Force input coverage to be only a byte in gpu shaders.

include/gpu/GrTypesPriv.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrTypesPriv_DEFINED
 #define GrTypesPriv_DEFINED
 
@@ skipping 52 matching lines @@
 //////////////////////////////////////////////////////////////////////////////
 
 /**
  * Types used to describe format of vertices in arrays.
   */
 enum GrVertexAttribType {
     kFloat_GrVertexAttribType = 0,
     kVec2f_GrVertexAttribType,
     kVec3f_GrVertexAttribType,
     kVec4f_GrVertexAttribType,
+
+    kUByte_GrVertexAttribType,   // unsigned byte, e.g. coverage
     kVec4ub_GrVertexAttribType,   // vector of 4 unsigned bytes, e.g. colors
 
     kLast_GrVertexAttribType = kVec4ub_GrVertexAttribType
 };
 static const int kGrVertexAttribTypeCount = kLast_GrVertexAttribType + 1;
 
 /**
  * Returns the vector size of the type.
  */
 static inline int GrVertexAttribTypeVectorCount(GrVertexAttribType type) {
     SkASSERT(type >= 0 && type < kGrVertexAttribTypeCount);
-    static const int kCounts[] = { 1, 2, 3, 4, 4 };
+    static const int kCounts[] = { 1, 2, 3, 4, 1, 4 };
     return kCounts[type];
 
     GR_STATIC_ASSERT(0 == kFloat_GrVertexAttribType);
     GR_STATIC_ASSERT(1 == kVec2f_GrVertexAttribType);
     GR_STATIC_ASSERT(2 == kVec3f_GrVertexAttribType);
     GR_STATIC_ASSERT(3 == kVec4f_GrVertexAttribType);
-    GR_STATIC_ASSERT(4 == kVec4ub_GrVertexAttribType);
+    GR_STATIC_ASSERT(4 == kUByte_GrVertexAttribType);
+    GR_STATIC_ASSERT(5 == kVec4ub_GrVertexAttribType);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kCounts) == kGrVertexAttribTypeCount);
 }
 
 /**
  * Returns the size of the attrib type in bytes.
  */
 static inline size_t GrVertexAttribTypeSize(GrVertexAttribType type) {
     SkASSERT(type >= 0 && type < kGrVertexAttribTypeCount);
     static const size_t kSizes[] = {
         sizeof(float),          // kFloat_GrVertexAttribType
         2*sizeof(float),        // kVec2f_GrVertexAttribType
         3*sizeof(float),        // kVec3f_GrVertexAttribType
         4*sizeof(float),        // kVec4f_GrVertexAttribType
+        1*sizeof(char),         // kUByte_GrVertexAttribType
         4*sizeof(char)          // kVec4ub_GrVertexAttribType
     };
     return kSizes[type];
 
     GR_STATIC_ASSERT(0 == kFloat_GrVertexAttribType);
     GR_STATIC_ASSERT(1 == kVec2f_GrVertexAttribType);
     GR_STATIC_ASSERT(2 == kVec3f_GrVertexAttribType);
     GR_STATIC_ASSERT(3 == kVec4f_GrVertexAttribType);
-    GR_STATIC_ASSERT(4 == kVec4ub_GrVertexAttribType);
+    GR_STATIC_ASSERT(4 == kUByte_GrVertexAttribType);
+    GR_STATIC_ASSERT(5 == kVec4ub_GrVertexAttribType);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kSizes) == kGrVertexAttribTypeCount);
 }
 
 /**
  * Semantic bindings for vertex attributes. kEffect means that the attribute is input to a
  * GrProcessor. Each binding other than kEffect may not appear more than once in the current set of
  * attributes. kPosition must be appear for exactly one attribute.
  */
 enum GrVertexAttribBinding {
     kPosition_GrVertexAttribBinding,    // required, must have vector count of 2
     kLocalCoord_GrVertexAttribBinding,  // must have vector count of 2
     kColor_GrVertexAttribBinding,       // must have vector count of 4
-    kCoverage_GrVertexAttribBinding,    // must have vector count of 4
+    kCoverage_GrVertexAttribBinding,    // must have a single byte
 
     kLastFixedFunction_GrVertexAttribBinding = kCoverage_GrVertexAttribBinding,
 
     kGeometryProcessor_GrVertexAttribBinding,      // vector length must agree with
                                         // GrProcessor::vertexAttribType() for each effect input to
                                         // which the attribute is mapped by GrDrawState::setEffect()
     kLast_GrVertexAttribBinding = kGeometryProcessor_GrVertexAttribBinding
 };
 
 static const int kGrVertexAttribBindingCnt = kLast_GrVertexAttribBinding + 1;
 static const int kGrFixedFunctionVertexAttribBindingCnt =
     kLastFixedFunction_GrVertexAttribBinding + 1;
 
 static inline int GrFixedFunctionVertexAttribVectorCount(GrVertexAttribBinding binding) {
     SkASSERT(binding >= 0 && binding < kGrFixedFunctionVertexAttribBindingCnt);
-    static const int kVecCounts[] = { 2, 2, 4, 4 };
+    static const int kVecCounts[] = { 2, 2, 4, 1 };
 
     return kVecCounts[binding];
 
     GR_STATIC_ASSERT(0 == kPosition_GrVertexAttribBinding);
     GR_STATIC_ASSERT(1 == kLocalCoord_GrVertexAttribBinding);
     GR_STATIC_ASSERT(2 == kColor_GrVertexAttribBinding);
     GR_STATIC_ASSERT(3 == kCoverage_GrVertexAttribBinding);
     GR_STATIC_ASSERT(kGrFixedFunctionVertexAttribBindingCnt == SK_ARRAY_COUNT(kVecCounts));
 }
 
@@ skipping 67 matching lines @@
 /**
  * Indicates the type of pending IO operations that can be recorded for gpu resources.
  */
 enum GrIOType {
     kRead_GrIOType,
     kWrite_GrIOType,
     kRW_GrIOType
 };
 
 #endif