July 8, 2009

Sky is not the limit!

Posted in Computer Graphics tagged , , , , , , , , , , , at 9:40 pm by sagito

After a short break due to WordPress maintenaince, I’m back to post about the new stuff that I implemented in the Conspiracy Engine! It now features skybox support, collision detection and a very complete particle engine!

Implementing a skybox was pretty easy. For those of you that do not know what a skybox is… Well, it is pretty much that, a box that represents the sky. So, what about that, why can’t it be just a cube with some texture mapped like every other object? Because unlike other objects, the skybox must move with the viewer… I.e., the user cannot get out of the box as the skybox itself must move with the camera. Just like a person can’t reach the horizon! So, how can one implement a skybox? Pretty easy, you get the view matrix (through IDirect3DDevice9::GetTransform(D3DTS_VIEW, &view);), reset the last row to 0.0 except for the last value and set the new view matrix. After that, the world matrix must be set as an identity too in order to remove any unwanted transformation. Then we can render the skybox! After rendering, we put back the old view and world matrix.

For collision detection, DirectX already provides some very useful functions that automatically calculate the bounding box and sphere for a given object! After that, I just took some optimization measures and converted the bounding box to an axis-aligned oriented bounding box (see http://www.toymaker.info/Games/html/collisions.html for more info). Then, the objects are tested for collision… If a collision happened, it is propagated through a chain of responsability to some entity that handles the event or discard if no one does…

Finally, the particle system was based on a tutorial from CodeSampler (http://www.codesampler.com/dx9src/dx9src_7.htm). The system described in this tutorial is awsome and very complete! Also, the code is very well structured and commented, so it was pretty easy to implement this too.

To end this (already long) post, here is an image of the engine with the skybox and the textured cube:




  1. Guilherme said,

    I love to see the evolution of your engine and the steps you take to bring it to life! Reporting the difficulties and issues you encounter during the creation process, how you managed to solve them, and your intelectual resources are a really great blueprint to new comers on graphics programming and directx programming itself (myself included. I’ll be sure to contact you whenever I’m stuck : p). Be sure to keep us updated with news regarding your engine improvements! Congratulations and best wishes, hoping to see a game running on it in a near feature (:

    • sagito said,

      In the first place, let me thank you for your interest in this project! It is very important to me to notice the support of other developers! 😀 I intend to go somehow further in this blog by providing some tutorials for common problems that I have faced while building each of the engines I brought to life! This is by far the most complex and which had bigger architectural problems. However, all have been solved and I intend to post some solutions as soon as possible! 😀

      I will keep you informed of the progress! 😉

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