Tuesday, July 21, 2009

Optimisation Fail

This is a maintenance/progress blog post so nothing exciting really. I just try to post a few times a month as any developer keeping a journal should.

I got rid of the vertex buffer and texture resource pools and created a mesh pool and each mesh has its' own vertex buffer and textures so the same thing is accomplished and the mesh resource manager is now way simpler. I used to have std::maps with pointers to the meshes in each list depending on what stage the mesh was in (needs building, built, and visible, cached and cache build) - now I have 3 std::vectors for 3 lists: needs building, built and visible.

The lists are stored in an array like this:

std::vector mMeshLists[3];

The built and visible lists are in index 0 and 1 and I swap them periodically like this:

mVisibleListIndex = (mBuiltListIndex + 1) % 2;

And the build list is always index 2.

Unfortunately, the app is still too jerky. Creating the textures on the graphics card is taking too long, generating the heightmaps is taking too long and it's not smooth even though I'm using threads for all the non-opengl stuff. Most of the time spikes are now happening in Ogre so I will probably have to add some profiling there to figure out what's going on.

Also, I switch over to DirectX 9 so that I can use NVidia's Perfhud tool to help me analyze how the graphics card and cpu are being utilized. That's been fun.

The only major bug I have at the moment is that the Render To Texture code that generates the terrain texture for each patch isn't working in DirectX right. My dynamic heightmap texture is not being created correctly and I don't know why yet. I have been experimenting with different pixel formats to no avail yet.

I'm almost thinking of doing another simpler version of the quad tree planet that uses geomippmapping and the planet size is restricted to 1025x1025 vertices per side - or maybe 2049x2049. This terrain is taking too much of my time to code that should be spent on other important game things!

1 comment:

Tristam MacDonald said...

On the flip side, once the terrain is working, you should never have to touch it again - with a little luck ;)