1 /* 2 * Copyright 2015 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef GrQuad_DEFINED 9 #define GrQuad_DEFINED 10 11 #include "include/core/SkMatrix.h" 12 #include "include/core/SkPoint.h" 13 #include "include/core/SkPoint3.h" 14 #include "src/base/SkVx.h" 15 #include "src/gpu/BufferWriter.h" 16 17 enum class GrQuadAAFlags; 18 19 /** 20 * GrQuad is a collection of 4 points which can be used to represent an arbitrary quadrilateral. The 21 * points make a triangle strip with CCW triangles (top-left, bottom-left, top-right, bottom-right). 22 */ 23 class GrQuad { 24 public: 25 // Quadrilaterals can be classified in several useful ways that assist AA tessellation and other 26 // analysis when drawing, in particular, knowing if it was originally a rectangle transformed by 27 // certain types of matrices: 28 enum class Type { 29 // The 4 points remain an axis-aligned rectangle; their logical indices may not respect 30 // TL, BL, TR, BR ordering if the transform was a 90 degree rotation or mirror. 31 kAxisAligned, 32 // The 4 points represent a rectangle subjected to a rotation, its corners are right angles. 33 kRectilinear, 34 // Arbitrary 2D quadrilateral; may have been a rectangle transformed with skew or some 35 // clipped polygon. Its w coordinates will all be 1. 36 kGeneral, 37 // Even more general-purpose than kGeneral, this allows the w coordinates to be non-unity. 38 kPerspective, 39 kLast = kPerspective 40 }; 41 static const int kTypeCount = static_cast<int>(Type::kLast) + 1; 42 43 // This enforces W == 1 for non-perspective quads, but does not initialize X or Y. 44 GrQuad() = default; 45 GrQuad(const GrQuad&) = default; 46 GrQuad(const SkRect & rect)47 explicit GrQuad(const SkRect& rect) 48 : fX{rect.fLeft, rect.fLeft, rect.fRight, rect.fRight} 49 , fY{rect.fTop, rect.fBottom, rect.fTop, rect.fBottom} {} 50 51 static GrQuad MakeFromRect(const SkRect&, const SkMatrix&); 52 53 // Creates a GrQuad from the quadrilateral 'pts', transformed by the matrix. The input 54 // points array is arranged as per SkRect::toQuad (top-left, top-right, bottom-right, 55 // bottom-left). The returned instance's point order will still be CCW tri-strip order. 56 static GrQuad MakeFromSkQuad(const SkPoint pts[4], const SkMatrix&); 57 58 GrQuad& operator=(const GrQuad&) = default; 59 point3(int i)60 SkPoint3 point3(int i) const { return {fX[i], fY[i], fW[i]}; } 61 point(int i)62 SkPoint point(int i) const { 63 if (fType == Type::kPerspective) { 64 return {fX[i] / fW[i], fY[i] / fW[i]}; 65 } else { 66 return {fX[i], fY[i]}; 67 } 68 } 69 writeVertex(int cornerIdx,skgpu::VertexWriter & w)70 void writeVertex(int cornerIdx, skgpu::VertexWriter& w) const { 71 w << this->point(cornerIdx); 72 } 73 bounds()74 SkRect bounds() const { 75 if (fType == GrQuad::Type::kPerspective) { 76 return this->projectedBounds(); 77 } 78 // Calculate min/max directly on the 4 floats, instead of loading/unloading into SIMD. Since 79 // there's no horizontal min/max, it's not worth it. Defining non-perspective case in header 80 // also leads to substantial performance boost due to inlining. 81 auto min = [](const float c[4]) { return std::min(std::min(c[0], c[1]), 82 std::min(c[2], c[3]));}; 83 auto max = [](const float c[4]) { return std::max(std::max(c[0], c[1]), 84 std::max(c[2], c[3]));}; 85 return { min(fX), min(fY), max(fX), max(fY) }; 86 } 87 isFinite()88 bool isFinite() const { 89 // If any coordinate is infinity or NaN, then multiplying it with 0 will make accum NaN 90 float accum = 0; 91 for (int i = 0; i < 4; ++i) { 92 accum *= fX[i]; 93 accum *= fY[i]; 94 accum *= fW[i]; 95 } 96 SkASSERT(0 == accum || SkScalarIsNaN(accum)); 97 return !SkScalarIsNaN(accum); 98 } 99 x(int i)100 float x(int i) const { return fX[i]; } y(int i)101 float y(int i) const { return fY[i]; } w(int i)102 float w(int i) const { return fW[i]; } iw(int i)103 float iw(int i) const { return sk_ieee_float_divide(1.f, fW[i]); } 104 x4f()105 skvx::Vec<4, float> x4f() const { return skvx::Vec<4, float>::Load(fX); } y4f()106 skvx::Vec<4, float> y4f() const { return skvx::Vec<4, float>::Load(fY); } w4f()107 skvx::Vec<4, float> w4f() const { return skvx::Vec<4, float>::Load(fW); } iw4f()108 skvx::Vec<4, float> iw4f() const { return 1.f / this->w4f(); } 109 quadType()110 Type quadType() const { return fType; } 111 hasPerspective()112 bool hasPerspective() const { return fType == Type::kPerspective; } 113 114 // True if anti-aliasing affects this quad. Only valid when quadType == kAxisAligned 115 bool aaHasEffectOnRect(GrQuadAAFlags edgeFlags) const; 116 117 // True if this quad is axis-aligned and still has its top-left corner at v0. Equivalently, 118 // quad == GrQuad(quad->bounds()). Axis-aligned quads with flips and rotations may exactly 119 // fill their bounds, but their vertex order will not match TL BL TR BR anymore. 120 bool asRect(SkRect* rect) const; 121 122 // The non-const pointers are provided to support modifying a GrQuad in-place, but care must be 123 // taken to keep its quad type aligned with the geometric nature of the new coordinates. xs()124 const float* xs() const { return fX; } xs()125 float* xs() { return fX; } ys()126 const float* ys() const { return fY; } ys()127 float* ys() { return fY; } ws()128 const float* ws() const { return fW; } ws()129 float* ws() { return fW; } 130 131 // Automatically ensures ws are 1 if new type is not perspective. setQuadType(Type newType)132 void setQuadType(Type newType) { 133 if (newType != Type::kPerspective && fType == Type::kPerspective) { 134 fW[0] = fW[1] = fW[2] = fW[3] = 1.f; 135 } 136 SkASSERT(newType == Type::kPerspective || 137 (SkScalarNearlyEqual(fW[0], 1.f) && SkScalarNearlyEqual(fW[1], 1.f) && 138 SkScalarNearlyEqual(fW[2], 1.f) && SkScalarNearlyEqual(fW[3], 1.f))); 139 140 fType = newType; 141 } 142 private: 143 template<typename T> 144 friend class GrQuadListBase; // for access to fX, fY, fW 145 GrQuad(const skvx::Vec<4,float> & xs,const skvx::Vec<4,float> & ys,Type type)146 GrQuad(const skvx::Vec<4, float>& xs, const skvx::Vec<4, float>& ys, Type type) 147 : fType(type) { 148 SkASSERT(type != Type::kPerspective); 149 xs.store(fX); 150 ys.store(fY); 151 } 152 GrQuad(const skvx::Vec<4,float> & xs,const skvx::Vec<4,float> & ys,const skvx::Vec<4,float> & ws,Type type)153 GrQuad(const skvx::Vec<4, float>& xs, const skvx::Vec<4, float>& ys, 154 const skvx::Vec<4, float>& ws, Type type) 155 : fW{} // Include fW in member initializer to avoid redundant default initializer 156 , fType(type) { 157 xs.store(fX); 158 ys.store(fY); 159 ws.store(fW); 160 } 161 162 // Defined in GrQuadUtils.cpp to share the coord clipping code 163 SkRect projectedBounds() const; 164 165 float fX[4]; 166 float fY[4]; 167 float fW[4] = {1.f, 1.f, 1.f, 1.f}; 168 169 Type fType = Type::kAxisAligned; 170 }; 171 172 template<> struct skgpu::VertexWriter::is_quad<GrQuad> : std::true_type {}; 173 174 // A simple struct representing the common work unit of a pair of device and local coordinates, as 175 // well as the edge flags controlling anti-aliasing for the quadrilateral when drawn. 176 struct DrawQuad { 177 GrQuad fDevice; 178 GrQuad fLocal; 179 GrQuadAAFlags fEdgeFlags; 180 }; 181 182 #endif 183