[rlgl]: Add rlGetProcAddress

src/rlgl.h

@@ -710,6 +710,7 @@ RLAPI void rlSetBlendFactorsSeparate(int glSrcRGB, int glDstRGB, int glSrcAlpha,
 RLAPI void rlglInit(int width, int height);             // Initialize rlgl (buffers, shaders, textures, states)
 RLAPI void rlglClose(void);                             // De-initialize rlgl (buffers, shaders, textures)
 RLAPI void rlLoadExtensions(void *loader);              // Load OpenGL extensions (loader function required)
+RLAPI void *rlGetProcAddress(const char *procName);     // Get OpenGL procedure address
 RLAPI int rlGetVersion(void);                           // Get current OpenGL version
 RLAPI void rlSetFramebufferWidth(int width);            // Set current framebuffer width
 RLAPI int rlGetFramebufferWidth(void);                  // Get default framebuffer width
@@ -1041,10 +1042,15 @@ RLAPI void rlLoadDrawQuad(void);     // Load and draw a quad
 // Types and Structures Definition
 //----------------------------------------------------------------------------------
 #if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
+
+typedef void *(*rlglLoadProc)(const char *name);   // OpenGL extension functions loader signature (same as GLADloadproc)
+
 typedef struct rlglData {
     rlRenderBatch *currentBatch;            // Current render batch
     rlRenderBatch defaultBatch;             // Default internal render batch
 
+    rlglLoadProc loader;                    // OpenGL function loader
+
     struct {
         int vertexCounter;                  // Current active render batch vertex counter (generic, used for all batches)
         float texcoordx, texcoordy;         // Current active texture coordinate (added on glVertex*())
@@ -1114,8 +1120,6 @@ typedef struct rlglData {
     } ExtSupported;     // Extensions supported flags
 } rlglData;
 
-typedef void *(*rlglLoadProc)(const char *name);   // OpenGL extension functions loader signature (same as GLADloadproc)
-
 #endif  // GRAPHICS_API_OPENGL_33 || GRAPHICS_API_OPENGL_ES2
 
 //----------------------------------------------------------------------------------
@@ -2567,6 +2571,8 @@ void rlLoadExtensions(void *loader)
     TRACELOG(RL_LOG_INFO, "    > Version:  %s", glGetString(GL_VERSION));
     TRACELOG(RL_LOG_INFO, "    > GLSL:     %s", glGetString(GL_SHADING_LANGUAGE_VERSION));
 
+    RLGL.loader = (rlglLoadProc)loader;
+
 #if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
     // NOTE: Anisotropy levels capability is an extension
     #ifndef GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT
@@ -2625,6 +2631,11 @@ void rlLoadExtensions(void *loader)
 #endif  // GRAPHICS_API_OPENGL_33 || GRAPHICS_API_OPENGL_ES2
 }
 
+// Get OpenGL procedure address
+void *rlGetProcAddress(const char *procName) {
+    return RLGL.loader(procName);
+}
+
 // Get current OpenGL version
 int rlGetVersion(void)
 {