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Artem Kharytoniuk kennyalive

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Computer programmer

kennyalive / inverse_of_TRS_matrix.cpp

Last active July 10, 2022 04:16

Inverse of translate+rotate+scale matrix

	// This implementation does not support shear transform.
	// Not-uniform scale is supported.
	//
	// If you need to support shear then 'true' matrix inversion algorithm
	// shoudl be used, for example, gaussian elimination will work.
	//
	Matrix3x4 get_inverse_transform(const Matrix3x4& m)
	{
	Vector3 scale = get_scale_from_transform(m);
	Vector3 inv_scale = Vector3(1) / scale;

kennyalive / intersect_triangle_watertight.cpp

Last active November 6, 2021 17:55

watertight triangle intersection with ray origin adjustment

	constexpr bool perform_expensive_numerical_analysis_to_prevent_intersection_behind_ray_origin = true; // could noticeable slowdown algorithm (like 2x)

	//
	// Sven Woop, Carsten Benthin, and Ingo Wald, Watertight Ray/Triangle Intersection,
	// Journal of Computer Graphics Techniques (JCGT), vol. 2, no. 1, 65-82, 2013
	// http://jcgt.org/published/0002/01/05/
	//
	float intersect_triangle_watertight(const Ray& ray, const Vector3& p0, const Vector3& p1, const Vector3& p2, Vector3* barycentrics)
	{
	const int kz = ray.direction.abs().max_dimension();

kennyalive / gist:b3271612452fb3f746d47185fdba99eb

Created September 13, 2021 21:03

Do not optimize out benchmark helpers

	#pragma optimize("", off)
	void dummy_modify_variable(void* p) {}
	void dummy_use_variable(const void *p) {}
	#pragma optimize("", on)

	template <typename T>
	void make_unpredictable_for_compiler(T& var) {
	dummy_modify_variable(&var);
	}

kennyalive / test_virtual_call.cpp

Created May 22, 2020 10:23

	#include <cstdio>
	#include <chrono>

	struct Timestamp {
	Timestamp() : t(std::chrono::steady_clock::now()) {}
	std::chrono::time_point<std::chrono::steady_clock> t;
	};
	double elapsed_milliseconds(Timestamp t) {
	auto duration = std::chrono::steady_clock::now() - t.t;
	auto nanoseconds = std::chrono::duration_cast<std::chrono::nanoseconds>(duration).count();

kennyalive / gist:1c2f998d8cb3acd385642df029ae368a

Created April 28, 2020 20:21

invert_bin_ply_normals

kennyalive / Text_File_Parser.cpp

Created September 21, 2019 22:08

Text file parsing.

	struct Text_File_Lines {
	std::string text;
	std::vector<size_t> line_start_positions; // the last element is a position at the end of the file
	};

	struct Text_File_Parser {
	private:
	size_t pos = 0;
	int line = -1;
	Text_File_Lines* text_file = nullptr;