On 03/05/2025 17:01, Russell Greene wrote:
vkGetPhysicalDeviceToolPropertiesEXT(dev, nb, array) If pToolProperties is NULL, then the number of tools currently active on physicalDevice is returned in pToolCount. Otherwise, pToolCount must point to a variable set by the application to the number of elements in the pToolProperties array, and on return the variable is overwritten with the number of structures actually written to pToolProperties. If pToolCount is less than the number of currently active tools, at most pToolCount structures will be written.It's in the spec. Different function, but all functions which write to an array follow the same signature.Sorry, I guess I wasn't clear about my question. I understand that you can fetch the size by setting the data pointer to NULL, etc. The question is "is there way to fetch the number of memory planes a modifier uses without allocating memory?"
...that's exactly what I posted.Set array to non-NULL, set nb to the array size you're giving it, and you'll get UP TO nb, no more, even if the driver has more.
If that's your concern, just fetch all info for all modifiers in the init function.My understanding is: 1. There is no fixed number of modifiers a driver can expose (this may be wrong, but seems to me it would be a strange limitation, and I don't see anything in the vk spec or drivers that indicat that this could be the case) 2. We don't know where in the modifier list the one we want info about is So therefore, we have to fetch the info for *all* modifiers, which as I understand it probably requires at least a slow path with an allocation for drivers that potentially have a lot of modifiers. If we're OK with a practical "we don't support drivers with more than X modifiers because we doubt it'll ever exist" then that's a valid answer as well.
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