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Diffstat (limited to '')
-rw-r--r-- | canvas/opengl/rectangularMultiColorGradientFragmentShader.glsl | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/canvas/opengl/rectangularMultiColorGradientFragmentShader.glsl b/canvas/opengl/rectangularMultiColorGradientFragmentShader.glsl new file mode 100644 index 000000000..ea17565c1 --- /dev/null +++ b/canvas/opengl/rectangularMultiColorGradientFragmentShader.glsl @@ -0,0 +1,51 @@ +/* -*- 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: */ |