From 91dde3ddcaf6ca5a7aa2d2e9815236ce2ddf698f Mon Sep 17 00:00:00 2001 From: Timothy Arceri Date: Thu, 26 May 2016 14:50:43 +1000 Subject: [PATCH] glsl: re-enable varying packing in GL4.4+ We can still do packing we just need to get the packing type from the consumer rather than the producer. Reviewed-by: Iago Toral Quiroga Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97033 --- src/compiler/glsl/link_varyings.cpp | 54 +++++++++++++---------------- 1 file changed, 24 insertions(+), 30 deletions(-) diff --git a/src/compiler/glsl/link_varyings.cpp b/src/compiler/glsl/link_varyings.cpp index 29362c4f21c..f6778b6a855 100644 --- a/src/compiler/glsl/link_varyings.cpp +++ b/src/compiler/glsl/link_varyings.cpp @@ -1405,10 +1405,26 @@ varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var) sizeof(*this->matches) * this->matches_capacity); } - const ir_variable *const var = (producer_var != NULL) - ? producer_var : consumer_var; - const gl_shader_stage stage = (producer_var != NULL) - ? producer_stage : consumer_stage; + /* We must use the consumer to compute the packing class because in GL4.4+ + * there is no guarantee interpolation qualifiers will match across stages. + * + * From Section 4.5 (Interpolation Qualifiers) of the GLSL 4.30 spec: + * + * "The type and presence of interpolation qualifiers of variables with + * the same name declared in all linked shaders for the same cross-stage + * interface must match, otherwise the link command will fail. + * + * When comparing an output from one stage to an input of a subsequent + * stage, the input and output don't match if their interpolation + * qualifiers (or lack thereof) are not the same." + * + * This text was also in at least revison 7 of the 4.40 spec but is no + * longer in revision 9 and not in the 4.50 spec. + */ + const ir_variable *const var = (consumer_var != NULL) + ? consumer_var : producer_var; + const gl_shader_stage stage = (consumer_var != NULL) + ? consumer_stage : producer_stage; const glsl_type *type = get_varying_type(var, stage); this->matches[this->num_matches].packing_class @@ -2023,40 +2039,18 @@ assign_varying_locations(struct gl_context *ctx, bool xfb_enabled = ctx->Extensions.EXT_transform_feedback && !unpackable_tess; - /* Disable varying packing for GL 4.4+ as there is no guarantee - * that interpolation qualifiers will match between shaders in these - * versions. We also disable packing on outward facing interfaces for - * SSO because in ES we need to retain the unpacked varying information - * for draw time validation. For desktop GL we could allow packing for - * versions < 4.4 but it's just safer not to do packing. + /* Disable packing on outward facing interfaces for SSO because in ES we + * need to retain the unpacked varying information for draw time + * validation. * * Packing is still enabled on individual arrays, structs, and matrices as * these are required by the transform feedback code and it is still safe * to do so. We also enable packing when a varying is only used for * transform feedback and its not a SSO. - * - * Varying packing currently only packs together varyings with matching - * interpolation qualifiers as the backends assume all packed components - * are to be processed in the same way. Therefore we cannot do packing in - * these versions of GL without the risk of mismatching interfaces. - * - * From Section 4.5 (Interpolation Qualifiers) of the GLSL 4.30 spec: - * - * "The type and presence of interpolation qualifiers of variables with - * the same name declared in all linked shaders for the same cross-stage - * interface must match, otherwise the link command will fail. - * - * When comparing an output from one stage to an input of a subsequent - * stage, the input and output don't match if their interpolation - * qualifiers (or lack thereof) are not the same." - * - * This text was also in at least revison 7 of the 4.40 spec but is no - * longer in revision 9 and not in the 4.50 spec. */ bool disable_varying_packing = ctx->Const.DisableVaryingPacking || unpackable_tess; - if ((ctx->API == API_OPENGL_CORE && ctx->Version >= 44) || - (prog->SeparateShader && (producer == NULL || consumer == NULL))) + if (prog->SeparateShader && (producer == NULL || consumer == NULL)) disable_varying_packing = true; varying_matches matches(disable_varying_packing, xfb_enabled, -- 2.30.2