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package org.distorted.library;
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import android.opengl.Matrix;
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///////////////////////////////////////////////////////////////////////////////////////////////////
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/**
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* Only used within the Distorted Library itself.
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*/
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class DistortedProjection
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{
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int width,height,depth,distance;
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float[] projectionMatrix;
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private boolean invert; // invert top with bottom? We don't do that for the projection to the screen,
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// but we need that for the projection to FBOs. (that's because each time we
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// render to FBO we invert the texture upside down because its vertex coords
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// are purposefully set upside down in DistortedBackground; so each time we
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// render through FBO we need to invert it once more to counter this effect)
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///////////////////////////////////////////////////////////////////////////////////////////////////
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public DistortedProjection(boolean inv)
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{
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invert = inv;
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projectionMatrix = new float[16];
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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void onSurfaceChanged(int surfaceWidth, int surfaceHeight)
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{
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width = surfaceWidth;
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height= surfaceHeight;
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float ratio = (float) surfaceWidth / surfaceHeight;
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float left =-ratio; //
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float right = ratio; // Create a new perspective projection matrix.
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float bottom = -1.0f; //
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float top = 1.0f; // any change to those values will have serious consequences!
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float near, far;
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if( Distorted.mFOV>0.0f ) // perspective projection
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{
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near= (float)(top / Math.tan(Distorted.mFOV*Math.PI/360));
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distance = (int)(height*near/(top-bottom));
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far = 2*distance-near;
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if( invert ) Matrix.frustumM(projectionMatrix, 0, left, right, top, bottom, near, far);
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else Matrix.frustumM(projectionMatrix, 0, left, right, bottom, top, near, far);
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}
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else // parallel projection
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{
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near= (float)(top / Math.tan(Math.PI/360));
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distance = (int)(height*near/(top-bottom));
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far = 2*distance-near;
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if( invert ) Matrix.orthoM(projectionMatrix, 0, -surfaceWidth/2, surfaceWidth/2, surfaceHeight/2,-surfaceHeight/2, near, far);
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else Matrix.orthoM(projectionMatrix, 0, -surfaceWidth/2, surfaceWidth/2,-surfaceHeight/2, surfaceHeight/2, near, far);
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}
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depth = (int)((far-near)/2);
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}
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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//
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