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math/frustum.cpp

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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.
+	// https://web.archive.org/web/20140211075800/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;
+}
+
+
+}