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106 lines
3.8 KiB
C++
106 lines
3.8 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* 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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*
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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. See the
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* GNU General Public License for more details.
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*
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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, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "math/frustum.h"
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namespace Math {
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Frustum::Frustum() {
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}
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void Frustum::setup(const Math::Matrix4 &matrix) {
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// Based on "Fast Extraction of Viewing Frustum Planes from the
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// World-View-Projection matrix" by Gil Gribb and Klaus Hartmann.
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// http://www.cs.otago.ac.nz/postgrads/alexis/planeExtraction.pdf
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_planes[0]._normal.x() = matrix.getValue(3, 0) + matrix.getValue(0, 0);
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_planes[0]._normal.y() = matrix.getValue(3, 1) + matrix.getValue(0, 1);
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_planes[0]._normal.z() = matrix.getValue(3, 2) + matrix.getValue(0, 2);
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_planes[0]._d = matrix.getValue(3, 3) + matrix.getValue(0, 3);
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_planes[1]._normal.x() = matrix.getValue(3, 0) - matrix.getValue(0, 0);
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_planes[1]._normal.y() = matrix.getValue(3, 1) - matrix.getValue(0, 1);
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_planes[1]._normal.z() = matrix.getValue(3, 2) - matrix.getValue(0, 2);
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_planes[1]._d = matrix.getValue(3, 3) - matrix.getValue(0, 3);
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_planes[2]._normal.x() = matrix.getValue(3, 0) - matrix.getValue(1, 0);
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_planes[2]._normal.y() = matrix.getValue(3, 1) - matrix.getValue(1, 1);
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_planes[2]._normal.z() = matrix.getValue(3, 2) - matrix.getValue(1, 2);
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_planes[2]._d = matrix.getValue(3, 3) - matrix.getValue(1, 3);
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_planes[3]._normal.x() = matrix.getValue(3, 0) + matrix.getValue(1, 0);
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_planes[3]._normal.y() = matrix.getValue(3, 1) + matrix.getValue(1, 1);
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_planes[3]._normal.z() = matrix.getValue(3, 2) + matrix.getValue(1, 2);
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_planes[3]._d = matrix.getValue(3, 3) + matrix.getValue(1, 3);
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_planes[4]._normal.x() = matrix.getValue(3, 0) + matrix.getValue(2, 0);
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_planes[4]._normal.y() = matrix.getValue(3, 1) + matrix.getValue(2, 1);
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_planes[4]._normal.z() = matrix.getValue(3, 2) + matrix.getValue(2, 2);
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_planes[4]._d = matrix.getValue(3, 3) + matrix.getValue(2, 3);
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_planes[5]._normal.x() = matrix.getValue(3, 0) - matrix.getValue(2, 0);
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_planes[5]._normal.y() = matrix.getValue(3, 1) - matrix.getValue(2, 1);
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_planes[5]._normal.z() = matrix.getValue(3, 2) - matrix.getValue(2, 2);
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_planes[5]._d = matrix.getValue(3, 3) - matrix.getValue(2, 3);
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for (int i = 0; i < 6; ++i) {
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_planes[i].normalize();
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}
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}
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bool Frustum::isInside(const Math::AABB &aabb) const {
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Math::Vector3d min = aabb.getMin();
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Math::Vector3d max = aabb.getMax();
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for (int i = 0; i < 6; ++i) {
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const Plane &plane = _planes[i];
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Math::Vector3d positive = min;
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if (plane._normal.x() >= 0.0f)
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positive.x() = max.x();
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if (plane._normal.y() >= 0.0f)
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positive.y() = max.y();
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if (plane._normal.z() >= 0.0f)
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positive.z() = max.z();
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float dist = _planes[i].getSignedDistance(positive);
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if (dist < 0.0f)
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return false;
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}
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return true;
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}
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bool Frustum::isTriangleInside(const Math::Vector3d &v0, const Math::Vector3d &v1, const Math::Vector3d &v2) const {
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for (int i = 0; i < 6; ++i) {
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const Plane &plane = _planes[i];
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// Inside if any point is above the plane. On the plane is in
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if (plane.getSignedDistance(v0) < 0.0f
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&& plane.getSignedDistance(v1) < 0.0f
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&& plane.getSignedDistance(v2) < 0.0f)
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return false;
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}
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return true;
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}
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}
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