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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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46
include/misc/Maths.h
View File

@@ -46,7 +46,10 @@ Vec3<T> Cross(const Vec3<T>& vect, const Vec3<T>& other) {
};
}
template<typename T>
T Dot(const Vec4<T>& vect, const Vec4<T>& other) {
return vect.x * other.x + vect.y * other.y + vect.z * other.z + vect.w * other.w;
}
//////////////////////////////////////////////////////////////////
// Matricies //
@@ -54,6 +57,8 @@ Vec3<T> Cross(const Vec3<T>& vect, const Vec3<T>& other) {
template<typename T>
struct Mat4 {
static const std::size_t MATRIX_SIZE = 4;
T x0, x1, x2, x3;
T y0, y1, y2, y3;
T z0, z1, z2, z3;
@@ -66,16 +71,44 @@ struct Mat4 {
T& operator[] (std::size_t offset) {
return reinterpret_cast<T*>(this)[offset];
}
T at(std::size_t row, std::size_t column) const {
return operator[](row * MATRIX_SIZE + column);
}
T& at(std::size_t row, std::size_t column) {
return operator[](row * MATRIX_SIZE + column);
}
};
typedef Mat4<float> Mat4f;
typedef Mat4<int> Mat4i;
typedef Mat4<double> Mat4d;
Mat4f Perspective(float fovY, float aspectRatio, float zNear, float zFar);
Mat4f Look(const Vec3f& eye, const Vec3f& center, const Vec3f& up);
template<typename T>
Vec4<T> Dot(const Mat4<T>& mat, const Vec4<T>& vect) {
return {
Dot(*reinterpret_cast<const Vec4<T>*>(&mat), vect),
Dot(*reinterpret_cast<const Vec4<T>*>(&mat[Mat4<T>::MATRIX_SIZE]), vect),
Dot(*reinterpret_cast<const Vec4<T>*>(&mat[2 * Mat4<T>::MATRIX_SIZE]), vect),
Dot(*reinterpret_cast<const Vec4<T>*>(&mat[3 * Mat4<T>::MATRIX_SIZE]), vect),
};
}
Mat4f Dot(const Mat4f& mat, const Mat4f& other);
template<typename T>
Mat4<T> Dot(const Mat4<T>& mat, const Mat4<T>& other) {
Mat4<T> result {};
for (std::size_t i = 0; i < Mat4<T>::MATRIX_SIZE; i++) {
for (std::size_t j = 0; j < Mat4<T>::MATRIX_SIZE; j++) {
for (std::size_t k = 0; k < Mat4<T>::MATRIX_SIZE; k++) {
result.at(i, j) = mat.at(i, k) * other.at(k, j);
}
}
}
return result;
}
template<typename T>
Mat4<T> Identity() {
@@ -109,5 +142,10 @@ Mat4<T> Transpose(const Mat4<T>& mat) {
return result;
}
Mat4f Perspective(float fovY, float aspectRatio, float zNear, float zFar);
Mat4f Look(const Vec3f& eye, const Vec3f& center, const Vec3f& up);
Mat4f Inverse(const Mat4f& mat);
} // namespace maths
} // namespace td

47
src/misc/Maths.cpp
View File

@@ -38,18 +38,45 @@ 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);
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;
}