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# Objective - The goal of this PR is to make it possible to move the density texture of a `FogVolume` over time in order to create dynamic effects like fog moving in the wind. - You could theoretically move the `FogVolume` itself, but this is not ideal, because the `FogVolume` AABB would eventually leave the area. If you want an area to remain foggy while also creating the impression that the fog is moving in the wind, a scrolling density texture is a better solution. ## Solution - The PR adds a `density_texture_offset` field to the `FogVolume` component. This offset is in the UVW coordinates of the density texture, meaning that a value of `(0.5, 0.0, 0.0)` moves the 3d texture by half along the x-axis. - Values above 1.0 are wrapped, a 1.5 offset is the same as a 0.5 offset. This makes it so that the density texture wraps around on the other side, meaning that a repeating 3d noise texture can seamlessly scroll forever. It also makes it easy to move the density texture over time by simply increasing the offset every frame. ## Testing - A `scrolling_fog` example has been added to demonstrate the feature. It uses the offset to scroll a repeating 3d noise density texture to create the impression of fog moving in the wind. - The camera is looking at a pillar with the sun peaking behind it. This highlights the effect the changing density has on the volumetric lighting interactions. - Temporal anti-aliasing combined with the `jitter` option of `VolumetricFogSettings` is used to improve the quality of the effect. --- ## Showcase https://github.com/user-attachments/assets/3aa50ebd-771c-4c99-ab5d-255c0c3be1a8 |
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bunny.ktx2 | ||
fog_noise.ktx2 |