1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ANDROID_HWUI_UV_MAPPER_H 18 #define ANDROID_HWUI_UV_MAPPER_H 19 20 #include "Rect.h" 21 22 namespace android { 23 namespace uirenderer { 24 25 /** 26 * This class can be used to map UV coordinates from the [0..1] 27 * range to other arbitrary ranges. All the methods below assume 28 * that the input values lie in the [0..1] range already. 29 */ 30 class UvMapper { 31 public: 32 /** 33 * Using this constructor is equivalent to not using any mapping at all. 34 * UV coordinates in the [0..1] range remain in the [0..1] range. 35 */ UvMapper()36 UvMapper(): mIdentity(true), mMinU(0.0f), mMaxU(1.0f), mMinV(0.0f), mMaxV(1.0f) { 37 } 38 39 /** 40 * Creates a new mapper with the specified ranges for U and V coordinates. 41 * The parameter minU must be < maxU and minV must be < maxV. 42 */ UvMapper(float minU,float maxU,float minV,float maxV)43 UvMapper(float minU, float maxU, float minV, float maxV): 44 mMinU(minU), mMaxU(maxU), mMinV(minV), mMaxV(maxV) { 45 checkIdentity(); 46 } 47 48 /** 49 * Returns true if calling the map*() methods has no effect (that is, 50 * texture coordinates remain in the 0..1 range.) 51 */ isIdentity()52 bool isIdentity() const { 53 return mIdentity; 54 } 55 56 /** 57 * Changes the U and V mapping ranges. 58 * The parameter minU must be < maxU and minV must be < maxV. 59 */ setMapping(float minU,float maxU,float minV,float maxV)60 void setMapping(float minU, float maxU, float minV, float maxV) { 61 mMinU = minU; 62 mMaxU = maxU; 63 mMinV = minV; 64 mMaxV = maxV; 65 checkIdentity(); 66 } 67 68 /** 69 * Maps a single value in the U range. 70 */ mapU(float & u)71 void mapU(float& u) const { 72 if (!mIdentity) u = lerp(mMinU, mMaxU, u); 73 } 74 75 /** 76 * Maps a single value in the V range. 77 */ mapV(float & v)78 void mapV(float& v) const { 79 if (!mIdentity) v = lerp(mMinV, mMaxV, v); 80 } 81 82 /** 83 * Maps the specified rectangle in place. This method assumes: 84 * - left = min. U 85 * - top = min. V 86 * - right = max. U 87 * - bottom = max. V 88 */ map(Rect & texCoords)89 void map(Rect& texCoords) const { 90 if (!mIdentity) { 91 texCoords.left = lerp(mMinU, mMaxU, texCoords.left); 92 texCoords.right = lerp(mMinU, mMaxU, texCoords.right); 93 texCoords.top = lerp(mMinV, mMaxV, texCoords.top); 94 texCoords.bottom = lerp(mMinV, mMaxV, texCoords.bottom); 95 } 96 } 97 98 /** 99 * Maps the specified UV coordinates in place. 100 */ map(float & u1,float & v1,float & u2,float & v2)101 void map(float& u1, float& v1, float& u2, float& v2) const { 102 if (!mIdentity) { 103 u1 = lerp(mMinU, mMaxU, u1); 104 u2 = lerp(mMinU, mMaxU, u2); 105 v1 = lerp(mMinV, mMaxV, v1); 106 v2 = lerp(mMinV, mMaxV, v2); 107 } 108 } 109 dump()110 void dump() const { 111 ALOGD("mapper[minU=%.2f maxU=%.2f minV=%.2f maxV=%.2f]", mMinU, mMaxU, mMinV, mMaxV); 112 } 113 114 private: lerp(float start,float stop,float amount)115 static float lerp(float start, float stop, float amount) { 116 return start + (stop - start) * amount; 117 } 118 checkIdentity()119 void checkIdentity() { 120 mIdentity = mMinU == 0.0f && mMaxU == 1.0f && mMinV == 0.0f && mMaxV == 1.0f; 121 } 122 123 bool mIdentity; 124 float mMinU; 125 float mMaxU; 126 float mMinV; 127 float mMaxV; 128 }; 129 130 }; // namespace uirenderer 131 }; // namespace android 132 133 #endif // ANDROID_HWUI_UV_MAPPER_H 134