From 6b33eab959433fdcb4f3fce7c571a83e8050cdf0 Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Tue, 19 Jul 2016 20:11:53 -0700 Subject: [PATCH] glsl: Define a gl_LastFragData built-in for older GLSL versions. The EXT_shader_framebuffer_fetch extension defines alternative language for GLES2 shaders where user-defined fragment outputs are not allowed. Instead of using inout user-defined fragment outputs the shader is expected to read from the gl_LastFragData built-in array. In addition this allows using the same language on desktop GLSL versions prior to 4.2 that support the deprecated gl_FragData built-in in preparation for the MESA_shader_framebuffer_fetch desktop GL extension. Both legacy and user-defined inout outputs have a common representation at the GLSL IR level, so it shouldn't make any difference for optimization passes and back-ends whether the application is using gl_LastFragData or user-defined outputs, all they'll see is a variable dereference of a fragment output at a certain interface location with the fb_fetch_output bit set to one. v2: Don't define the built-in variable on GLSL versions for which gl_FragData exists but is deprecated. (Ken) Reviewed-by: Kenneth Graunke --- src/compiler/glsl/builtin_variables.cpp | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/src/compiler/glsl/builtin_variables.cpp b/src/compiler/glsl/builtin_variables.cpp index c9d8b1c..cb5f730 100644 --- a/src/compiler/glsl/builtin_variables.cpp +++ b/src/compiler/glsl/builtin_variables.cpp @@ -1134,6 +1134,16 @@ builtin_variable_generator::generate_fs_special_vars() array(vec4_t, state->Const.MaxDrawBuffers), "gl_FragData"); } + if (state->has_framebuffer_fetch() && !state->is_version(130, 300)) { + ir_variable *const var = + add_output(FRAG_RESULT_DATA0, + array(vec4_t, state->Const.MaxDrawBuffers), + "gl_LastFragData"); + var->data.precision = GLSL_PRECISION_MEDIUM; + var->data.read_only = 1; + var->data.fb_fetch_output = 1; + } + if (state->es_shader && state->language_version == 100 && state->EXT_blend_func_extended_enable) { /* We make an assumption here that there will only ever be one dual-source draw buffer * In case this assumption is ever proven to be false, make sure to assert here -- 2.7.4