OpenMiner/source/common/core/BlockGeometry.cpp
2020-03-17 22:22:22 +01:00

97 lines
3.3 KiB
C++

/*
* =====================================================================================
*
* OpenMiner
*
* Copyright (C) 2018-2020 Unarelith, Quentin Bazin <openminer@unarelith.net>
* Copyright (C) 2019-2020 the OpenMiner contributors (see CONTRIBUTORS.md)
*
* This file is part of OpenMiner.
*
* OpenMiner is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* OpenMiner 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with OpenMiner; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* =====================================================================================
*/
#include <mutex>
#include "BlockGeometry.hpp"
namespace BlockGeometry {
glm::mat3 orientMatrices[nOrientations];
static void doInitOrientation(void);
void initOrientation() {
static int orientInitialized = false;
static std::mutex orientInitMutex;
std::lock_guard<std::mutex> lock(orientInitMutex);
if (!orientInitialized) {
doInitOrientation();
orientInitialized = true;
}
}
static void doInitOrientation() {
// Build all 24 rotation matrices for the orientation field
// Local rotation of top face
glm::mat3 topRotation{
1, 0, 0,
0, 1, 0,
0, 0, 1,
};
// Matrix for a rotation of 90 degrees CCW around the Z axis, used to
// rotate the top face in 90 degree steps around its local Z axis.
const glm::mat3 rotate90Z{
// Note glm matrices are column-major, so each row here is
// actually a column of the matrix.
0, 1, 0,
-1, 0, 0,
0, 0, 1,
};
// Rotations that place the top face on each of the axes
const glm::mat3 rot2axis[nAxes]{
{ 1, 0, 0, 0, 1, 0, 0, 0, 1}, // top face on +Z, no rotation (identity matrix)
{ 1, 0, 0, 0, -1, 0, 0, 0, -1}, // top face on -Z, rotating around the X axis
{ 1, 0, 0, 0, 0, -1, 0, 1, 0}, // top face on +Y, rotating around the X axis
{ 1, 0, 0, 0, 0, 1, 0, -1, 0}, // top face on -Y, rotating around the X axis
{ 0, 0, 1, 0, 1, 0, -1, 0, 0}, // top face on +X, rotating around the Y axis
{ 0, 0, -1, 0, 1, 0, 1, 0, 0}, // top face on -X, rotating around the Y axis
};
for (int axis = 0; axis < nAxes; ++axis) {
for (int angle = 0; angle < nRots; ++angle) {
// Rotate the top around itself, then rotate it to each face
orientMatrices[axis * 4 + angle] = rot2axis[axis] * topRotation;
// Next top rotation
topRotation = rotate90Z * topRotation;
}
}
// Since we use bit masking, we add eight dummy orientations to the normal
// set of 24 to complete a power of two, to make the code robust against
// invalid orientation values.
for (int axis = nAxes; axis < nAxesP2; ++axis) {
for (int angle = 0; angle < nRots; ++angle) {
orientMatrices[axis * nRots + angle] = orientMatrices[0];
}
}
}
} // namespace BlockGeometry