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62 lines
1.9 KiB
Plaintext
62 lines
1.9 KiB
Plaintext
/*
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This file is part of Caelum.
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See http://www.ogre3d.org/wiki/index.php/Caelum
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Copyright (c) 2006-2007 Caelum team. See Contributors.txt for details.
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Caelum is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Caelum 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. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with Caelum. If not, see <http://www.gnu.org/licenses/>.
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*/
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// Get how much of a certain point on the moon is seen (or not) because of the phase.
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// uv is the rect position on moon; as seen from the earth.
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// phase ranges from 0 to 2
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float MoonPhaseFactor(float2 uv, float phase)
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{
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float alpha = 1.0;
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float srefx = uv.x - 0.5;
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float refx = abs(uv.x - 0.5);
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float refy = abs(uv.y - 0.5);
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float refxfory = sqrt(0.25 - refy * refy);
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float xmin = -refxfory;
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float xmax = refxfory;
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float xmin1 = (xmax - xmin) * (phase / 2) + xmin;
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float xmin2 = (xmax - xmin) * phase + xmin;
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if (srefx < xmin1) {
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alpha = 0;
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} else if (srefx < xmin2 && xmin1 != xmin2) {
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alpha = (srefx - xmin1) / (xmin2 - xmin1);
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}
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return alpha;
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}
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void PhaseMoonFP
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(
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in float2 uv: TEXCOORD0,
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uniform float phase,
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uniform sampler2D moonDisc: register(s0),
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out float4 outcol : COLOR
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)
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{
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outcol = tex2D(moonDisc, uv);
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float alpha = MoonPhaseFactor(uv, phase);
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// Get luminance from the texture.
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float lum = dot(outcol.rgb, float3(0.3333, 0.3333, 0.3333));
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//float lum = dot(outcol.rgb, float3(0.3, 0.59, 0.11));
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outcol.a = min(outcol.a, lum * alpha);
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outcol.rgb /= lum;
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}
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