Currently I have a diffuse map with clouds that are tiling horizontally on a simple plane (panning for movement).
I have the texture mapped to a simple plane geometry.
My desired effect would be to have the clouds themselves masked by the alpha in the cloud diffuse texture, but also have the edge of the plane have a soft fade on both ends. This way, when the clouds are panning, there is a soft transition from the edge of the geometry and not a harsh one.
Any help or insights would be appreciated, thank you!!!
I’ll try to summarize what I understood:
You have a texture 1 with a diffuse map of clouds. Those clouds pan over sky. The same texture 1 has a mask in the Apha channel that says, where clouds are and where they are not. The mask should not pan. You want additionally a bounding box with soft edges around the whole thing. This box also does not pan.
We sample both the Alpha Mask and the Diffuse Map from the same texture, but because their UVs are different, we have to have different Textures Samples. We multiply the Alpha with the Diffuse Map Mask, so the cloud has a density of 0 when the Alpha is 0 and shows the Diffuse Map when Alpha is 1.
We have multiple options for a soft bounding box. You could use a BoxMask2D for a cube cut-out. RadialGradientExponential makes a sphere. And at last Texture Mask works with any shape you can draw and works like your Alpha Mask. Be sure to select Sample Source “Shared:Clamp” or the bounding box texture will repeat itself. Pick one and multiply it with the Result of the multiplication of your Diffuse Map and Alpha Mask.
I feel like this is a rather strange way of making a cloud. I hope this still helps you. I would suggest this 5min [video segment][2] from Ryan Brucks about cloud shapes.
