Revise attribute binding interface

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
 
+#include "GrTypes.h"
 #include "SkTArray.h"
 
 /**
- * Types of shader-language-specific boxed variables we can create.
- * (Currently only GrGLShaderVars, but should be applicable to other shader
- * languages.)
+ * Types of shader-language-specific boxed variables we can create. (Currently only GrGLShaderVars,
+ * but should be applicable to other shader languages.)
  */
 enum GrSLType {
     kVoid_GrSLType,
     kFloat_GrSLType,
     kVec2f_GrSLType,
     kVec3f_GrSLType,
     kVec4f_GrSLType,
     kMat33f_GrSLType,
     kMat44f_GrSLType,
-    kSampler2D_GrSLType
+    kSampler2D_GrSLType,
+
+    kLast_GrSLType = kSampler2D_GrSLType
 };
+static const int kGrSLTypeCount = kLast_GrSLType + 1;
 
 /**
- * Types used to describe format of vertices in arrays
+ * Gets the vector size of the SLType. Returns -1 for void, matrices, and samplers.
+ */
+static inline int GrSLTypeVectorCount(GrSLType type) {
+    GrAssert(type >= 0 && type < kGrSLTypeCount);
+    static const int kCounts[] = { -1, 1, 2, 3, 4, -1, -1, -1 };
+    return kCounts[type];
+
+    GR_STATIC_ASSERT(0 == kVoid_GrSLType);
+    GR_STATIC_ASSERT(1 == kFloat_GrSLType);
+    GR_STATIC_ASSERT(2 == kVec2f_GrSLType);
+    GR_STATIC_ASSERT(3 == kVec3f_GrSLType);
+    GR_STATIC_ASSERT(4 == kVec4f_GrSLType);
+    GR_STATIC_ASSERT(5 == kMat33f_GrSLType);
+    GR_STATIC_ASSERT(6 == kMat44f_GrSLType);
+    GR_STATIC_ASSERT(7 == kSampler2D_GrSLType);
+    GR_STATIC_ASSERT(GR_ARRAY_COUNT(kCounts) == kGrSLTypeCount);
+}
+
+static inline GrSLType GrSLFloatVectorType(int count) {
+    GrAssert(count > 0 && count <= 4);
+    return (GrSLType)(count);
+
+    GR_STATIC_ASSERT(kFloat_GrSLType == 1);
+    GR_STATIC_ASSERT(kVec2f_GrSLType == 2);
+    GR_STATIC_ASSERT(kVec3f_GrSLType == 3);
+    GR_STATIC_ASSERT(kVec4f_GrSLType == 4);
+}
+
+/**
+ * Types used to describe format of vertices in arrays.
   */
 enum GrVertexAttribType {
     kFloat_GrVertexAttribType = 0,
     kVec2f_GrVertexAttribType,
     kVec3f_GrVertexAttribType,
     kVec4f_GrVertexAttribType,
     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) {
+    GrAssert(type >= 0 && type < kGrVertexAttribTypeCount);
+    static const int kCounts[] = { 1, 2, 3, 4, 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(GR_ARRAY_COUNT(kCounts) == kGrVertexAttribTypeCount);
+}
+
+/**
+ * Returns the size of the attrib type in bytes.
+ */
+static inline size_t GrVertexAttribTypeSize(GrVertexAttribType type) {
+    GrAssert(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
+        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(GR_ARRAY_COUNT(kSizes) == kGrVertexAttribTypeCount);
+}
+
+/**
+ * Semantic bindings for vertex attributes. kEffect means that the attribute is input to a GrEffect.
+ * 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
+
+    kLastFixedFunction_GrVertexAttribBinding = kCoverage_GrVertexAttribBinding,
+
+    kEffect_GrVertexAttribBinding,      // vector length must agree with
+                                        // GrEffect::vertexAttribType() for each effect input to
+                                        // which the attribute is mapped by GrDrawState::setEffect()
+    kLast_GrVertexAttribBinding = kEffect_GrVertexAttribBinding
+};
+
+static const int kGrVertexAttribBindingCnt = kLast_GrVertexAttribBinding + 1;
+static const int kGrFixedFunctionVertexAttribBindingCnt =
+    kLastFixedFunction_GrVertexAttribBinding + 1;
+
+static const int GrFixedFunctionVertexAttribVectorCount(GrVertexAttribBinding binding) {
+    GrAssert(binding >= 0 && binding < kGrFixedFunctionVertexAttribBindingCnt);
+    static const int kVecCounts[] = { 2, 2, 4, 4 };
+
+    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));
+}
+
 struct GrVertexAttrib {
-    inline void set(GrVertexAttribType type, size_t offset) {
-        fType = type; fOffset = offset;
+    inline void set(GrVertexAttribType type, size_t offset, GrVertexAttribBinding binding) {
+        fType = type;
+        fOffset = offset;
+        fBinding = binding;
     }
     bool operator==(const GrVertexAttrib& other) const {
-        return fType == other.fType && fOffset == other.fOffset;
+        return fType == other.fType && fOffset == other.fOffset && fBinding == other.fBinding;
     };
     bool operator!=(const GrVertexAttrib& other) const { return !(*this == other); }
 
-    GrVertexAttribType fType;
-    size_t             fOffset;
+    GrVertexAttribType      fType;
+    size_t                  fOffset;
+    GrVertexAttribBinding   fBinding;
 };
 
-template <int N>
-class GrVertexAttribArray : public SkSTArray<N, GrVertexAttrib, true> {};
+template <int N> class GrVertexAttribArray : public SkSTArray<N, GrVertexAttrib, true> {};
 
 #endif