Call glActiveTexture and glClientActiveTexture through cogl_get_proc_address

All GL functions that are defined in a version later than 1.1 need to
be called through cogl_get_proc_address because the Windows GL DLL
does not export them to directly link against.

common/cogl-material.c

@@ -22,6 +22,11 @@
 #include "../gles/cogl-gles2-wrapper.h"
 #endif
 
+#ifdef HAVE_COGL_GL
+#define glActiveTexture ctx->pf_glActiveTexture
+#define glClientActiveTexture ctx->pf_glClientActiveTexture
+#endif
+
 static void _cogl_material_free (CoglMaterial *tex);
 static void _cogl_material_layer_free (CoglMaterialLayer *layer);
 

common/cogl-vertex-buffer.c

@@ -153,6 +153,8 @@
 #define glDeleteBuffers ctx->pf_glDeleteBuffersARB
 #define glMapBuffer ctx->pf_glMapBufferARB
 #define glUnmapBuffer ctx->pf_glUnmapBufferARB
+#define glActiveTexture ctx->pf_glActiveTexture
+#define glClientActiveTexture ctx->pf_glClientActiveTexture
 #ifndef GL_ARRAY_BUFFER
 #define GL_ARRAY_BUFFER GL_ARRAY_BUFFER_ARB
 #endif

gl/cogl-context.c

@@ -135,6 +135,8 @@ cogl_create_context ()
   _context->pf_glUniformMatrix4fvARB = NULL;
 
   _context->pf_glDrawRangeElements = NULL;
+  _context->pf_glActiveTexture = NULL;
+  _context->pf_glClientActiveTexture = NULL;
 
   /* Initialise the clip stack */
   _cogl_clip_stack_state_init ();

gl/cogl-context.h

@@ -162,6 +162,9 @@ typedef struct
   COGL_PFNGLUNIFORMMATRIX4FVARBPROC                pf_glUniformMatrix4fvARB;
 
   COGL_PFNGLDRAWRANGEELEMENTSPROC                  pf_glDrawRangeElements;
+
+  COGL_PFNGLACTIVETEXTUREPROC                      pf_glActiveTexture;
+  COGL_PFNGLCLIENTACTIVETEXTUREPROC                pf_glClientActiveTexture;
 } CoglContext;
 
 CoglContext *

gl/cogl-defines.h.in

@@ -1026,6 +1026,14 @@ typedef void
    GLenum                type,
    const GLvoid         *indices);
 
+typedef void
+  (APIENTRYP             COGL_PFNGLACTIVETEXTUREPROC)
+  (GLenum                texture);
+
+typedef void
+  (APIENTRYP             COGL_PFNGLCLIENTACTIVETEXTUREPROC)
+  (GLenum                texture);
+
 G_END_DECLS
 
 #endif

gl/cogl-texture.c

@@ -54,6 +54,8 @@
 #ifdef HAVE_COGL_GL
 
 #define glDrawRangeElements ctx->pf_glDrawRangeElements
+#define glActiveTexture ctx->pf_glActiveTexture
+#define glClientActiveTexture ctx->pf_glClientActiveTexture
 
 #else
 

gl/cogl.c

@@ -1083,12 +1083,18 @@ _cogl_features_init ()
       flags |= COGL_FEATURE_VBOS;
     }
 
-  /* This should always be available because it is defined in GL 1.2,
-     but we can't call it directly because under Windows functions >
-     1.1 aren't exported */
+  /* These should always be available because they are defined in GL
+     1.2, but we can't call it directly because under Windows
+     functions > 1.1 aren't exported */
   ctx->pf_glDrawRangeElements =
         (COGL_PFNGLDRAWRANGEELEMENTSPROC)
         cogl_get_proc_address ("glDrawRangeElements");
+  ctx->pf_glActiveTexture =
+        (COGL_PFNGLACTIVETEXTUREPROC)
+        cogl_get_proc_address ("glActiveTexture");
+  ctx->pf_glClientActiveTexture =
+        (COGL_PFNGLCLIENTACTIVETEXTUREPROC)
+        cogl_get_proc_address ("glClientActiveTexture");
 
   /* Cache features */
   ctx->feature_flags = flags;

gles/cogl-texture.c

@@ -56,6 +56,8 @@
 #ifdef HAVE_COGL_GL
 
 #define glDrawRangeElements ctx->pf_glDrawRangeElements
+#define glActiveTexture ctx->pf_glActiveTexture
+#define glClientActiveTexture ctx->pf_glClientActiveTexture
 
 #else