cocos-creator-template/assets/effects/internal/builtin-graphics.effect

// Effect Syntax Guide: https://github.com/cocos-creator/docs-3d/blob/master/zh/material-system/effect-syntax.md

CCEffect %{
  techniques:
  - passes:
    - vert: vs:vert
      frag: fs:frag
      blendState:
        targets:
        - blend: true
          blendSrc: one
          blendDst: one_minus_src_alpha
          blendSrcAlpha: one
          blendDstAlpha: one_minus_src_alpha
      rasterizerState:
        cullMode: none
      depthStencilState:
        depthTest: false
        depthWrite: false
}%

CCProgram vs %{
  precision highp float;

  #include <builtin/uniforms/cc-global>
  #include <builtin/uniforms/cc-local>

  in vec3 a_position;

  in vec4 a_color;
  out vec4 v_color;

  in float a_dist;
  out float v_dist;

  vec4 vert () {
    vec4 pos = vec4(a_position, 1);
    pos = cc_matViewProj * cc_matWorld * pos;

    v_color = a_color;
    v_dist = a_dist;

    return pos;
  }
}%

CCProgram fs %{
  #pragma extension([GL_OES_standard_derivatives, __VERSION__ < 300])

  precision highp float;

  in vec4 v_color;
  in float v_dist;

  vec4 frag () {
    vec4 o = v_color;

    #if __VERSION__ < 300
      #ifdef GL_OES_standard_derivatives
        float aa = fwidth(v_dist);
      #else
        float aa = 0.05;
      #endif
    #else
      float aa = fwidth(v_dist);
    #endif

    float alpha = 1. - smoothstep(-aa, 0., abs(v_dist) - 1.0);
    o.rgb *= o.a;
    o *= alpha;

    return o;
  }
}%