 3U);
    PP_EXPECT(h, commands[10].mesh_desc.index_count == 3U);
    PP_EXPECT(h, commands[10].mesh_desc.topology == PrimitiveTopology::triangles);
    PP_EXPECT(h, commands[11].kind == RecordedRenderCommandKind::end_render_pass);
    PP_EXPECT(h, recorded_render_command_kind_name(commands[10].kind) == std::string_view("draw"));

    PP_EXPECT(h, context.upload_texture(
                     texture,
                     ReadbackRegion { .x = 4, .y = 5, .width = 8, .height = 3 },
                     upload_bytes)
                     .ok());
    const auto commands_after_upload = device.commands();
    PP_EXPECT(h, commands_after_upload.size() == 13U);
    PP_EXPECT(h, commands_after_upload[12].kind == RecordedRenderCommandKind::upload_texture);
    PP_EXPECT(h, commands_after_upload[12].texture_desc.extent.width == 64U);
    PP_EXPECT(h, commands_after_upload[12].readback_region.x == 4U);
    PP_EXPECT(h, commands_after_upload[12].upload_bytes == 96U);
    PP_EXPECT(h, recorded_render_command_kind_name(commands_after_upload[12].kind) == std::string_view("upload_texture"));

    PP_EXPECT(h, context.read_texture(
                     texture,
                     ReadbackRegion { .x = 4, .y = 5, .width = 8, .height = 3 },
                     readback_buffer)
                     .ok());
    const auto commands_after_readback = device.commands();
    PP_EXPECT(h, commands_after_readback.size() == 14U);
    PP_EXPECT(h, commands_after_readback[13].kind == RecordedRenderCommandKind::read_texture);
    PP_EXPECT(h, commands_after_readback[13].texture_desc.extent.width == 64U);
    PP_EXPECT(h, commands_after_readback[13].readback_region.x == 4U);
    PP_EXPECT(h, commands_after_readback[13].readback_region.height == 3U);
    PP_EXPECT(h, commands_after_readback[13].readback_bytes == 96U);
    PP_EXPECT(h, recorded_render_command_kind_name(commands_after_readback[13].kind) == std::string_view("read_texture"));

    PP_EXPECT(h, context.capture_frame(target, readback_buffer).ok());
    const auto commands_after_capture = device.commands();
    PP_EXPECT(h, commands_after_capture.size() == 15U);
    PP_EXPECT(h, commands_after_capture[14].kind == RecordedRenderCommandKind::capture_frame);
    PP_EXPECT(h, commands_after_capture[14].target_desc.extent.width == 64U);
    PP_EXPECT(h, commands_after_capture[14].target_desc.extent.height == 32U);
    PP_EXPECT(h, commands_after_capture[14].capture_bytes == 8192U);
    PP_EXPECT(h, recorded_render_command_kind_name(commands_after_capture[14].kind) == std::string_view("capture_frame"));

    PP_EXPECT(h, context.blit_render_target(
                     target,
                     ReadbackRegion { .x = 0, .y = 0, .width = 16, .height = 8 },
                     blit_target,
                     ReadbackRegion { .x = 2, .y = 3, .width = 8, .height = 4 },
                     BlitFilter::linear)
                     .ok());
    const auto commands_after_blit = device.commands();
    PP_EXPECT(h, commands_after_blit.size() == 16U);
    PP_EXPECT(h, commands_after_blit[15].kind == RecordedRenderCommandKind::blit_render_target);
    PP_EXPECT(h, commands_after_blit[15].source_desc.extent.width == 64U);
    PP_EXPECT(h, commands_after_blit[15].destination_desc.extent.height == 32U);
    PP_EXPECT(h, commands_after_blit[15].source_region.width == 16U);
    PP_EXPECT(h, commands_after_blit[15].destination_region.x == 2U);
    PP_EXPECT(h, commands_after_blit[15].blit_filter == BlitFilter::linear);
    PP_EXPECT(h, commands_after_blit[15].blit_source_bytes == 512U);
    PP_EXPECT(h, commands_after_blit[15].blit_destination_bytes == 128U);
    PP_EXPECT(h, recorded_render_command_kind_name(commands_after_blit[15].kind) == std::string_view("blit_render_target"));

    device.clear();
    PP_EXPECT(h, device.commands().empty());
}

void recording_renderer_rejects_invalid_command_order_and_targets(pp::tests::Harness& h)
{
    RecordingRenderDevice device;
    RecordingRenderTarget target(TextureDesc {
        .extent = Extent2D { .width = 32, .height = 16 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    });
    RecordingRenderTarget non_render_target(TextureDesc {
        .extent = Extent2D { .width = 32, .height = 16 },
        .format = TextureFormat::rgba8,
        .render_target = false,
    });
    RecordingRenderTarget r8_target(TextureDesc {
        .extent = Extent2D { .width = 32, .height = 16 },
        .format = TextureFormat::r8,
        .render_target = true,
    });
    RecordingTexture2D texture(TextureDesc {
        .extent = Extent2D { .width = 32, .height = 16 },
        .format = TextureFormat::rgba8,
        .render_target = true,
    });
    RecordingReadbackBuffer small_readback_buffer(3U);
    RecordingReadbackBuffer full_readback_buffer(32U * 16U * 4U);
    const std::array<std::byte, 4> one_pixel_upload {};
    const std::array<std::byte, 3> undersized_upload {};
    RecordingShaderProgram shader("strict-shader");
    RecordingMesh mesh(MeshDesc { .vertex_count = 3, .topology = PrimitiveTopology::triangles });
    RecordingMesh empty_mesh(MeshDesc {});

    auto& context = device.immediate_context();
    const auto draw_before_begin = context.draw();
    PP_EXPECT(h, !draw_before_begin.ok());
    PP_EXPECT(h, draw_before_begin.code == StatusCode::invalid_argument);

    const auto blend_before_begin = context.set_blend_state(BlendState {});
    PP_EXPECT(h, !blend_before_begin.ok());
    PP_EXPECT(h, blend_before_begin.code == StatusCode::invalid_argument);

    const auto scissor_before_begin = context.set_scissor(ScissorRect {});
    PP_EXPECT(h, !scissor_before_begin.ok());
    PP_EXPECT(h, scissor_before_begin.code == StatusCode::invalid_argument);

    const auto depth_before_begin = context.set_depth_state(DepthState {});
    PP_EXPECT(h, !depth_before_begin.ok());
    PP_EXPECT(h, depth_before_begin.code == StatusCode::invalid_argument);

    const auto sampler_before_begin = context.bind_sampler(0, SamplerDesc {});
    PP_EXPECT(h, !sampler_before_begin.ok());
    PP_EXPECT(h, sampler_before_begin.code == StatusCode::invalid_argument);

    const auto invalid_target = context.begin_render_pass(non_render_target, ClearColor {});
    PP_EXPECT(h, !invalid_target.ok());
    PP_EXPECT(h, invalid_target.code == StatusCode::invalid_argument);
    PP_EXPECT(h, device.commands().empty());

    PP_EXPECT(h, context.begin_render_pass(target, ClearColor {}).ok());
    const auto upload_during_render_pass = context.upload_texture(
        texture,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        one_pixel_upload);
    PP_EXPECT(h, !upload_during_render_pass.ok());
    PP_EXPECT(h, upload_during_render_pass.code == StatusCode::invalid_argument);

    const auto read_during_render_pass = context.read_texture(
        texture,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        full_readback_buffer);
    PP_EXPECT(h, !read_during_render_pass.ok());
    PP_EXPECT(h, read_during_render_pass.code == StatusCode::invalid_argument);

    const auto capture_during_render_pass = context.capture_frame(target, full_readback_buffer);
    PP_EXPECT(h, !capture_during_render_pass.ok());
    PP_EXPECT(h, capture_during_render_pass.code == StatusCode::invalid_argument);

    const auto blit_during_render_pass = context.blit_render_target(
        target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        BlitFilter::nearest);
    PP_EXPECT(h, !blit_during_render_pass.ok());
    PP_EXPECT(h, blit_during_render_pass.code == StatusCode::invalid_argument);

    const auto nested_begin = context.begin_render_pass(target, ClearColor {});
    PP_EXPECT(h, !nested_begin.ok());
    PP_EXPECT(h, nested_begin.code == StatusCode::invalid_argument);

    auto invalid_blend = BlendState {};
    invalid_blend.source_color = static_cast<BlendFactor>(255);
    const auto invalid_blend_state = context.set_blend_state(invalid_blend);
    PP_EXPECT(h, !invalid_blend_state.ok());
    PP_EXPECT(h, invalid_blend_state.code == StatusCode::invalid_argument);

    PP_EXPECT(h, context.set_blend_state(BlendState {
                     .enabled = true,
                     .source_color = BlendFactor::source_alpha,
                     .destination_color = BlendFactor::one_minus_source_alpha,
                 })
                     .ok());
    PP_EXPECT(h, context.set_scissor(ScissorRect {
                     .enabled = true,
                     .x = 0,
                     .y = 0,
                     .width = 16,
                     .height = 8,
                 })
                     .ok());

    const auto invalid_scissor = context.set_scissor(ScissorRect {
        .enabled = true,
        .x = 31,
        .y = 15,
        .width = 2,
        .height = 1,
    });
    PP_EXPECT(h, !invalid_scissor.ok());
    PP_EXPECT(h, invalid_scissor.code == StatusCode::out_of_range);

    auto invalid_depth = DepthState {};
    invalid_depth.compare = static_cast<CompareOp>(255);
    const auto invalid_depth_state = context.set_depth_state(invalid_depth);
    PP_EXPECT(h, !invalid_depth_state.ok());
    PP_EXPECT(h, invalid_depth_state.code == StatusCode::invalid_argument);

    PP_EXPECT(h, context.set_depth_state(DepthState {
                     .test_enabled = true,
                     .write_enabled = true,
                     .compare = CompareOp::less_or_equal,
                 })
                     .ok());

    const auto draw_without_bindings = context.draw();
    PP_EXPECT(h, !draw_without_bindings.ok());
    PP_EXPECT(h, draw_without_bindings.code == StatusCode::invalid_argument);

    PP_EXPECT(h, context.bind_shader(shader).ok());
    const auto bind_texture_bad_slot = context.bind_texture(max_texture_slots, texture);
    PP_EXPECT(h, !bind_texture_bad_slot.ok());
    PP_EXPECT(h, bind_texture_bad_slot.code == StatusCode::out_of_range);
    PP_EXPECT(h, context.bind_texture(0, texture).ok());

    const auto bind_sampler_bad_slot = context.bind_sampler(max_texture_slots, SamplerDesc {});
    PP_EXPECT(h, !bind_sampler_bad_slot.ok());
    PP_EXPECT(h, bind_sampler_bad_slot.code == StatusCode::out_of_range);

    auto invalid_sampler = SamplerDesc {};
    invalid_sampler.min_filter = static_cast<SamplerFilter>(255);
    const auto bind_invalid_sampler = context.bind_sampler(0, invalid_sampler);
    PP_EXPECT(h, !bind_invalid_sampler.ok());
    PP_EXPECT(h, bind_invalid_sampler.code == StatusCode::invalid_argument);

    PP_EXPECT(h, context.bind_sampler(0, SamplerDesc {}).ok());

    const auto draw_without_mesh = context.draw();
    PP_EXPECT(h, !draw_without_mesh.ok());
    PP_EXPECT(h, draw_without_mesh.code == StatusCode::invalid_argument);

    const auto invalid_mesh = context.bind_mesh(empty_mesh);
    PP_EXPECT(h, !invalid_mesh.ok());
    PP_EXPECT(h, invalid_mesh.code == StatusCode::invalid_argument);

    PP_EXPECT(h, context.bind_mesh(mesh).ok());
    PP_EXPECT(h, context.draw().ok());
    context.end_render_pass();

    const auto viewport_after_end = context.set_viewport(Viewport { .x = 0, .y = 0, .width = 1, .height = 1 });
    PP_EXPECT(h, !viewport_after_end.ok());
    PP_EXPECT(h, viewport_after_end.code == StatusCode::invalid_argument);

    const auto blend_after_end = context.set_blend_state(BlendState {});
    PP_EXPECT(h, !blend_after_end.ok());
    PP_EXPECT(h, blend_after_end.code == StatusCode::invalid_argument);

    const auto scissor_after_end = context.set_scissor(ScissorRect {});
    PP_EXPECT(h, !scissor_after_end.ok());
    PP_EXPECT(h, scissor_after_end.code == StatusCode::invalid_argument);

    const auto depth_after_end = context.set_depth_state(DepthState {});
    PP_EXPECT(h, !depth_after_end.ok());
    PP_EXPECT(h, depth_after_end.code == StatusCode::invalid_argument);

    const auto bind_texture_after_end = context.bind_texture(0, texture);
    PP_EXPECT(h, !bind_texture_after_end.ok());
    PP_EXPECT(h, bind_texture_after_end.code == StatusCode::invalid_argument);

    const auto bind_sampler_after_end = context.bind_sampler(0, SamplerDesc {});
    PP_EXPECT(h, !bind_sampler_after_end.ok());
    PP_EXPECT(h, bind_sampler_after_end.code == StatusCode::invalid_argument);

    const auto read_outside_bounds = context.read_texture(
        texture,
        ReadbackRegion { .x = 31, .y = 15, .width = 2, .height = 1 },
        full_readback_buffer);
    PP_EXPECT(h, !read_outside_bounds.ok());
    PP_EXPECT(h, read_outside_bounds.code == StatusCode::out_of_range);

    const auto upload_outside_bounds = context.upload_texture(
        texture,
        ReadbackRegion { .x = 31, .y = 15, .width = 2, .height = 1 },
        one_pixel_upload);
    PP_EXPECT(h, !upload_outside_bounds.ok());
    PP_EXPECT(h, upload_outside_bounds.code == StatusCode::out_of_range);

    const auto upload_with_wrong_size = context.upload_texture(
        texture,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        undersized_upload);
    PP_EXPECT(h, !upload_with_wrong_size.ok());
    PP_EXPECT(h, upload_with_wrong_size.code == StatusCode::invalid_argument);

    const auto read_into_small_buffer = context.read_texture(
        texture,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        small_readback_buffer);
    PP_EXPECT(h, !read_into_small_buffer.ok());
    PP_EXPECT(h, read_into_small_buffer.code == StatusCode::out_of_range);

    const auto capture_into_small_buffer = context.capture_frame(target, small_readback_buffer);
    PP_EXPECT(h, !capture_into_small_buffer.ok());
    PP_EXPECT(h, capture_into_small_buffer.code == StatusCode::out_of_range);

    const auto capture_non_target = context.capture_frame(non_render_target, full_readback_buffer);
    PP_EXPECT(h, !capture_non_target.ok());
    PP_EXPECT(h, capture_non_target.code == StatusCode::invalid_argument);

    const auto blit_non_target = context.blit_render_target(
        non_render_target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        BlitFilter::nearest);
    PP_EXPECT(h, !blit_non_target.ok());
    PP_EXPECT(h, blit_non_target.code == StatusCode::invalid_argument);

    const auto blit_mismatched_format = context.blit_render_target(
        target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        r8_target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        BlitFilter::nearest);
    PP_EXPECT(h, !blit_mismatched_format.ok());
    PP_EXPECT(h, blit_mismatched_format.code == StatusCode::invalid_argument);

    const auto blit_outside_bounds = context.blit_render_target(
        target,
        ReadbackRegion { .x = 31, .y = 15, .width = 2, .height = 1 },
        target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        BlitFilter::nearest);
    PP_EXPECT(h, !blit_outside_bounds.ok());
    PP_EXPECT(h, blit_outside_bounds.code == StatusCode::out_of_range);

    const auto blit_bad_filter = context.blit_render_target(
        target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        target,
        ReadbackRegion { .x = 0, .y = 0, .width = 1, .height = 1 },
        static_cast<BlitFilter>(255));
    PP_EXPECT(h, !blit_bad_filter.ok());
    PP_EXPECT(h, blit_bad_filter.code == StatusCode::invalid_argument);
}

}

int main()
{
    pp::tests::Harness harness;
    harness.run("computes_texture_sizes", computes_texture_sizes);
    harness.run("rejects_invalid_or_excessive_extents", rejects_invalid_or_excessive_extents);
    harness.run("validates_readback_bounds", validates_readback_bounds);
    harness.run("computes_readback_byte_sizes", computes_readback_byte_sizes);
    harness.run("computes_frame_capture_byte_sizes", computes_frame_capture_byte_sizes);
    harness.run("validates_blit_contract", validates_blit_contract);
    harness.run("validates_blend_contract", validates_blend_contract);
    harness.run("validates_depth_contract", validates_depth_contract);
    harness.run("validates_sampler_contract", validates_sampler_contract);
    harness.run("validates_viewports_and_mesh_descriptors", validates_viewports_and_mesh_descriptors);
    harness.run("validates_shader_program_descriptors", validates_shader_program_descriptors);
    harness.run("validates_panopainter_shader_catalog", validates_panopainter_shader_catalog);
    harness.run("rejects_invalid_shader_catalogs", rejects_invalid_shader_catalogs);
    harness.run("renderer_interfaces_support_backend_neutral_dispatch", renderer_interfaces_support_backend_neutral_dispatch);
    harness.run("recording_renderer_records_valid_command_sequences", recording_renderer_records_valid_command_sequences);
    harness.run("recording_renderer_rejects_invalid_command_order_and_targets", recording_renderer_rejects_invalid_command_order_and_targets);
    return harness.finish();
}