Resolved Max number of Compute Buffers on mobile

Hello everyone,
i saw in the Unity documentation here that there is a limit of Compute Buffers count on GLES 3.1 and lower Platforms.

Platform-specific differences

• OpenGL ES 3.1 (for (Android, iOS, tvOS platforms) only guarantees support for 4 compute buffers at a time. Actual implementations typically support more, but in general if developing for OpenGL ES, you should consider grouping related data in structs rather than having each data item in its own buffer.

but i dont see any information about this on device's SystemInfo, the only thing i can get is how many compute buffers are supported by a single Vertex/Fragment.. shader.

does this mean some GLES 3.1 platform can only support 4+ Compute Buffers in total or per shader ?

thank!

 

thanks for the explanation!

sorry but im new to shaders and GPU stuff.
what do you mean by per stage ?
let's say i have 3 fragment Shaders. A, B, C
in your example there's a limit of 32 Compute buffers per stage, does this mean 32 for A, 32 for B and 32 for C. or 32 for all of them?

also: does this mean 32 CB for all Compute Shaders or per Compute Shader ?

 

Necro, in case someone comes here looking for a problem related to their compute buffers not working in the vertex stage.

Turns out, a lot of Mali GPUs using the OpenGL driver support 0 compute buffer (Structured Buffer) bindings to the vertex stage of the shader. AFAIK vulkan for the same GPUs has no such restriction.

The variable you want to check at runtime is

SystemInfo.maxComputeBufferInputsVertex

.
This will mostly come up if you're using DrawMeshInstancedIndirect. Based on this number, you would have to fallback on using float/vector constant buffers to read data in the vertex shader.

 

Hi! I have a couple of what seem to me like newbie questions, doing my best to understand.

• Is the limit set per shader or per material instance (all instances added together can have more than 4 but not individually)?
• If i have 4 buffers that are declared in the whole shader and is only used in the vertex and not in the fragment, the buffers used count as 4 per stage and not 8?
• I'm coding in a generated shader graph shader. It makes multiple passes and all passes have the same buffer (read only) included. Is this buffer a shared one or each pass makes a copy of it? In the case of 8 passes do the compute buffers count as 8 per stage?
• Is there a limit for compute shaders that you can run on mobile? (where supported)

Edit: i received a great answer here: https://forum.unity.com/threads/compatibility-buffer-newbie-questions.1291802/