text: /*
   * Copyright 2013 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #define ATRACE_TAG ATRACE_TAG_GRAPHICS
  
  #include "ProgramCache.h"
  
  #include <GLES2/gl2.h>
  #include <GLES2/gl2ext.h>
  #include <log/log.h>
  #include <renderengine/private/Description.h>
  #include <utils/String8.h>
  #include <utils/Trace.h>
  #include "Program.h"
  
  ANDROID_SINGLETON_STATIC_INSTANCE(android::renderengine::gl::ProgramCache)
  
  namespace android {
  namespace renderengine {
  namespace gl {
  
  /*
   * A simple formatter class to automatically add the endl and
   * manage the indentation.
   */
  
  class Formatter;
  static Formatter& indent(Formatter& f);
  static Formatter& dedent(Formatter& f);
  
  class Formatter {
      String8 mString;
      int mIndent;
      typedef Formatter& (*FormaterManipFunc)(Formatter&);
      friend Formatter& indent(Formatter& f);
      friend Formatter& dedent(Formatter& f);
  
  public:
      Formatter() : mIndent(0) {}
  
      String8 getString() const { return mString; }
  
      friend Formatter& operator<<(Formatter& out, const char* in) {
          for (int i = 0; i < out.mIndent; i++) {
              out.mString.append("    ");
          }
          out.mString.append(in);
          out.mString.append("\n");
          return out;
      }
      friend inline Formatter& operator<<(Formatter& out, const String8& in) {
          return operator<<(out, in.string());
      }
      friend inline Formatter& operator<<(Formatter& to, FormaterManipFunc func) {
          return (*func)(to);
      }
  };
  Formatter& indent(Formatter& f) {
      f.mIndent++;
      return f;
  }
  Formatter& dedent(Formatter& f) {
      f.mIndent--;
      return f;
  }
  
  void ProgramCache::primeCache(EGLContext context, bool useColorManagement) {
      auto& cache = mCaches[context];
      uint32_t shaderCount = 0;
      uint32_t keyMask = Key::BLEND_MASK | Key::OPACITY_MASK | Key::ALPHA_MASK | Key::TEXTURE_MASK
          | Key::ROUNDED_CORNERS_MASK;
      // Prime the cache for all combinations of the above masks,
      // leaving off the experimental color matrix mask options.
  
      nsecs_t timeBefore = systemTime();
      for (uint32_t keyVal = 0; keyVal <= keyMask; keyVal++) {
          Key shaderKey;
          shaderKey.set(keyMask, keyVal);
          uint32_t tex = shaderKey.getTextureTarget();
          if (tex != Key::TEXTURE_OFF && tex != Key::TEXTURE_EXT && tex != Key::TEXTURE_2D) {
              continue;
          }
          if (cache.count(shaderKey) == 0) {
              cache.emplace(shaderKey, generateProgram(shaderKey));
              shaderCount++;
          }
      }
  
      // Prime for sRGB->P3 conversion
      if (useColorManagement) {
          Key shaderKey;
          shaderKey.set(Key::BLEND_MASK | Key::OUTPUT_TRANSFORM_MATRIX_MASK | Key::INPUT_TF_MASK |
                                Key::OUTPUT_TF_MASK,
                        Key::BLEND_PREMULT | Key::OUTPUT_TRANSFORM_MATRIX_ON | Key::INPUT_TF_SRGB |
                                Key::OUTPUT_TF_SRGB);
          for (int i = 0; i < 16; i++) {
              shaderKey.set(Key::OPACITY_MASK,
                            (i & 1) ? Key::OPACITY_OPAQUE : Key::OPACITY_TRANSLUCENT);
              shaderKey.set(Key::ALPHA_MASK, (i & 2) ? Key::ALPHA_LT_ONE : Key::ALPHA_EQ_ONE);
  
              // Cache rounded corners
              shaderKey.set(Key::ROUNDED_CORNERS_MASK,
                            (i & 4) ? Key::ROUNDED_CORNERS_ON : Key::ROUNDED_CORNERS_OFF);
  
              // Cache texture off option for window transition
              shaderKey.set(Key::TEXTURE_MASK, (i & 8) ? Key::TEXTURE_EXT : Key::TEXTURE_OFF);
              if (cache.count(shaderKey) == 0) {
                  cache.emplace(shaderKey, generateProgram(shaderKey));
                  shaderCount++;
              }
          }
      }
  
      nsecs_t timeAfter = systemTime();
      float compileTimeMs = static_cast<float>(timeAfter - timeBefore) / 1.0E6;
      ALOGD("shader cache generated - %u shaders in %f ms\n", shaderCount, compileTimeMs);
  }
  
  ProgramCache::Key ProgramCache::computeKey(const Description& description) {
      Key needs;
      needs.set(Key::TEXTURE_MASK,
                !description.textureEnabled
                        ? Key::TEXTURE_OFF
                        : description.texture.getTextureTarget() == GL_TEXTURE_EXTERNAL_OES
                                ? Key::TEXTURE_EXT
                                : description.texture.getTextureTarget() == GL_TEXTURE_2D
                                        ? Key::TEXTURE_2D
                                        : Key::TEXTURE_OFF)
              .set(Key::ALPHA_MASK, (description.color.a < 1) ? Key::ALPHA_LT_ONE : Key::ALPHA_EQ_ONE)
              .set(Key::BLEND_MASK,
                   description.isPremultipliedAlpha ? Key::BLEND_PREMULT : Key::BLEND_NORMAL)
              .set(Key::OPACITY_MASK,
                   description.isOpaque ? Key::OPACITY_OPAQUE : Key::OPACITY_TRANSLUCENT)
              .set(Key::Key::INPUT_TRANSFORM_MATRIX_MASK,
                   description.hasInputTransformMatrix()
                           ? Key::INPUT_TRANSFORM_MATRIX_ON : Key::INPUT_TRANSFORM_MATRIX_OFF)
              .set(Key::Key::OUTPUT_TRANSFORM_MATRIX_MASK,
                   description.hasOutputTransformMatrix() || description.hasColorMatrix()
                           ? Key::OUTPUT_TRANSFORM_MATRIX_ON
                           : Key::OUTPUT_TRANSFORM_MATRIX_OFF)
              .set(Key::ROUNDED_CORNERS_MASK,
                   description.cornerRadius > 0
                           ? Key::ROUNDED_CORNERS_ON : Key::ROUNDED_CORNERS_OFF);
  
      needs.set(Key::Y410_BT2020_MASK,
                description.isY410BT2020 ? Key::Y410_BT2020_ON : Key::Y410_BT2020_OFF);
  
      if (needs.hasTransformMatrix() ||
          (description.inputTransferFunction != description.outputTransferFunction)) {
          switch (description.inputTransferFunction) {
              case Description::TransferFunction::LINEAR:
              default:
                  needs.set(Key::INPUT_TF_MASK, Key::INPUT_TF_LINEAR);
                  break;
              case Description::TransferFunction::SRGB:
                  needs.set(Key::INPUT_TF_MASK, Key::INPUT_TF_SRGB);
                  break;
              case Description::TransferFunction::ST2084:
                  needs.set(Key::INPUT_TF_MASK, Key::INPUT_TF_ST2084);
                  break;
              case Description::TransferFunction::HLG:
                  needs.set(Key::INPUT_TF_MASK, Key::INPUT_TF_HLG);
                  break;
          }
  
          switch (description.outputTransferFunction) {
              case Description::TransferFunction::LINEAR:
              default:
                  needs.set(Key::OUTPUT_TF_MASK, Key::OUTPUT_TF_LINEAR);
                  break;
              case Description::TransferFunction::SRGB:
                  needs.set(Key::OUTPUT_TF_MASK, Key::OUTPUT_TF_SRGB);
                  break;
              case Description::TransferFunction::ST2084:
                  needs.set(Key::OUTPUT_TF_MASK, Key::OUTPUT_TF_ST2084);
                  break;
              case Description::TransferFunction::HLG:
                  needs.set(Key::OUTPUT_TF_MASK, Key::OUTPUT_TF_HLG);
                  break;
          }
      }
  
      return needs;
  }
  
  // Generate EOTF that converts signal values to relative display light,
  // both normalized to [0, 1].
  void ProgramCache::generateEOTF(Formatter& fs, const Key& needs) {
      switch (needs.getInputTF()) {
          case Key::INPUT_TF_SRGB:
              fs << R"__SHADER__(
                  float EOTF_sRGB(float srgb) {
                      return srgb <= 0.04045 ? srgb / 12.92 : pow((srgb + 0.055) / 1.055, 2.4);
                  }
  
                  vec3 EOTF_sRGB(const vec3 srgb) {
                      return vec3(EOTF_sRGB(srgb.r), EOTF_sRGB(srgb.g), EOTF_sRGB(srgb.b));
                  }
  
                  vec3 EOTF(const vec3 srgb) {
                      return sign(srgb.rgb) * EOTF_sRGB(abs(srgb.rgb));
                  }
              )__SHADER__";
              break;
          case Key::INPUT_TF_ST2084:
              fs << R"__SHADER__(
                  vec3 EOTF(const highp vec3 color) {
                      const highp float m1 = (2610.0 / 4096.0) / 4.0;
                      const highp float m2 = (2523.0 / 4096.0) * 128.0;
                      const highp float c1 = (3424.0 / 4096.0);
                      const highp float c2 = (2413.0 / 4096.0) * 32.0;
                      const highp float c3 = (2392.0 / 4096.0) * 32.0;
  
                      highp vec3 tmp = pow(clamp(color, 0.0, 1.0), 1.0 / vec3(m2));
                      tmp = max(tmp - c1, 0.0) / (c2 - c3 * tmp);
                      return pow(tmp, 1.0 / vec3(m1));
                  }
              )__SHADER__";
              break;
          case Key::INPUT_TF_HLG:
              fs << R"__SHADER__(
                  highp float EOTF_channel(const highp float channel) {
                      const highp float a = 0.17883277;
                      const highp float b = 0.28466892;
                      const highp float c = 0.55991073;
                      return channel <= 0.5 ? channel * channel / 3.0 :
                              (exp((channel - c) / a) + b) / 12.0;
                  }
  
                  vec3 EOTF(const highp vec3 color) {
                      return vec3(EOTF_channel(color.r), EOTF_channel(color.g),
                              EOTF_channel(color.b));
                  }
              )__SHADER__";
              break;
          default:
              fs << R"__SHADER__(
                  vec3 EOTF(const vec3 linear) {
                      return linear;
                  }
              )__SHADER__";
              break;
      }
  }
  
  void ProgramCache::generateToneMappingProcess(Formatter& fs, const Key& needs) {
      // Convert relative light to absolute light.
      switch (needs.getInputTF()) {
          case Key::INPUT_TF_ST2084:
              fs << R"__SHADER__(
                  highp vec3 ScaleLuminance(highp vec3 color) {
                      return color * 10000.0;
                  }
              )__SHADER__";
              break;
          case Key::INPUT_TF_HLG:
              fs << R"__SHADER__(
                  highp vec3 ScaleLuminance(highp vec3 color) {
                      // The formula is:
                      // alpha * pow(Y, gamma - 1.0) * color + beta;
                      // where alpha is 1000.0, gamma is 1.2, beta is 0.0.
                      return color * 1000.0 * pow(color.y, 0.2);
                  }
              )__SHADER__";
              break;
          default:
              fs << R"__SHADER__(
                  highp vec3 ScaleLuminance(highp vec3 color) {
                      return color * displayMaxLuminance;
                  }
              )__SHADER__";
              break;
      }
  
      // Tone map absolute light to display luminance range.
      switch (needs.getInputTF()) {
          case Key::INPUT_TF_ST2084:
          case Key::INPUT_TF_HLG:
              switch (needs.getOutputTF()) {
                  case Key::OUTPUT_TF_HLG:
                      // Right now when mixed PQ and HLG contents are presented,
                      // HLG content will always be converted to PQ. However, for
                      // completeness, we simply clamp the value to [0.0, 1000.0].
                      fs << R"__SHADER__(
                          highp vec3 ToneMap(highp vec3 color) {
                              return clamp(color, 0.0, 1000.0);
                          }
                      )__SHADER__";
                      break;
                  case Key::OUTPUT_TF_ST2084:
                      fs << R"__SHADER__(
                          highp vec3 ToneMap(highp vec3 color) {
                              return color;
                          }
                      )__SHADER__";
                      break;
                  default:
                      fs << R"__SHADER__(
                          highp vec3 ToneMap(highp vec3 color) {
                              const float maxMasteringLumi = 1000.0;
                              const float maxContentLumi = 1000.0;
                              const float maxInLumi = min(maxMasteringLumi, maxContentLumi);
                              float maxOutLumi = displayMaxLuminance;
  
                              float nits = color.y;
  
                              // clamp to max input luminance
                              nits = clamp(nits, 0.0, maxInLumi);
  
                              // scale [0.0, maxInLumi] to [0.0, maxOutLumi]
                              if (maxInLumi <= maxOutLumi) {
                                  return color * (maxOutLumi / maxInLumi);
                              } else {
                                  // three control points
                                  const float x0 = 10.0;
                                  const float y0 = 17.0;
                                  float x1 = maxOutLumi * 0.75;
                                  float y1 = x1;
                                  float x2 = x1 + (maxInLumi - x1) / 2.0;
                                  float y2 = y1 + (maxOutLumi - y1) * 0.75;
  
                                  // horizontal distances between the last three control points
                                  float h12 = x2 - x1;
                                  float h23 = maxInLumi - x2;
                                  // tangents at the last three control points
                                  float m1 = (y2 - y1) / h12;
                                  float m3 = (maxOutLumi - y2) / h23;
                                  float m2 = (m1 + m3) / 2.0;
  
                                  if (nits < x0) {
                                      // scale [0.0, x0] to [0.0, y0] linearly
                                      float slope = y0 / x0;
                                      return color * slope;
                                  } else if (nits < x1) {
                                      // scale [x0, x1] to [y0, y1] linearly
                                      float slope = (y1 - y0) / (x1 - x0);
                                      nits = y0 + (nits - x0) * slope;
                                  } else if (nits < x2) {
                                      // scale [x1, x2] to [y1, y2] using Hermite interp
                                      float t = (nits - x1) / h12;
                                      nits = (y1 * (1.0 + 2.0 * t) + h12 * m1 * t) * (1.0 - t) * (1.0 - t) +
                                              (y2 * (3.0 - 2.0 * t) + h12 * m2 * (t - 1.0)) * t * t;
                                  } else {
                                      // scale [x2, maxInLumi] to [y2, maxOutLumi] using Hermite interp
                                      float t = (nits - x2) / h23;
                                      nits = (y2 * (1.0 + 2.0 * t) + h23 * m2 * t) * (1.0 - t) * (1.0 - t) +
                                              (maxOutLumi * (3.0 - 2.0 * t) + h23 * m3 * (t - 1.0)) * t * t;
                                  }
                              }
  
                              // color.y is greater than x0 and is thus non-zero
                              return color * (nits / color.y);
                          }
                      )__SHADER__";
                      break;
              }
              break;
          default:
              // inverse tone map; the output luminance can be up to maxOutLumi.
              fs << R"__SHADER__(
                  highp vec3 ToneMap(highp vec3 color) {
                      const float maxOutLumi = 3000.0;
  
                      const float x0 = 5.0;
                      const float y0 = 2.5;
                      float x1 = displayMaxLuminance * 0.7;
                      float y1 = maxOutLumi * 0.15;
                      float x2 = displayMaxLuminance * 0.9;
                      float y2 = maxOutLumi * 0.45;
                      float x3 = displayMaxLuminance;
                      float y3 = maxOutLumi;
  
                      float c1 = y1 / 3.0;
                      float c2 = y2 / 2.0;
                      float c3 = y3 / 1.5;
  
                      float nits = color.y;
  
                      float scale;
                      if (nits <= x0) {
                          // scale [0.0, x0] to [0.0, y0] linearly
                          const float slope = y0 / x0;
                          return color * slope;
                      } else if (nits <= x1) {
                          // scale [x0, x1] to [y0, y1] using a curve
                          float t = (nits - x0) / (x1 - x0);
                          nits = (1.0 - t) * (1.0 - t) * y0 + 2.0 * (1.0 - t) * t * c1 + t * t * y1;
                      } else if (nits <= x2) {
                          // scale [x1, x2] to [y1, y2] using a curve
                          float t = (nits - x1) / (x2 - x1);
                          nits = (1.0 - t) * (1.0 - t) * y1 + 2.0 * (1.0 - t) * t * c2 + t * t * y2;
                      } else {
                          // scale [x2, x3] to [y2, y3] using a curve
                          float t = (nits - x2) / (x3 - x2);
                          nits = (1.0 - t) * (1.0 - t) * y2 + 2.0 * (1.0 - t) * t * c3 + t * t * y3;
                      }
  
                      // color.y is greater than x0 and is thus non-zero
                      return color * (nits / color.y);
                  }
              )__SHADER__";
              break;
      }
  
      // convert absolute light to relative light.
      switch (needs.getOutputTF()) {
          case Key::OUTPUT_TF_ST2084:
              fs << R"__SHADER__(
                  highp vec3 NormalizeLuminance(highp vec3 color) {
                      return color / 10000.0;
                  }
              )__SHADER__";
              break;
          case Key::OUTPUT_TF_HLG:
              fs << R"__SHADER__(
                  highp vec3 NormalizeLuminance(highp vec3 color) {
                      return color / 1000.0 * pow(color.y / 1000.0, -0.2 / 1.2);
                  }
              )__SHADER__";
              break;
          default:
              fs << R"__SHADER__(
                  highp vec3 NormalizeLuminance(highp vec3 color) {
                      return color / displayMaxLuminance;
                  }
              )__SHADER__";
              break;
      }
  }
  
  // Generate OOTF that modifies the relative scence light to relative display light.
  void ProgramCache::generateOOTF(Formatter& fs, const ProgramCache::Key& needs) {
      if (!needs.needsToneMapping()) {
          fs << R"__SHADER__(
              highp vec3 OOTF(const highp vec3 color) {
                  return color;
              }
          )__SHADER__";
      } else {
          generateToneMappingProcess(fs, needs);
          fs << R"__SHADER__(
              highp vec3 OOTF(const highp vec3 color) {
                  return NormalizeLuminance(ToneMap(ScaleLuminance(color)));
              }
          )__SHADER__";
      }
  }
  
  // Generate OETF that converts relative display light to signal values,
  // both normalized to [0, 1]
  void ProgramCache::generateOETF(Formatter& fs, const Key& needs) {
      switch (needs.getOutputTF()) {
          case Key::OUTPUT_TF_SRGB:
              fs << R"__SHADER__(
                  float OETF_sRGB(const float linear) {
                      return linear <= 0.0031308 ?
                              linear * 12.92 : (pow(linear, 1.0 / 2.4) * 1.055) - 0.055;
                  }
  
                  vec3 OETF_sRGB(const vec3 linear) {
                      return vec3(OETF_sRGB(linear.r), OETF_sRGB(linear.g), OETF_sRGB(linear.b));
                  }
  
                  vec3 OETF(const vec3 linear) {
                      return sign(linear.rgb) * OETF_sRGB(abs(linear.rgb));
                  }
              )__SHADER__";
              break;
          case Key::OUTPUT_TF_ST2084:
              fs << R"__SHADER__(
                  vec3 OETF(const vec3 linear) {
                      const highp float m1 = (2610.0 / 4096.0) / 4.0;
                      const highp float m2 = (2523.0 / 4096.0) * 128.0;
                      const highp float c1 = (3424.0 / 4096.0);
                      const highp float c2 = (2413.0 / 4096.0) * 32.0;
                      const highp float c3 = (2392.0 / 4096.0) * 32.0;
  
                      highp vec3 tmp = pow(linear, vec3(m1));
                      tmp = (c1 + c2 * tmp) / (1.0 + c3 * tmp);
                      return pow(tmp, vec3(m2));
                  }
              )__SHADER__";
              break;
          case Key::OUTPUT_TF_HLG:
              fs << R"__SHADER__(
                  highp float OETF_channel(const highp float channel) {
                      const highp float a = 0.17883277;
                      const highp float b = 0.28466892;
                      const highp float c = 0.55991073;
                      return channel <= 1.0 / 12.0 ? sqrt(3.0 * channel) :
                              a * log(12.0 * channel - b) + c;
                  }
  
                  vec3 OETF(const highp vec3 color) {
                      return vec3(OETF_channel(color.r), OETF_channel(color.g),
                              OETF_channel(color.b));
                  }
              )__SHADER__";
              break;
          default:
              fs << R"__SHADER__(
                  vec3 OETF(const vec3 linear) {
                      return linear;
                  }
              )__SHADER__";
              break;
      }
  }
  
  String8 ProgramCache::generateVertexShader(const Key& needs) {
      Formatter vs;
      if (needs.isTexturing()) {
          vs << "attribute vec4 texCoords;"
             << "varying vec2 outTexCoords;";
      }
      if (needs.hasRoundedCorners()) {
          vs << "attribute lowp vec4 cropCoords;";
          vs << "varying lowp vec2 outCropCoords;";
      }
      vs << "attribute vec4 position;"
         << "uniform mat4 projection;"
         << "uniform mat4 texture;"
         << "void main(void) {" << indent << "gl_Position = projection * position;";
      if (needs.isTexturing()) {
          vs << "outTexCoords = (texture * texCoords).st;";
      }
      if (needs.hasRoundedCorners()) {
          vs << "outCropCoords = cropCoords.st;";
      }
      vs << dedent << "}";
      return vs.getString();
  }
  
  String8 ProgramCache::generateFragmentShader(const Key& needs) {
      Formatter fs;
      if (needs.getTextureTarget() == Key::TEXTURE_EXT) {
          fs << "#extension GL_OES_EGL_image_external : require";
      }
  
      // default precision is required-ish in fragment shaders
      fs << "precision mediump float;";
  
      if (needs.getTextureTarget() == Key::TEXTURE_EXT) {
          fs << "uniform samplerExternalOES sampler;"
             << "varying vec2 outTexCoords;";
      } else if (needs.getTextureTarget() == Key::TEXTURE_2D) {
          fs << "uniform sampler2D sampler;"
             << "varying vec2 outTexCoords;";
      }
  
      if (needs.hasRoundedCorners()) {
          // Rounded corners implementation using a signed distance function.
          fs << R"__SHADER__(
              uniform float cornerRadius;
              uniform vec2 cropCenter;
              varying vec2 outCropCoords;
  
              /**
               * This function takes the current crop coordinates and calculates an alpha value based
               * on the corner radius and distance from the crop center.
               */
              float applyCornerRadius(vec2 cropCoords)
              {
                  vec2 position = cropCoords - cropCenter;
                  // Scale down the dist vector here, as otherwise large corner
                  // radii can cause floating point issues when computing the norm
                  vec2 dist = (abs(position) - cropCenter + vec2(cornerRadius)) / 16.0;
                  // Once we've found the norm, then scale back up.
                  float plane = length(max(dist, vec2(0.0))) * 16.0;
                  return 1.0 - clamp(plane - cornerRadius, 0.0, 1.0);
              }
              )__SHADER__";
      }
  
      if (needs.getTextureTarget() == Key::TEXTURE_OFF || needs.hasAlpha()) {
          fs << "uniform vec4 color;";
      }
  
      if (needs.isY410BT2020()) {
          fs << R"__SHADER__(
              vec3 convertY410BT2020(const vec3 color) {
                  const vec3 offset = vec3(0.0625, 0.5, 0.5);
                  const mat3 transform = mat3(
                      vec3(1.1678,  1.1678, 1.1678),
                      vec3(   0.0, -0.1878, 2.1481),
                      vec3(1.6836, -0.6523,   0.0));
                  // Y is in G, U is in R, and V is in B
                  return clamp(transform * (color.grb - offset), 0.0, 1.0);
              }
              )__SHADER__";
      }
  
      if (needs.hasTransformMatrix() || (needs.getInputTF() != needs.getOutputTF())) {
          // Currently, display maximum luminance is needed when doing tone mapping.
          if (needs.needsToneMapping()) {
              fs << "uniform float displayMaxLuminance;";
          }
  
          if (needs.hasInputTransformMatrix()) {
              fs << "uniform mat4 inputTransformMatrix;";
              fs << R"__SHADER__(
                  highp vec3 InputTransform(const highp vec3 color) {
                      return clamp(vec3(inputTransformMatrix * vec4(color, 1.0)), 0.0, 1.0);
                  }
              )__SHADER__";
          } else {
              fs << R"__SHADER__(
                  highp vec3 InputTransform(const highp vec3 color) {
                      return color;
                  }
              )__SHADER__";
          }
  
          // the transformation from a wider colorspace to a narrower one can
          // result in >1.0 or <0.0 pixel values
          if (needs.hasOutputTransformMatrix()) {
              fs << "uniform mat4 outputTransformMatrix;";
              fs << R"__SHADER__(
                  highp vec3 OutputTransform(const highp vec3 color) {
                      return clamp(vec3(outputTransformMatrix * vec4(color, 1.0)), 0.0, 1.0);
                  }
              )__SHADER__";
          } else {
              fs << R"__SHADER__(
                  highp vec3 OutputTransform(const highp vec3 color) {
                      return clamp(color, 0.0, 1.0);
                  }
              )__SHADER__";
          }
  
          generateEOTF(fs, needs);
          generateOOTF(fs, needs);
          generateOETF(fs, needs);
      }
  
      fs << "void main(void) {" << indent;
      if (needs.isTexturing()) {
          fs << "gl_FragColor = texture2D(sampler, outTexCoords);";
          if (needs.isY410BT2020()) {
              fs << "gl_FragColor.rgb = convertY410BT2020(gl_FragColor.rgb);";
          }
      } else {
          fs << "gl_FragColor.rgb = color.rgb;";
          fs << "gl_FragColor.a = 1.0;";
      }
      if (needs.isOpaque()) {
          fs << "gl_FragColor.a = 1.0;";
      }
      if (needs.hasAlpha()) {
          // modulate the current alpha value with alpha set
          if (needs.isPremultiplied()) {
              // ... and the color too if we're premultiplied
              fs << "gl_FragColor *= color.a;";
          } else {
              fs << "gl_FragColor.a *= color.a;";
          }
      }
  
      if (needs.hasTransformMatrix() || (needs.getInputTF() != needs.getOutputTF())) {
          if (!needs.isOpaque() && needs.isPremultiplied()) {
              // un-premultiply if needed before linearization
              // avoid divide by 0 by adding 0.5/256 to the alpha channel
              fs << "gl_FragColor.rgb = gl_FragColor.rgb / (gl_FragColor.a + 0.0019);";
          }
          fs << "gl_FragColor.rgb = "
                "OETF(OutputTransform(OOTF(InputTransform(EOTF(gl_FragColor.rgb)))));";
          if (!needs.isOpaque() && needs.isPremultiplied()) {
              // and re-premultiply if needed after gamma correction
              fs << "gl_FragColor.rgb = gl_FragColor.rgb * (gl_FragColor.a + 0.0019);";
          }
      }
  
      if (needs.hasRoundedCorners()) {
          if (needs.isPremultiplied()) {
              fs << "gl_FragColor *= vec4(applyCornerRadius(outCropCoords));";
          } else {
              fs << "gl_FragColor.a *= applyCornerRadius(outCropCoords);";
          }
      }
  
      fs << dedent << "}";
      return fs.getString();
  }
  
  std::unique_ptr<Program> ProgramCache::generateProgram(const Key& needs) {
      ATRACE_CALL();
  
      // vertex shader
      String8 vs = generateVertexShader(needs);
  
      // fragment shader
      String8 fs = generateFragmentShader(needs);
  
      return std::make_unique<Program>(needs, vs.string(), fs.string());
  }
  
  void ProgramCache::useProgram(EGLContext context, const Description& description) {
      // generate the key for the shader based on the description
      Key needs(computeKey(description));
  
      // look-up the program in the cache
      auto& cache = mCaches[context];
      auto it = cache.find(needs);
      if (it == cache.end()) {
          // we didn't find our program, so generate one...
          nsecs_t time = systemTime();
          it = cache.emplace(needs, generateProgram(needs)).first;
          time = systemTime() - time;
  
          ALOGV(">>> generated new program for context %p: needs=%08X, time=%u ms (%zu programs)",
                context, needs.mKey, uint32_t(ns2ms(time)), cache.size());
      }
  
      // here we have a suitable program for this description
      std::unique_ptr<Program>& program = it->second;
      if (program->isValid()) {
          program->use();
          program->setUniforms(description);
      }
  }
  
  } // namespace gl
  } // namespace renderengine
  } // namespace android
  