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Here are some articles & tutorials I've written. May some of them be useful for you...
######### Coding Tutorials
 ######### Math/Theory Articles
######### Reverse Code Engineering Tutorials
######### Crackmes/Reversemes Solutions


######### "Coding" Tutorials

Writing a Loader in Delphi

Date : May 2002

Description :
Demonstrates how to manipulate another program's memory in order to change its behaviour. Only Windows API functions are used, so it should be no problem to convert it into another language.

######### View Article online
######### Download Article + Source Code (27KB)


Writing a Patcher in Delphi

Date : May 2002

Description :
Demonstrates how to code your own little tool which changes bytes in another file. Useful if you want to write something like a savegame editor. In my example we'll change a string. In this tut 2 ways are covered: one using delphi functions, the other using Win API functions for file-access.

######### View Article online
######### Download Article + Source Code (56KB)


Inserting a splash screen into an Exe file (through a dll) - "The easy way"

Date : November 2003

Description :
Demonstrates how to add a splash screen to a PE file. To make less changes as possible to the exe file, we'll code a dll with the splash screen and add it simply to the import table.

######### View Article online
######### Download Article + Source Code (225KB)


Simple Collision of Two Balls

Date : May 2006

Description :
Some time ago I dealt with 2D collisions of balls. So why not share what I have thought of :-) Here are some notes concerning simple 1D/2D collision of balls and two applets showing this stuff in action. Source included in the zip file.

######### View Article & Applets online
 ######### Download whole package (55kb)


Introduction to Curves

Date : July 2007

Description :
Discusses Linear Interpolation of two points, Quadratic & Cubic Bezier Curves, The Bernstein Form of a Bézier Curve, The de Casteljau Algorithm and Degree Elevation.

######### View Article


Polygon Algorithms

Date : September 2007 - January 2009

Description :
Discusses Polygon Convexity, Polygon Filling with the Scanline Algorithm and Polygon Triangulation with Kong's Algorithm.

######### Go to Article


Bresenham-Algorithm

Date : December 2010

Description :
My own notes about the Cohen-Sutherland-Algorithm for clipping 2D lines against a rectangle.

######### Beam me to the article and the applet


Cohen-Sutherland-Algorithm

Date : December 2007

Description :
My own notes about the Cohen-Sutherland-Algorithm for clipping 2D lines against a rectangle.

######### Cohen-Sutherland-Algorithm (Articles & Applet)


Cohen-Hodgman-Algorithm

Date : December 2007

Description :
My own notes about the Sutherland-Hodgman-Algorithm for clipping a polygon against a rectangle.

######### Sutherland-Hodgman-Algorithm (Article & Applet)


Welzl's 'Smallest enclosing disk' Algorithm

Date : May 2008

Description :
My own notes about Welzl's algorithm for calculating a smallest enclosing disk (minimal enclosing circle) of a set of points in the plane.

######### Welzl's Algorithm (Article & Applet)


14-15 Puzzle

Date : February 2010

Description :
Personal notes I made while I coded an applet as well as an automatic solver for the 14-15 puzzle.

######### 14-15 Puzzle Applet Online + Theory & Implementation Details


Parsing Algorithms

Date : October 2010

Description :
Article and source code about evaluating mathematical expressions using three different algorithms.

######### Article and source code

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######### Math & Theory Tutorials

The Derivative of Bernstein Polynomials

Date : August 2007

Description :
While reading about Bézier curves, I came several times across the formula for the derivative of Bernstein polynomials but I found nowhere how to get there. Also the fact that a Bernstein polynomial has just one maximum in [0,1], more specific at t = i/n, is easy to see but I did not find the proof in any book so here is my try to show it.

######### Download (PDF, 38KB)


Proof of Pascal's Rule

Date : March 2008

Description :
Again I delt with Bézier curves and especially with the recursive formula of the de Casteljau Algorithm which bases on the recursive formula of Bernstein polynomials which finally bases on Pascal's Rule. None of the books here lying on my table contains the proof so here it is - in fact short and really simple!

######### Download (PDF, 29KB)

The Birthday Paradox

Date : April 2010

Description :
This document contains my own notes about the so-called Birthday Problem or Birthday Paradox. This was written due to personal interest, in order to fully understand everything but also to get the required knowledge to explain this problem others in a logical way. Therefore, I also compare it to a similar problem and emphasize the difference. You should have a basic understanding of logic and probability calculation.

######### Download (PDF, 579KB)

Rotation Derivation

Date : September 2011

Description :
A short primer on how to derivate the rotation of a point around the x-, y- and z-axis-

######### Download (PDF, 480KB)

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