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mesa: Skip ES 3.0/3.1 transform feedback primitive counting error. 

This error condition is not implementable when using tessellation or
geometry shaders.  The text was also removed from the ES 3.2 spec.
I believe the intended behavior is to remove the error condition
when either OES_geometry_shader or OES_tessellation_shader are
exposed.

v2: Quote a better part of issue 13 (suggested by Ian).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
This commit is contained in:
Kenneth Graunke 2015-10-29 00:21:18 -07:00
parent 23b2bcd460
commit 7314007925
1 changed files with 17 additions and 1 deletions
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18
src/mesa/main/api_validate.c
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@ -546,8 +546,24 @@ validate_draw_arrays(struct gl_context *ctx, const char *func,
*
* This is in contrast to the behaviour of desktop GL, where the extra
* primitives are silently dropped from the transform feedback buffer.
*
* This text is removed in ES 3.2, presumably because it's not really
* implementable with geometry and tessellation shaders. In fact,
* the OES_geometry_shader spec says:
*
* "(13) Does this extension change how transform feedback operates
* compared to unextended OpenGL ES 3.0 or 3.1?
*
* RESOLVED: Yes. Because dynamic geometry amplification in a geometry
* shader can make it difficult if not impossible to predict the amount
* of geometry that may be generated in advance of executing the shader,
* the draw-time error for transform feedback buffer overflow conditions
* is removed and replaced with the GL behavior (primitives are not
* written and the corresponding counter is not updated)..."
*/
if (_mesa_is_gles3(ctx) && _mesa_is_xfb_active_and_unpaused(ctx)) {
if (_mesa_is_gles3(ctx) && _mesa_is_xfb_active_and_unpaused(ctx) &&
!_mesa_has_OES_geometry_shader(ctx) &&
!_mesa_has_OES_tessellation_shader(ctx)) {
size_t prim_count = vbo_count_tessellated_primitives(mode, count, 1);
if (xfb_obj->GlesRemainingPrims < prim_count) {
_mesa_error(ctx, GL_INVALID_OPERATION,