[Mesa-dev] ARB_query_buffer_object driver interface

[Ilia Mirkin]

Hello,

I've started working on implementing ARB_query_buffer_object, and am
trying to work out the driver interface. I'm thinking something along
these lines:

    void (*CheckQuery)(struct gl_context *ctx, struct gl_query_object *q);
    void (*WaitQuery)(struct gl_context *ctx, struct gl_query_object *q);
+   void (*StoreQueryResult)(struct gl_context *ctx, struct gl_query_object *q,
+                            struct gl_buffer_object *buf, intptr_t offset,
+                            bool is64bit, bool wait);

Which would only work for GL_QUERY_RESULT and GL_QUERY_RESULT_NO_WAIT.
The other queries (GL_QUERY_RESULT_AVAILABLE and GL_QUERY_TYPE) would
manually update the buffer using the BufferSubData call. This new call
would only be used for when a buffer is bound.

The alternative would be to also pass in the pname to the driver
backend instead of the wait bool, and have it write in the 1/0 result
for available, and the query type for GL_QUERY_TYPE.

Thoughts?

  -ilia