some conceptual questions about billboards

Problems building or running the engine, queries about how to use features etc.
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Niubbo
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some conceptual questions about billboards

Post by Niubbo »

Ogre Version: 1.12.8
Operating System: WIn10
Render System: Dx11

Hi

I have some questions related to the billboardset uses:

how much far the individual billboards can be positioned from the billboardset position before is better switch to use different billboards set at place of only one (I speak from the point of view of performance and technical limitations)?

If I use billboards from different billboardset for represent an object (because I cannot switch material on the same billboardset used by other objects at the same time), is better for the performance to create and remove billboards following the set I need to use in a specific frame or is better use the texture coordinates to point to transparent zone of texture for the billboards I want to hide?

Defining the coordinate of a billboard using setTexcoordIndex() and using the predefined coordinates of the billboardset, is much better than use setTexcoordRect() at billboard level or they're more or less equivalent as performance?

thank you
paroj
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Re: some conceptual questions about billboards

Post by paroj »

Niubbo wrote: Thu Jun 17, 2021 4:31 pm how much far the individual billboards can be positioned from the billboardset position before is better switch to use different billboards set at place of only one (I speak from the point of view of performance and technical limitations)?
performance-wise this does not matter. You might get into precision issues - to solve them you would need to use camera relative rendering in combination with multiple billboard sets.
Niubbo wrote: Thu Jun 17, 2021 4:31 pm If I use billboards from different billboardset for represent an object (because I cannot switch material on the same billboardset used by other objects at the same time), is better for the performance to create and remove billboards following the set I need to use in a specific frame or is better use the texture coordinates to point to transparent zone of texture for the billboards I want to hide?
Note that you can also use vertexcolours to modify the appearance of individual billboards. Transparent objects are still drawn, so this will probably be the slowest option. You could also try moving the billboards behind the camera, so they get culled. Ultimately, you have to benchmark what is the fastest for you.
Niubbo wrote: Thu Jun 17, 2021 4:31 pm Defining the coordinate of a billboard using setTexcoordIndex() and using the predefined coordinates of the billboardset, is much better than use setTexcoordRect() at billboard level or they're more or less equivalent as performance?
they are equivalent.
Niubbo
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Re: some conceptual questions about billboards

Post by Niubbo »

thanks you Paroj
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