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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#version 120
uniform int i_nColors;
uniform sampler1D t_colorArray4d;
uniform sampler1D t_stopArray1d;
uniform mat3x2 m_transform;
varying vec2 v_textureCoords2d;
int max(int x, int y)
{
if(x > y)
return x;
return y;
}
int findBucket(float t)
{
int nMinBucket=0;
while( nMinBucket < i_nColors &&
texture1D(t_stopArray1d, nMinBucket).s < t )
++nMinBucket;
return max(nMinBucket-1,0);
}
void main(void)
{
vec2 v = abs( vec2(m_transform * vec3(v_textureCoords2d,1)) );
float fAlpha = 1 - max(v.x, v.y);
int nMinBucket=findBucket( fAlpha );
float fLerp =
(fAlpha-texture1D(t_stopArray1d, nMinBucket).s) /
(texture1D(t_stopArray1d, nMinBucket+1).s -
texture1D(t_stopArray1d, nMinBucket).s);
gl_FragColor = mix(texture1D(t_colorArray4d, nMinBucket),
texture1D(t_colorArray4d, nMinBucket+1),
fLerp);
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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