buffer: make _bind() return base pointer

We now make _cogl_buffer_bind return a base pointer for the bound buffer
which can be used with OpenGL. The pointer will be NULL for GPU based
buffers or may point to an malloc'd buffer. Since OpenGL expects an
offset instead of a pointer when dealing with buffer objects this means
we can handle fallback malloc buffers and GPU buffers in a consistent
way.

1 files changed, 10 insertions, 7 deletions

diff --git a/cogl/cogl-buffer.c b/cogl/cogl-buffer.c
index 5ed466a1..ebe8e610 100644
--- a/cogl/cogl-buffer.c
+++ b/cogl/cogl-buffer.c
@@ -351,28 +351,31 @@ _cogl_buffer_hints_to_gl_enum (CoglBufferUsageHint  usage_hint,
 }
 #endif
 
-void
+void *
 _cogl_buffer_bind (CoglBuffer *buffer, CoglBufferBindTarget target)
 {
-  _COGL_GET_CONTEXT (ctx, NO_RETVAL);
+  _COGL_GET_CONTEXT (ctx, NULL);
 
-  g_return_if_fail (buffer != NULL);
+  g_return_val_if_fail (buffer != NULL, NULL);
 
   /* Don't allow binding the buffer to multiple targets at the same time */
-  g_return_if_fail (ctx->current_buffer[buffer->last_target] != buffer);
+  g_return_val_if_fail (ctx->current_buffer[buffer->last_target] != buffer,
+                        NULL);
 
   /* Don't allow nesting binds to the same target */
-  g_return_if_fail (ctx->current_buffer[target] == NULL);
+  g_return_val_if_fail (ctx->current_buffer[target] == NULL, NULL);
 
   buffer->last_target = target;
+  ctx->current_buffer[target] = buffer;
 
   if (buffer->flags & COGL_BUFFER_FLAG_BUFFER_OBJECT)
     {
       GLenum gl_target = convert_bind_target_to_gl_target (buffer->last_target);
       GE( glBindBuffer (gl_target, buffer->gl_handle) );
+      return NULL;
     }
-
-  ctx->current_buffer[target] = buffer;
+  else
+    return buffer->data;
 }
 
 void