meta/blit: Always try to enable GL_ARB_sample_shading

Previously this extension was only enabled when blitting between two
multisampled buffers. However I don't think it does any harm to just
enable it all the time. The ‘enable’ option is used instead of
‘require’ so that the shader will still compile if the extension isn't
available in the cases where it isn't used. This will make the next
patch simpler because it wants to add another optional extension.

Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>

diff --git a/src/mesa/drivers/common/meta_blit.c b/src/mesa/drivers/common/meta_blit.c
index b92c2e2..496ce45 100644 (file)
--- a/src/mesa/drivers/common/meta_blit.c
+++ b/src/mesa/drivers/common/meta_blit.c
@@ -357,17 +357,11 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
        shader_index == BLIT_MSAA_SHADER_2D_MULTISAMPLE_ARRAY_DEPTH_COPY ||
        shader_index == BLIT_MSAA_SHADER_2D_MULTISAMPLE_DEPTH_COPY) {
       char *sample_index;
-      const char *arb_sample_shading_extension_string;
 
       if (dst_is_msaa) {
-         arb_sample_shading_extension_string = "#extension GL_ARB_sample_shading : enable";
          sample_index = "gl_SampleID";
          name = "depth MSAA copy";
       } else {
-         /* Don't need that extension, since we're drawing to a single-sampled
-          * destination.
-          */
-         arb_sample_shading_extension_string = "";
          /* From the GL 4.3 spec:
           *
           *     "If there is a multisample buffer (the value of SAMPLE_BUFFERS
@@ -397,7 +391,7 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
       fs_source = ralloc_asprintf(mem_ctx,
                                   "#version 130\n"
                                   "#extension GL_ARB_texture_multisample : enable\n"
-                                  "%s\n"
+                                  "#extension GL_ARB_sample_shading : enable\n"
                                   "uniform sampler2DMS%s texSampler;\n"
                                   "in %s texCoords;\n"
                                   "out vec4 out_color;\n"
@@ -406,7 +400,6 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
                                   "{\n"
                                   "   gl_FragDepth = texelFetch(texSampler, i%s(texCoords), %s).r;\n"
                                   "}\n",
-                                  arb_sample_shading_extension_string,
                                   sampler_array_suffix,
                                   texcoord_type,
                                   texcoord_type,
@@ -416,14 +409,12 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
        * sample).  Yes, this is ridiculous.
        */
       char *sample_resolve;
-      const char *arb_sample_shading_extension_string;
       const char *merge_function;
       name = ralloc_asprintf(mem_ctx, "%svec4 MSAA %s",
                              vec4_prefix,
                              dst_is_msaa ? "copy" : "resolve");
 
       if (dst_is_msaa) {
-         arb_sample_shading_extension_string = "#extension GL_ARB_sample_shading : enable";
          sample_resolve = ralloc_asprintf(mem_ctx, "   out_color = texelFetch(texSampler, i%s(texCoords), gl_SampleID);", texcoord_type);
          merge_function = "";
       } else {
@@ -439,8 +430,6 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
                "vec4 merge(vec4 a, vec4 b) { return (a + b); }\n";
          }
 
-         arb_sample_shading_extension_string = "";
-
          /* We're assuming power of two samples for this resolution procedure.
           *
           * To avoid losing any floating point precision if the samples all
@@ -496,7 +485,7 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
       fs_source = ralloc_asprintf(mem_ctx,
                                   "#version 130\n"
                                   "#extension GL_ARB_texture_multisample : enable\n"
-                                  "%s\n"
+                                  "#extension GL_ARB_sample_shading : enable\n"
                                   "#define gvec4 %svec4\n"
                                   "uniform %ssampler2DMS%s texSampler;\n"
                                   "in %s texCoords;\n"
@@ -507,7 +496,6 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
                                   "{\n"
                                   "%s\n" /* sample_resolve */
                                   "}\n",
-                                  arb_sample_shading_extension_string,
                                   vec4_prefix,
                                   vec4_prefix,
                                   sampler_array_suffix,