cocos-creator-template/assets/chunks/common/texture/texture-lod.chunk

// Copyright (c) 2017-2020 Xiamen Yaji Software Co., Ltd.

#pragma extension([GL_EXT_shader_texture_lod, __VERSION__ < 130])

vec4 fragTextureLod (sampler2D tex, vec2 coord, float lod) {
  #if __VERSION__ < 130
    #ifdef GL_EXT_shader_texture_lod
      return texture2DLodEXT(tex, coord, lod);
    #else
      return texture2D(tex, coord, lod); // fallback to bias
    #endif
  #else
    return textureLod(tex, coord, lod);
  #endif
}

vec4 fragTextureLod (samplerCube tex, vec3 coord, float lod) {
  #if __VERSION__ < 130
    #ifdef GL_EXT_shader_texture_lod
      return textureCubeLodEXT(tex, coord, lod);
    #else
      return textureCube(tex, coord, lod); // fallback to bias
    #endif
  #else
      return textureLod(tex, coord, lod);
  #endif
}

vec4 fragTextureGrad (sampler2D tex, vec2 P, vec2 dPdx, vec2 dPdy) {
  #if __VERSION__ < 130
    #ifdef GL_EXT_shader_texture_lod
      return texture2DGradEXT(tex, P, dPdx, dPdy);
    #else
      return texture2D(tex, P);
    #endif
  #else
    #if defined(CC_USE_WGPU)
      return textureLod(tex, P, 0.0);
    #else
      return textureGrad(tex, P, dPdx, dPdy);
    #endif
  #endif
}

vec4 fragTextureGrad (samplerCube tex, vec3 P, vec3 dPdx, vec3 dPdy) {
  #if __VERSION__ < 130
    #ifdef GL_EXT_shader_texture_lod
      return textureCubeGradEXT(tex, P, dPdx, dPdy);
    #else
      return textureCube(tex, P);
    #endif
  #else
    #if defined(CC_USE_WGPU)
      return textureLod(tex, P, 0.0);
    #else
      return textureGrad(tex, P, dPdx, dPdy);
    #endif
  #endif
}