ProjectArcade

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// Simple fake reflection shader; created to use in PPSSPP.
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// Without excessive samples and complex nested loops
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// (to make it compatible with low-end GPUs and to ensure ps_2_0 compatibility).
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#ifdef GL_ES
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precision mediump float;
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precision mediump int;
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#endif
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uniform sampler2D sampler0;
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varying vec2 v_texcoord0;	
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uniform vec4 u_setting;
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void main()
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{
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  //get the pixel color
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  vec3 color = texture2D(sampler0, v_texcoord0.xy).rgb;
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  float gray = (color.r + color.g + color.b) / 3.0;
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  float saturation = (abs(color.r - gray) + abs(color.g - gray) + abs(color.b - gray)) / 3.0;
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  //persistent random offset to hide that the reflection is wrong
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  float rndx = mod(v_texcoord0.x + gray, 0.03) + mod(v_texcoord0.y + saturation, 0.05);
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  float rndy = mod(v_texcoord0.y + saturation, 0.03) + mod(v_texcoord0.x + gray, 0.05);
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  //show the effect mainly on the bottom part of the screen
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  float step = (max(gray, saturation) + 0.1) * v_texcoord0.y;
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  //the fake reflection is just a watered copy of the frame moved slightly lower
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  vec3 reflection = texture2D(sampler0, v_texcoord0 + vec2(rndx, rndy - min(v_texcoord0.y, 0.25)) * step).rgb;
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  //apply parameters and mix the colors
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  reflection *= 4.0 * (1.0 - gray) * u_setting.x;
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  reflection *= reflection * step * u_setting.y;
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  gl_FragColor = vec4(color + reflection, 1.0);
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}
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