2048px Shader for iPhone

Unity Engine
1

I like to add a 2048x1024 texture to a sphere, but obviously ran into the limitation of Unity iPhone which currently doesn’t support textures larger than 1024x1024.

I’m by no means an expert when it comes to shaders, so here’s my idea: I guess it should possible to write a custom shader, which takes two 1024x1024 input textures and stitches them together seamlessly. Anything that might cause trouble here? Are there any implementations already around which wouldn’t force me to reinvent the wheel?

Thanks -

2

Here’s the simplest one I can think of. Just paint white in the vertex color alpha for texture 1, and black for texture 2. It doesn’t matter where you put the vertices for the half of the sphere that doesn’t correspond with the texture, but you will need a seam there to get a hard white/black edge. Considering this is a sphere, you may be able to use the same UV map for both textures, if the seam is on a great circle. Otherwise, use the second shader; UV1 is for Texture 1, UV2 for texture 2.

I’ve gotta tell you, though, I’ve tried this before, and didn’t really find it to be worth doing. It’s not really any faster than using two materials, from my testing. It could actually be a good deal slower, if you’re looking perpendicular to the seam, and your sphere has a lot of verts.

Shader "2 Tex, Vert Blend, 1 UV" {

Properties
{
	_MainTex ("Texture 1  (RGB)", 2D) = ""
	_Texture2 ("Texture 2  (RGB)", 2D) = ""
}

SubShader 
{		
	BindChannels
	{
		Bind "vertex", vertex
		Bind "texcoord", texcoord
		Bind "color" color
	}

	Pass
	{	
		SetTexture[_MainTex]						
		SetTexture[_Texture2] {Combine previous Lerp(primary) texture}
	}
}

}

Shader "2 Tex, Vert Blend, 2 UVs" {

Properties
{
	_MainTex ("Texture 1  (RGB)", 2D) = ""
	_Texture2 ("Texture 2  (RGB)", 2D) = ""
}

SubShader 
{		
	BindChannels
	{
		Bind "vertex", vertex
		Bind "texcoord", texcoord0
		Bind "texcoord1", texcoord1
		Bind "color", color
	}

	Pass
	{	
		SetTexture[_MainTex]						
		SetTexture[_Texture2] {Combine previous Lerp(primary) texture}
	}
}

}
3

Interesting, thanks. I have a few different approaches right now, I’ll go through them and see what works best.