no-op clear if buffer width or height is zero (bug 7205)

diff --git a/src/mesa/main/buffers.c b/src/mesa/main/buffers.c
index 0e3ed155841ecb68e1091fb7b54e9d5504e51186..11bd173e35c2bb0a954d10b89d4944c3d05a01cb 100644 (file)
--- a/src/mesa/main/buffers.c
+++ b/src/mesa/main/buffers.c
@@ -140,6 +140,9 @@ _mesa_Clear( GLbitfield mask )
       return;
    }
 
+   if (ctx->DrawBuffer->Width == 0 || ctx->DrawBuffer->Height == 0)
+      return;
+
    if (ctx->RenderMode == GL_RENDER) {
       GLbitfield bufferMask;