bgc-c/basic-geometry/matrix3x3.c

#include "matrix3x3.h"

// ================= Inversion ================== //

int bg_fp32_matrix3x3_invert(BgFP32Matrix3x3* matrix)
{
    const float determinant = bg_fp32_matrix3x3_get_determinant(matrix);

    if (-BG_FP32_EPSYLON <= determinant && determinant <= BG_FP32_EPSYLON) {
        return 0;
    }

    const float r1c1 = matrix->r2c2 * matrix->r3c3 - matrix->r2c3 * matrix->r3c2;
    const float r1c2 = matrix->r1c3 * matrix->r3c2 - matrix->r1c2 * matrix->r3c3;
    const float r1c3 = matrix->r1c2 * matrix->r2c3 - matrix->r1c3 * matrix->r2c2;

    const float r2c1 = matrix->r2c3 * matrix->r3c1 - matrix->r2c1 * matrix->r3c3;
    const float r2c2 = matrix->r1c1 * matrix->r3c3 - matrix->r1c3 * matrix->r3c1;
    const float r2c3 = matrix->r1c3 * matrix->r2c1 - matrix->r1c1 * matrix->r2c3;

    const float r3c1 = matrix->r2c1 * matrix->r3c2 - matrix->r2c2 * matrix->r3c1;
    const float r3c2 = matrix->r1c2 * matrix->r3c1 - matrix->r1c1 * matrix->r3c2;
    const float r3c3 = matrix->r1c1 * matrix->r2c2 - matrix->r1c2 * matrix->r2c1;

    const float multiplier = 1.0f / determinant;

    matrix->r1c1 = r1c1 * multiplier;
    matrix->r1c2 = r1c2 * multiplier;
    matrix->r1c3 = r1c3 * multiplier;

    matrix->r2c1 = r2c1 * multiplier;
    matrix->r2c2 = r2c2 * multiplier;
    matrix->r2c3 = r2c3 * multiplier;

    matrix->r3c1 = r3c1 * multiplier;
    matrix->r3c2 = r3c2 * multiplier;
    matrix->r3c3 = r3c3 * multiplier;

    return 1;
}

int bg_fp64_matrix3x3_invert(BgFP64Matrix3x3* matrix)
{
    const double determinant = bg_fp64_matrix3x3_get_determinant(matrix);

    if (-BG_FP64_EPSYLON <= determinant && determinant <= BG_FP64_EPSYLON) {
        return 0;
    }

    const double r1c1 = matrix->r2c2 * matrix->r3c3 - matrix->r2c3 * matrix->r3c2;
    const double r1c2 = matrix->r1c3 * matrix->r3c2 - matrix->r1c2 * matrix->r3c3;
    const double r1c3 = matrix->r1c2 * matrix->r2c3 - matrix->r1c3 * matrix->r2c2;

    const double r2c1 = matrix->r2c3 * matrix->r3c1 - matrix->r2c1 * matrix->r3c3;
    const double r2c2 = matrix->r1c1 * matrix->r3c3 - matrix->r1c3 * matrix->r3c1;
    const double r2c3 = matrix->r1c3 * matrix->r2c1 - matrix->r1c1 * matrix->r2c3;

    const double r3c1 = matrix->r2c1 * matrix->r3c2 - matrix->r2c2 * matrix->r3c1;
    const double r3c2 = matrix->r1c2 * matrix->r3c1 - matrix->r1c1 * matrix->r3c2;
    const double r3c3 = matrix->r1c1 * matrix->r2c2 - matrix->r1c2 * matrix->r2c1;

    const double multiplier = 1.0 / determinant;

    matrix->r1c1 = r1c1 * multiplier;
    matrix->r1c2 = r1c2 * multiplier;
    matrix->r1c3 = r1c3 * multiplier;

    matrix->r2c1 = r2c1 * multiplier;
    matrix->r2c2 = r2c2 * multiplier;
    matrix->r2c3 = r2c3 * multiplier;

    matrix->r3c1 = r3c1 * multiplier;
    matrix->r3c2 = r3c2 * multiplier;
    matrix->r3c3 = r3c3 * multiplier;

    return 1;
}

// ================ Make Inverted =============== //

int bg_fp32_matrix3x3_set_inverted(const BgFP32Matrix3x3* matrix, BgFP32Matrix3x3* result)
{
    const float determinant = bg_fp32_matrix3x3_get_determinant(matrix);

    if (-BG_FP32_EPSYLON <= determinant && determinant <= BG_FP32_EPSYLON) {
        return 0;
    }

    const float r1c1 = matrix->r2c2 * matrix->r3c3 - matrix->r2c3 * matrix->r3c2;
    const float r1c2 = matrix->r1c3 * matrix->r3c2 - matrix->r1c2 * matrix->r3c3;
    const float r1c3 = matrix->r1c2 * matrix->r2c3 - matrix->r1c3 * matrix->r2c2;

    const float r2c1 = matrix->r2c3 * matrix->r3c1 - matrix->r2c1 * matrix->r3c3;
    const float r2c2 = matrix->r1c1 * matrix->r3c3 - matrix->r1c3 * matrix->r3c1;
    const float r2c3 = matrix->r1c3 * matrix->r2c1 - matrix->r1c1 * matrix->r2c3;

    const float r3c1 = matrix->r2c1 * matrix->r3c2 - matrix->r2c2 * matrix->r3c1;
    const float r3c2 = matrix->r1c2 * matrix->r3c1 - matrix->r1c1 * matrix->r3c2;
    const float r3c3 = matrix->r1c1 * matrix->r2c2 - matrix->r1c2 * matrix->r2c1;

    const float multiplier = 1.0f / determinant;

    result->r1c1 = r1c1 * multiplier;
    result->r1c2 = r1c2 * multiplier;
    result->r1c3 = r1c3 * multiplier;

    result->r2c1 = r2c1 * multiplier;
    result->r2c2 = r2c2 * multiplier;
    result->r2c3 = r2c3 * multiplier;

    result->r3c1 = r3c1 * multiplier;
    result->r3c2 = r3c2 * multiplier;
    result->r3c3 = r3c3 * multiplier;

    return 1;
}

int bg_fp64_matrix3x3_set_inverted(const BgFP64Matrix3x3* matrix, BgFP64Matrix3x3* result)
{
    const double determinant = bg_fp64_matrix3x3_get_determinant(matrix);

    if (-BG_FP64_EPSYLON <= determinant && determinant <= BG_FP64_EPSYLON) {
        return 0;
    }

    const double r1c1 = matrix->r2c2 * matrix->r3c3 - matrix->r2c3 * matrix->r3c2;
    const double r1c2 = matrix->r1c3 * matrix->r3c2 - matrix->r1c2 * matrix->r3c3;
    const double r1c3 = matrix->r1c2 * matrix->r2c3 - matrix->r1c3 * matrix->r2c2;

    const double r2c1 = matrix->r2c3 * matrix->r3c1 - matrix->r2c1 * matrix->r3c3;
    const double r2c2 = matrix->r1c1 * matrix->r3c3 - matrix->r1c3 * matrix->r3c1;
    const double r2c3 = matrix->r1c3 * matrix->r2c1 - matrix->r1c1 * matrix->r2c3;

    const double r3c1 = matrix->r2c1 * matrix->r3c2 - matrix->r2c2 * matrix->r3c1;
    const double r3c2 = matrix->r1c2 * matrix->r3c1 - matrix->r1c1 * matrix->r3c2;
    const double r3c3 = matrix->r1c1 * matrix->r2c2 - matrix->r1c2 * matrix->r2c1;

    const double multiplier = 1.0 / determinant;

    result->r1c1 = r1c1 * multiplier;
    result->r1c2 = r1c2 * multiplier;
    result->r1c3 = r1c3 * multiplier;

    result->r2c1 = r2c1 * multiplier;
    result->r2c2 = r2c2 * multiplier;
    result->r2c3 = r2c3 * multiplier;

    result->r3c1 = r3c1 * multiplier;
    result->r3c2 = r3c2 * multiplier;
    result->r3c3 = r3c3 * multiplier;

    return 1;
}