mesa: Support BindBuffer{Base,Offset,Range} with a buffer of 0.

_mesa_lookup_bufferobj returns NULL for 0, which caused us to say
"there's no such buffer object" and raise an error, rather than
correctly binding the shared NullBufferObj.

Now you can unbind your buffers.

NOTE: This is a candidate for stable release branches.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Brian Paul <brianp@vmware.com>

diff --git a/src/mesa/main/transformfeedback.c b/src/mesa/main/transformfeedback.c
index f2c1435d9e76f1cfb3881985f6ab54d74b90c6e1..1bd76d130fda0a09fa135bce3f182e7833ee1ae2 100644 (file)
--- a/src/mesa/main/transformfeedback.c
+++ b/src/mesa/main/transformfeedback.c
@@ -470,7 +470,12 @@ _mesa_BindBufferRange(GLenum target, GLuint index,
       return;
    }  
 
-   bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   if (buffer == 0) {
+      bufObj = ctx->Shared->NullBufferObj;
+   } else {
+      bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   }
+
    if (!bufObj) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferRange(invalid buffer=%u)", buffer);
@@ -518,7 +523,12 @@ _mesa_BindBufferBase(GLenum target, GLuint index, GLuint buffer)
       return;
    }
 
-   bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   if (buffer == 0) {
+      bufObj = ctx->Shared->NullBufferObj;
+   } else {
+      bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   }
+
    if (!bufObj) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferBase(invalid buffer=%u)", buffer);
@@ -574,7 +584,12 @@ _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, GLuint buffer,
       return;
    }
 
-   bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   if (buffer == 0) {
+      bufObj = ctx->Shared->NullBufferObj;
+   } else {
+      bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   }
+
    if (!bufObj) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferOffsetEXT(invalid buffer=%u)", buffer);