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Michael Grand

Member Since 22 Jan 2005
Offline Last Active May 04 2015 09:10 AM

Topics I've Started

Haukr - Top-Down Vertical Scrolling SHMUP

23 April 2014 - 12:03 AM

Play Haukr



Haukr is a top-down vertical scrolling shoot 'em up, designed in a style similar to old arcade games.  My brother and I started work on this game last year because we wanted to put together a small, fun game. While games like this do exist, there do not seem to be many in this exact genre and style.  Being fans of the genre, we decided to add our own game to the list smile.png  We hope you enjoy playing it as much as we enjoyed making it!



Use the arrow keys to fly around the screen. Tap the space bar to fire your warplane's weapons.



Destroy all enemies in your path!  Collect gold coins to gain additional lives, and large blue coins to upgrade your warplane's weapons.  If you manage to reach the end, the game will return you to the main menu.

How to use behavior driven design to make a game?

31 January 2012 - 09:08 AM

I am trying to figure out how to use behavior driven design (BDD) to create a game. When you open the game, a programmatically animated intro is played, which then transitions into the main menu.

From my understanding of BDD, it doesn't handle this kind of situation very well. It seems to be oriented towards users interacting with menus, due to the required first step of a user story.

What would the user stories be for this particular part of the game? I have some thoughts, but I really need to see examples of how BDD would be used to develop a game like this; all of the examples I have found deal with things like ATMs and blenders.

Terminate not called after SDL_SetVideoMode() with SDL_OPENGL?

21 January 2012 - 04:49 PM

This is a somewhat strange bug. The following code works fine:
#include <SDL.h>
#include <windows.h>
#include <exception>

void term()
	MessageBox(NULL, "Terminate", "Debug", MB_OK);

int SDL_main(int argc, char *argv[])
	throw (0);
	SDL_SetVideoMode(800, 600, 0, SDL_OPENGL);
	return (0);

However, in this version of the code term() is never called:
#include <SDL.h>
#include <windows.h>
#include <exception>

void term()
	MessageBox(NULL, "Terminate", "Debug", MB_OK);

int SDL_main(int argc, char *argv[])
	SDL_SetVideoMode(800, 600, 0, SDL_OPENGL);
	throw (0);
	return (0);

The only difference between the two pieces of code is that in the broken one, I am throwing the exception after calling SDL_SetVideoMode() rather than before it. Another thing to note is that the second example works if I remove the SDL_OPENGL flag.

I am compiling with Microsoft Visual C++ 2005, I am using SDL version 1.2.15 although I have also tested it with version 1.2.14 and the problem still exists, and I am running it on Windows XP SP3 Home. My graphics card is an ATI Radeon X1300 PRO, and my computer completely supports up to OpenGL 2.1. I have the latest graphics card drivers.

I suspect the issue is related to passing the exception from C++ code to C code (SDL 1.2.15 is written in C, but my program is written in C++), but if possible I'd like to know exactly what is going wrong.

What to study in prep for writing a physics engine?

14 June 2011 - 11:49 AM

I'm planning on going through the resources Chris Hecker recommends in his article Physics References, however that article (from what I gather) was written in around 1997: 14 years ago.

I suspect that there have been new developments since the article was put together, which brings us to the reason for this post: Do you guys have any additions/changes to the list he gives? For example, changing the order in which a topic is studied, a new and better book for a particular topic in the list, new topics to add to the study list (with accompanying book recommendations if you can), etc.

I like the fact that he discusses each set of books and the pros/cons. If you guys could provide similar notes with your recommendations, as well as when I should study that topic (right after reading the Calculus book? After reading everything else in that list?) and what I will be able to do in my physics engine after I study it (like his "milestones"), it would really help Posted Image

To help you decide what recommendations to make, I'll do my best to describe where I am in math. I should note though that I am currently planning on going through each resource in that list (with exceptions to duplicates), including topics I am familiar with. The main reason for this (as you will probably see in the following) is that while I might know overall about a particular topic, I usually don't have a whole lot of experience mainly due to not studying from a textbook with problem sets.

Basic math

Addition, subtraction, multiplication, division, fractions...

Algebra I

I learned this from a textbox, but unfortunately I do not have the title available to me at the moment.


I learned this from Geometry: Seeing, Doing, Understanding 3rd Edition by Harold R. Jacobs. Due to a lack of interest, and having other things to study, I only ever made it to chapter 9, lesson 1 (about half-way).

Algebra II

I never studied this from a textbook, but I did pickup on parts of it by studying other areas of math and programming. Using this page as a reference for what is studied in Algebra II, I am familiar with the following:

  • Solving Equations and Inequalities - I don't have much experience with inequalities, but I know how to work with them.
  • Graphs and Functions
  • Systems of Equations and Inequalities - I don't have much experience with solving systems, but I know the gist of it.
  • Polynomials and Factoring - I don't have much experience with polynomials (I can't recite from memory the various methods of dealing with them), but I do know what they are and I am familiar with how to work with them.
  • Fractional Expressions
  • Powers and Roots
  • Complex Numbers - I know what these are basically, but I have very close to zero experience with them.
  • Quadratic Equations - Most of my experience with solving these is by using the quadratic formula (which I have derived for myself several times before, once by accident).
  • Quadratic Functions - Most of my experience with these is from learning Calculus.
  • Coordinate Geometry - I'm familiar with this, but I usually need to use a reference whenever I have need of it.
  • Exponential and Logarithmic Functions - I get the terms "exponential function" and "power function" mixed up regularly, and I require references when working with logarithms (particularly natural log).
  • Probability - As far as I know, I don't have direct experience or knowledge of this.


I never studied this formally, but I picked up on parts of it from studying other things and programming. Using this page as a reference for what is studied, this is what I know:

  • Angle measurement
  • Chords - I am familiar with the term, but I don't have much experience or knowledge of the thing itself.
  • Sines
  • Cosines
  • Tangents and slope - I am familiar with this only through studying Calculus.
  • The trigonometry of right triangles - I know how to use the inverse functions, but I am not all that familiar with the rest.
  • The trigonometric functions and their inverses - I'm not very familiar with the properties of sines and cosines, although I have looked them up and made use of them in the past.
  • Computing trigonometric functions - As far as I know, I have no knowledge of this.
  • The trigonometry of oblique triangles - I'm not familiar with the law of sines or cosines.
  • Area of a triangle - I am familiar with a = bh/2 but not the method they describe in this section.
  • Summary of trigonometric identities - I am familiar with SOH-CAH-TOA, but my situation with the trigonometric identities is the same as my situation with the properties.


I learned this from the Calculus section at Brightstorm. I watched every single video in that section.

Multivariable Calculus

I learned this by watching the 18.02 lectures at MIT OpenCourseWare. I made sure I understood each lecture by pausing and rewatching, but I did not do any of the homework assignments or exams, and I did not have the textbook.

Differential Equations

I learned this by watching the first 4-7 (I don't remember the exact lecture I stopped on) 18.03 lectures at MIT OpenCourseWare. I did not have the textbook, and I did not do the homework assignments or exams.

Linear Algebra

I learned this from reading 3D Math Primer for Graphics and Game Development.

Set Theory

I know the basics, mostly from an introduction I had in between basic math and algebra I, as well as from studying other things.

Graph Theory

I am currently studying this from Introductory Graph Theory by Gary Chartrand.


I plan on studying this using Introduction to Topology 3rd Edition by Bert Mendelson, possibly after I am through the graph theory book.

Abstract Algebra

I plan on studying this using A Book of Abstract Algebra 2nd Edition by Charles C. Pinter, possibly after I am through the topology book. The order may vary depending on if I find that one book is dependent on the other, or I find that I am missing some prerequisite.

Linear/Quadratic Programming and LCP

I know of their existence and a tiny bit about what they are as well as what they are used for in a physics engine. I do not have any experience with these or knowledge of how to work with them.


I started learning this from the Physics Tutorial at The Physics Classroom. I did all exercises and I read up to and through the chapter "Circular Motion and Satellite Motion". It became a bit too vague however, so I switched to learning from here: http://electron9.phy...35d/Modules.asp. I went through each module up to and including "Rotational Motion", doing all of the problems in addition to understanding what was being taught.

Physics Simulation

I have read through most of the papers by David Baraff, although I did not completely understand them. I have also gone through various other papers including "Nonconvex Rigid Bodies with Stacking" and "A Unified Framework for Rigid Body Dynamics", the latter being the most helpful. I have also gone through Erin Catto's GDC2006 slides and the source for Box2D Lite. I have glanced through some of the chapters in Game Physics 2nd Edition by David H. Eberly, as well as Chris Hecker's Game Developer Magazine columns sans the one on 3D physics. I have also written several physics engines, however they have not worked very well.

Collision Detection

Most of what I know about collision detection I have learned from Real-Time Collision Detection by Christer Ericson. I have not read the book cover to cover though.

Preventing detail in dark areas from being revealed by increasing brightness

19 April 2011 - 10:39 AM

A common technique for avoiding the darkness system in a game is to adjust your monitor's brightness. One example of this is Tibia, where caves and such are supposed to be barely visible unless you have a torch, but adjusting your monitor's brightness allows you to see everything without one. How would you prevent this?

One rough idea I had was to somehow change the colors around so that there are more colors the brighter you go, and less the darker you go. The idea behind this is that it would smear anything which is in low-light. The main advantage of increasing brightness is to see detail, even if that detail is pretty much in black-and-white, so smearing should prevent the user from gaining anything. What are your thoughts on this technique? Is it an actual well-known technique which goes by its own name? I should note that I have very little experience working with shaders and any kind of post-processing effects. I pretty much only know that they exist and roughly where they belong in the graphics pipeline.