framework2

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/*
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 *  KaleidoscopePass.cpp
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 *
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 *  Copyright (c) 2012, Neil Mendoza, http://www.neilmendoza.com
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 *  All rights reserved. 
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 *  
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 *  Redistribution and use in source and binary forms, with or without 
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 *  modification, are permitted provided that the following conditions are met: 
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 *  
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 *  * Redistributions of source code must retain the above copyright notice, 
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 *    this list of conditions and the following disclaimer. 
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 *  * Redistributions in binary form must reproduce the above copyright 
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 *    notice, this list of conditions and the following disclaimer in the 
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 *    documentation and/or other materials provided with the distribution. 
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 *  * Neither the name of Neil Mendoza nor the names of its contributors may be used 
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 *    to endorse or promote products derived from this software without 
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 *    specific prior written permission. 
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 *  
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 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
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 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
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 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
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 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
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 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
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 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
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 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
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 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
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 *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
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 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
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 *  POSSIBILITY OF SUCH DAMAGE. 
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 *
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 */
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#include "KaleidoscopePass.h"
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namespace itg
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{
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    KaleidoscopePass::KaleidoscopePass(const ofVec2f& aspect, bool arb, float segments) :
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        segments(segments), RenderPass(aspect, arb, "kaleido")
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    {
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        string fragShaderSrc = STRINGIFY(
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            uniform sampler2D tex;
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            uniform float segments;
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            void main()
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            {
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                vec2 uv = gl_TexCoord[0].st;
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                vec2 normed = 2.0 * uv - 1.0;
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                float r = length(normed);
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                float theta = atan(normed.y / abs(normed.x));
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                theta *= segments;
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                vec2 newUv = (vec2(r * cos(theta), r * sin(theta)) + 1.0) / 2.0;
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                gl_FragColor = texture2D(tex, newUv);
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            }
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        );
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        shader.setupShaderFromSource(GL_FRAGMENT_SHADER, fragShaderSrc);
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        shader.linkProgram();
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#ifdef _ITG_TWEAKABLE
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        addParameter("segs", this->segments, "min=-20 max=20");
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#endif
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    }
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    void KaleidoscopePass::render(ofFbo& readFbo, ofFbo& writeFbo, ofTexture& depth)
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    {
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        writeFbo.begin();
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        shader.begin();
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        shader.setUniformTexture("tex", readFbo.getTexture(), 0);
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        shader.setUniform1f("segments", segments);
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        texturedQuad(0, 0, writeFbo.getWidth(), writeFbo.getHeight());
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        shader.end();
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        writeFbo.end();
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    }
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}
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