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glmath.cpp
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97 lines (80 loc) · 2.82 KB
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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/glmath.h"
namespace Math {
// function based on gluUnProject from Mesa 5.0 glu GPLv2+ licensed sources
bool gluMathUnProject(const Vector3d &win, const Matrix4 &mvpMatrix, const Common::Rect &viewport, Vector3d &obj) {
Matrix4 A;
Vector4d in, out;
in.x() = (win.x() - viewport.left) * 2 / viewport.width() - 1.0;
in.y() = (win.y() - viewport.top) * 2 / viewport.height() - 1.0;
in.z() = 2 * win.z() - 1.0;
in.w() = 1.0;
A = mvpMatrix;
A.inverse();
out = A.transform(in);
if (out.w() == 0.0)
return false;
obj.x() = out.x() / out.w();
obj.y() = out.y() / out.w();
obj.z() = out.z() / out.w();
return true;
}
// function based on gluPerspective from Mesa 5.0 glu GPLv2+ licensed sources
Matrix4 makePerspectiveMatrix(double fovy, double aspect, double zNear, double zFar) {
double xmin, xmax, ymin, ymax;
ymax = zNear * tan(fovy * M_PI / 360.0);
ymin = -ymax;
xmin = ymin * aspect;
xmax = ymax * aspect;
return makeFrustumMatrix(xmin, xmax, ymin, ymax, zNear, zFar);
}
Matrix4 makeFrustumMatrix(double left, double right, double bottom, double top, double zNear, double zFar) {
Matrix4 proj;
proj(0, 0) = (2.0f * zNear) / (right - left);
proj(1, 1) = (2.0f * zNear) / (top - bottom);
proj(2, 0) = (right + left) / (right - left);
proj(2, 1) = (top + bottom) / (top - bottom);
proj(2, 2) = -(zFar + zNear) / (zFar - zNear);
proj(2, 3) = -1.0f;
proj(3, 2) = -(2.0f * zFar * zNear) / (zFar - zNear);
proj(3, 3) = 0.0f;
return proj;
}
Matrix4 makeLookAtMatrix(const Vector3d &eye, const Vector3d ¢er, const Vector3d &up) {
Vector3d f = (center - eye).getNormalized();
Vector3d u = up.getNormalized();
Vector3d s = Vector3d::crossProduct(f, u).getNormalized();
u = Vector3d::crossProduct(s, f);
Math::Matrix4 look;
look(0, 0) = s.x();
look(1, 0) = s.y();
look(2, 0) = s.z();
look(0, 1) = u.x();
look(1, 1) = u.y();
look(2, 1) = u.z();
look(0, 2) = -f.x();
look(1, 2) = -f.y();
look(2, 2) = -f.z();
look(3, 3) = 1.0;
return look;
}
}