OpenGL: Handle legacy functions and tokens more gracefully for OpenGL…

… variants that may not have them.
TASEmulators · Jul 6, 2024 · c962c55 · c962c55
1 parent 76fe5f7
commit c962c55
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Showing 3 changed files with 44 additions and 18 deletions.
diff --git a/desmume/src/OGLRender.cpp b/desmume/src/OGLRender.cpp
@@ -55,11 +55,6 @@
 	#define OGL_TEXTURE_SRC_CI_FOG     GL_UNSIGNED_BYTE
 	#define OGL_TEXTURE_SRC_EDGE_COLOR GL_UNSIGNED_BYTE
 	#define OGL_TEXTURE_SRC_TOON_TABLE GL_UNSIGNED_SHORT_5_5_5_1
-
-	#define GL_TEXTURE_1D GL_TEXTURE_2D
-	#define glTexSubImage1D(target, level, xoffset, width, format, type, pixels)
-
-	#define glClearDepth(depth) glClearDepthf(depth)
 #else
 	#error Unknown OpenGL variant.
 #endif
@@ -229,7 +224,7 @@ OGLEXT(PFNGLDELETEBUFFERSPROC, glDeleteBuffers) // Core in v1.5
 OGLEXT(PFNGLBINDBUFFERPROC, glBindBuffer) // Core in v1.5
 OGLEXT(PFNGLBUFFERDATAPROC, glBufferData) // Core in v1.5
 OGLEXT(PFNGLBUFFERSUBDATAPROC, glBufferSubData) // Core in v1.5
-#if !defined(GL_ES_VERSION_3_0)
+#if defined(GL_VERSION_1_5)
 OGLEXT(PFNGLMAPBUFFERPROC, glMapBuffer) // Core in v1.5
 #endif
 OGLEXT(PFNGLUNMAPBUFFERPROC, glUnmapBuffer) // Core in v1.5
@@ -304,7 +299,7 @@ static void OGLLoadEntryPoints_Legacy()
 	INITOGLEXT(PFNGLBINDBUFFERPROC, glBindBuffer) // Core in v1.5
 	INITOGLEXT(PFNGLBUFFERDATAPROC, glBufferData) // Core in v1.5
 	INITOGLEXT(PFNGLBUFFERSUBDATAPROC, glBufferSubData) // Core in v1.5
-#if !defined(GL_ES_VERSION_3_0)
+#if defined(GL_VERSION_1_5)
 	INITOGLEXT(PFNGLMAPBUFFERPROC, glMapBuffer) // Core in v1.5
 #endif
 	INITOGLEXT(PFNGLUNMAPBUFFERPROC, glUnmapBuffer) // Core in v1.5
@@ -2795,9 +2790,7 @@ Render3DError OpenGLRenderer_1_2::CreatePBOs()
 	glGenBuffers(1, &OGLRef.pboRenderDataID);
 	glBindBuffer(GL_PIXEL_PACK_BUFFER, OGLRef.pboRenderDataID);
 	glBufferData(GL_PIXEL_PACK_BUFFER, this->_framebufferColorSizeBytes, NULL, GL_STREAM_READ);
-#if !defined(GL_ES_VERSION_3_0)
 	this->_mappedFramebuffer = (Color4u8 *__restrict)glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
-#endif
 
 	return OGLERROR_NOERR;
 }
@@ -5381,9 +5374,7 @@ Render3DError OpenGLRenderer_1_2::RenderFinish()
 
 		if (this->isPBOSupported)
 		{
-#if !defined(GL_ES_VERSION_3_0)
 			this->_mappedFramebuffer = (Color4u8 *__restrict)glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
-#endif
 		}
 		else
 		{
@@ -5452,9 +5443,7 @@ Render3DError OpenGLRenderer_1_2::SetFramebufferSize(size_t w, size_t h)
 
 		if (this->_mappedFramebuffer != NULL)
 		{
-#if !defined(GL_ES_VERSION_3_0)
 			this->_mappedFramebuffer = (Color4u8 *__restrict)glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
-#endif
 			glFinish();
 		}
 	}
@@ -5795,9 +5784,7 @@ Render3DError OpenGLRenderer_2_1::RenderFinish()
 		{
 			return OGLERROR_BEGINGL_FAILED;
 		}
-#if !defined(GL_ES_VERSION_3_0)
 		this->_mappedFramebuffer = (Color4u8 *__restrict)glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
-#endif
 		ENDGL();
 	}
 

diff --git a/desmume/src/OGLRender.h b/desmume/src/OGLRender.h
@@ -178,7 +178,7 @@ EXTERNOGLEXT(PFNGLDELETEBUFFERSPROC, glDeleteBuffers) // Core in v1.5
 EXTERNOGLEXT(PFNGLBINDBUFFERPROC, glBindBuffer) // Core in v1.5
 EXTERNOGLEXT(PFNGLBUFFERDATAPROC, glBufferData) // Core in v1.5
 EXTERNOGLEXT(PFNGLBUFFERSUBDATAPROC, glBufferSubData) // Core in v1.5
-#if !defined(GL_ES_VERSION_3_0)
+#if defined(GL_VERSION_1_5)
 EXTERNOGLEXT(PFNGLMAPBUFFERPROC, glMapBuffer) // Core in v1.5
 #endif
 EXTERNOGLEXT(PFNGLUNMAPBUFFERPROC, glUnmapBuffer) // Core in v1.5
@@ -199,8 +199,10 @@ EXTERNOGLEXT(PFNGLCLEARBUFFERFVPROC, glClearBufferfv) // Core in v3.0 and ES v3.
 EXTERNOGLEXT(PFNGLCLEARBUFFERFIPROC, glClearBufferfi) // Core in v3.0 and ES v3.0
 
 // Shaders
-#if !defined(GL_ES_VERSION_3_0)
+#if defined(GL_VERSION_3_0)
 EXTERNOGLEXT(PFNGLBINDFRAGDATALOCATIONPROC, glBindFragDataLocation) // Core in v3.0, not available in ES
+#endif
+#if defined(GL_VERSION_3_3) || defined(GL_ARB_blend_func_extended)
 EXTERNOGLEXT(PFNGLBINDFRAGDATALOCATIONINDEXEDPROC, glBindFragDataLocationIndexed) // Core in v3.3, not available in ES
 #endif
 
@@ -222,7 +224,7 @@ EXTERNOGLEXT(PFNGLBINDRENDERBUFFERPROC, glBindRenderbuffer) // Core in v3.0 and
 EXTERNOGLEXT(PFNGLRENDERBUFFERSTORAGEPROC, glRenderbufferStorage) // Core in v3.0 and ES v2.0
 EXTERNOGLEXT(PFNGLRENDERBUFFERSTORAGEMULTISAMPLEPROC, glRenderbufferStorageMultisample) // Core in v3.0 and ES v3.0
 EXTERNOGLEXT(PFNGLDELETERENDERBUFFERSPROC, glDeleteRenderbuffers) // Core in v3.0 and ES v2.0
-#if !defined(GL_ES_VERSION_3_0)
+#if defined(GL_VERSION_3_2) || defined(GL_ARB_texture_multisample)
 EXTERNOGLEXT(PFNGLTEXIMAGE2DMULTISAMPLEPROC, glTexImage2DMultisample) // Core in v3.2, not available in ES
 #endif
 
@@ -304,6 +306,38 @@ EXTERNOGLEXT(PFNGLDELETERENDERBUFFERSEXTPROC, glDeleteRenderbuffersEXT)
 
 #endif // GL_EXT_framebuffer_object
 
+// OPENGL CORE EQUIVALENTS FOR LEGACY FUNCTIONS
+// Some OpenGL variants, such as OpenGL ES, do not include certain legacy functions in their
+// API. The loss of these functions will cause compile time errors when referenced, and so
+// we will redeclare them to something that is supported for the sake of compiling.
+//
+// Do note that a redeclared function will most likely not work in exactly the same way as
+// a native legacy version, and so implmentations are responsible for overriding any methods
+// that use these legacy functions to whatever is available in the specific OpenGL variant.
+
+#ifndef GL_VERSION_1_2
+	// These legacy functions can be promoted to later core equivalents without any further
+	// modification. In other words, these are one-to-one drop-in replacements.
+	#define glClearDepth(depth) glClearDepthf(depth)
+	#define glDrawBuffer(x) glDrawBuffers(1, ((GLenum[]){x}))
+
+	// 1D textures may not exist for a particular OpenGL variant, so they will be promoted to
+	// 2D textures instead. Implementations need to modify their GLSL shaders accordingly to
+	// treat any 1D textures as 2D textures instead.
+	#define GL_TEXTURE_1D GL_TEXTURE_2D
+	#define glTexImage1D(target, level, internalformat, width, border, format, type, pixels) glTexImage2D(target, level, internalformat, width, 1, border, format, type, pixels)
+	#define glTexSubImage1D(target, level, xoffset, width, format, type, pixels) glTexSubImage2D(target, level, xoffset, 0, width, 1, format, type, pixels)
+#endif
+
+#ifndef GL_VERSION_1_5
+	// Calling glMapBuffer with an OpenGL variant that forgoes legacy functions will cause a
+	// GL_INVALID_OPERATION error if used in practice. Implementations need to override any
+	// methods that would call glMapBuffer with glMapBufferRange.
+	#define GL_READ_ONLY  GL_MAP_READ_BIT
+	#define GL_WRITE_ONLY GL_MAP_WRITE_BIT
+	#define glMapBuffer(target, access) glMapBufferRange(target, 0, 0, access)
+#endif
+
 // Define the minimum required OpenGL version for the driver to support
 #if defined(OPENGL_VARIANT_STANDARD)
 	#define OGLRENDER_MINIMUM_DRIVER_VERSION_REQUIRED_MAJOR    1

diff --git a/desmume/src/OGLRender_3_2.cpp b/desmume/src/OGLRender_3_2.cpp
@@ -39,7 +39,9 @@ OGLEXT(PFNGLCLEARBUFFERFIPROC, glClearBufferfi) // Core in v3.0 and ES v3.0
 
 // Shaders
 OGLEXT(PFNGLBINDFRAGDATALOCATIONPROC, glBindFragDataLocation) // Core in v3.0, not available in ES
+#if defined(GL_VERSION_3_3) || defined(GL_ARB_blend_func_extended)
 OGLEXT(PFNGLBINDFRAGDATALOCATIONINDEXEDPROC, glBindFragDataLocationIndexed) // Core in v3.3, not available in ES
+#endif
 
 // Buffer Objects
 OGLEXT(PFNGLMAPBUFFERRANGEPROC, glMapBufferRange) // Core in v3.0 and ES v3.0
@@ -84,6 +86,9 @@ void OGLLoadEntryPoints_3_2()
 
 	// Shaders
 	INITOGLEXT(PFNGLBINDFRAGDATALOCATIONPROC, glBindFragDataLocation) // Core in v3.0, not available in ES
+#if defined(GL_VERSION_3_3) || defined(GL_ARB_blend_func_extended)
+	INITOGLEXT(PFNGLBINDFRAGDATALOCATIONINDEXEDPROC, glBindFragDataLocationIndexed) // Core in v3.3, not available in ES
+#endif
 
 	// Buffer Objects
 	INITOGLEXT(PFNGLMAPBUFFERRANGEPROC, glMapBufferRange) // Core in v3.0 and ES v3.0