Orion Engine Blog

Wow, January disappeared fast! There just never seems to be enough time in the day, and the days just seem to keep getting shorter.

I finished several hard problems last month. I also fixed a lot of little bugs that have been bothering me for a while. For example, there was a weird bug with my TGA file loader that caused images compressed using RLE (run length encoding) to look funny sometimes. I also finished adding support for the mouse wheel to my 3D window/control library. Now you can use the mouse wheel to move the vertical scroll bar on a text box.

It always makes me feel good to know that my code is more complete and robust. I don’t want to move too far ahead, if there are still unresolved issues.

I finally got busy and wrote the code that was needed to perform a ray-intersection test with the terrain height map data.  Not only will this be useful for determining where projectiles collide with the ground, I can now also keep the 3rd person camera from clipping with the terrain.

I was worried, but the final algorithm turned out to be fairly simple.  I basically generate points to test on the height map using a 2D line drawing algorithm, by projecting the 3D line segment onto the two-dimensional height map data.  Using simple interpolation, I can calculate the height of the 3D line segment at the height map point I’m currently testing.  I then compare this height with the value stored in the height map data.  If the point on the terrain is higher than the line segment at this point, then an intersection was found.

I finished the new “limits” scene object today. It’s used to show the selection state of objects within the Orion Genesis world builder. It can even be used to visualize a bounding volume within the tool. It’s also going to be utilized in the game to show when an object, such as an avatar, has been selected (i.e. it was clicked on with the mouse).

There are lots of new updates to the user interface in the game. I hope to have a new patch ready before too long. Things are moving along very smoothly right now. It feels good to not have any road blocks in my way for a change.

I hope everyone has a great new year! Stay out of trouble. Stay tuned, I’ll be posting more blog updates next year!

The core engine code is actually pretty stable now. In fact, I don’t have to make changes to this code very often at all. However, I decided it was time to finally go back and address a few problematic issues before moving forward.

I made some minor changes to the base particle system class. There is now a parameter that can be used to set the render pass that will be used to draw the particles. This allows better control of what the particles are actually blended with during rendering. The particle systems look even better in the game now.

The 2D window/control library was also given some recent attention. The control mouse over state is more accurate now. Before, while moving the mouse quickly, the old code would sometimes select more than one control (i.e. a button) at a time. There were also certain circumstances that caused more than one popup text window to be stacked up on top of each other. These bugs, as well as some others, have all been fixed. The user interface in the game feels a lot more solid now.

I tried to use the red-black tree container template the other day and discovered that the iterator does not work correctly. I need to look into this and find out what the problem is. Then I’m going to get back to the game code again right away. The latest game client updates are looking awesome!