Altos Patch 1.11 Notes
January 24, 2023
In Altos 1.11, I've introduced an update to the weathermap system and improved the rendering quality of high altitude clouds. I've also added a new 2D Cloud texture that is the new default for high altitude and skybox clouds. It looks great.
The weathermap is a texture that describes where volumetric clouds are able to form.
Before this update, you could only use pre-baked textures as your weathermap, and these weathermaps were static in space - no panning or scrolling.
Now, there is a new type of Weathermap in town: Procedural. Infinite clouds, no pre-baking required. You can also set a new Weathermap Velocity parameter that will pan your weathermap over time, as well as a Weathermap Scale parameter that determines how closely packed your clouds will be. Further, you can define the Value Range output from the procedural noise. This acts as a secondary cloud coverage setting, masking clouds from some areas and guaranteeing clouds in others.
Texture-based weathermaps are still supported. They also benefit from the new Weathermap Velocity parameter, so you can now pan your Texture-based weathermap overhead.
High Altitude Clouds
I use constantly changing noise offsets to determine the position in space where I sample from our cloud volume. This helps us to sample across the complete cloud shape while integrating the results using our Temporal Anti-Aliasing. However, the noise offsets are not required for High Altitude Clouds, but were being used anyway. As a result, the High Altitude Clouds could sometimes be unusually noisy or could be rendered below their defined height (as a result of the offset).
Going forward, I've decoupled the High Altitude Clouds from the noise offsets system so that these clouds render more consistently in space and with higher quality.