mesa: Add a function to query whether a meta-op is in progress.

This is needed by i965 to ensure that transform feedback counters are
not incremented during meta-ops.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/common/meta.c

@@ -984,6 +984,16 @@ _mesa_meta_end(struct gl_context *ctx)
 }
 
 
+/**
+ * Determine whether Mesa is currently in a meta state.
+ */
+GLboolean
+_mesa_meta_in_progress(struct gl_context *ctx)
+{
+   return ctx->Meta->SaveStackDepth != 0;
+}
+
+
 /**
  * Convert Z from a normalized value in the range [0, 1] to an object-space
  * Z coordinate in [-1, +1] so that drawing at the new Z position with the

src/mesa/drivers/common/meta.h

@@ -69,6 +69,9 @@ _mesa_meta_begin(struct gl_context *ctx, GLbitfield state);
 extern void
 _mesa_meta_end(struct gl_context *ctx);
 
+extern GLboolean
+_mesa_meta_in_progress(struct gl_context *ctx);
+
 extern void
 _mesa_meta_BlitFramebuffer(struct gl_context *ctx,
                            GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,