mesa/samplerobj: Avoid crash in sampler query if texture unit is disabled

Sampler queries are so far made only for enabled texture unit. But if
any code would query sampler before checking texture unit state that
would result to NULL deference.

Making the inline helper easier to use with NULL check makes a lot sense
because compiler is likely to combine the checks for the current texture.

Signed-off-by: Pauli Nieminen <pauli.nieminen@linux.intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/mesa/main/samplerobj.h b/src/mesa/main/samplerobj.h
index 2b0cd794665a7c6fe1be6b856ead4176007f36d8..e70ee4881ad968a6ff43ccad3113496f89ad15c9 100644 (file)
--- a/src/mesa/main/samplerobj.h
+++ b/src/mesa/main/samplerobj.h
@@ -33,8 +33,10 @@ _mesa_get_samplerobj(struct gl_context *ctx, GLuint unit)
 {
    if (ctx->Texture.Unit[unit].Sampler)
       return ctx->Texture.Unit[unit].Sampler;
-   else
+   else if (ctx->Texture.Unit[unit]._Current)
       return &ctx->Texture.Unit[unit]._Current->Sampler;
+   else
+      return NULL;
 }