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/*
* ShadowVolume.cpp
*
* Copyright (C) 2009 Matthias Schiffer <matthias@gamezock.de>
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "ShadowVolume.h"
#include "MathUtil.h"
#include "gl.h"
namespace Zoom {
ShadowVolume::ShadowVolume(const Triangle &t, const vmml::vec3f &lightPos) : visible(true) {
MathUtil::Plane trianglePlane(t);
for(int i = 0; i < 3; ++i) {
rays[i].p = t.getVertex(i);
}
if(trianglePlane.isInFront(lightPos)) {
visible = false;
return;
}
for(int i = 0; i < 3; ++i) {
rays[i].dir = rays[i].p - lightPos;
}
}
void ShadowVolume::render() const {
if(!visible)
return;
glVertex3fv(rays[0].p.array);
glVertex3fv(rays[1].p.array);
glVertex3fv(rays[2].p.array);
for(int i = 0; i < 3; ++i) {
const Ray &r1 = rays[i];
const Ray &r2 = rays[(i+1)%3];
glVertex3fv(r1.p.array);
glVertex4fv(vmml::vec4f(r1.dir, 0).array);
glVertex3fv(r2.p.array);
glVertex3fv(r2.p.array);
glVertex4fv(vmml::vec4f(r1.dir, 0).array);
glVertex4fv(vmml::vec4f(r2.dir, 0).array);
}
glVertex4fv(vmml::vec4f(rays[2].dir, 0).array);
glVertex4fv(vmml::vec4f(rays[1].dir, 0).array);
glVertex4fv(vmml::vec4f(rays[0].dir, 0).array);
}
}
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