Add renderer blend state contract

src/renderer_api/recording_renderer.cpp

@@ -122,6 +122,24 @@ pp::foundation::Status RecordingCommandContext::set_viewport(Viewport viewport)
     return pp::foundation::Status::success();
 }
 
+pp::foundation::Status RecordingCommandContext::set_blend_state(BlendState state) noexcept
+{
+    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;
+    }
+
+    push_command(commands_, RecordedRenderCommand {
+        .kind = RecordedRenderCommandKind::set_blend_state,
+        .blend_state = state,
+    });
+    return pp::foundation::Status::success();
+}
+
 pp::foundation::Status RecordingCommandContext::bind_shader(IShaderProgram& shader) noexcept
 {
     if (!in_render_pass_) {
@@ -400,6 +418,8 @@ const char* recorded_render_command_kind_name(RecordedRenderCommandKind kind) no
         return "begin_render_pass";
     case RecordedRenderCommandKind::set_viewport:
         return "set_viewport";
+    case RecordedRenderCommandKind::set_blend_state:
+        return "set_blend_state";
     case RecordedRenderCommandKind::bind_shader:
         return "bind_shader";
     case RecordedRenderCommandKind::bind_texture:

src/renderer_api/recording_renderer.h

@@ -10,6 +10,7 @@ namespace pp::renderer {
 enum class RecordedRenderCommandKind : std::uint8_t {
     begin_render_pass,
     set_viewport,
+    set_blend_state,
     bind_shader,
     bind_texture,
     bind_mesh,
@@ -27,6 +28,7 @@ struct RecordedRenderCommand {
     TextureDesc target_desc {};
     ClearColor clear_color {};
     Viewport viewport {};
+    BlendState blend_state {};
     MeshDesc mesh_desc {};
     TextureDesc texture_desc {};
     std::uint32_t texture_slot = 0;
@@ -98,6 +100,7 @@ public:
         IRenderTarget& target,
         ClearColor clear_color) noexcept override;
     [[nodiscard]] pp::foundation::Status set_viewport(Viewport viewport) noexcept override;
+    [[nodiscard]] pp::foundation::Status set_blend_state(BlendState state) noexcept override;
     [[nodiscard]] pp::foundation::Status bind_shader(IShaderProgram& shader) noexcept override;
     [[nodiscard]] pp::foundation::Status bind_texture(
         std::uint32_t slot,

src/renderer_api/renderer_api.cpp

@@ -131,6 +131,63 @@ pp::foundation::Status validate_viewport(Viewport viewport, Extent2D target_exte
     return pp::foundation::Status::success();
 }
 
+pp::foundation::Status validate_blend_factor(BlendFactor factor) noexcept
+{
+    switch (factor) {
+    case BlendFactor::zero:
+    case BlendFactor::one:
+    case BlendFactor::source_alpha:
+    case BlendFactor::one_minus_source_alpha:
+    case BlendFactor::destination_alpha:
+    case BlendFactor::one_minus_destination_alpha:
+        return pp::foundation::Status::success();
+    }
+
+    return pp::foundation::Status::invalid_argument("blend factor is not supported");
+}
+
+pp::foundation::Status validate_blend_op(BlendOp op) noexcept
+{
+    switch (op) {
+    case BlendOp::add:
+    case BlendOp::subtract:
+    case BlendOp::reverse_subtract:
+        return pp::foundation::Status::success();
+    }
+
+    return pp::foundation::Status::invalid_argument("blend operation is not supported");
+}
+
+pp::foundation::Status validate_blend_state(BlendState state) noexcept
+{
+    const auto source_color = validate_blend_factor(state.source_color);
+    if (!source_color.ok()) {
+        return source_color;
+    }
+
+    const auto destination_color = validate_blend_factor(state.destination_color);
+    if (!destination_color.ok()) {
+        return destination_color;
+    }
+
+    const auto color_op = validate_blend_op(state.color_op);
+    if (!color_op.ok()) {
+        return color_op;
+    }
+
+    const auto source_alpha = validate_blend_factor(state.source_alpha);
+    if (!source_alpha.ok()) {
+        return source_alpha;
+    }
+
+    const auto destination_alpha = validate_blend_factor(state.destination_alpha);
+    if (!destination_alpha.ok()) {
+        return destination_alpha;
+    }
+
+    return validate_blend_op(state.alpha_op);
+}
+
 pp::foundation::Status validate_mesh_desc(MeshDesc desc) noexcept
 {
     if (desc.vertex_count == 0) {
@@ -324,4 +381,38 @@ const char* blit_filter_name(BlitFilter filter) noexcept
     return "unknown";
 }
 
+const char* blend_factor_name(BlendFactor factor) noexcept
+{
+    switch (factor) {
+    case BlendFactor::zero:
+        return "zero";
+    case BlendFactor::one:
+        return "one";
+    case BlendFactor::source_alpha:
+        return "source_alpha";
+    case BlendFactor::one_minus_source_alpha:
+        return "one_minus_source_alpha";
+    case BlendFactor::destination_alpha:
+        return "destination_alpha";
+    case BlendFactor::one_minus_destination_alpha:
+        return "one_minus_destination_alpha";
+    }
+
+    return "unknown";
+}
+
+const char* blend_op_name(BlendOp op) noexcept
+{
+    switch (op) {
+    case BlendOp::add:
+        return "add";
+    case BlendOp::subtract:
+        return "subtract";
+    case BlendOp::reverse_subtract:
+        return "reverse_subtract";
+    }
+
+    return "unknown";
+}
+
 }

src/renderer_api/renderer_api.h

@@ -65,6 +65,35 @@ enum class BlitFilter : std::uint8_t {
     linear,
 };
 
+enum class BlendFactor : std::uint8_t {
+    zero,
+    one,
+    source_alpha,
+    one_minus_source_alpha,
+    destination_alpha,
+    one_minus_destination_alpha,
+};
+
+enum class BlendOp : std::uint8_t {
+    add,
+    subtract,
+    reverse_subtract,
+};
+
+struct BlendState {
+    bool enabled = false;
+    BlendFactor source_color = BlendFactor::one;
+    BlendFactor destination_color = BlendFactor::zero;
+    BlendOp color_op = BlendOp::add;
+    BlendFactor source_alpha = BlendFactor::one;
+    BlendFactor destination_alpha = BlendFactor::zero;
+    BlendOp alpha_op = BlendOp::add;
+    bool write_r = true;
+    bool write_g = true;
+    bool write_b = true;
+    bool write_a = true;
+};
+
 struct MeshDesc {
     std::uint32_t vertex_count = 0;
     std::uint32_t index_count = 0;
@@ -126,6 +155,7 @@ public:
         IRenderTarget& target,
         ClearColor clear_color) noexcept = 0;
     [[nodiscard]] virtual pp::foundation::Status set_viewport(Viewport viewport) noexcept = 0;
+    [[nodiscard]] virtual pp::foundation::Status set_blend_state(BlendState state) noexcept = 0;
     [[nodiscard]] virtual pp::foundation::Status bind_shader(IShaderProgram& shader) noexcept = 0;
     [[nodiscard]] virtual pp::foundation::Status bind_texture(
         std::uint32_t slot,
@@ -163,6 +193,9 @@ public:
 [[nodiscard]] std::uint32_t bytes_per_pixel(TextureFormat format) noexcept;
 [[nodiscard]] pp::foundation::Status validate_extent(Extent2D extent) noexcept;
 [[nodiscard]] pp::foundation::Status validate_viewport(Viewport viewport, Extent2D target_extent) noexcept;
+[[nodiscard]] pp::foundation::Status validate_blend_factor(BlendFactor factor) noexcept;
+[[nodiscard]] pp::foundation::Status validate_blend_op(BlendOp op) noexcept;
+[[nodiscard]] pp::foundation::Status validate_blend_state(BlendState state) noexcept;
 [[nodiscard]] pp::foundation::Status validate_mesh_desc(MeshDesc desc) noexcept;
 [[nodiscard]] pp::foundation::Status validate_texture_slot(std::uint32_t slot) noexcept;
 [[nodiscard]] pp::foundation::Status validate_shader_program_desc(ShaderProgramDesc desc) noexcept;
@@ -179,5 +212,7 @@ public:
 [[nodiscard]] const char* texture_format_name(TextureFormat format) noexcept;
 [[nodiscard]] const char* primitive_topology_name(PrimitiveTopology topology) noexcept;
 [[nodiscard]] const char* blit_filter_name(BlitFilter filter) noexcept;
+[[nodiscard]] const char* blend_factor_name(BlendFactor factor) noexcept;
+[[nodiscard]] const char* blend_op_name(BlendOp op) noexcept;
 
 }