1// 2// Copyright (c) 2002-2010 The ANGLE Project Authors. All rights reserved. 3// Use of this source code is governed by a BSD-style license that can be 4// found in the LICENSE file. 5// 6 7// vertexconversion.h: A library of vertex conversion classes that can be used to build 8// the FormatConverter objects used by the buffer conversion system. 9 10#ifndef LIBGLESV2_VERTEXCONVERSION_H_ 11#define LIBGLESV2_VERTEXCONVERSION_H_ 12 13#include <limits> 14#include <cstdint> 15#include <cstddef> 16 17namespace rx 18{ 19 20// Conversion types: 21// static const bool identity: true if this is an identity transform, false otherwise 22// static U convert(T): convert a single element from the input type to the output type 23// typedef ... OutputType: the type produced by this conversion 24 25template <class T> 26struct Identity 27{ 28 static const bool identity = true; 29 30 typedef T OutputType; 31 32 static T convert(T x) 33 { 34 return x; 35 } 36}; 37 38template <class FromT, class ToT> 39struct Cast 40{ 41 static const bool identity = false; 42 43 typedef ToT OutputType; 44 45 static ToT convert(FromT x) 46 { 47 return static_cast<ToT>(x); 48 } 49}; 50 51template <class T> 52struct Cast<T, T> 53{ 54 static const bool identity = true; 55 56 typedef T OutputType; 57 58 static T convert(T x) 59 { 60 return static_cast<T>(x); 61 } 62}; 63 64template <class T> 65struct Normalize 66{ 67 static const bool identity = false; 68 69 typedef float OutputType; 70 71 static float convert(T x) 72 { 73 typedef std::numeric_limits<T> NL; 74 float f = static_cast<float>(x); 75 76 if (NL::is_signed) 77 { 78 // const float => VC2008 computes it at compile time 79 // static const float => VC2008 computes it the first time we get here, stores it to memory with static guard and all that. 80 const float divisor = 1.0f/(2*static_cast<float>(NL::max())+1); 81 return (2*f+1)*divisor; 82 } 83 else 84 { 85 return f/NL::max(); 86 } 87 } 88}; 89 90template <class FromType, std::size_t ScaleBits> 91struct FixedToFloat 92{ 93 static const bool identity = false; 94 95 typedef float OutputType; 96 97 static float convert(FromType x) 98 { 99 const float divisor = 1.0f / static_cast<float>(static_cast<FromType>(1) << ScaleBits); 100 return static_cast<float>(x) * divisor; 101 } 102}; 103 104// Widen types: 105// static const unsigned int initialWidth: number of components before conversion 106// static const unsigned int finalWidth: number of components after conversion 107 108// Float is supported at any size. 109template <std::size_t N> 110struct NoWiden 111{ 112 static const std::size_t initialWidth = N; 113 static const std::size_t finalWidth = N; 114}; 115 116// SHORT, norm-SHORT, norm-UNSIGNED_SHORT are supported but only with 2 or 4 components 117template <std::size_t N> 118struct WidenToEven 119{ 120 static const std::size_t initialWidth = N; 121 static const std::size_t finalWidth = N+(N&1); 122}; 123 124template <std::size_t N> 125struct WidenToFour 126{ 127 static const std::size_t initialWidth = N; 128 static const std::size_t finalWidth = 4; 129}; 130 131// Most types have 0 and 1 that are just that. 132template <class T> 133struct SimpleDefaultValues 134{ 135 static T zero() { return static_cast<T>(0); } 136 static T one() { return static_cast<T>(1); } 137}; 138 139// But normalised types only store [0,1] or [-1,1] so 1.0 is represented by the max value. 140template <class T> 141struct NormalizedDefaultValues 142{ 143 static T zero() { return static_cast<T>(0); } 144 static T one() { return std::numeric_limits<T>::max(); } 145}; 146 147// Converter: 148// static const bool identity: true if this is an identity transform (with no widening) 149// static const std::size_t finalSize: number of bytes per output vertex 150// static void convertArray(const void *in, std::size_t stride, std::size_t n, void *out): convert an array of vertices. Input may be strided, but output will be unstrided. 151 152template <class InT, class WidenRule, class Converter, class DefaultValueRule = SimpleDefaultValues<InT> > 153struct VertexDataConverter 154{ 155 typedef typename Converter::OutputType OutputType; 156 typedef InT InputType; 157 158 static const bool identity = (WidenRule::initialWidth == WidenRule::finalWidth) && Converter::identity; 159 static const std::size_t finalSize = WidenRule::finalWidth * sizeof(OutputType); 160 161 static void convertArray(const uint8_t *input, size_t stride, size_t n, uint8_t *output) 162 { 163 OutputType *out = reinterpret_cast<OutputType*>(output); 164 165 for (std::size_t i = 0; i < n; i++) 166 { 167 const InputType *ein = reinterpret_cast<const InputType*>(input + i * stride); 168 169 copyComponent(out, ein, 0, static_cast<OutputType>(DefaultValueRule::zero())); 170 copyComponent(out, ein, 1, static_cast<OutputType>(DefaultValueRule::zero())); 171 copyComponent(out, ein, 2, static_cast<OutputType>(DefaultValueRule::zero())); 172 copyComponent(out, ein, 3, static_cast<OutputType>(DefaultValueRule::one())); 173 174 out += WidenRule::finalWidth; 175 } 176 } 177 178 private: 179 static void copyComponent(OutputType *out, const InputType *in, std::size_t elementindex, OutputType defaultvalue) 180 { 181 if (WidenRule::finalWidth > elementindex) 182 { 183 if (WidenRule::initialWidth > elementindex) 184 { 185 out[elementindex] = Converter::convert(in[elementindex]); 186 } 187 else 188 { 189 out[elementindex] = defaultvalue; 190 } 191 } 192 } 193}; 194 195} 196 197#endif // LIBGLESV2_VERTEXCONVERSION_H_ 198