On 10/07/2011 04:23 PM, Brian Paul wrote:
> On 10/07/2011 04:55 PM, Chad Versace wrote:
>> If this flag is set, then _mesa_meta_begin will save/restore the state of
>> GL_SELECT and GL_FEEDBACK render modes.
>>
>> Intel's futue resolve meta-ops will require this, since buffer resolves
>> may occur when the GL_RENDER_MODE is GL_SELECT.
>>
>> Signed-off-by: Chad Versace<c...@chad-versace.us>
>> ---
>> src/mesa/drivers/common/meta.c | 26 ++++++++++++++++++++++++++
>> src/mesa/drivers/common/meta.h | 1 +
>> 2 files changed, 27 insertions(+), 0 deletions(-)
>>
>> diff --git a/src/mesa/drivers/common/meta.c b/src/mesa/drivers/common/meta.c
>> index 5b73dcd..fc25f92 100644
>> --- a/src/mesa/drivers/common/meta.c
>> +++ b/src/mesa/drivers/common/meta.c
>> @@ -172,6 +172,11 @@ struct save_state
>> struct gl_query_object *CondRenderQuery;
>> GLenum CondRenderMode;
>>
>> + /** MESA_META_SELECT_FEEDBACK */
>> + GLenum RenderMode;
>> + struct gl_selection Select;
>> + struct gl_feedback Feedback;
>> +
>> /** Miscellaneous (always disabled) */
>> GLboolean Lighting;
>> };
>> @@ -608,6 +613,17 @@ _mesa_meta_begin(struct gl_context *ctx, GLbitfield
>> state)
>> _mesa_EndConditionalRender();
>> }
>>
>> + if (state& MESA_META_SELECT_FEEDBACK) {
>> + save->RenderMode = ctx->RenderMode;
>> + if (ctx->RenderMode == GL_SELECT) {
>> + save->Select = ctx->Select; /* struct copy */
>> + _mesa_RenderMode(GL_RENDER);
>> + } else if (ctx->RenderMode == GL_FEEDBACK) {
>> + save->Feedback = ctx->Feedback; /* struct copy */
>> + _mesa_RenderMode(GL_RENDER);
>> + }
>> + }
>> +
>> /* misc */
>> {
>> save->Lighting = ctx->Light.Enabled;
>> @@ -893,6 +909,16 @@ _mesa_meta_end(struct gl_context *ctx)
>> save->CondRenderMode);
>> }
>>
>> + if (state& MESA_META_SELECT_FEEDBACK) {
>> + if (save->RenderMode == GL_SELECT) {
>> + ctx->Select = save->Select;
>> + _mesa_RenderMode(GL_SELECT);
>> + } else if (save->RenderMode == GL_FEEDBACK) {
>> + ctx->Feedback = save->Feedback;
>> + _mesa_RenderMode(GL_FEEDBACK);
>> + }
>> + }
>
> You might need to switch the order of calling _mesa_RenderMode() and
> assigning the ctx->Feedback/Select state. That is:
>
> _mesa_RenderMode(GL_FEEDBACK);
> ctx->Feedback = save->Feedback;
My intuition also thought this was the correct order. But a Piglit test proved
my intuition wrong.
>
> I presume that after _mesa_meta_end() is called, we want the
> selection/feedback state to be just as it was before _mesa_meta_begin() was
> called, right?
Right.
> When _mesa_RenderMode() is called it mucks with various ctx->Select or
> ctx->Feedback fields. So we need to assign/restore the old
> ctx->Select/Feedback state _after_ that if we want to restore things just as
> they were.
>
> What do you think?
>
> -Brian
_mesa_RenderMode clobbers and checks the state like this:
current mode new mode clobbers asserts
--------------------------------------------------------------
RENDER * nothing
SELECT * ctx.Select
FEEDBACK * ctx.Feedback.Count
* RENDER nothing
* SELECT ctx.Select.BufferSize
> 0
* FEEDBACK
ctx.Feedback.BufferSize > 0
So in meta_begin, we need to save the state before calling glRenderMode in
order to prevent the state from getting clobbered. And in meta_end, we need to
restore the state before calling glRenderMode in order to prevent the
assertions from failing.
--
Chad Versace
c...@chad-versace.us
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