45 lines
1.4 KiB
GLSL
45 lines
1.4 KiB
GLSL
// -----------------------------------------------------------------------------
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// Copyright (c) 2009-2016 Nicolas P. Rougier. All rights reserved.
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// Distributed under the (new) BSD License.
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// -----------------------------------------------------------------------------
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/* ---------------------------------------------------------
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Compute antialiased fragment color for a filled shape.
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Parameters:
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-----------
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distance : signed distance to border (in pixels)
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linewidth: Stroke line width (in pixels)
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antialias: Stroke antialiased area (in pixels)
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fill: Fill color
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Return:
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-------
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Fragment color (vec4)
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--------------------------------------------------------- */
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vec4 filled(float distance, float linewidth, float antialias, vec4 bg_color)
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{
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vec4 frag_color;
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float t = linewidth/2.0 - antialias;
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float signed_distance = distance;
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float border_distance = abs(signed_distance) - t;
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float alpha = border_distance/antialias;
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alpha = exp(-alpha*alpha);
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if( border_distance < 0.0 )
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frag_color = bg_color;
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else if( signed_distance < 0.0 )
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frag_color = bg_color;
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else
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frag_color = vec4(bg_color.rgb, alpha * bg_color.a);
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return frag_color;
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}
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vec4 filled(float distance, float linewidth, float antialias, vec4 fg_color, vec4 bg_color)
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{
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return filled(distance, linewidth, antialias, fg_color);
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} |