src/ta_math.c


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/*
 * Tuxánci 2 - A first person shooter
 * Copyright (C) 2025-2026  Connor Thomson
 *
 * 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 <https://www.gnu.org/licenses/>.
 */

#include <string.h>
#include "ta_math.h"

double ta_rad(double degrees) {
    return degrees * (PI / (CIRCLE_DEG / 2));
}

void ta_matrix_identity(float *matrix) {
    for (int index = 0; index < TA_MATRIX_ELEMENTS; index++) {
        matrix[index] = index % 5 == 0 ? 1.0f : 0.0f;
    }
}

void ta_matrix_multiply(float *result, const float *left, const float *right) {
    float product[TA_MATRIX_ELEMENTS];
    for (int column = 0; column < 4; column++) for (int row = 0; row < 4; row++) {
        product[column * 4 + row] = 0.0f;
        for (int inner = 0; inner < 4; inner++) {
            product[column * 4 + row] += left[inner * 4 + row] * right[column * 4 + inner];
        }
    }
    memcpy(result, product, sizeof(product));
}