cogl-vertex-buffer: Add support for unsigned int indices

This adds a COGL_INDICES_TYPE_UNSIGNED_INT enum value so that unsigned
ints can be used with cogl_vertex_buffer_indices_new.  Unsigned ints
are not supported in core on GLES so a feature flag has also been
added to advertise this. GLES only sets the feature if the
GL_OES_element_index_uint extension is available. It is an error to
call indices_new() with unsigned ints unless the feature is
advertised.

http://bugzilla.openedhand.com/show_bug.cgi?id=1998

cogl/cogl-types.h

@@ -199,6 +199,9 @@ typedef enum { /*< prefix=COGL_PIXEL_FORMAT >*/
  * @COGL_FEATURE_STENCIL_BUFFER: Stencil buffer support
  * @COGL_FEATURE_VBOS: VBO support
  * @COGL_FEATURE_PBOS: PBO support
+ * @COGL_FEATURE_UNSIGNED_INT_INDICES: Set if
+ *     %COGL_INDICES_TYPE_UNSIGNED_INT is supported in
+ *     cogl_vertex_buffer_indices_new().
  *
  * Flags for the supported features.
  *
@@ -217,7 +220,8 @@ typedef enum
   COGL_FEATURE_FOUR_CLIP_PLANES       = (1 << 9),
   COGL_FEATURE_STENCIL_BUFFER         = (1 << 10),
   COGL_FEATURE_VBOS		      = (1 << 11),
-  COGL_FEATURE_PBOS		      = (1 << 12)
+  COGL_FEATURE_PBOS		      = (1 << 12),
+  COGL_FEATURE_UNSIGNED_INT_INDICES   = (1 << 13)
 } CoglFeatureFlags;
 
 /**

cogl/cogl-vertex-buffer.c

@@ -171,6 +171,11 @@
 
 #endif
 
+/* This isn't defined in the GLES headers */
+#ifndef GL_UNSIGNED_INT
+#define GL_UNSIGNED_INT 0x1405
+#endif
+
 /*
  * GL/GLES compatability defines for shader things:
  */
@@ -1782,8 +1787,10 @@ get_indices_type_size (GLuint indices_type)
 {
   if (indices_type == GL_UNSIGNED_BYTE)
     return sizeof (GLubyte);
-  if (indices_type == GL_UNSIGNED_SHORT)
+  else if (indices_type == GL_UNSIGNED_SHORT)
     return sizeof (GLushort);
+  else if (indices_type == GL_UNSIGNED_INT)
+    return sizeof (GLuint);
   else
     {
       g_critical ("Unknown indices type %d\n", indices_type);
@@ -1809,6 +1816,14 @@ cogl_vertex_buffer_indices_new (CoglIndicesType  indices_type,
     indices->type = GL_UNSIGNED_BYTE;
   else if (indices_type == COGL_INDICES_TYPE_UNSIGNED_SHORT)
     indices->type = GL_UNSIGNED_SHORT;
+  else if (indices_type == COGL_INDICES_TYPE_UNSIGNED_INT)
+    {
+      g_return_val_if_fail (cogl_features_available
+                            (COGL_FEATURE_UNSIGNED_INT_INDICES),
+                            COGL_INVALID_HANDLE);
+
+      indices->type = GL_UNSIGNED_INT;
+    }
   else
     {
       g_critical ("unknown indices type %d", indices_type);

cogl/cogl-vertex-buffer.h

@@ -301,14 +301,22 @@ cogl_vertex_buffer_draw (CoglHandle       handle,
  * CoglIndicesType:
  * @COGL_INDICES_TYPE_UNSIGNED_BYTE: Your indices are unsigned bytes
  * @COGL_INDICES_TYPE_UNSIGNED_SHORT: Your indices are unsigned shorts
+ * @COGL_INDICES_TYPE_UNSIGNED_INT: Your indices are unsigned ints
  *
  * You should aim to use the smallest data type that gives you enough
  * range, since it reduces the size of your index array and can help
  * reduce the demand on memory bandwidth.
+ *
+ * Note that %COGL_INDICES_TYPE_UNSIGNED_INT is only supported if the
+ * %COGL_FEATURE_UNSIGNED_INT_INDICES feature is available. This
+ * should always be available on OpenGL but on OpenGL ES it will only
+ * be available if the GL_OES_element_index_uint extension is
+ * advertized.
  */
 typedef enum {
   COGL_INDICES_TYPE_UNSIGNED_BYTE,
   COGL_INDICES_TYPE_UNSIGNED_SHORT,
+  COGL_INDICES_TYPE_UNSIGNED_INT,
 } CoglIndicesType;
 
 /**

cogl/driver/gl/cogl.c

@@ -185,7 +185,8 @@ _cogl_features_init (void)
 
   _cogl_get_gl_version (&gl_major, &gl_minor);
 
-  flags = COGL_FEATURE_TEXTURE_READ_PIXELS;
+  flags = (COGL_FEATURE_TEXTURE_READ_PIXELS
+           | COGL_FEATURE_UNSIGNED_INT_INDICES);
 
   gl_extensions = (const char*) glGetString (GL_EXTENSIONS);
 

cogl/driver/gles/cogl-feature-functions.h

@@ -70,3 +70,9 @@ COGL_FEATURE_FUNCTION (void, glDeleteFramebuffers,
 COGL_FEATURE_FUNCTION (void, glGenerateMipmap,
                        (GLenum                target))
 COGL_FEATURE_END ()
+
+COGL_FEATURE_BEGIN (element_index_uint, 255, 255,
+                    "OES\0",
+                    "element_index_uint\0",
+                    COGL_FEATURE_UNSIGNED_INT_INDICES)
+COGL_FEATURE_END ()