Expand modulate, add, subtract, extract component glsl helpers.

src/gpu/gl/GrGLSL.cpp

Index: src/gpu/gl/GrGLSL.cpp
===================================================================
--- src/gpu/gl/GrGLSL.cpp	(revision 8735)
+++ src/gpu/gl/GrGLSL.cpp	(working copy)
@@ -87,76 +87,28 @@
     return GrGLSLVectorNonhomogCoords(GrSLTypeToVecLength(type));
 }
 
-GrSLConstantVec GrGLSLModulate4f(SkString* outAppend,
-                                 const char* in0,
-                                 const char* in1,
-                                 GrSLConstantVec default0,
-                                 GrSLConstantVec default1) {
-    GrAssert(NULL != outAppend);
-
-    bool has0 = NULL != in0 && '\0' != *in0;
-    bool has1 = NULL != in1 && '\0' != *in1;
-
-    GrAssert(has0 || kNone_GrSLConstantVec != default0);
-    GrAssert(has1 || kNone_GrSLConstantVec != default1);
-
-    if (!has0 && !has1) {
-        GrAssert(kZeros_GrSLConstantVec == default0 || kOnes_GrSLConstantVec == default0);
-        GrAssert(kZeros_GrSLConstantVec == default1 || kOnes_GrSLConstantVec == default1);
-        if (kZeros_GrSLConstantVec == default0 || kZeros_GrSLConstantVec == default1) {
-            outAppend->append(GrGLSLZerosVecf(4));
-            return kZeros_GrSLConstantVec;
-        } else {
-            // both inputs are ones vectors
-            outAppend->append(GrGLSLOnesVecf(4));
-            return kOnes_GrSLConstantVec;
+namespace {
+    void append_tabs(SkString* outAppend, int tabCnt) {
+        static const char kTabs[] = "\t\t\t\t\t\t\t\t";
+        while (tabCnt) {
+            int cnt = GrMin((int)GR_ARRAY_COUNT(kTabs), tabCnt);
+            outAppend->append(kTabs, cnt);
+            tabCnt -= cnt;
         }
-    } else if (!has0) {
-        GrAssert(kZeros_GrSLConstantVec == default0 || kOnes_GrSLConstantVec == default0);
-        if (kZeros_GrSLConstantVec == default0) {
-            outAppend->append(GrGLSLZerosVecf(4));
-            return kZeros_GrSLConstantVec;
-        } else {
-            outAppend->appendf("vec4(%s)", in1);
-            return kNone_GrSLConstantVec;
-        }
-    } else if (!has1) {
-        GrAssert(kZeros_GrSLConstantVec == default1 || kOnes_GrSLConstantVec == default1);
-        if (kZeros_GrSLConstantVec == default1) {
-            outAppend->append(GrGLSLZerosVecf(4));
-            return kZeros_GrSLConstantVec;
-        } else {
-            outAppend->appendf("vec4(%s)", in0);
-            return kNone_GrSLConstantVec;
-        }
-    } else {
-        outAppend->appendf("vec4(%s * %s)", in0, in1);
-        return kNone_GrSLConstantVec;
     }
 }
 
-namespace {
-void append_tabs(SkString* outAppend, int tabCnt) {
-    static const char kTabs[] = "\t\t\t\t\t\t\t\t";
-    while (tabCnt) {
-        int cnt = GrMin((int)GR_ARRAY_COUNT(kTabs), tabCnt);
-        outAppend->append(kTabs, cnt);
-        tabCnt -= cnt;
-    }
-}
-}
-
 GrSLConstantVec GrGLSLMulVarBy4f(SkString* outAppend,
                                  int tabCnt,
                                  const char* vec4VarName,
                                  const char* mulFactor,
                                  GrSLConstantVec mulFactorDefault) {
     bool haveFactor = NULL != mulFactor && '\0' != *mulFactor;
-
+    
     GrAssert(NULL != outAppend);
     GrAssert(NULL != vec4VarName);
     GrAssert(kNone_GrSLConstantVec != mulFactorDefault || haveFactor);
-
+    
     if (!haveFactor) {
         if (kOnes_GrSLConstantVec == mulFactorDefault) {
             return kNone_GrSLConstantVec;
@@ -172,31 +124,24 @@
     return kNone_GrSLConstantVec;
 }
 
-GrSLConstantVec GrGLSLAdd4f(SkString* outAppend,
-                            const char* in0,
-                            const char* in1,
-                            GrSLConstantVec default0,
-                            GrSLConstantVec default1) {
-    GrAssert(NULL != outAppend);
-
-    bool has0 = NULL != in0 && '\0' != *in0;
-    bool has1 = NULL != in1 && '\0' != *in1;
-
-    if (!has0 && !has1) {
-        GrAssert(kZeros_GrSLConstantVec == default0);
-        GrAssert(kZeros_GrSLConstantVec == default1);
-        outAppend->append(GrGLSLZerosVecf(4));
-        return kZeros_GrSLConstantVec;
-    } else if (!has0) {
-        GrAssert(kZeros_GrSLConstantVec == default0);
-        outAppend->appendf("vec4(%s)", in1);
-        return kNone_GrSLConstantVec;
-    } else if (!has1) {
-        GrAssert(kZeros_GrSLConstantVec == default1);
-        outAppend->appendf("vec4(%s)", in0);
-        return kNone_GrSLConstantVec;
+GrSLConstantVec GrGLSLGetComponent4f(SkString* outAppend,
+                                     const char* expr,
+                                     GrColorComponentFlags component,
+                                     GrSLConstantVec defaultExpr,
+                                     bool omitIfConst) {
+    if (NULL == expr || '\0' == *expr) {
+        GrAssert(defaultExpr != kNone_GrSLConstantVec);
+        if (!omitIfConst) {
+            if (kOnes_GrSLConstantVec == defaultExpr) {
+                outAppend->append("1.0");
+            } else {
+                GrAssert(kZeros_GrSLConstantVec == defaultExpr);
+                outAppend->append("0.0");
+            }
+        }
+        return defaultExpr;
     } else {
-        outAppend->appendf("(vec4(%s) + vec4(%s))", in0, in1);
+        outAppend->appendf("(%s).%c", expr, GrColorComponentFlagToChar(component));
         return kNone_GrSLConstantVec;
     }
 }