Catalin 's Blog

I am moving my blog / site to a new location: www.catalinzima.com

There you will find all my samples and tutorials, and all new stuff will be hosted there.

The site has different sections containing tutorials, samples and other miscellaneous downloads. Also, it begins its existence with a new goal: 12 months, 12 samples. You can read about what this means, in my welcome post, here. I hope you enjoy the site.

Thank you,
Catalin Zima

P.S. This blog will remain alive, for announcements and whatever else it will be needed for.

In response to some people asking me how to start learning shader programming, I made a list of some resources that could prove helpful when learning HLSL:

The Shader Series, found on creators.xna.com are a very good set of articles and samples, that explain the basic knowledge needed to understand and write shaders in HLSL.

• Shader Series - Introduction
• Shader Series - Fixed Function to Programmable Pipeline
• Shader Series - Coordinate Systems 
• Shader Series 1 - Vertex Lighting
• Shader Series 2 - Textures and Colors
• Shader Series 3 - Per-Pixel Lighting Sample
• Shader Series 4 - Materials and Multiple Light Sources

Riemer Grootjans also has a series of tutorials on HLSL, which can be found on his site.

A very good book on shaders (in my opinion, the best book on shaders I've read) is The Microsoft DirectX 9 Programmable Graphics Pipeline by Kris Gray. I found this book extremely useful, with very good explanations, and nicely structured. The code samples, however, are in C/C++, but for most people that shouldn't be a problem.

After mastering the basics, you can explore other samples and articles, which can be found on www.ziggyware.com and creators.xna.com.

Another good place to find information on shaders are the web pages of the two big GPU manufacturers, NVIDIA and ATI. Each site has a section devoted to developers, which are great places for everyone, beginners are advanced users alike. Both sites provide code samples, documentation, tools and SDK's. Out of these, my favorites are NVIDIA Shader Library, NVIDIA SDK and ATI SDK. Most important, these site contains lots of articles and presentations from various conferences, which explain a wide range of effects and techniques, and how they are achieved on the GPU. Admittedly, most of them do not provide HLSL code, but the idea and algorithm is almost always more important than the code itself.

For advanced effects and usages of the GPU, I recommend the GPU Gems series and the ShaderX series.

Finally, as a recommendations for those who want to learn HLSL, try to examine as many samples as possible, and play with the HLSL code to see what happens when changing values, until you understand why things happen the way they do. Don't start by doing HDR Lighting, or Relief Mapping. Start with the small tutorials, and understand what happens and why before going on to the more spectacular samples. Last, but not least, don't be afraid to look at C/C++ samples. The DirectX SDK contains some very good samples of HLSL. I know, they're written in C/C++, but the shader code stays the same when going from C++ to XNA.

After I've seen some people asking how to do this on the forums, I decided to make a small class that allows us to draw Pies in 2D in XNA.

To use it, just create a new Pie2D object. The constructor receives parameters for the radius, angle and tessellation. These can also be modified at runtime, and the shape will be altered appropriately.

I made a sample that shows how to use this class. You can download it here: Pie2DSample.zip

A pie could be useful in 2D games for various effects, like enemy visibility area, flashlights, shields, etc.

    A friend of mine asked me about a small XNA sample where he could manipulate a model using the mouse. I made something up quick. It is not much, but I though I'd share it with the community, maybe someone will find it useful.

Controls:

• Left Mouse Button + Drag to rotate the model around the Y axis
• Right Mouse Button + Drag to scale the model

You can download it here: MouseManipulator.zip

I happily announce that I have again won Ziggyware's XNA Holiday Contest

The three winning articles are:

1. Deferred Shading in XNA - Catalin Zima

2. Depth of Field - Kyle Schouviller

3. Shadow Mapping - Andrew Joll

I'd like to congratulate all who entered, and thank Ziggyware for organizing the contest.