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Implement mat3_inverse function #49

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Implement mat3_inverse function #49

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33 changes: 31 additions & 2 deletions mathc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1507,7 +1507,7 @@ mfloat_t** vec3_orthonormalization(mfloat_t result[3][3], mfloat_t basis[3][3])
mfloat_t v0[3];
mfloat_t v1[3];
mfloat_t v2[3];

for(int32_t i = 0; i < 3; ++i) {
v0[i] = basis[0][i];
v1[i] = basis[1][i];
Expand Down Expand Up @@ -2465,7 +2465,36 @@ mfloat_t *mat3_multiply_f(mfloat_t *result, mfloat_t *m0, mfloat_t f)

mfloat_t *mat3_inverse(mfloat_t *result, mfloat_t *m0)
{
result = m0;
mfloat_t inverse[MAT3_SIZE];
mfloat_t inverted_determinant;
mfloat_t m11 = m0[0];
mfloat_t m21 = m0[1];
mfloat_t m31 = m0[2];
mfloat_t m12 = m0[3];
mfloat_t m22 = m0[4];
mfloat_t m32 = m0[5];
mfloat_t m13 = m0[6];
mfloat_t m23 = m0[7];
mfloat_t m33 = m0[8];
inverse[0] = m22 * m33 - m32 * m23;
inverse[3] = m13 * m32 - m12 * m33;
inverse[6] = m12 * m23 - m13 * m22;
inverse[1] = m23 * m31 - m21 * m33;
inverse[4] = m11 * m33 - m13 * m31;
inverse[7] = m21 * m13 - m11 * m23;
inverse[2] = m21 * m32 - m31 * m22;
inverse[5] = m31 * m12 - m11 * m32;
inverse[8] = m11 * m22 - m21 * m12;
inverted_determinant = MFLOAT_C(1.0) / (m11 * inverse[0] + m21 * inverse[3] + m31 * inverse[6]);
result[0] = inverse[0] * inverted_determinant;
result[1] = inverse[1] * inverted_determinant;
result[2] = inverse[2] * inverted_determinant;
result[3] = inverse[3] * inverted_determinant;
result[4] = inverse[4] * inverted_determinant;
result[5] = inverse[5] * inverted_determinant;
result[6] = inverse[6] * inverted_determinant;
result[7] = inverse[7] * inverted_determinant;
result[8] = inverse[8] * inverted_determinant;
return result;
}

Expand Down