// Copyright (c) 2017-2020 Xiamen Yaji Software Co., Ltd.
CCEffect %{
  editor:
    hide: true
  techniques:
  - passes:
    - vert: grid-vs:vert
      frag: grid-fs:frag
      priority: min + 11
      depthStencilState:
        depthTest: true
        depthWrite: false
      blendState:
        targets:
        - blend: true
          blendSrc: src_alpha
          blendDst: one_minus_src_alpha
          blendDstAlpha: one_minus_src_alpha
}%

CCProgram grid-vs %{
  precision mediump float;
  #include <builtin/uniforms/cc-local>
  #include <builtin/uniforms/cc-global>

  in vec2 a_position;
  in vec4 a_color;
  out vec4 color;
  out vec3 pos_w;

  vec4 vert () {
    vec4 position = vec4(a_position, 0, 1);
    vec4 pos = cc_matWorld * position;
    pos_w = pos.xyz;
    color = a_color;

    pos = cc_matProj * (cc_matView * cc_matWorld) * position;
    return pos;
  }
}%

CCProgram grid-fs %{
  precision mediump float;
  #include <builtin/uniforms/cc-global>
  #include <legacy/output>

  in vec4 color;
  in vec3 pos_w;

  vec4 frag () {
    vec4 o = color;

    // fade out at grazing angles
    float scale = abs(normalize(cc_cameraPos.xyz - pos_w).y);
    if (scale < 0.5) o.a *= max(0.3, scale * 2.0);

    return CCFragOutput(o);
  }
}%