Module: Mesa Branch: master Commit: 6e5b882339e9128348f0e7b828230f07338fce55 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=6e5b882339e9128348f0e7b828230f07338fce55
Author: Brian Paul <[email protected]> Date: Mon Dec 18 12:32:56 2017 -0700 glsl: disable vec3 packing/splitting in tfb separate mode This fixes a varying packing issue when using transform feedback in GL_SEPARATE_ATTRIBS mode. By time we get to linking, we already know that the number of feedback attributes is under the GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS limit so packing isn't as critical. In fact, packing/splitting vec3 attributes can cause trouble because splitting effectively creates another TFB output which can exceed device limits. So, disable vec3 packing when it's not needed to avoid that issue. Fixes the Piglit ext_transform_feedback-separate test on VMware driver. Reviewed-by: Timothy Arceri <[email protected]> --- src/compiler/glsl/link_varyings.cpp | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/src/compiler/glsl/link_varyings.cpp b/src/compiler/glsl/link_varyings.cpp index e0f3afb961..0a484ce132 100644 --- a/src/compiler/glsl/link_varyings.cpp +++ b/src/compiler/glsl/link_varyings.cpp @@ -1777,6 +1777,16 @@ varying_matches::assign_locations(struct gl_shader_program *prog, bool previous_var_xfb_only = false; unsigned previous_packing_class = ~0u; + /* For tranform feedback separate mode, we know the number of attributes + * is <= the number of buffers. So packing isn't critical. In fact, + * packing vec3 attributes can cause trouble because splitting a vec3 + * effectively creates an additional transform feedback output. The + * extra TFB output may exceed device driver limits. + */ + const bool dont_pack_vec3 = + (prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS && + prog->TransformFeedback.NumVarying > 0); + for (unsigned i = 0; i < this->num_matches; i++) { unsigned *location = &generic_location; const ir_variable *var; @@ -1810,7 +1820,9 @@ varying_matches::assign_locations(struct gl_shader_program *prog, if (var->data.must_be_shader_input || (this->disable_varying_packing && !(previous_var_xfb_only && var->data.is_xfb_only)) || - (previous_packing_class != this->matches[i].packing_class )) { + (previous_packing_class != this->matches[i].packing_class) || + (this->matches[i].packing_order == PACKING_ORDER_VEC3 && + dont_pack_vec3)) { *location = ALIGN(*location, 4); } _______________________________________________ mesa-commit mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-commit
