Inital commit

vendor/rmlui_backend/RmlUi_Renderer_GL3.h

@@ -0,0 +1,210 @@
+#pragma once
+
+#include <RmlUi/Core/RenderInterface.h>
+#include <RmlUi/Core/Types.h>
+#include <bitset>
+
+enum class ProgramId;
+enum class UniformId;
+class RenderLayerStack;
+namespace Gfx {
+struct ProgramData;
+struct FramebufferData;
+} // namespace Gfx
+
+class RenderInterface_GL3 : public Rml::RenderInterface {
+public:
+	RenderInterface_GL3();
+	~RenderInterface_GL3();
+
+	// Returns true if the renderer was successfully constructed.
+	explicit operator bool() const { return static_cast<bool>(program_data); }
+
+	// The viewport should be updated whenever the window size changes.
+	void SetViewport(int viewport_width, int viewport_height, int viewport_offset_x = 0, int viewport_offset_y = 0);
+
+	// Sets up OpenGL states for taking rendering commands from RmlUi.
+	void BeginFrame();
+	// Draws the result to the backbuffer and restores OpenGL state.
+	void EndFrame();
+
+	// Optional, can be used to clear the active framebuffer.
+	void Clear();
+
+	// -- Inherited from Rml::RenderInterface --
+
+	Rml::CompiledGeometryHandle CompileGeometry(Rml::Span<const Rml::Vertex> vertices, Rml::Span<const int> indices) override;
+	void RenderGeometry(Rml::CompiledGeometryHandle handle, Rml::Vector2f translation, Rml::TextureHandle texture) override;
+	void ReleaseGeometry(Rml::CompiledGeometryHandle handle) override;
+
+	Rml::TextureHandle LoadTexture(Rml::Vector2i& texture_dimensions, const Rml::String& source) override;
+	Rml::TextureHandle GenerateTexture(Rml::Span<const Rml::byte> source_data, Rml::Vector2i source_dimensions) override;
+	void ReleaseTexture(Rml::TextureHandle texture_handle) override;
+
+	void EnableScissorRegion(bool enable) override;
+	void SetScissorRegion(Rml::Rectanglei region) override;
+
+	void EnableClipMask(bool enable) override;
+	void RenderToClipMask(Rml::ClipMaskOperation mask_operation, Rml::CompiledGeometryHandle geometry, Rml::Vector2f translation) override;
+
+	void SetTransform(const Rml::Matrix4f* transform) override;
+
+	Rml::LayerHandle PushLayer() override;
+	void CompositeLayers(Rml::LayerHandle source, Rml::LayerHandle destination, Rml::BlendMode blend_mode,
+		Rml::Span<const Rml::CompiledFilterHandle> filters) override;
+	void PopLayer() override;
+
+	Rml::TextureHandle SaveLayerAsTexture() override;
+
+	Rml::CompiledFilterHandle SaveLayerAsMaskImage() override;
+
+	Rml::CompiledFilterHandle CompileFilter(const Rml::String& name, const Rml::Dictionary& parameters) override;
+	void ReleaseFilter(Rml::CompiledFilterHandle filter) override;
+
+	Rml::CompiledShaderHandle CompileShader(const Rml::String& name, const Rml::Dictionary& parameters) override;
+	void RenderShader(Rml::CompiledShaderHandle shader_handle, Rml::CompiledGeometryHandle geometry_handle, Rml::Vector2f translation,
+		Rml::TextureHandle texture) override;
+	void ReleaseShader(Rml::CompiledShaderHandle effect_handle) override;
+
+	// Can be passed to RenderGeometry() to enable texture rendering without changing the bound texture.
+	static constexpr Rml::TextureHandle TextureEnableWithoutBinding = Rml::TextureHandle(-1);
+	// Can be passed to RenderGeometry() to leave the bound texture and used program unchanged.
+	static constexpr Rml::TextureHandle TexturePostprocess = Rml::TextureHandle(-2);
+
+	// -- Utility functions for clients --
+
+	const Rml::Matrix4f& GetTransform() const;
+	void ResetProgram();
+
+private:
+	void UseProgram(ProgramId program_id);
+	int GetUniformLocation(UniformId uniform_id) const;
+	void SubmitTransformUniform(Rml::Vector2f translation);
+
+	void BlitLayerToPostprocessPrimary(Rml::LayerHandle layer_handle);
+	void RenderFilters(Rml::Span<const Rml::CompiledFilterHandle> filter_handles);
+
+	void SetScissor(Rml::Rectanglei region, bool vertically_flip = false);
+
+	void DrawFullscreenQuad();
+	void DrawFullscreenQuad(Rml::Vector2f uv_offset, Rml::Vector2f uv_scaling = Rml::Vector2f(1.f));
+
+	void RenderBlur(float sigma, const Gfx::FramebufferData& source_destination, const Gfx::FramebufferData& temp, Rml::Rectanglei window_flipped);
+
+	static constexpr size_t MaxNumPrograms = 32;
+	std::bitset<MaxNumPrograms> program_transform_dirty;
+
+	Rml::Matrix4f transform;
+	Rml::Matrix4f projection;
+
+	ProgramId active_program = {};
+	Rml::Rectanglei scissor_state;
+
+	int viewport_width = 0;
+	int viewport_height = 0;
+	int viewport_offset_x = 0;
+	int viewport_offset_y = 0;
+
+	Rml::CompiledGeometryHandle fullscreen_quad_geometry = {};
+
+	Rml::UniquePtr<const Gfx::ProgramData> program_data;
+
+	/*
+	    Manages render targets, including the layer stack and postprocessing framebuffers.
+
+	    Layers can be pushed and popped, creating new framebuffers as needed. Typically, geometry is rendered to the top
+	    layer. The layer framebuffers may have MSAA enabled.
+
+	    Postprocessing framebuffers are separate from the layers, and are commonly used to apply texture-wide effects
+	    such as filters. They are used both as input and output during rendering, and do not use MSAA.
+	*/
+	class RenderLayerStack {
+	public:
+		RenderLayerStack();
+		~RenderLayerStack();
+
+		// Push a new layer. All references to previously retrieved layers are invalidated.
+		Rml::LayerHandle PushLayer();
+
+		// Pop the top layer. All references to previously retrieved layers are invalidated.
+		void PopLayer();
+
+		const Gfx::FramebufferData& GetLayer(Rml::LayerHandle layer) const;
+		const Gfx::FramebufferData& GetTopLayer() const;
+		Rml::LayerHandle GetTopLayerHandle() const;
+
+		const Gfx::FramebufferData& GetPostprocessPrimary() { return EnsureFramebufferPostprocess(0); }
+		const Gfx::FramebufferData& GetPostprocessSecondary() { return EnsureFramebufferPostprocess(1); }
+		const Gfx::FramebufferData& GetPostprocessTertiary() { return EnsureFramebufferPostprocess(2); }
+		const Gfx::FramebufferData& GetBlendMask() { return EnsureFramebufferPostprocess(3); }
+
+		void SwapPostprocessPrimarySecondary();
+
+		void BeginFrame(int new_width, int new_height);
+		void EndFrame();
+
+	private:
+		void DestroyFramebuffers();
+		const Gfx::FramebufferData& EnsureFramebufferPostprocess(int index);
+
+		int width = 0, height = 0;
+
+		// The number of active layers is manually tracked since we re-use the framebuffers stored in the fb_layers stack.
+		int layers_size = 0;
+
+		Rml::Vector<Gfx::FramebufferData> fb_layers;
+		Rml::Vector<Gfx::FramebufferData> fb_postprocess;
+	};
+
+	RenderLayerStack render_layers;
+
+	struct GLStateBackup {
+		bool enable_cull_face;
+		bool enable_blend;
+		bool enable_stencil_test;
+		bool enable_scissor_test;
+		bool enable_depth_test;
+
+		int viewport[4];
+		int scissor[4];
+
+		int active_texture;
+
+		int stencil_clear_value;
+		float color_clear_value[4];
+		unsigned char color_writemask[4];
+
+		int blend_equation_rgb;
+		int blend_equation_alpha;
+		int blend_src_rgb;
+		int blend_dst_rgb;
+		int blend_src_alpha;
+		int blend_dst_alpha;
+
+		struct Stencil {
+			int func;
+			int ref;
+			int value_mask;
+			int writemask;
+			int fail;
+			int pass_depth_fail;
+			int pass_depth_pass;
+		};
+		Stencil stencil_front;
+		Stencil stencil_back;
+	};
+	GLStateBackup glstate_backup = {};
+};
+
+/**
+    Helper functions for the OpenGL 3 renderer.
+ */
+namespace RmlGL3 {
+
+// Loads OpenGL functions. Optionally, the out message describes the loaded GL version or an error message on failure.
+bool Initialize(Rml::String* out_message = nullptr);
+
+// Unloads OpenGL functions.
+void Shutdown();
+
+} // namespace RmlGL3