Add renderer scissor 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_scissor(ScissorRect scissor) noexcept
+{
+    if (!in_render_pass_) {
+        return pp::foundation::Status::invalid_argument("render pass has not begun");
+    }
+
+    const auto status = validate_scissor(scissor, active_target_.extent);
+    if (!status.ok()) {
+        return status;
+    }
+
+    push_command(commands_, RecordedRenderCommand {
+        .kind = RecordedRenderCommandKind::set_scissor,
+        .scissor = scissor,
+    });
+    return pp::foundation::Status::success();
+}
+
 pp::foundation::Status RecordingCommandContext::set_blend_state(BlendState state) noexcept
 {
     if (!in_render_pass_) {
@@ -418,6 +436,8 @@ const char* recorded_render_command_kind_name(RecordedRenderCommandKind kind) no
         return "begin_render_pass";
     case RecordedRenderCommandKind::set_viewport:
         return "set_viewport";
+    case RecordedRenderCommandKind::set_scissor:
+        return "set_scissor";
     case RecordedRenderCommandKind::set_blend_state:
         return "set_blend_state";
     case RecordedRenderCommandKind::bind_shader:

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_scissor,
     set_blend_state,
     bind_shader,
     bind_texture,
@@ -28,6 +29,7 @@ struct RecordedRenderCommand {
     TextureDesc target_desc {};
     ClearColor clear_color {};
     Viewport viewport {};
+    ScissorRect scissor {};
     BlendState blend_state {};
     MeshDesc mesh_desc {};
     TextureDesc texture_desc {};
@@ -100,6 +102,7 @@ public:
         IRenderTarget& target,
         ClearColor clear_color) noexcept override;
     [[nodiscard]] pp::foundation::Status set_viewport(Viewport viewport) noexcept override;
+    [[nodiscard]] pp::foundation::Status set_scissor(ScissorRect scissor) 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(

src/renderer_api/renderer_api.cpp

@@ -131,6 +131,38 @@ pp::foundation::Status validate_viewport(Viewport viewport, Extent2D target_exte
     return pp::foundation::Status::success();
 }
 
+pp::foundation::Status validate_scissor(ScissorRect scissor, Extent2D target_extent) noexcept
+{
+    const auto extent_status = validate_extent(target_extent);
+    if (!extent_status.ok()) {
+        return extent_status;
+    }
+
+    if (!scissor.enabled) {
+        return pp::foundation::Status::success();
+    }
+
+    if (scissor.x < 0 || scissor.y < 0) {
+        return pp::foundation::Status::invalid_argument("scissor origin must be non-negative");
+    }
+
+    if (scissor.width == 0 || scissor.height == 0) {
+        return pp::foundation::Status::invalid_argument("scissor size must be greater than zero");
+    }
+
+    const auto x = static_cast<std::uint32_t>(scissor.x);
+    const auto y = static_cast<std::uint32_t>(scissor.y);
+    if (x > target_extent.width || y > target_extent.height) {
+        return pp::foundation::Status::out_of_range("scissor origin is outside the render target");
+    }
+
+    if (scissor.width > target_extent.width - x || scissor.height > target_extent.height - y) {
+        return pp::foundation::Status::out_of_range("scissor exceeds render target bounds");
+    }
+
+    return pp::foundation::Status::success();
+}
+
 pp::foundation::Status validate_blend_factor(BlendFactor factor) noexcept
 {
     switch (factor) {

src/renderer_api/renderer_api.h

@@ -47,6 +47,14 @@ struct Viewport {
     float max_depth = 1.0F;
 };
 
+struct ScissorRect {
+    bool enabled = false;
+    std::int32_t x = 0;
+    std::int32_t y = 0;
+    std::uint32_t width = 0;
+    std::uint32_t height = 0;
+};
+
 struct ClearColor {
     float r = 0.0F;
     float g = 0.0F;
@@ -155,6 +163,7 @@ 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_scissor(ScissorRect scissor) 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(
@@ -193,6 +202,7 @@ 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_scissor(ScissorRect scissor, 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;