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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "math/frustum.h"
namespace Math {
Frustum::Frustum() {
}
void Frustum::setup(const Math::Matrix4 &matrix) {
// Based on "Fast Extraction of Viewing Frustum Planes from the
// World-View-Projection matrix" by Gil Gribb and Klaus Hartmann.
// http://www.cs.otago.ac.nz/postgrads/alexis/planeExtraction.pdf
_planes[0]._normal.x() = matrix.getValue(3, 0) + matrix.getValue(0, 0);
_planes[0]._normal.y() = matrix.getValue(3, 1) + matrix.getValue(0, 1);
_planes[0]._normal.z() = matrix.getValue(3, 2) + matrix.getValue(0, 2);
_planes[0]._d = matrix.getValue(3, 3) + matrix.getValue(0, 3);
_planes[1]._normal.x() = matrix.getValue(3, 0) - matrix.getValue(0, 0);
_planes[1]._normal.y() = matrix.getValue(3, 1) - matrix.getValue(0, 1);
_planes[1]._normal.z() = matrix.getValue(3, 2) - matrix.getValue(0, 2);
_planes[1]._d = matrix.getValue(3, 3) - matrix.getValue(0, 3);
_planes[2]._normal.x() = matrix.getValue(3, 0) - matrix.getValue(1, 0);
_planes[2]._normal.y() = matrix.getValue(3, 1) - matrix.getValue(1, 1);
_planes[2]._normal.z() = matrix.getValue(3, 2) - matrix.getValue(1, 2);
_planes[2]._d = matrix.getValue(3, 3) - matrix.getValue(1, 3);
_planes[3]._normal.x() = matrix.getValue(3, 0) + matrix.getValue(1, 0);
_planes[3]._normal.y() = matrix.getValue(3, 1) + matrix.getValue(1, 1);
_planes[3]._normal.z() = matrix.getValue(3, 2) + matrix.getValue(1, 2);
_planes[3]._d = matrix.getValue(3, 3) + matrix.getValue(1, 3);
_planes[4]._normal.x() = matrix.getValue(3, 0) + matrix.getValue(2, 0);
_planes[4]._normal.y() = matrix.getValue(3, 1) + matrix.getValue(2, 1);
_planes[4]._normal.z() = matrix.getValue(3, 2) + matrix.getValue(2, 2);
_planes[4]._d = matrix.getValue(3, 3) + matrix.getValue(2, 3);
_planes[5]._normal.x() = matrix.getValue(3, 0) - matrix.getValue(2, 0);
_planes[5]._normal.y() = matrix.getValue(3, 1) - matrix.getValue(2, 1);
_planes[5]._normal.z() = matrix.getValue(3, 2) - matrix.getValue(2, 2);
_planes[5]._d = matrix.getValue(3, 3) - matrix.getValue(2, 3);
for (int i = 0; i < 6; ++i) {
_planes[i].normalize();
}
}
bool Frustum::isInside(const Math::AABB &aabb) const {
Math::Vector3d min = aabb.getMin();
Math::Vector3d max = aabb.getMax();
for (int i = 0; i < 6; ++i) {
const Plane &plane = _planes[i];
Math::Vector3d positive = min;
if (plane._normal.x() >= 0.0f)
positive.x() = max.x();
if (plane._normal.y() >= 0.0f)
positive.y() = max.y();
if (plane._normal.z() >= 0.0f)
positive.z() = max.z();
float dist = _planes[i].getSignedDistance(positive);
if (dist < 0.0f)
return false;
}
return true;
}
bool Frustum::isTriangleInside(const Math::Vector3d &v0, const Math::Vector3d &v1, const Math::Vector3d &v2) const {
for (int i = 0; i < 6; ++i) {
const Plane &plane = _planes[i];
// Inside if any point is above the plane. On the plane is in
if (plane.getSignedDistance(v0) < 0.0f
&& plane.getSignedDistance(v1) < 0.0f
&& plane.getSignedDistance(v2) < 0.0f)
return false;
}
return true;
}
}
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