Always clear window with black color instead of background color

Always use black color to clear the window with all graphics backends, instead of using `cl_background_color` or `cl_background_entities_color`, respectively, as the clear color. The respective map background color is rendered using a quad in `CMapLayers` instead, so this should not affect appearance of maps. This does not have any noticeable effect on FPS. Previously, the unused part of the window (when it is resized smaller than 5:4 aspect ratio), was colored using the map background color, whereas now it will be cleared black consistently.

The color parameters of the `IGraphics::Clear` function and of the `SCommand_Clear` command are removed, as we always expect the screen to be cleared black now.

The parameter `ForceClearNow` of the `IGraphics::Clear` function was already unused previously and is also removed.

src/engine/client/backend/opengl/backend_opengl.cpp

@@ -937,7 +937,7 @@ void CCommandProcessorFragment_OpenGL::Cmd_Clear(const CCommandBuffer::SCommand_
 	{
 		glDisable(GL_SCISSOR_TEST);
 	}
-	glClearColor(pCommand->m_Color.r, pCommand->m_Color.g, pCommand->m_Color.b, 0.0f);
+	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 	if(ClipWasEnabled)
 	{

src/engine/client/backend/opengl/backend_opengl3.cpp

@@ -414,8 +414,6 @@ bool CCommandProcessorFragment_OpenGL3_3::Cmd_Init(const SCommand_Init *pCommand
 
 	m_vTextures.resize(CCommandBuffer::MAX_TEXTURES);
 
-	m_ClearColor.r = m_ClearColor.g = m_ClearColor.b = -1.f;
-
 	// fix the alignment to allow even 1byte changes, e.g. for alpha components
 	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 
@@ -687,11 +685,7 @@ void CCommandProcessorFragment_OpenGL3_3::Cmd_Clear(const CCommandBuffer::SComma
 	{
 		glDisable(GL_SCISSOR_TEST);
 	}
-	if(pCommand->m_Color.r != m_ClearColor.r || pCommand->m_Color.g != m_ClearColor.g || pCommand->m_Color.b != m_ClearColor.b)
+	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
-	{
-		glClearColor(pCommand->m_Color.r, pCommand->m_Color.g, pCommand->m_Color.b, 0.0f);
-		m_ClearColor = pCommand->m_Color;
-	}
 	glClear(GL_COLOR_BUFFER_BIT);
 	if(ClipWasEnabled)
 	{

src/engine/client/backend/opengl/backend_opengl3.h

@@ -67,8 +67,6 @@ protected:
 
 	std::vector<TWGLuint> m_vBufferObjectIndices;
 
-	CCommandBuffer::SColorf m_ClearColor;
-
 	void InitPrimExProgram(CGLSLPrimitiveExProgram *pProgram, class CGLSLCompiler *pCompiler, class IStorage *pStorage, bool Textured, bool Rotationless);
 
 	bool IsNewApi() override { return true; }

src/engine/client/backend/vulkan/backend_vulkan.cpp

@@ -1059,8 +1059,6 @@ private:
 
 	SDL_Window *m_pWindow;
 
-	std::array<float, 4> m_aClearColor = {0, 0, 0, 0};
-
 	struct SRenderCommandExecuteBuffer
 	{
 		CCommandBuffer::ECommandBufferCMD m_Command;
@@ -1077,8 +1075,6 @@ private:
 
 		VkBuffer m_IndexBuffer;
 
-		bool m_ClearColorInRenderThread = false;
-
 		bool m_HasDynamicState = false;
 		VkViewport m_Viewport;
 		VkRect2D m_Scissor;
@@ -2445,7 +2441,7 @@ protected:
 		RenderPassInfo.renderArea.offset = {0, 0};
 		RenderPassInfo.renderArea.extent = m_VKSwapImgAndViewportExtent.m_SwapImageViewport;
 
-		VkClearValue ClearColorVal = {{{m_aClearColor[0], m_aClearColor[1], m_aClearColor[2], m_aClearColor[3]}}};
+		VkClearValue ClearColorVal = {{{0.0f, 0.0f, 0.0f, 0.0f}}};
 		RenderPassInfo.clearValueCount = 1;
 		RenderPassInfo.pClearValues = &ClearColorVal;
 
@@ -6715,37 +6711,19 @@ public:
 
 	void Cmd_Clear_FillExecuteBuffer(SRenderCommandExecuteBuffer &ExecBuffer, const CCommandBuffer::SCommand_Clear *pCommand)
 	{
-		if(!pCommand->m_ForceClear)
-		{
-			bool ColorChanged = m_aClearColor[0] != pCommand->m_Color.r || m_aClearColor[1] != pCommand->m_Color.g ||
-					    m_aClearColor[2] != pCommand->m_Color.b || m_aClearColor[3] != pCommand->m_Color.a;
-			m_aClearColor[0] = pCommand->m_Color.r;
-			m_aClearColor[1] = pCommand->m_Color.g;
-			m_aClearColor[2] = pCommand->m_Color.b;
-			m_aClearColor[3] = pCommand->m_Color.a;
-			if(ColorChanged)
-				ExecBuffer.m_ClearColorInRenderThread = true;
-		}
-		else
-		{
-			ExecBuffer.m_ClearColorInRenderThread = true;
-		}
 		ExecBuffer.m_EstimatedRenderCallCount = 0;
 	}
 
 	[[nodiscard]] bool Cmd_Clear(const SRenderCommandExecuteBuffer &ExecBuffer, const CCommandBuffer::SCommand_Clear *pCommand)
 	{
-		if(ExecBuffer.m_ClearColorInRenderThread)
+		std::array<VkClearAttachment, 1> aAttachments = {VkClearAttachment{VK_IMAGE_ASPECT_COLOR_BIT, 0, VkClearValue{VkClearColorValue{{0.0f, 0.0f, 0.0f, 0.0f}}}}};
-		{
+		std::array<VkClearRect, 1> aClearRects = {VkClearRect{{{0, 0}, m_VKSwapImgAndViewportExtent.m_SwapImageViewport}, 0, 1}};
-			std::array<VkClearAttachment, 1> aAttachments = {VkClearAttachment{VK_IMAGE_ASPECT_COLOR_BIT, 0, VkClearValue{VkClearColorValue{{pCommand->m_Color.r, pCommand->m_Color.g, pCommand->m_Color.b, pCommand->m_Color.a}}}}};
-			std::array<VkClearRect, 1> aClearRects = {VkClearRect{{{0, 0}, m_VKSwapImgAndViewportExtent.m_SwapImageViewport}, 0, 1}};
 
-			VkCommandBuffer *pCommandBuffer;
+		VkCommandBuffer *pCommandBuffer;
-			if(!GetGraphicCommandBuffer(pCommandBuffer, ExecBuffer.m_ThreadIndex))
+		if(!GetGraphicCommandBuffer(pCommandBuffer, ExecBuffer.m_ThreadIndex))
-				return false;
+			return false;
-			auto &CommandBuffer = *pCommandBuffer;
+		auto &CommandBuffer = *pCommandBuffer;
-			vkCmdClearAttachments(CommandBuffer, aAttachments.size(), aAttachments.data(), aClearRects.size(), aClearRects.data());
+		vkCmdClearAttachments(CommandBuffer, aAttachments.size(), aAttachments.data(), aClearRects.size(), aClearRects.data());
-		}
 
 		return true;
 	}

src/engine/client/client.cpp

@@ -891,17 +891,7 @@ const char *CClient::ErrorString() const
 
 void CClient::Render()
 {
-	if(g_Config.m_ClOverlayEntities)
+	Graphics()->Clear();
-	{
-		ColorRGBA bg = color_cast<ColorRGBA>(ColorHSLA(g_Config.m_ClBackgroundEntitiesColor));
-		Graphics()->Clear(bg.r, bg.g, bg.b);
-	}
-	else
-	{
-		ColorRGBA bg = color_cast<ColorRGBA>(ColorHSLA(g_Config.m_ClBackgroundColor));
-		Graphics()->Clear(bg.r, bg.g, bg.b);
-	}
-
 	GameClient()->OnRender();
 	DebugRender();
 
@@ -2728,7 +2718,7 @@ void CClient::Run()
 	}
 
 	// make sure the first frame just clears everything to prevent undesired colors when waiting for io
-	Graphics()->Clear(0, 0, 0);
+	Graphics()->Clear();
 	Graphics()->Swap();
 
 	// init sound, allowed to fail
@@ -3783,7 +3773,7 @@ void CClient::UpdateAndSwap()
 {
 	Input()->Update();
 	Graphics()->Swap();
-	Graphics()->Clear(0, 0, 0);
+	Graphics()->Clear();
 }
 
 void CClient::ServerBrowserUpdate()

src/engine/client/graphics_threaded.cpp

@@ -833,14 +833,9 @@ void CGraphics_Threaded::TextureSet(CTextureHandle TextureId)
 	m_State.m_Texture = TextureId.Id();
 }
 
-void CGraphics_Threaded::Clear(float r, float g, float b, bool ForceClearNow)
+void CGraphics_Threaded::Clear()
 {
 	CCommandBuffer::SCommand_Clear Cmd;
-	Cmd.m_Color.r = r;
-	Cmd.m_Color.g = g;
-	Cmd.m_Color.b = b;
-	Cmd.m_Color.a = 0;
-	Cmd.m_ForceClear = ForceClearNow;
 	AddCmd(Cmd);
 }
 

src/engine/client/graphics_threaded.h

@@ -213,8 +213,6 @@ public:
 	{
 		SCommand_Clear() :
 			SCommand(CMD_CLEAR) {}
-		SColorf m_Color;
-		bool m_ForceClear;
 	};
 
 	struct SCommand_Signal : public SCommand
@@ -991,7 +989,7 @@ public:
 
 	void TextureSet(CTextureHandle TextureId) override;
 
-	void Clear(float r, float g, float b, bool ForceClearNow = false) override;
+	void Clear() override;
 
 	void QuadsBegin() override;
 	void QuadsEnd() override;

src/engine/graphics.h

@@ -306,8 +306,7 @@ public:
 	virtual void WindowDestroyNtf(uint32_t WindowId) = 0;
 	virtual void WindowCreateNtf(uint32_t WindowId) = 0;
 
-	// ForceClearNow forces the backend to trigger a clear, even at performance cost, else it might be delayed by one frame
+	virtual void Clear() = 0;
-	virtual void Clear(float r, float g, float b, bool ForceClearNow = false) = 0;
 
 	virtual void ClipEnable(int x, int y, int w, int h) = 0;
 	virtual void ClipDisable() = 0;

src/game/client/components/maplayers.cpp

@@ -1412,6 +1412,23 @@ void CMapLayers::OnRender()
 	CUIRect Screen;
 	Graphics()->GetScreen(&Screen.x, &Screen.y, &Screen.w, &Screen.h);
 
+	if(m_Type == TYPE_BACKGROUND || m_Type == TYPE_BACKGROUND_FORCE)
+	{
+		Graphics()->TextureClear();
+		Graphics()->QuadsBegin();
+		if(g_Config.m_ClOverlayEntities)
+		{
+			Graphics()->SetColor(color_cast<ColorRGBA>(ColorHSLA(g_Config.m_ClBackgroundEntitiesColor)));
+		}
+		else
+		{
+			Graphics()->SetColor(color_cast<ColorRGBA>(ColorHSLA(g_Config.m_ClBackgroundColor)));
+		}
+		IGraphics::CQuadItem QuadItem(Screen.x, Screen.y, Screen.w, Screen.h);
+		Graphics()->QuadsDrawTL(&QuadItem, 1);
+		Graphics()->QuadsEnd();
+	}
+
 	vec2 Center = GetCurCamera()->m_Center;
 
 	bool PassedGameLayer = false;

src/game/client/gameclient.cpp

@@ -1092,12 +1092,12 @@ void CGameClient::RenderShutdownMessage()
 		dbg_assert(false, "Invalid client state for quitting message");
 
 	// This function only gets called after the render loop has already terminated, so we have to call Swap manually.
-	Graphics()->Clear(0.0f, 0.0f, 0.0f);
+	Graphics()->Clear();
 	Ui()->MapScreen();
 	TextRender()->TextColor(TextRender()->DefaultTextColor());
 	Ui()->DoLabel(Ui()->Screen(), pMessage, 16.0f, TEXTALIGN_MC);
 	Graphics()->Swap();
-	Graphics()->Clear(0.0f, 0.0f, 0.0f);
+	Graphics()->Clear();
 }
 
 void CGameClient::OnRconType(bool UsernameReq)

src/game/editor/editor.cpp

@@ -7718,7 +7718,7 @@ void CEditor::RenderMenubar(CUIRect MenuBar)
 void CEditor::Render()
 {
 	// basic start
-	Graphics()->Clear(0.0f, 0.0f, 0.0f);
+	Graphics()->Clear();
 	CUIRect View = *Ui()->Screen();
 	Ui()->MapScreen();
 	m_CursorType = CURSOR_NORMAL;