OpenGLRenderer: Take advantage of glClipControl if available

include/Nazara/OpenGLRenderer/Wrapper/Context.hpp

@@ -52,7 +52,10 @@ namespace Nz::GL
 
 	enum class Extension
 	{
+		ClipControl,
+		DebugOutput,
 		DepthClamp,
+		PolygonMode,
 		SpirV,
 		StorageBuffers,
 		TextureCompressionS3tc,
@@ -149,6 +152,8 @@ namespace Nz::GL
 			inline bool IsExtensionSupported(Extension extension) const;
 			inline bool IsExtensionSupported(const std::string& extension) const;
 
+			inline bool HasZeroToOneDepth() const;
+
 			bool Initialize(const ContextParams& params);
 
 			inline void NotifyBufferDestruction(GLuint buffer) const;
@@ -253,6 +258,7 @@ namespace Nz::GL
 			mutable State m_state;
 			mutable bool m_didCollectErrors;
 			mutable bool m_hadAnyError;
+			bool m_hasZeroToOneDepth;
 	};
 }
 

include/Nazara/OpenGLRenderer/Wrapper/Context.inl

@@ -51,6 +51,11 @@ namespace Nz::GL
 		return m_supportedExtensions.find(extension) != m_supportedExtensions.end();
 	}
 
+	inline bool Context::HasZeroToOneDepth() const
+	{
+		return m_hasZeroToOneDepth;
+	}
+
 	inline void Context::NotifyBufferDestruction(GLuint buffer) const
 	{
 		for (GLuint& boundBuffer : m_state.bufferTargets)

include/Nazara/OpenGLRenderer/Wrapper/CoreFunctions.hpp

@@ -13,7 +13,7 @@
 #include <GLES3/gl32.h>
 #include <GLES2/gl2ext.h>
 
-// Define some OpenGL (not ES) extensions
+// Define some OpenGL (not ES) defines/function types
 #define GL_POINT                           0x1B00
 #define GL_LINE                            0x1B01
 #define GL_FILL                            0x1B02
@@ -22,8 +22,21 @@
 #define GL_TEXTURE_CUBE_MAP_SEAMLESS       0x884F
 typedef void (GL_APIENTRYP PFNGLDRAWBUFFERPROC) (GLenum buf);
 typedef void (GL_APIENTRYP PFNGLPOLYGONMODEPROC) (GLenum face, GLenum mode);
+
+// Clip control (OpenGL 4.5)
+#define GL_LOWER_LEFT                      0x8CA1
+#define GL_UPPER_LEFT                      0x8CA2
+#define GL_NEGATIVE_ONE_TO_ONE             0x935E
+#define GL_ZERO_TO_ONE                     0x935F
+#define GL_CLIP_ORIGIN                     0x935C
+#define GL_CLIP_DEPTH_MODE                 0x935D
+typedef void (GL_APIENTRYP PFNGLCLIPCONTROLPROC) (GLenum origin, GLenum depth);
+
+// SPIR-V shaders (OpenGL 4.6)
 typedef void (GL_APIENTRYP PFNGLSPECIALIZESHADERPROC) (GLuint shader, const GLchar* pEntryPoint, GLuint numSpecializationConstants, const GLuint* pConstantIndex, const GLuint* pConstantValue);
 
+/*** Functions ***/
+
 // OpenGL core
 #define NAZARA_OPENGLRENDERER_FOREACH_GLES_FUNC(cb, extCb) \
 	cb(glActiveTexture, PFNGLACTIVETEXTUREPROC) \
@@ -183,6 +196,8 @@ typedef void (GL_APIENTRYP PFNGLSPECIALIZESHADERPROC) (GLuint shader, const GLch
 	extCb(glObjectLabel, PFNGLOBJECTLABELPROC) \
 	extCb(glPopDebugGroup, PFNGLPOPDEBUGGROUPPROC) \
 	extCb(glPushDebugGroup, PFNGLPUSHDEBUGGROUPPROC) \
+	/* OpenGL 4.5 - GL_ARB_clip_control/GL_EXT_clip_control */ \
+	extCb(glClipControl, PFNGLCLIPCONTROLPROC) \
 	/* OpenGL 4.6 - GL_ARB_spirv_extensions */\
 	extCb(glSpecializeShader, PFNGLSPECIALIZESHADERPROC) \
 

src/Nazara/OpenGLRenderer/OpenGLShaderModule.cpp

@@ -96,8 +96,11 @@ namespace Nz
 		{
 			return context.IsExtensionSupported(std::string(ext));
 		};
+
 		env.flipYPosition = true;
-		env.remapZPosition = true;
+
+		if (!context.HasZeroToOneDepth())
+			env.remapZPosition = true;
 
 		nzsl::GlslWriter writer;
 		writer.SetEnv(env);

src/Nazara/OpenGLRenderer/Wrapper/Context.cpp

@@ -109,7 +109,8 @@ namespace Nz::GL
 	m_vaoCache(*this),
 	m_device(device),
 	m_didCollectErrors(false),
-	m_hadAnyError(false)
+	m_hadAnyError(false),
+	m_hasZeroToOneDepth(false)
 	{
 	}
 
@@ -381,6 +382,22 @@ namespace Nz::GL
 
 		m_extensionStatus.fill(ExtensionStatus::NotSupported);
 
+		// Clip control
+		if (m_params.type == ContextType::OpenGL && glVersion >= 450)
+			m_extensionStatus[UnderlyingCast(Extension::ClipControl)] = ExtensionStatus::Core;
+		else if (m_supportedExtensions.count("GL_ARB_clip_control"))
+			m_extensionStatus[UnderlyingCast(Extension::ClipControl)] = ExtensionStatus::ARB;
+		else if (m_supportedExtensions.count("GL_EXT_clip_control"))
+			m_extensionStatus[UnderlyingCast(Extension::ClipControl)] = ExtensionStatus::EXT;
+
+		// Debug output
+		if ((m_params.type == ContextType::OpenGL && glVersion >= 430) || (m_params.type == ContextType::OpenGL_ES && glVersion >= 320))
+			m_extensionStatus[UnderlyingCast(Extension::DebugOutput)] = ExtensionStatus::Core;
+		else if (m_supportedExtensions.count("GL_KHR_debug"))
+			m_extensionStatus[UnderlyingCast(Extension::DepthClamp)] = ExtensionStatus::KHR;
+		else if (m_supportedExtensions.count("GL_ARB_debug_output"))
+			m_extensionStatus[UnderlyingCast(Extension::DepthClamp)] = ExtensionStatus::ARB;
+
 		// Depth clamp
 		if (m_params.type == ContextType::OpenGL && glVersion >= 320)
 			m_extensionStatus[UnderlyingCast(Extension::DepthClamp)] = ExtensionStatus::Core;
@@ -391,6 +408,12 @@ namespace Nz::GL
 		else if (m_supportedExtensions.count("GL_NV_depth_clamp"))
 			m_extensionStatus[UnderlyingCast(Extension::DepthClamp)] = ExtensionStatus::Vendor;
 
+		// Polygon mode
+		if (m_params.type == ContextType::OpenGL)
+			m_extensionStatus[UnderlyingCast(Extension::PolygonMode)] = ExtensionStatus::Core;
+		else if (m_supportedExtensions.count("GL_NV_polygon_mode"))
+			m_extensionStatus[UnderlyingCast(Extension::DepthClamp)] = ExtensionStatus::Vendor;
+
 		// SPIR-V support
 		if (m_params.type == ContextType::OpenGL && glVersion >= 460)
 			m_extensionStatus[UnderlyingCast(Extension::SpirV)] = ExtensionStatus::Core;
@@ -421,6 +444,14 @@ namespace Nz::GL
 #undef NAZARA_OPENGLRENDERER_EXT_FUNC
 #undef NAZARA_OPENGLRENDERER_FUNC
 
+		// Match Vulkan convention if supported (so we don't have to inject code in the shader to fix it)
+		if (glClipControl)
+		{
+			// TODO: Using GL_UPPER_LEFT causes some issues I still have to figure out
+			glClipControl(GL_LOWER_LEFT, GL_ZERO_TO_ONE);
+			m_hasZeroToOneDepth = true;
+		}
+
 		// Always enable cubemap sampling (as it's the guaranteed behavior on Vulkan and OpenGL ES 3.0)
 		if (m_params.type == ContextType::OpenGL && (glVersion >= 320 || m_supportedExtensions.count("GL_ARB_seamless_cube_map")))
 			glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
@@ -847,7 +878,14 @@ namespace Nz::GL
 	{
 		SymbolLoader loader(*this);
 
-		if (function == "glDebugMessageCallback")
+		if (function == "glClipControl")
+		{
+			constexpr std::size_t functionIndex = UnderlyingCast(FunctionIndex::glClipControl);
+
+			return loader.Load<PFNGLCLIPCONTROLEXTPROC, functionIndex>(glClipControl, "glClipControlEXT", false); //< from GL_EXT_clip_control
+
+		}
+		else if (function == "glDebugMessageCallback")
 		{
 			constexpr std::size_t functionIndex = UnderlyingCast(FunctionIndex::glDebugMessageCallback);