[Mesa-dev] [PATCH 20/22] meta/blit: Don't dynamically select the MSAA "emit" function

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

Just include all 3 versions in the shader.  The GLSL type system will
pick the correct one.  This simplifies the code a bit, and it helps pave
the way for additional simplifications.

For vec4 outputs, we have to make out_color not be a shader output.
Otherwise the shader will fail to compile due to static writes to both a
user-defined output and gl_FragColor.  This is pretty ugly, and I think
it should be fixed by not writing to gl_FragColor... but that has its
own challenges.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
---
 src/mesa/drivers/common/meta_blit.c | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/src/mesa/drivers/common/meta_blit.c b/src/mesa/drivers/common/meta_blit.c
index 72428f9..355c937 100644
--- a/src/mesa/drivers/common/meta_blit.c
+++ b/src/mesa/drivers/common/meta_blit.c
@@ -550,19 +550,6 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
             }
          }
 
-         /* Scale the final result. */
-         if (src_datatype == GL_UNSIGNED_INT || src_datatype == GL_INT) {
-            ralloc_asprintf_append(&sample_resolve,
-                                   "   for (int i = 0; i < out_color.length(); i++)\n"
-                                   "      out_color[i] = sample_%d_0;\n",
-                                   samples);
-         } else {
-            ralloc_asprintf_append(&sample_resolve,
-                                   "   for (int i = 0; i < out_color.length(); i++)\n"
-                                   "      out_color[i] = sample_%d_0 / %f;\n",
-                                   samples, (float)samples);
-         }
-
          fs_source = ralloc_asprintf(mem_ctx,
                                      "#version 130\n"
                                      "#extension GL_ARB_texture_multisample: require\n"
@@ -575,17 +562,25 @@ setup_glsl_msaa_blit_shader(struct gl_context *ctx,
                                      "ivec4 merge(ivec4 a, ivec4 b) { return (a >> 1) + (b >> 1) + (a & b & 1); }\n"
                                      /* The divide will happen at the end for floats. */
                                      "vec4 merge(vec4 a, vec4 b) { return a + b; }\n"
+                                     "void emit2(gvec4 s) { for (int i = 0; i < out_color.length(); i++) out_color[i] = s; }\n"
+                                     "void emit(ivec4 s) { emit2(gvec4(s)); }\n"
+                                     "void emit(uvec4 s) { emit2(gvec4(s)); }\n"
+                                     /* Scale the final result. */
+                                     "void emit(vec4 s) { emit2(gvec4(s / %f)); }\n"
                                      "\n"
                                      "void main()\n"
                                      "{\n"
                                      "%s\n" /* sample_resolve */
+                                     "    emit(sample_%d_0);\n"
                                      "}\n",
                                      vec4_prefix,
                                      vec4_prefix,
                                      sampler_array_suffix,
                                      texcoord_type,
                                      drawFb->_NumColorDrawBuffers,
-                                     sample_resolve);
+                                     (float) samples,
+                                     sample_resolve,
+                                     samples);
       }
 
       vs_source = ralloc_asprintf(mem_ctx,
-- 
2.5.0