Extending Unity Built-In Skybox Panoramic Shader

Hi there. I modified the built-in Unity skybox panoramic shader to support blending between two textures. This is helpful for cross-fading between two skies.

Here is the original Unity shader:
https://raw.githubusercontent.com/c...DefaultResourcesExtra/Skybox-Panoramic.shader

Here is my modified version:
https://gist.github.com/stonstad/28346c2b9d6668a2d697564a2e9909b9

There are separate properties for each sky (texture, gamma, and tint) and a single blend property specifies the blend between each output.

OK, it works! But I am conceptually confused at whether it would be possible to implement an independent rotation for each texture.

Spoiler

To implement independent rotation... here is what I tried:

1) Adding a new vertex property to v2f. This does not work for me because vertex stream processing is one vertex at a time. Not sure what I was thinking there.

2) UV texture translation. This does not work for me because each texture is spherical HDR and 4096x2048 pixels.

I thought about applying the original shader to two meshes and performing rotation via transforms in the hierarchy. But the potential downside to this approach is that the sky color would not contribute to scene lighting. I could then disable skybox environment lighting and use reflection probes, but then that seems like extra effort.

Is there a technique or approach I might try? Thank you so much for your thoughts and expertise!

 

Nothing dumb about that, this would totally work if you wanted to do it this way. But if you're going to stick to equirectangular ("Latitude Longitude Layout") maps there's a way, way easier method.

First, more than half of the shader code exists to handle a "6 Frames Layout" texture. If you delete all of the shader code in the

#ifdef _MAPPING_6_FRAMES_LAYOUT

blocks, the original will end up being much more manageable. Rotating an equirectangular UV is as simple as adding to the

uv.x

, or

tc.x

in this shader.

Code (csharp):

1. float2 tc = ToRadialCoords(i.texcoord);
2. half4 tex1 = tex2D (_Texture1, tc);
3. // you want _Rotation2 to be a 0 to 360 like the original value
4. tc.x = frac(tc.x + (_Rotation2 - _Rotation) / 360.0);
5. half4 tex2 = tex2D (_Texture2, tc);

And you're done.

 

Thank you @bgolus! Your proposed solution is flawless. If anyone needs it the updated source is available here: https://gist.github.com/stonstad/28346c2b9d6668a2d697564a2e9909b9

 

This work perfectly thanks a lot and great job!
You rock

 

Saved my life today! Thank you stonstad!

 

Shaun Tonstad Thanks so much

 

Awesome, you're the GOAT!