37 lines
1.3 KiB
Text
37 lines
1.3 KiB
Text
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/// ============================================================================
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/*
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Copyright (C) 2004 Robert Beckebans <trebor_7@users.sourceforge.net>
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Please see the file "AUTHORS" for a list of contributors
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/// ============================================================================
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// fresnel approximation
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float fast_fresnel(float3 I, float3 N, float3 fresnel_values)
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{
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float power = fresnel_values.x;
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float scale = fresnel_values.y;
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float bias = fresnel_values.z;
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return bias + pow(1.0 - dot(I, N), power) * scale;
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}
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float3 CG_Expand(float3 v)
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{
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return (v - 0.5) * 2; // expand a range-compressed vector
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}
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