Add renderer readback command contract

src/renderer_api/recording_renderer.h

@@ -13,6 +13,7 @@ enum class RecordedRenderCommandKind : std::uint8_t {
     bind_shader,
     bind_mesh,
     draw,
+    read_texture,
     end_render_pass,
     trace_marker,
 };
@@ -23,6 +24,9 @@ struct RecordedRenderCommand {
     ClearColor clear_color {};
     Viewport viewport {};
     MeshDesc mesh_desc {};
+    TextureDesc texture_desc {};
+    ReadbackRegion readback_region {};
+    std::uint64_t readback_bytes = 0;
     const char* component = "";
     const char* name = "";
 };
@@ -83,6 +87,10 @@ public:
     [[nodiscard]] pp::foundation::Status bind_shader(IShaderProgram& shader) noexcept override;
     [[nodiscard]] pp::foundation::Status bind_mesh(IMesh& mesh) noexcept override;
     [[nodiscard]] pp::foundation::Status draw() noexcept override;
+    [[nodiscard]] pp::foundation::Status read_texture(
+        ITexture2D& texture,
+        ReadbackRegion region,
+        IReadbackBuffer& destination) noexcept override;
     void end_render_pass() noexcept override;
 
     [[nodiscard]] bool in_render_pass() const noexcept;