From d8b7f4d73f9b2b8ce4a5b74a014bf597296b2bfc Mon Sep 17 00:00:00 2001
From: Ryan Houdek <Sonicadvance1@gmail.com>
Date: Sat, 28 Dec 2013 01:04:52 -0600
Subject: [PATCH] [Android] Support grabbing OpenGL extensions and a function
 for checking for support.

---
 Externals/GLES3/GLES3/gl3.h                   |  2 +-
 .../VideoBackends/OGL/Src/GLFunctions.cpp     | 22 +++++++++++++++++++
 .../Core/VideoBackends/OGL/Src/GLFunctions.h  |  4 ++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/Externals/GLES3/GLES3/gl3.h b/Externals/GLES3/GLES3/gl3.h
index 01cbeaacf7..afee172f9c 100644
--- a/Externals/GLES3/GLES3/gl3.h
+++ b/Externals/GLES3/GLES3/gl3.h
@@ -996,7 +996,7 @@ GL_APICALL void           GL_APIENTRY glClearBufferiv (GLenum buffer, GLint draw
 GL_APICALL void           GL_APIENTRY glClearBufferuiv (GLenum buffer, GLint drawbuffer, const GLuint* value);
 GL_APICALL void           GL_APIENTRY glClearBufferfv (GLenum buffer, GLint drawbuffer, const GLfloat* value);
 GL_APICALL void           GL_APIENTRY glClearBufferfi (GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil);
-GL_APICALL const GLubyte* GL_APIENTRY glGetStringi (GLenum name, GLuint index);
+//GL_APICALL const GLubyte* GL_APIENTRY glGetStringi (GLenum name, GLuint index);
 GL_APICALL void           GL_APIENTRY glCopyBufferSubData (GLenum readTarget, GLenum writeTarget, GLintptr readOffset, GLintptr writeOffset, GLsizeiptr size);
 GL_APICALL void           GL_APIENTRY glGetUniformIndices (GLuint program, GLsizei uniformCount, const GLchar* const* uniformNames, GLuint* uniformIndices);
 GL_APICALL void           GL_APIENTRY glGetActiveUniformsiv (GLuint program, GLsizei uniformCount, const GLuint* uniformIndices, GLenum pname, GLint* params);
diff --git a/Source/Core/VideoBackends/OGL/Src/GLFunctions.cpp b/Source/Core/VideoBackends/OGL/Src/GLFunctions.cpp
index c91908ea11..505326b1ea 100644
--- a/Source/Core/VideoBackends/OGL/Src/GLFunctions.cpp
+++ b/Source/Core/VideoBackends/OGL/Src/GLFunctions.cpp
@@ -5,7 +5,9 @@
 #include "DriverDetails.h"
 #include "GLFunctions.h"
 #include "Log.h"
+
 #include <dlfcn.h>
+#include <unordered_map>
 
 #ifdef USE_GLES3
 PFNGLMAPBUFFERRANGEPROC glMapBufferRange;
@@ -13,6 +15,7 @@ PFNGLUNMAPBUFFERPROC glUnmapBuffer;
 PFNGLBINDBUFFERRANGEPROC glBindBufferRange;
 
 PFNGLBLITFRAMEBUFFERPROC glBlitFramebuffer;
+PFNGLGETSTRINGIPROC glGetStringi;
 
 PFNGLGENVERTEXARRAYSPROC glGenVertexArrays;
 PFNGLDELETEVERTEXARRAYSPROC glDeleteVertexArrays;
@@ -49,6 +52,8 @@ PFNGLGENQUERIESPROC glGenQueries;
 namespace GLFunc
 {
 	void *self;
+	std::unordered_map<std::string, bool> _extensions;
+
 	void LoadFunction(const char *name, void **func)
 	{
 #ifdef USE_GLES3
@@ -67,10 +72,27 @@ namespace GLFunc
 #endif
 	}
 
+	bool SupportsExt(std::string ext)
+	{
+		return _extensions.find(ext) != _extensions.end();
+	}
+
+	void InitExtensions()
+	{
+		GLint NumExtension = 0;
+		glGetIntegerv(GL_NUM_EXTENSIONS, &NumExtension);
+		for (GLint i = 0; i < NumExtension; ++i)
+			_extensions[std::string((const char*)glGetStringi(GL_EXTENSIONS, i))] = true;
+	}
+
 	void Init()
 	{
 		self = dlopen(NULL, RTLD_LAZY);
 
+		LoadFunction("glGetStringi", (void**)&glGetStringi);
+		
+		InitExtensions();
+
 		LoadFunction("glUnmapBuffer", (void**)&glUnmapBuffer);
 		LoadFunction("glBeginQuery", (void**)&glBeginQuery);
 		LoadFunction("glEndQuery", (void**)&glEndQuery);
diff --git a/Source/Core/VideoBackends/OGL/Src/GLFunctions.h b/Source/Core/VideoBackends/OGL/Src/GLFunctions.h
index cbfde1276c..7cdd5476ba 100644
--- a/Source/Core/VideoBackends/OGL/Src/GLFunctions.h
+++ b/Source/Core/VideoBackends/OGL/Src/GLFunctions.h
@@ -10,8 +10,10 @@ typedef GLvoid* (*PFNGLMAPBUFFERPROC) (GLenum target, GLenum access);
 typedef GLvoid* (*PFNGLMAPBUFFERRANGEPROC) (GLenum target, GLintptr offset, GLsizeiptr length, GLbitfield access);
 typedef void (*PFNGLBINDBUFFERRANGEPROC) (GLenum target, GLuint index, GLuint buffer, GLintptr offset, GLsizeiptr size);
 typedef GLboolean (*PFNGLUNMAPBUFFERPROC) (GLenum target);
+typedef GLubyte* (*PFNGLGETSTRINGIPROC) (GLenum name, GLuint index);
 
 typedef void (*PFNGLBLITFRAMEBUFFERPROC) (GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter);
+
 // VAOS
 typedef void (*PFNGLGENVERTEXARRAYSPROC) (GLsizei n, GLuint* arrays);
 typedef void (*PFNGLDELETEVERTEXARRAYSPROC) (GLsizei n, const GLuint* arrays);
@@ -63,6 +65,7 @@ extern PFNGLMAPBUFFERRANGEPROC glMapBufferRange;
 extern PFNGLBINDBUFFERRANGEPROC glBindBufferRange;
 
 extern PFNGLBLITFRAMEBUFFERPROC glBlitFramebuffer;
+extern PFNGLGETSTRINGIPROC glGetStringi;
 
 extern PFNGLGENVERTEXARRAYSPROC glGenVertexArrays;
 extern PFNGLDELETEVERTEXARRAYSPROC glDeleteVertexArrays;
@@ -95,5 +98,6 @@ extern PFNGLUNIFORMBLOCKBINDINGPROC glUniformBlockBinding;
 namespace GLFunc
 {
 	void Init();
+	bool SupportsExt(std::string ext);
 }
 #endif