libcruft-util/geom/frustum.cpp
Danny Robson f6056153e3 rename root namespace from util to cruft
This places, at long last, the core library code into the same namespace
as the extended library code.
2018-08-05 14:42:02 +10:00

61 lines
2.5 KiB
C++

/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Copyright 2018 Danny Robson <danny@nerdcruft.net>
*/
#include "frustum.hpp"
using cruft::geom::frustum;
///////////////////////////////////////////////////////////////////////////////
template <typename T>
frustum<T>::frustum (const matrix4<T> &transform)
{
// left
planes[X_NEG].coefficients[0] = transform[3][0] + transform[0][0];
planes[X_NEG].coefficients[1] = transform[3][1] + transform[0][1];
planes[X_NEG].coefficients[2] = transform[3][2] + transform[0][2];
planes[X_NEG].coefficients[3] = transform[3][3] + transform[0][3];
// Right clipping plane
planes[X_POS].coefficients[0] = transform[3][0] - transform[0][0];
planes[X_POS].coefficients[1] = transform[3][1] - transform[0][1];
planes[X_POS].coefficients[2] = transform[3][2] - transform[0][2];
planes[X_POS].coefficients[3] = transform[3][3] - transform[0][3];
// Top clipping plane
planes[Y_POS].coefficients[0] = transform[3][0] - transform[1][0];
planes[Y_POS].coefficients[1] = transform[3][1] - transform[1][1];
planes[Y_POS].coefficients[2] = transform[3][2] - transform[1][2];
planes[Y_POS].coefficients[3] = transform[3][3] - transform[1][3];
// Bottom clipping plane
planes[Y_NEG].coefficients[0] = transform[3][0] + transform[1][0];
planes[Y_NEG].coefficients[1] = transform[3][1] + transform[1][1];
planes[Y_NEG].coefficients[2] = transform[3][2] + transform[1][2];
planes[Y_NEG].coefficients[3] = transform[3][3] + transform[1][3];
// Near clipping plane
planes[Z_POS].coefficients[0] = transform[3][0] + transform[2][0];
planes[Z_POS].coefficients[1] = transform[3][1] + transform[2][1];
planes[Z_POS].coefficients[2] = transform[3][2] + transform[2][2];
planes[Z_POS].coefficients[3] = transform[3][3] + transform[2][3];
// Far clipping plane
planes[Z_NEG].coefficients[0] = transform[3][0] - transform[2][0];
planes[Z_NEG].coefficients[1] = transform[3][1] - transform[2][1];
planes[Z_NEG].coefficients[2] = transform[3][2] - transform[2][2];
planes[Z_NEG].coefficients[3] = transform[3][3] - transform[2][3];
for (auto &p: planes)
p = normalised (p);
}
///////////////////////////////////////////////////////////////////////////////
template struct cruft::geom::frustum<float>;