Addtional UVs with flipbook start frame (Unity 5.6)

Graphics Shaders & Materials
1

I’m unclear about additional UV channels in particle system.
When I use TEXCOORD0.zw for UV1 (“UV2” in TSA module), the flipbook actually begins at frame 1, when normally TEXCOORD0.xy/UV0 begins at frame 0. This means if I need to locate frame 0 of UV1, I need to scroll the texture offset x backward in material property or shader uv according to texture sheet division OR just move “UV2” upward in custom vertex stream so UV1 uses TEXCOORD0.xy instead, none of these workarounds is ideal.

TEXCOORD1 for UV2/3 (“UV3/4” in TSA module?) is something weirder which I would let the attached unitypackage speak for itself.

3063986--230289--ps_flipbook_oddity.jpg
3063986--230289--ps_flipbook_oddity.jpg1920×1080 358 KB

3063986–230290–20170510_bugreport_particlesystem_uv2_flipbook.unitypackage (59.4 KB)

2

The first UV describes the current flipbook frame.
The second UV describes the next flipbook frame.

This is so, when the animation is between frames, you can read both frames and blend between them. (Using the AnimBlend stream).

3

So am I supposed to share TEXCOORD0.xy across all textures in my shader for consistent flipbook frame?