Route RTT blit readback through renderer GL

src/renderer_gl/opengl_capabilities.h

@@ -141,6 +141,32 @@ struct OpenGlTexture2DReadbackResult {
     bool pixels_read = false;
 };
 
+struct OpenGlFramebufferRect {
+    std::int32_t x0 = 0;
+    std::int32_t y0 = 0;
+    std::int32_t x1 = 0;
+    std::int32_t y1 = 0;
+};
+
+struct OpenGlFramebufferBlit {
+    std::uint32_t source_framebuffer = 0;
+    std::uint32_t destination_framebuffer = 0;
+    OpenGlFramebufferRect source_rect;
+    OpenGlFramebufferRect destination_rect;
+    std::uint32_t mask = 0;
+    std::uint32_t filter = 0;
+};
+
+struct OpenGlFramebufferReadback {
+    std::uint32_t framebuffer = 0;
+    std::int32_t x = 0;
+    std::int32_t y = 0;
+    std::int32_t width = 0;
+    std::int32_t height = 0;
+    OpenGlReadbackFormat format;
+    void* pixels = nullptr;
+};
+
 struct OpenGlWindowsWglContextConfig {
     std::array<std::int32_t, 9> context_attributes {};
     std::array<std::int32_t, 15> pixel_format_attributes {};
@@ -223,6 +249,17 @@ using OpenGlReadPixelsFn = void (*)(
     std::uint32_t pixel_format,
     std::uint32_t component_type,
     void* pixels) noexcept;
+using OpenGlBlitFramebufferFn = void (*)(
+    std::int32_t source_x0,
+    std::int32_t source_y0,
+    std::int32_t source_x1,
+    std::int32_t source_y1,
+    std::int32_t destination_x0,
+    std::int32_t destination_y0,
+    std::int32_t destination_x1,
+    std::int32_t destination_y1,
+    std::uint32_t mask,
+    std::uint32_t filter) noexcept;
 
 struct OpenGlStateDispatch {
     OpenGlCapabilityFn enable = nullptr;
@@ -332,6 +369,18 @@ struct OpenGlTexture2DReadbackDispatch {
     OpenGlDeleteObjectsFn delete_framebuffers = nullptr;
 };
 
+struct OpenGlFramebufferBlitDispatch {
+    OpenGlGetIntegerFn get_integer = nullptr;
+    OpenGlBindFramebufferFn bind_framebuffer = nullptr;
+    OpenGlBlitFramebufferFn blit_framebuffer = nullptr;
+};
+
+struct OpenGlFramebufferReadbackDispatch {
+    OpenGlGetIntegerFn get_integer = nullptr;
+    OpenGlBindFramebufferFn bind_framebuffer = nullptr;
+    OpenGlReadPixelsFn read_pixels = nullptr;
+};
+
 [[nodiscard]] OpenGlCapabilities detect_opengl_capabilities(
     std::span<const std::string_view> extensions,
     OpenGlRuntime runtime) noexcept;
@@ -382,6 +431,12 @@ struct OpenGlTexture2DReadbackDispatch {
 [[nodiscard]] pp::foundation::Result<OpenGlTexture2DReadbackResult> readback_opengl_texture_2d(
     OpenGlTexture2DReadback readback,
     OpenGlTexture2DReadbackDispatch dispatch) noexcept;
+[[nodiscard]] pp::foundation::Status blit_opengl_framebuffer(
+    OpenGlFramebufferBlit blit,
+    OpenGlFramebufferBlitDispatch dispatch) noexcept;
+[[nodiscard]] pp::foundation::Status readback_opengl_framebuffer(
+    OpenGlFramebufferReadback readback,
+    OpenGlFramebufferReadbackDispatch dispatch) noexcept;
 
 [[nodiscard]] std::uint32_t extension_count_query() noexcept;
 [[nodiscard]] std::uint32_t extension_string_name() noexcept;