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-rw-r--r--canvas/opengl/radialMultiColorGradientFragmentShader.glsl55
1 files changed, 55 insertions, 0 deletions
diff --git a/canvas/opengl/radialMultiColorGradientFragmentShader.glsl b/canvas/opengl/radialMultiColorGradientFragmentShader.glsl
new file mode 100644
index 000000000..ebc6d6f5f
--- /dev/null
+++ b/canvas/opengl/radialMultiColorGradientFragmentShader.glsl
@@ -0,0 +1,55 @@
+/* -*- 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;
+const vec2 v_center2d = vec2(0,0);
+
+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)
+{
+ float fAlpha =
+ clamp( 1.0 - distance(
+ vec2( m_transform * vec3(v_textureCoords2d,1)),
+ v_center2d),
+ 0.0, 1.0 );
+
+ 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: */