45 lines
1.4 KiB
GLSL
45 lines
1.4 KiB
GLSL
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// Based on Jon Kennedy's heat haze shader
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// Copyright (c) 2002-2006 3Dlabs Inc. Ltd.
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uniform float osgOcean_Frequency;
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uniform float osgOcean_Offset;
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uniform float osgOcean_Speed;
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uniform vec2 osgOcean_ScreenRes;
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uniform sampler2DRect osgOcean_FrameBuffer;
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varying vec4 vEyePos;
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void main (void)
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{
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vec2 index;
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// perform the div by w to put the texture into screen space
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float recipW = 1.0 / vEyePos.w;
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vec2 eye = vEyePos.xy * vec2(recipW);
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float blend = max(1.0 - eye.y, 0.0);
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// calc the wobble
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// index.s = eye.x ;
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index.s = eye.x + blend * sin( osgOcean_Frequency * 5.0 * eye.x + osgOcean_Offset * osgOcean_Speed ) * 0.004;
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index.t = eye.y + blend * sin( osgOcean_Frequency * 5.0 * eye.y + osgOcean_Offset * osgOcean_Speed ) * 0.004;
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// scale and shift so we're in the range 0-1
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index.s = index.s * 0.5 + 0.5;
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index.t = index.t * 0.5 + 0.5;
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vec2 recipRes = vec2(1.0/osgOcean_ScreenRes.x, 1.0/osgOcean_ScreenRes.y);
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index.s = clamp(index.s, 0.0, 1.0 - recipRes.x);
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index.t = clamp(index.t, 0.0, 1.0 - recipRes.y);
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// scale the texture so we just see the rendered framebuffer
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index.s = index.s * osgOcean_ScreenRes.x;
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index.t = index.t * osgOcean_ScreenRes.y;
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vec3 RefractionColor = vec3( texture2DRect( osgOcean_FrameBuffer, index ) );
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gl_FragColor = vec4( RefractionColor, 1.0 );
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//gl_FragColor = texture2DRect( osgOcean_FrameBuffer, gl_TexCoord[0].st );
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}
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