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more maths

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This commit is contained in:
Simon Pribylski
2023-06-03 18:22:01 +02:00
parent 95c92ec6c9
commit f2fcc348d7
2 changed files with 80 additions and 15 deletions
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49
src/misc/Maths.cpp
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@@ -38,20 +38,47 @@ Mat4f Look(const Vec3f& eye, const Vec3f& front, const Vec3f& up) {
return result;
}
Mat4f Dot(const Mat4f& mat, const Mat4f& other) {
Mat4f result {};
Mat4f Inverse(const Mat4f& mat) {
float s0 = mat.at(0, 0) * mat.at(1, 1) - mat.at(1, 0) * mat.at(0, 1);
float s1 = mat.at(0, 0) * mat.at(1, 2) - mat.at(1, 0) * mat.at(0, 2);
float s2 = mat.at(0, 0) * mat.at(1, 3) - mat.at(1, 0) * mat.at(0, 3);
float s3 = mat.at(0, 1) * mat.at(1, 2) - mat.at(1, 1) * mat.at(0, 2);
float s4 = mat.at(0, 1) * mat.at(1, 3) - mat.at(1, 1) * mat.at(0, 3);
float s5 = mat.at(0, 2) * mat.at(1, 3) - mat.at(1, 2) * mat.at(0, 3);
static const std::size_t MAT_SIZE = 4;
float c5 = mat.at(2, 2) * mat.at(3, 3) - mat.at(3, 2) * mat.at(2, 3);
float c4 = mat.at(2, 1) * mat.at(3, 3) - mat.at(3, 1) * mat.at(2, 3);
float c3 = mat.at(2, 1) * mat.at(3, 2) - mat.at(3, 1) * mat.at(2, 2);
float c2 = mat.at(2, 0) * mat.at(3, 3) - mat.at(3, 0) * mat.at(2, 3);
float c1 = mat.at(2, 0) * mat.at(3, 2) - mat.at(3, 0) * mat.at(2, 2);
float c0 = mat.at(2, 0) * mat.at(3, 1) - mat.at(3, 0) * mat.at(2, 1);
for (std::size_t i = 0; i < MAT_SIZE; i++) {
for (std::size_t j = 0; j < MAT_SIZE; j++) {
for (std::size_t k = 0; k < MAT_SIZE; k++) {
result[i * MAT_SIZE + j] += mat[i * MAT_SIZE + k] * other[k * MAT_SIZE + j];
}
}
}
// Should check for 0 determinant
float invdet = 1.0 / (s0 * c5 - s1 * c4 + s2 * c3 + s3 * c2 - s4 * c1 + s5 * c0);
return result;
Mat4f result;
result.at(0, 0) = ( mat.at(1, 1) * c5 - mat.at(1, 2) * c4 + mat.at(1, 3) * c3) * invdet;
result.at(0, 1) = (-mat.at(0, 1) * c5 + mat.at(0, 2) * c4 - mat.at(0, 3) * c3) * invdet;
result.at(0, 2) = ( mat.at(3, 1) * s5 - mat.at(3, 2) * s4 + mat.at(3, 3) * s3) * invdet;
result.at(0, 3) = (-mat.at(2, 1) * s5 + mat.at(2, 2) * s4 - mat.at(2, 3) * s3) * invdet;
result.at(1, 0) = (-mat.at(1, 0) * c5 + mat.at(1, 2) * c2 - mat.at(1, 3) * c1) * invdet;
result.at(1, 1) = ( mat.at(0, 0) * c5 - mat.at(0, 2) * c2 + mat.at(0, 3) * c1) * invdet;
result.at(1, 2) = (-mat.at(3, 0) * s5 + mat.at(3, 2) * s2 - mat.at(3, 3) * s1) * invdet;
result.at(1, 3) = ( mat.at(2, 0) * s5 - mat.at(2, 2) * s2 + mat.at(2, 3) * s1) * invdet;
result.at(2, 0) = ( mat.at(1, 0) * c4 - mat.at(1, 1) * c2 + mat.at(1, 3) * c0) * invdet;
result.at(2, 1) = (-mat.at(0, 0) * c4 + mat.at(0, 1) * c2 - mat.at(0, 3) * c0) * invdet;
result.at(2, 2) = ( mat.at(3, 0) * s4 - mat.at(3, 1) * s2 + mat.at(3, 3) * s0) * invdet;
result.at(2, 3) = (-mat.at(2, 0) * s4 + mat.at(2, 1) * s2 - mat.at(2, 3) * s0) * invdet;
result.at(3, 0) = (-mat.at(1, 0) * c3 + mat.at(1, 1) * c1 - mat.at(1, 2) * c0) * invdet;
result.at(3, 1) = ( mat.at(0, 0) * c3 - mat.at(0, 1) * c1 + mat.at(0, 2) * c0) * invdet;
result.at(3, 2) = (-mat.at(3, 0) * s3 + mat.at(3, 1) * s1 - mat.at(3, 2) * s0) * invdet;
result.at(3, 3) = ( mat.at(2, 0) * s3 - mat.at(2, 1) * s1 + mat.at(2, 2) * s0) * invdet;
return result;
}
} // namespace maths