cocos-creator-template/assets/effects/util/splash-screen.effect

// Copyright (c) 2017-2020 Xiamen Yaji Software Co., Ltd.
CCEffect %{
  techniques:
  - name: default
    passes:
    - vert: splash-screen-vs:vert
      frag: splash-screen-fs:frag
      properties:
        mainTexture:    { value: grey }
        resolution:     { value: [640, 960], target: u_buffer0.xy }
        percent:        { value: 0.5, target: u_percent }
        scale:          { value: [200, 500], target: u_buffer1.xy }
        translate:       { value: [320, 480], target: u_buffer1.zw }
      depthStencilState:
        depthTest: false
        depthWrite: false
      blendState:
        targets:
        - blend: true
          blendSrc: src_alpha
          blendDst: one_minus_src_alpha
          blendDstAlpha: one_minus_src_alpha
      rasterizerState:
        cullMode: none
}%

CCProgram splash-screen-vs %{
  precision mediump float;

  #pragma define u_resolution      u_buffer0.xy
  #pragma define u_worldScale      u_buffer1.xy
  #pragma define u_worldTranslate  u_buffer1.zw

  in vec2 a_position;
  in vec2 a_texCoord;
  out vec2 v_uv;
  uniform Constant {
    vec4 u_buffer0;
    vec4 u_buffer1;
    mat4 u_projection;
  };

  vec4 vert () {
    vec2 worldPos = a_position * u_worldScale + u_worldTranslate;
    vec2 clipSpace = worldPos / u_resolution * 2.0 - 1.0;
    vec4 screenPos = u_projection * vec4(clipSpace, 0.0, 1.0);
    v_uv = a_texCoord;
    return screenPos;
  }
}%

CCProgram splash-screen-fs %{
  precision mediump float;

  in vec2 v_uv;
  uniform Factor {
    float u_percent;
  };
  uniform sampler2D mainTexture;

  vec4 frag () {
    vec4 color = texture(mainTexture, v_uv);
    float percent = clamp(u_percent, 0.0, 1.0);
    color.xyz *= percent;
    return color;
  }
}%