Every Windows programming needs a main entry point. That being said, you may be wondering what this entry point is. The main entry point for any Windows program is called WinMain. The function prototype for WinMain is a little confusing at first, but as we continue to work with it you'll notice it becomes much easier to understand. Well. we've told you what it is; now were going to show you! Here's the prototype for WinMain

Welcome to the seventh lesson in my OpenGL series! In this lesson we will learn about Projections and even put them to some simple use to see them in action. Some of you may have realized that weÕve used projection transformations in code before, and your right, we have. The difference is now we will discuss how they work, and then demonstrate these concepts.

simple fact that OpenGL is only a graphics API means that any user interaction, or things like screen and window issues needs to be handled by the operating system. Most operating systems come with a set of extensions that tie OpenGL together with user interaction and window management. This tends to make our lives a little bit easier, but only if we know how to take advantage of this option. In Windows this set of functions are called the wiggle functions. Each of these functions is prefixed with wgl

Welcome to another fine lesson in C++! Today you'll be introduced to the wonderful world of OpenGL. OpenGL is a fairly straight forward -- although at many times confusing -- concept. OpenGL gives the programmer an interface with the graphics hardware. OpenGL is a low-level, widely supported modeling and rendering software package, available on all platforms. It can be used in a range of graphics applications, such as games, CAD design, or modeling (to name a few).

The competition between OpenGL and DirectX is possibly as well known as the wars waged between AMD and Intel enthusiasts. This topic has sparked the fires of many flame wars throughout the years, and I donÕt anticipate that changing anytime soon. I wonÕt preach why I prefer OpenGL over DirectX, but rather lay out the facts and let you make that decision. So letÕs dive in! erhaps the most obvious difference is that DirectX, as opposed to OpenGL, is more than just a graphics API. DirectX contains tools to deal with such components of a game as sound, music, input, networking, and multimedia. On the other hand, OpenGL is strictly a graphics API. So what aspect of OpenGL sets it apart from the DirectX graphics component?

In this lesson I shall introduce several functions and show you actual OpenGL rendering in a program. Prior to showing you the code, however, I want to go over a few things with you. This will give you a better understanding of what is going on when you do see the code, so you don't stare at the screen wondering what you're looking at. So, on with the show.

The previous method of doing the rotations is called using Euler angles. It's probably the simplest way of doing rotations, but it has some problems. The biggest problem is called gimbal lock. You may or may not have already encountered this if you wrote code according to the last tutorial. If you encountered it and noticed it, without knowing what it was, you may have spent hours trying to figure out where you went wrong in your code, carefully comparing every line of your code to the tutorial, trying to find the difference. If that happened, I'm sorry. There is nothing wrong with your code; there is something wrong with the math. If you'll recall, I told you two very important things, which you probably didn't connect in the last tutorial. 1) Matrix multiplication is not commutative. A*B != B*A. 2) We generated matRotationTotal by doing matRotationX * matRotationY * matRotationZ. If there was nothing wrong with the math, you should have been able to do matRotationY*matRotationZ*matRotationX, or any other order, and gotten exactly the same results. But you wouldn't. This problem is the root cause of gimbal lock. Trying to visualize this might blow your mind, so if you don't understand the next paragraph, don't worry too much. Just remember that Gimbal Lock happens when one axis gets rotated before another axis, and the axes are no longer mutually perpendicular. It can be a large problem, or it can go unnoticed, depending on the application.

At this time we will take a look into the vast world of Windows programming. Since this tutorial is based entirely on programming done within the Windows environment, it will be required of you to have access to a Windows machine and compiler. For the programs we will be creating you will need a base understanding of the mechanics and structuring of the Windows operating system. Not to worry, however, because I am going to teach this to you! Microsoft Windows is a multi-tasking operating system that allows multiple applications, referred to here on out as processes. Every process in Windows is given a certain amount of time, called a time slice, where the application is given the right to control the system without being interrupted by the other processes. The runtime priority and the amount of time allocated to a process are determined by the scheduler. The scheduler is, simply put, the manager of this multi-tasking operating system, ensuring that each process is given the time and the priority it needs depending on the current state of the system.

Okay, so I assume going into this tutorial that you know how to perform matrix multiplication. I don't care to explain it, and it's available all over the Internet. However, once you know how to perform that operation, you should be good to go for this tutorial.The way presented for doing rotations in the last tutorial wasn't really a good one. It works just fine in two dimensions, but as soon as you want to rotate around the X or Y-axes, it becomes more difficult. Sure, it's easy to make equations that will represent a rotation on any one of those axes, but just go ahead and try to make equations that will represent changes on three axes at once. If you manage to pull that off, make sure to let us know. Meanwhile, I'll present a way to do the rotations with matrices

The purpose of this tutorial series is to explain the math involved behind rotating points in three dimensions. It will start out by describing how to use a rotation matrix to rotate a point over the Z-axis, simply because this is the easiest rotation to visualize and implement. It's just like a clock hand going around. Then, the tutorials will move on to give you the matrices for rotation over the x and y axes, tell you how to use them, and then give you a matrix which will allow rotations around an arbitrary axis. Translation matrices will also be covered. There will be talk of cameras and simply rotating objects, and then will move on to quaternions, which are the solution to the problem of gimbal lock, which is encountered when using Euler angles. I may mention some other things, or I may not. The current plan is to type these until I get sick of it. It will start out by describing how to use a rotation matrix to rotate a point over the Z-axis, simply because this is the easiest rotation to visualize and implement. It's just like a clock hand going around. Then, the tutorials will move on to give you the matrices for rotation over the x and y axes, tell you how to use them, and then give you a matrix which will allow rotations around an arbitrary axis. Translation matrices will also be covered. There will be talk of cameras and simply rotating objects, and then will move on to quaternions, which are the solution to the problem of gimbal lock, which is encountered when using Euler angles. I may mention some other things, or I may not. The current plan is to type these until I get sick of it.