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2023-04-23 21:57:20 +08:00

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C++

#pragma once
// glm math.
// 0. glm force compute on radians.
// 1. glm vulkan depth force 0 to 1.
// 2. glm enable experimental.
#define GLM_FORCE_RADIANS
#define GLM_FORCE_DEPTH_ZERO_TO_ONE
#define GLM_ENABLE_EXPERIMENTAL
// Common glm headers
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtx/hash.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/matrix_inverse.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtx/euler_angles.hpp>
#include <glm/gtx/quaternion.hpp>
#include <glm/gtx/matrix_decompose.hpp>
namespace engine
{
// namespace alias to ensure all glm header under this file's macro control.
namespace math = glm;
// From https://github.com/TheCherno/Hazel/blob/master/Hazel/src/Hazel/Math/Math.cpp
inline bool decomposeTransform(const math::mat4& transform, math::vec3& translation, math::vec3& rotation, math::vec3& scale)
{
using namespace math;
using T = float;
mat4 LocalMatrix(transform);
// Normalize the matrix.
if (epsilonEqual(LocalMatrix[3][3], static_cast<float>(0), epsilon<T>()))
{
return false;
}
// First, isolate perspective. This is the messiest.
if (
epsilonNotEqual(LocalMatrix[0][3], static_cast<T>(0), epsilon<T>()) ||
epsilonNotEqual(LocalMatrix[1][3], static_cast<T>(0), epsilon<T>()) ||
epsilonNotEqual(LocalMatrix[2][3], static_cast<T>(0), epsilon<T>()))
{
// Clear the perspective partition
LocalMatrix[0][3] = LocalMatrix[1][3] = LocalMatrix[2][3] = static_cast<T>(0);
LocalMatrix[3][3] = static_cast<T>(1);
}
// Next take care of translation (easy).
translation = vec3(LocalMatrix[3]);
LocalMatrix[3] = vec4(0, 0, 0, LocalMatrix[3].w);
vec3 Row[3]{};//, Pdum3;
// Now get scale and shear.
for (length_t i = 0; i < 3; ++i)
{
for (length_t j = 0; j < 3; ++j)
{
Row[i][j] = LocalMatrix[i][j];
}
}
// Compute X scale factor and normalize first row.
scale.x = length(Row[0]);
Row[0] = detail::scale(Row[0], static_cast<T>(1));
scale.y = length(Row[1]);
Row[1] = detail::scale(Row[1], static_cast<T>(1));
scale.z = length(Row[2]);
Row[2] = detail::scale(Row[2], static_cast<T>(1));
// At this point, the matrix (in rows[]) is orthonormal.
// Check for a coordinate system flip. If the determinant
// is -1, then negate the matrix and the scaling factors.
#if 0
Pdum3 = cross(Row[1], Row[2]); // v3Cross(row[1], row[2], Pdum3);
if (dot(Row[0], Pdum3) < 0)
{
for (length_t i = 0; i < 3; i++)
{
scale[i] *= static_cast<T>(-1);
Row[i] *= static_cast<T>(-1);
}
}
#endif
rotation.y = asin(-Row[0][2]);
if (cos(rotation.y) != 0.f)
{
rotation.x = atan2(Row[1][2], Row[2][2]);
rotation.z = atan2(Row[0][1], Row[0][0]);
}
else
{
rotation.x = atan2(-Row[2][0], Row[1][1]);
rotation.z = 0;
}
return true;
}
}