Split distance vector into direction and magnitude components

src/core/SkNormalBevelSource.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkNormalBevelSource.h"
 
 #include "SkNormalSource.h"
@@ skipping 68 matching lines @@
                                                                  "NormalizedWidth",
                                                                  &normalizedWidthUniName);
                 fNormalizedHeightUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                                   kFloat_GrSLType,
                                                                   kDefault_GrSLPrecision,
                                                                   "NormalizedHeight",
                                                                   &normalizedHeightUniName);
             }
 
             // Here we are splitting the distance vector into length and normalized direction
-            // TODO: Output these values from the geometry processor frag code instead of the vector
-            fragBuilder->codeAppendf("float dv_length = length(%s);",
+            fragBuilder->codeAppendf("float dv_length = %s.z;",
                                      fragBuilder->distanceVectorName());
-            fragBuilder->codeAppendf("vec2 dv_norm = normalize(%s);",
+            fragBuilder->codeAppendf("vec2 dv_norm = %s.xy;",
                                      fragBuilder->distanceVectorName());
 
             // Asserting presence of necessary uniforms
             SkASSERT(widthUniName);
 
             fragBuilder->codeAppend( "vec3 normal;");
             fragBuilder->codeAppendf("if (dv_length >= %s) {", widthUniName);
             fragBuilder->codeAppend( "    normal = vec3(0.0, 0.0, 1.0);");
             fragBuilder->codeAppend( "} else {");
             this->emitMath(fragBuilder, fp.fBevelType, widthUniName, heightUniName,
@@ skipping 197 matching lines @@
 sk_sp<SkNormalSource> SkNormalSource::MakeBevel(BevelType type, SkScalar width, SkScalar height) {
     /* TODO make sure this checks are tolerant enough to account for loss of conversion when GPUs
        use 16-bit float types. We don't want to assume stuff is non-zero on the GPU and be wrong.*/
     SkASSERT(width > 0.0f && !SkScalarNearlyZero(width));
     if (SkScalarNearlyZero(height)) {
         return SkNormalSource::MakeFlat();
     }
 
     return sk_make_sp<SkNormalBevelSourceImpl>(type, width, height);
 }