more maths

include/misc/Maths.h

@@ -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