CCEffect %{
  techniques:
  - passes:
    - vert: sky-vs:vert
      frag: sky-fs:frag
      properties: &props
        environmentMap:     { value: grey }
      priority: max - 10
      rasterizerState: &r1
        cullMode: none
      depthStencilState: &d1
        depthTest: true
        depthWrite: false
    - vert: sky-vs:vert
      frag: sky-fs:frag
      propertyIndex: 0
      priority: max - 10
      phase: deferred-forward
      rasterizerState: *r1
      depthStencilState: *d1
}%

CCProgram sky-vs %{
  precision highp float;
  #include <builtin/uniforms/cc-global>
  #include <legacy/decode>

  out mediump vec4 viewDir;

  vec4 vert () {
    CCDecode(viewDir);

    mat4 matViewRotOnly = mat4(mat3(cc_matView));
    vec4 pos = matViewRotOnly * viewDir;

    // orthographic projection adaptation
    if (cc_matProj[3].w > 0.0) {
      mat4 matProj = cc_matProj;
      // default ortho height 10 approximate to default FOV 45
      // stretch x by 2 to remedy perspective effect
      // w = sin(45/2), h = 2 * w, _11 = 2 / w, _22 = 2 / h
      matProj[0].x = 5.2;
      matProj[1].y = 2.6;
      matProj[2].zw = vec2(-1.0);
      matProj[3].zw = vec2(0.0);
      // position is modified inside branches to work around a vk driver bug seen in
      // low-end Qualcomm devices (Adreno 512, Oppo R11, cocos-creator/3d-tasks#9236)
      pos = matProj * pos;
    } else {
      pos = cc_matProj * pos;
    }

    pos.z = 0.99999 * pos.w;
    return pos;
  }
}%

CCProgram sky-fs %{
  precision mediump float;
  #include <builtin/uniforms/cc-global>
  #include <builtin/uniforms/cc-environment>
  #include <common/texture/texture-lod>
  #include <common/data/unpack>
  #include <common/color/gamma>
  #include <common/color/tone-mapping>
  #include <legacy/output-standard>
  #include <common/math/coordinates>

  in mediump vec4 viewDir;

  uniform samplerCube environmentMap;
  vec4 frag () {
    vec3 rotationDir = RotationVecFromAxisY(viewDir.xyz, cc_surfaceTransform.z, cc_surfaceTransform.w);
    #if USE_RGBE_CUBEMAP
      vec3 c = unpackRGBE(fragTextureLod(environmentMap, rotationDir.xyz, 0.0));
    #else
      vec3 c = SRGBToLinear(fragTextureLod(environmentMap, rotationDir.xyz, 0.0).rgb);
    #endif

    vec4 color = vec4(c * cc_ambientSky.w, 1.0);
    #if CC_USE_RGBE_OUTPUT
      color = packRGBE(color.rgb);
    #else
      color.rgb = HDRToLDR(color.rgb);
      color.rgb = LinearToSRGB(color.rgb);
    #endif

    //todo: change to CCFragOutput when sky render queue has been fixed with custom pipeline
    //return CCFragOutput(color);
    return color;
  }
}%