From de445478915af41e1e078cbb8c2cbcce340f83b6 Mon Sep 17 00:00:00 2001
From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Mon, 10 Nov 2008 11:42:42 -0700
Subject: [PATCH] mesa: initial support for uniform variable initializers.

This lets one specify initial values for uniforms in the code, avoiding
the need to call glUniform() in some cases.

(cherry picked from commit 379ff8c9567940ebff44870cf7b0202882445fa6)
---
 src/mesa/shader/slang/slang_codegen.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/src/mesa/shader/slang/slang_codegen.c b/src/mesa/shader/slang/slang_codegen.c
index d83e3b01e6b..a76b6da32b4 100644
--- a/src/mesa/shader/slang/slang_codegen.c
+++ b/src/mesa/shader/slang/slang_codegen.c
@@ -3705,11 +3705,6 @@ _slang_codegen_global_variable(slang_assemble_ctx *A, slang_variable *var,
       const GLint totalSize = array_size(size, var->array_len);
       const GLuint swizzle = _slang_var_swizzle(totalSize, 0);
 
-      if (var->initializer) {
-         slang_info_log_error(A->log, "illegal initializer for uniform '%s'", varName);
-         return GL_FALSE;
-      }
-
       if (prog) {
          /* user-defined uniform */
          if (datatype == GL_NONE) {
@@ -3734,6 +3729,12 @@ _slang_codegen_global_variable(slang_assemble_ctx *A, slang_variable *var,
                 * "f.a"  (GL_FLOAT_VEC3)
                 * "f.b"  (GL_FLOAT_VEC4)
                 */
+
+               if (var->initializer) {
+                  slang_info_log_error(A->log,
+                     "unsupported initializer for uniform '%s'", varName);
+                  return GL_FALSE;
+               }
             }
             else {
                slang_info_log_error(A->log,
@@ -3747,6 +3748,22 @@ _slang_codegen_global_variable(slang_assemble_ctx *A, slang_variable *var,
                                                  totalSize, datatype);
             store = _slang_new_ir_storage_swz(PROGRAM_UNIFORM, uniformLoc,
                                               totalSize, swizzle);
+            if (var->initializer) {
+               _slang_simplify(var->initializer, &A->space, A->atoms);
+               if (var->initializer->type == SLANG_OPER_LITERAL_FLOAT ||
+                   var->initializer->type == SLANG_OPER_LITERAL_INT) {
+                  /* simple float/vector initializer */
+                  GLfloat *uniformValue =
+                     prog->Parameters->ParameterValues[uniformLoc];
+                  COPY_4V(uniformValue, var->initializer->literal);
+               }
+               else {
+                  /* complex initializer */
+                  slang_info_log_error(A->log,
+                     "unsupported initializer for uniform '%s'", varName);
+                  return GL_FALSE;
+               }
+            }
          }
       }
       else {
-- 
2.30.2