Add #define directives to GrGLSLShaderBuilder

src/gpu/glsl/GrGLSLShaderBuilder.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLSLShaderBuilder_DEFINED
 #define GrGLSLShaderBuilder_DEFINED
 
@@ skipping 42 matching lines @@
     /** Does the work of appendTextureLookup and modulates the result by modulation. The result is
         always a vec4. modulation and the swizzle specified by GrGLSLTextureSampler must both be
         vec4 or float. If modulation is "" or nullptr it this function acts as though
         appendTextureLookup were called. */
     void appendTextureLookupAndModulate(const char* modulation,
                                         const GrGLSLTextureSampler&,
                                         const char* coordName,
                                         GrSLType coordType = kVec2f_GrSLType);
 
     /**
+    * Adds a #define directive to the top of the shader.
+    */
+    void define(const char* macro, const char* replacement) {
+        this->definitions().appendf("#define %s %s\n", macro, replacement);
+    }
+
+    void define(const char* macro, int replacement) {
+        this->definitions().appendf("#define %s %i\n", macro, replacement);
+    }
+
+    void definef(const char* macro, const char* replacement, ...) {
+       this->definitions().appendf("#define %s ", macro);
+       va_list args;
+       va_start(args, replacement);
+       this->definitions().appendVAList(replacement, args);
+       va_end(args);
+       this->definitions().append("\n");
+    }
+
+    /**
     * Called by GrGLSLProcessors to add code to one of the shaders.
     */
     void codeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
        va_list args;
        va_start(args, format);
        this->code().appendVAList(format, args);
        va_end(args);
     }
 
     void codeAppend(const char* str) { this->code().append(str); }
@@ skipping 72 matching lines @@
 
     void nextStage() {
         fShaderStrings.push_back();
         fCompilerStrings.push_back(this->code().c_str());
         fCompilerStringLengths.push_back((int)this->code().size());
         fCodeIndex++;
     }
 
     SkString& versionDecl() { return fShaderStrings[kVersionDecl]; }
     SkString& extensions() { return fShaderStrings[kExtensions]; }
+    SkString& definitions() { return fShaderStrings[kDefinitions]; }
     SkString& precisionQualifier() { return fShaderStrings[kPrecisionQualifier]; }
     SkString& layoutQualifiers() { return fShaderStrings[kLayoutQualifiers]; }
     SkString& uniforms() { return fShaderStrings[kUniforms]; }
     SkString& inputs() { return fShaderStrings[kInputs]; }
     SkString& outputs() { return fShaderStrings[kOutputs]; }
     SkString& functions() { return fShaderStrings[kFunctions]; }
     SkString& main() { return fShaderStrings[kMain]; }
     SkString& code() { return fShaderStrings[fCodeIndex]; }
 
     virtual void onFinalize() = 0;
 
     enum {
         kVersionDecl,
         kExtensions,
+        kDefinitions,
         kPrecisionQualifier,
         kLayoutQualifiers,
         kUniforms,
         kInputs,
         kOutputs,
         kFunctions,
         kMain,
         kCode,
     };
 
@@ skipping 11 matching lines @@
     SkSTArray<1, SkString> fLayoutParams[kLastInterfaceQualifier + 1];
     int fCodeIndex;
     bool fFinalized;
 
     friend class GrGLSLProgramBuilder;
     friend class GrGLProgramBuilder;
     friend class GrGLPathProgramBuilder; // to access fInputs.
     friend class GrVkProgramBuilder;
 };
 #endif