@greyhoundgames: If you have a comment, you should leave it as a comment if you can, not as an answer as it makes it more difficult for other users to find what they are looking for.
As far as the problem that we’re trying to solve, this is what the response was from Unity:
Sprites are designed with the assumption that you define a fixed texture area for the Sprite - so the texture offset feature is removed from SpriteRenderer. However UV hacks can still be done in a vertex shader.
So, you probably need to write a custom shader where you can modify the UV’s and put it on your Sprite or stick with your 3D quad/plane approach, which I ended up doing due to simplicity sake.
EDIT:
Here are a few scripts I have that help solve the problem.
As I mentioned earlier you need a shader that can move the UV’s on the 3D quad. This is a shader that Blends Color, Transparency, and can move UV’s on a mesh.
SHADER
// unlit, vertex color, alpha blended, offset uv's
// cull off
Shader "BlendVertexColorWithUV"
{
Properties
{
_MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
}
SubShader
{
Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
ZWrite Off Lighting Off Cull Off Fog { Mode Off } Blend SrcAlpha OneMinusSrcAlpha
LOD 110
Pass
{
CGPROGRAM
#pragma vertex vert_vct
#pragma fragment frag_mult
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"
sampler2D _MainTex;
float4 _MainTex_ST;
struct vin_vct
{
float4 vertex : POSITION;
float4 color : COLOR;
float2 texcoord : TEXCOORD0;
};
struct v2f_vct
{
float4 vertex : POSITION;
fixed4 color : COLOR;
float2 texcoord : TEXCOORD0;
};
v2f_vct vert_vct(vin_vct v)
{
v2f_vct o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.color = v.color;
o.texcoord = TRANSFORM_TEX (v.texcoord, _MainTex);;
return o;
}
fixed4 frag_mult(v2f_vct i) : COLOR
{
fixed4 col = tex2D(_MainTex, i.texcoord) * i.color;
return col;
}
ENDCG
}
}
SubShader
{
Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
ZWrite Off Blend SrcAlpha OneMinusSrcAlpha Cull Off Fog { Mode Off }
LOD 100
BindChannels
{
Bind "Vertex", vertex
Bind "TexCoord", texcoord
Bind "Color", color
}
Pass
{
Lighting Off
SetTexture [_MainTex] { combine texture * primary }
}
}
}
Here’s a script that accesses the mesh texture UV’s and automatically scrolls the texture’s UV’s, but you can move the UV’s however you like:
Access Texture UV’s Example Script
using UnityEngine;
using System.Collections;
public class UIAnimatingBackground : MonoBehaviour
{
protected Material textureToAnimate;
protected Vector2 uvOffset = Vector2.zero;
public Vector2 uvAnimationRate = new Vector2( 0.3f, 0.3f );
public string textureName = "_MainTex";
protected MeshRenderer backgroundMeshRenderer;
[SerializeField]
protected bool resetPositionToZero = true;
protected void Start()
{
backgroundMeshRenderer = GetComponent<MeshRenderer>();
if(backgroundMeshRenderer != null)
{
if(resetPositionToZero)
backgroundMeshRenderer.transform.position = Vector3.zero;
textureToAnimate = backgroundMeshRenderer.material;
}
}
protected void Update()
{
if(textureToAnimate != null)
{
if(uvOffset.x >= 1.0f)
{
uvOffset.x = 0.0f;
}
if(uvOffset.y >= 1.0f)
{
uvOffset.y = 0.0f;
}
uvOffset += uvAnimationRate * Time.deltaTime;
textureToAnimate.mainTextureOffset = uvOffset;
}
}
}
Once these are set up, you create a Quad Mesh in the Unity scene. Attach the UV script component to the Quad Mesh, and set the shader material to the BlendVertexColorWithUV shader. To place the mesh quad in front of or behind the sprites you can change it’s z position in the inspector, or change the layer it is on to draw before the Sprites.
