mat.c

#include "mat.h"

#include <malloc.h>
#include <memory.h>
#include <stdlib.h>

mat _mat_init_matrix(int linear_size_x, int linear_size_y) {
    mat m;
    m.size_x = linear_size_x;
    m.size_y = linear_size_y;
    m.data = (float*)malloc(sizeof(float)*linear_size_x*linear_size_y);
    return m;
}
void _mat_free_matrix(mat *mat) {
    free(mat->data);
}

float* _mat_index_data(mat *mat, int x, int y) {
    return mat->data+(y*mat->size_x)+x;
}
float* _mat4_index_data(mat4x4 *mat, int x, int y) {
    return (*mat)+(y*4)+x;
}
float* _mat2_index_data(mat2x2 *mat, int x, int y) {
    return (*mat)+(y*2)+x;
}

void _mat4_mult(mat4x4* _restrict m1, mat4x4* _restrict m2, mat4x4 *buf) {
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            float sum = 0.0f;
            for (int k = 0; k < 4; ++k) {
                sum += (*_mat4_index_data(m1, i, k)) * (*_mat4_index_data(m2, k, j));
            }
            *_mat4_index_data(buf, i, j) = sum;
        }
    }
}
void _mat2_mult(mat2x2* _restrict m1, mat2x2* _restrict m2, mat2x2 *buf) {
    for (int i = 0; i < 2; ++i) {
        for (int j = 0; j < 2; ++j) {
            float sum = 0.0f;
            for (int k = 0; k < 2; ++k) {
                sum += (*_mat2_index_data(m1, i, k)) * (*_mat2_index_data(m2, k, j));
            }
            *_mat2_index_data(buf, i, j) = sum;
        }
    }
}

mat _mat_mult(mat* _restrict m1, mat* _restrict m2) {
    if (m1->size_y != m2->size_x) {
        exit(1);
    }

    const int rows = m1->size_x;
    const int cols = m2->size_y;
    const int inner = m1->size_y;

    mat prod = _mat_init_matrix(rows, cols);
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            float sum = 0.0f;
            for (int k = 0; k < inner; ++k) {
                sum += (*_mat_index_data(m1, i, k)) * (*_mat_index_data(m2, k, j));
            }
            *_mat_index_data(&prod, i, j) = sum;
        }
    }
    return prod;
}

void _mat4_mult_vec(mat4x4* m,
    float x, float y, float z, float w, 
    float *destX, float *destY, float *destZ, float *destW
) {
    const float vec[4] = { x, y, z, w };
    float sum[4] = { 0, 0, 0, 0 };

    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            sum[i] += (*_mat4_index_data(m, i, j)) * vec[j];
        }
    }
    *destX = sum[0];
    *destY = sum[1];
    *destZ = sum[2];
    *destW = sum[3];
}

void _mat2_mult_vec(mat2x2* m,
    float x, float y,
    float *destX, float *destY
) {
    const float vec[2] = { x, y };
    float sum[2] = { 0, 0 };

    for (int i = 0; i < 2; ++i) {
        for (int j = 0; j < 2; ++j) {
            sum[i] += (*_mat2_index_data(m, i, j)) * vec[j];
        }
    }
    *destX = sum[0];
    *destY = sum[1];
}