Wednesday, 13 April 2016

Random Explosions And Animated Particles

After having spent an inordinate amount of March as some sort of filthy casual nodev type, it was time to fill out the tax return and get back to cracking on with yesdev.


The stock way Torque3DMIT deals with projectile impact is to spawn an explosion, which is made up of a 3D animated object and/or particle effects with the option for sub-explosions. All well and good, but this does not really generate much variation. I decided to expand this into multiple explosion datablocks that would be choosen between randomly. I was slightly confused about how to pack/unpack using an array list of numbered keys, and whilst I didn't receive any build errors I could not get it to work in practice so chose a thoroughly less elegant solution. I simply listed 3 extra explosions for the projectile, had the engine check whether the datablocks were kosher, and then randomise which one to use, falling back on to the default explosion if problems occured.

And here it is in initial testing. Wooo! Pretty colours!

 I had also been practicing using animation with my particles via videoing fire and smoke and then creating a sprite sheet from the stills. This looks so much better than having static particles, allowing for flickering flames and billowing smoke. Animating particles not only looks good with all stuff moving but they save on performance by allowing you to use a single particle for the effect rather than multiples ones to create the illusion of movement or volume.


Since previously playing around with the idea of animating particles using sprite sheets, I had had my attention brought to a particle generator called TimeLineFX. For a poxy 30 of Her Majesty's British Quids (that's like 45 Seditiously Ungrateful Former Colonial Bucks or something like 5 trillion Emus) it was well worth the cash. It features a huge array of demo libraries and vast options for creating and exporting sprites sheets of animated particles.


To keep overhead low, I decided to use quick spawning, single particles which had a sprite sheet for weapon impact/explosions. By combing multiple emitters into an explosion constisting of starting impact flash, blast shockwave, ending sparks, all of which are basically a single particle playing through their animation and then deleting. Couple this with a small number of additional multiple particles for a puff of smoke and a few random sparks to add depth, and then make four of them as a variation on a theme and it gives a very nice selection of explosions.


I also took the concept of using a low overhead, singular animated particle to replace the build up to my 3D model of an energy blast from the offensive powerup named "Super Orbital Laser". Instead of having a fast growing glow with multiple balls of light getting sucked into it, I could use a single sprite sheet. End explosion still needs work but the 2 second buildup was what I was after.


And here's a test with 4 different types of glow and blends, though the two main versions are close enough for it to be almost impossible to tell.



So, next up, more of the same, more fancy animated explosions, more fixing errors with various special attacks which don't fire when triggered. More of the day in day out problems and conundrums of indiedev.

Wednesday, 24 February 2016

Detail And Layering Map Tests

I've been playing around and testing with materials to try and get a good work procedure for creating variation.

First up, I used some open source art resources from the Torque3D Pacific Demo, which can now be found free for download with all art assets here http://wiki.torque3d.org/main:downloads. I amalgamated various terrain textures with their images marked _detail for overlays, such as grass, dry ground and volcanic rock to create a starting texture. I used the detail textures as specMaps and the original normalMaps, before testing the various slots of detailMap and detailNormalMap in the matieral.


Adding a detail map with a scale of 1 made the highlights and shadows of the diffuseMap stand out more. Hardly surprising as the detailMap is taken from the diffuse. Increasing the strength of the detailNM increased the grain of the image. Scaling the detailMap across the diffuse caused a more even grain without sharpening specific features. I thought that textures tended to look better close up the more sharp they were, and the opposite further away.

Next up I tested layering textures. The idea was to create new materials without having to manually merge two images in an image editing app, thus saving on texture memory in the long run. I took a grass texture for the base layer0, and overlayed it with the volcanic rock texture in layer1, to which I had added an alpha channel. The alpha channel was quite simple, I simply boosted contrast on the reference image and took highlights, mid, and shadows.


After intial testing I thought that the grass was somewhat washed out so I boosted the reduced the mid levels of the alpha channel so that it favoured the grass over 50-50 mixing. Originally I had based the alpha channel directly from the contrast of the texture, but found it better to boost the hightlights and then expand them for white, then expand a smaller area for mixed and have the remaining as fully translucent black. This let much more of both layers appear with only limited fade, making the whole thing sharper.

For the final test I added a mask onto the grass texture to simulate earth or dirt (though this could have done this with another layer between grass and rock to again reduce image quantity and thus texture memory, but these are only tests for visual effect). I hoped this would give a more naturalistic effect rather than just having rock sticking out of grass.

Rock and Alpha Channel (at 25% scale) Very 1-0 with only a little semi-transparent

I also noticed in previous tests that whilst detailMaps, detailNMs and specMaps worked on higher layers, standard normalMaps only used the base layer0. To give the rock layer some extra height, I used the volcanic Nm and Spec for layer0 with the grass texture. I had used the rocks alpha channel to paste dirt over the grass and now reduced the size of the white and grey levels so that more of the dirt would show around the edges. I proceeded to do various tests to see it looked, changing detailMaps, detailNMs, and even tweaking layer1 diffuse.


Eventually my eyes went all googly from looking at tiny changes.


Friday, 12 February 2016

World Building Test And The Secret Of Grass

Onwards to world building. I had decided to dispense with the stock terrain and foliage systems, and instead thought of constructing each level out of custom meshes.
With the game's perspective being topdown/high-isometric, I had decided that polycount would not be much of an issue for the whole thing to run smoothly, as not too much of the game world would ever be visible at any one time. I intend to tonemap all of the world geometry with third-party app pureLight, though I've also used Blender to do this previously, and then set the in-game lighting to incorporate lightmaps, so that the diffuse/albedo map is influenced by the tonemap but the normal/specular maps are altered by the dynamic lighting.

Before I could getting cracking on world building, there was the small issue of coming up with a functioning work process, as well as load testing, and the awkward issue of how to get grass to animate without using the forestObject's moving foliage shaders. Players love stuff on screen, and if there's one thing they love more than stuff on screen it's moving stuff on screen.


How do I into grass?

First up, basic construction testing. I decided on a 10x10 mesh with multiple textures of grass, dirt, and rock - 1 drawcall per material. I was not particularly bothered about polycount for testing so there's a lot more geometry than needed. I wanted to create a few islands of grass and rock to make it look more interesting. Specular was initially somewhat overkill and really needed toning down to almost off, but just enough to create some very slight highlights. I modeled the mesh for some physical depth, raising grass and rock layers.



Not bad for a start but the edges of the grass and dirt were a little hard. Of course in real life, grass and dirt don't just fade into one another, but in video games things look odd without blending. I tried various levels of blends but found that just 2 worked fine for what I wanted. Spreading the blend over a metre seemed enough distance  to break up the harshness of the change from dirt to grass.



Satisfied with how modeling was going I moved on to grass and immediately hit problems. I found a grass image to use as a placeholder and covered the grass terrain texture in a couple of thousand planes for testing. With the game's high viewpoint, having straight polys looked bad, so I set about dividing the meshes and bending them over at an angle so everything leaned and tilted. Polys facing directly away from the main lightsource had some strange and frankly annoying blackness to their planes. Using an emissive material solved this - but then everything looked like a uniformed colour and became just an amorphous mass. Adding subscattering to the shadows helped to ease the harsh blackness of the polys but it still didn't appear as though they were being properly illuminated.



So off I went on an intrepid quest to find out what the hell was going wrong via insert-your-favourite-internet-search-engine-here. Normals were the problem. Foliage normals apparently need to point up to receive proper lighting. But alas the ancient 2.44 version of Blender from 2007 which I still use - because ... convenience - cannot into normal editing - however the new 2.76 version can. Luckily most of the hotkeys seem to be the same so it wasn't too difficult to pick up, and normal editing itself is just a modifier.

Goodbye horrible black stuff ruining the aesthetics of my foliage

I had decided that making an animated texture for moving grass would give the look I desired with very low overhead. I had created a huge level with over 9000 meshes for load testing, and just to see how bad it would be,  I used bone animation to move the grass polys and the framerate immdiately died to around 20 fps. So, just as expected then, back to animated textures.

I created a high poly grass mesh in Blender based on this little gem found on the internet (http://forums.torque3d.org/viewtopic.php?f=18&t=18#p53), and then animated it using multiple bones, and rendered out the frames. I tried various frame numbers and speeds, and it shouldn't be too much of a surprise that the more frames an animation has, the better it looks, so I settled on 32 frames. I found that the grass didn't really need much movement in the animation, and in fact looked better with less, rather than wildly thrashing about with higher movement. The renders also scaled nicely. Originally taken at 256 pixels, it gave a rather terrifying size of 8192 pixels, way more than older GPUs would want to cope with. It could be reduced via "nearest neighbour" to prevent blurring to 64x2048 and still look good.



One thing which I had noticed was an annoying uniformity of movement in the animation which gave an unpleasant  "swelling" effect. Setting different planes to different parts of the UV map meant that they played different parts of the animation and helped break up the regularity. I also decided to create multiple animations based on differing meshes and combine them all into a single atlas/mega texture. I ended up with 1 thick grass render with lots of grass stalks, a thinner medium one, and 2 thin small ones. I then combined the 2 small ones to be anew  medium one, and finally added the other medium to create a new thick mesh. All in all, this gave meanimations for 6 different sized grass clumps to help combat the sameness of just one animated texture. Combined together on a single 2048 pixel image, there was plenty of space for further cosmetic variations such as colour, lightness/darkness, saturation changes and the sort.
I had a little play around with alpha reference to see the difference have thick to thin grass made.


Quite happy with conquering the secrets of grass I moved on to load bearing. I had previously created a 1 kilometre level, filling it 10,300 copies of the mesh. Viewed in it's totality it was 119 million polys, 124,000 drawcalls and a mspf of 666.667 - which gave me a sudden urge to play Iron Maiden's greatest hits. However, even close in the result was 40 million polys and 5 fps. A quick check of culling revealed ... well, not as much culling as I had hoped. With the camera set back and angled a lot more was rendering in the fustrum than was actually visible. Of course during these tests I had no "Level Of Detail" for my 10K meshes. I made multiple levels of LOD and set up the options preferences so that they reduced polys and materials the lower you set it, but also LODed hard outside of the immediate camera view. In the end I had things down to show the highest LOD on screen all at once with 70 fps, 665K polys with 913 drawcalls and half of that is shadowing which won't feature as much once I start using lightmaps and the diffuse material filters the main dynamic light source.

I also tested less instances of meshes, combining 9 of them into a single object. This reduced the total number of meshes from 10,300 to a mere 1,160. Polys went up slightly to 772K, drawcalls fell dramatically to just 235 - a third of which was shadows, and fps rose to a thrilling 100+ fps. All of which was somewhat to be expected.

So here's what that all looks like with the additions of screen spaced ambient occlusion and a vignette shader around the edges. I think having the grass bent over a little more might help aesthetically, but I'm quite pleased with the result and the performance.