Day/Night Cycle and Performance

Yllah » Devlog

2 years ago by Pampou

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Here are some updates about Yllah. As always, things may change until the next release.

New call effect

The call effect is now more accurate and based on the character design.

Day / Night Cycle

The day/night cycle will add more depth to the world of Yllah, as it will allows us to introduce some effects/events depending on time. Color schemes can be different too and offers the opportunity to re-discover areas once sun is going for a nap.

Fancy Stuff

The game contains some more foliage.

Added some butterflies because why not

Performance

One main issue who appeared quite early is performance issues. After creating all this foliage and trees. The framerate was in pain. So several tricks were used : Impostors and GPU Instancing.

GPU Instancing was mainly used for the interactive grass and allowed a save of an enormous amount of draw calls. See by yourself :

The other trick is using LOD Impostors. Instead of having several levels of details for a model, there are 2 variants of the model : The original and the Impostor. Basically, the Impostor is a plane with a 2D representation of the 3D model but several angles are taken into the baking process and prevent the billboard effect.

For example, here is a simple scene with a lot of trees :

Without the Impostors system, the frustrum catches about 2.2 million triangles. But with the Impostors System :

The amount of triangles shown reduces from 2.2 million to 416k triangles. Worth saving approx. 1.8 million triangles. The computer is now cooler.

Here is a wireframe view :

The closest trees are drawn as full models while others on the background got their Impostor variant.

All these tools, GPU Instancing, LOD Impostors and other stuff like the Occlusion System will keep the performance stable if used properly.
That's all for this post. Until next time.

Pampou

P.S. : Oh, and we also tried Procedural Animations for some reason.