Object culling curiosities. Opinions, guys?
BlitzMax Forums/BlitzMax Programming/Object culling curiosities. Opinions, guys?
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| Say I have a bunch of objects scattered around a map. This is a tile-based, scrollable, zoomable map. I want objects in the camera's view to be drawn and objects off the screen to be ignored, naturally. (Objects are z-sorted, then drawn on top of the tiles in a seperate loop.) How would you guys go about this? I can think of 2 methods offhand. 1. Cycle through each object on the map and use an If-statement to check if it's visible. (Very amature, and with thousands of objects, it's very slow) 2. Attach each object to a ground tile, so that the same code that draws the ground tiles automatically knows when to draw in any visible objects. (Used with good results in the past. It's limited though, you don't have the freedom to bunch too many objects together, and the object cannot stray too far from its home tile, or else it disappears along with the tile before it's off the edge of the map.) What methods do you guys use? |
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| Ignore me - thought I was in the BB3D forum :D |
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| I forgive you. |
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| Can't each tile have a list of objects currently associated to it rather than a single object? Depending on how many objects are involved drawing 1-2 that are just off-screen shouldn't matter. |
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| Yeah, I can do that too. So are you saying you favour the "hometile" system, and that it's my best option? I'm sure the pros have some crazy, high-level methods of object culling. I'd like to be blown away trying to read one of those algorithms! That's kind of what I'm after in this thread. |
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| I think they go with what works rather than anything clever. Don't think of it as a hometile system but more a wau of abstracting x/y coordinates into something more vague just to find out if the object is on-screen. The 'tile' they belong to doesn't really have to be the same size as your graphical tile. e.g. Tilesize 32*32, object 'holder' 128*128. You only want to know if the object is in a tile that's on-screen then you can draw it with it's own x/y. |
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| But isn't a clever solution always best way to do it? To me, "clever" implies efficiency and versatility. I could use some of that. The hometile system I've been working on for forever now allows drag-n-drop placement and it runs very efficiently. But I'm not dellusioned. I know there are games out there running systems that are 10x more efficient and versatile! I have much to learn! .. right? But anyway, what you said about abstracting it and making it independant of the visual terrain tiles sounds like a good idea. |
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| The idea is get it working and check the results. If it does what you want, in the time that you want then it's a result and clever enough. If not, you can then optimise or have a rethink. |
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