1/* 2 * Copyright (C) 2015 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#include "renderstate/TextureState.h" 17 18#include "Caches.h" 19#include "utils/TraceUtils.h" 20 21#include <GLES3/gl3.h> 22#include <memory> 23#include <SkCanvas.h> 24#include <SkBitmap.h> 25 26namespace android { 27namespace uirenderer { 28 29// Width of mShadowLutTexture, defines how accurate the shadow alpha lookup table is 30static const int SHADOW_LUT_SIZE = 128; 31 32// Must define as many texture units as specified by kTextureUnitsCount 33const GLenum kTextureUnits[] = { 34 GL_TEXTURE0, 35 GL_TEXTURE1, 36 GL_TEXTURE2, 37 GL_TEXTURE3 38}; 39 40TextureState::TextureState() 41 : mTextureUnit(0) { 42 glActiveTexture(kTextureUnits[0]); 43 resetBoundTextures(); 44 45 GLint maxTextureUnits; 46 glGetIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS, &maxTextureUnits); 47 LOG_ALWAYS_FATAL_IF(maxTextureUnits < kTextureUnitsCount, 48 "At least %d texture units are required!", kTextureUnitsCount); 49 glPixelStorei(GL_UNPACK_ALIGNMENT, 1); 50} 51 52TextureState::~TextureState() { 53 if (mShadowLutTexture != nullptr) { 54 mShadowLutTexture->deleteTexture(); 55 } 56} 57 58/** 59 * Maps shadow geometry 'alpha' varying (1 for darkest, 0 for transparent) to 60 * darkness at that spot. Input values of 0->1 should be mapped within the same 61 * range, but can affect the curve for a different visual falloff. 62 * 63 * This is used to populate the shadow LUT texture for quick lookup in the 64 * shadow shader. 65 */ 66static float computeShadowOpacity(float ratio) { 67 // exponential falloff function provided by UX 68 float val = 1 - ratio; 69 return exp(-val * val * 4.0) - 0.018; 70} 71 72void TextureState::constructTexture(Caches& caches) { 73 if (mShadowLutTexture == nullptr) { 74 mShadowLutTexture.reset(new Texture(caches)); 75 76 unsigned char bytes[SHADOW_LUT_SIZE]; 77 for (int i = 0; i < SHADOW_LUT_SIZE; i++) { 78 float inputRatio = i / (SHADOW_LUT_SIZE - 1.0f); 79 bytes[i] = computeShadowOpacity(inputRatio) * 255; 80 } 81 mShadowLutTexture->upload(GL_ALPHA, SHADOW_LUT_SIZE, 1, GL_ALPHA, GL_UNSIGNED_BYTE, &bytes); 82 mShadowLutTexture->setFilter(GL_LINEAR); 83 mShadowLutTexture->setWrap(GL_CLAMP_TO_EDGE); 84 } 85} 86 87void TextureState::activateTexture(GLuint textureUnit) { 88 LOG_ALWAYS_FATAL_IF(textureUnit >= kTextureUnitsCount, 89 "Tried to use texture unit index %d, only %d exist", 90 textureUnit, kTextureUnitsCount); 91 if (mTextureUnit != textureUnit) { 92 glActiveTexture(kTextureUnits[textureUnit]); 93 mTextureUnit = textureUnit; 94 } 95} 96 97void TextureState::resetActiveTexture() { 98 mTextureUnit = -1; 99} 100 101void TextureState::bindTexture(GLuint texture) { 102 if (mBoundTextures[mTextureUnit] != texture) { 103 glBindTexture(GL_TEXTURE_2D, texture); 104 mBoundTextures[mTextureUnit] = texture; 105 } 106} 107 108void TextureState::bindTexture(GLenum target, GLuint texture) { 109 if (target == GL_TEXTURE_2D) { 110 bindTexture(texture); 111 } else { 112 // GLConsumer directly calls glBindTexture() with 113 // target=GL_TEXTURE_EXTERNAL_OES, don't cache this target 114 // since the cached state could be stale 115 glBindTexture(target, texture); 116 } 117} 118 119void TextureState::deleteTexture(GLuint texture) { 120 // When glDeleteTextures() is called on a currently bound texture, 121 // OpenGL ES specifies that the texture is then considered unbound 122 // Consider the following series of calls: 123 // 124 // glGenTextures -> creates texture name 2 125 // glBindTexture(2) 126 // glDeleteTextures(2) -> 2 is now unbound 127 // glGenTextures -> can return 2 again 128 // 129 // If we don't call glBindTexture(2) after the second glGenTextures 130 // call, any texture operation will be performed on the default 131 // texture (name=0) 132 133 unbindTexture(texture); 134 135 glDeleteTextures(1, &texture); 136} 137 138void TextureState::resetBoundTextures() { 139 for (int i = 0; i < kTextureUnitsCount; i++) { 140 mBoundTextures[i] = 0; 141 } 142} 143 144void TextureState::unbindTexture(GLuint texture) { 145 for (int i = 0; i < kTextureUnitsCount; i++) { 146 if (mBoundTextures[i] == texture) { 147 mBoundTextures[i] = 0; 148 } 149 } 150} 151 152} /* namespace uirenderer */ 153} /* namespace android */ 154 155