Optimizing lots of boxes or planes

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Optimizing lots of boxes or planes

(3 posts) (3 voices)

Started 9 months ago by Ben Roberts
Latest reply from Bill Hollings

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Ben Roberts
Member
I'm trying to build a 3d object out of lots, 200 - 2500, of boxes. I'm doing this by :
```
//parentNode to add boxes to
CC3Node *parentNode = [ImageHandler make3DNodeFromImage:image];

//single generic box to copy
CC3BoundingBox bb;
bb.minimum=cc3v(-0.5,-0.5,1);
bb.maximum=cc3v(0.5,0.5,0.0);

CC3BoxNode *genericBox = [CC3BoxNode node];
[genericBox populateAsSolidBox:bb];

//loop over array of data adding boxes as i go
for(x to y){
    CC3BoxNode *box=[genericBox copyAutoreleased];
    // ... set color and location ...
    [parentNode addChild:box];
}

[world addChild:parentNode];
[world createGLBuffers];
[world releaseRedundantData];
```
This works and displays exactly as i wanted it to ... but it's extremely slow to animate. With 350 boxes i get about 16FPS and for the app i'm building i want to have 5k+ boxes. Using CC3PerformanceStatistics I'm seeing that each box added also adds a GL call which I'm assuming is the issue. How can i optimize this creation process to get higher FPS?

I did try using only CC3PlaneNode nodes to draw the visible faces but this was actually worse (far fewer faces but many more GL calls).

p.s. Bill, thank you - cocos3d is already awesome.
Posted 9 months ago #
saimonx
Member

What I do it is to get the distance between the camera and the nodes. if it is less than X, i display it.

Also, when my nodes are behind the camera view, i remove it.

With this implementation i never get slow FPS.

Posted 9 months ago #
Bill Hollings
Moderator

@Ben Roberts

What you are describing is a particle system. It will be coming soon to cocos3d (by October), but is not truly here yet.

In the meantime, you can accomplish much the same by creating one large mesh of all your objects, and manipulating the vertex locations individually, using the locationAt: and setLocation:at: methods of the CC3VertexLocations array in your mesh. That way, the whole mesh will be submitted to the GL engine in one call.

Be sure to set the shouldAllowVertexBuffering property to NO so that the vertices will remain in main memory for manipulation. If you are only changing a few vertices on each update, you could leave shouldAllowVertexBuffering set to YES, to allow the GL VBO's to be created, set the shouldReleaseRedundantData property to NO, to also keep the data in memory, and use the updateGLBufferStartingAt:forLength: method to update the GL VBO data from the data you have changed.

@saimonx

cocos3d will automatically do what you are describing. cocos3d automatically culls all nodes outside the camera's frustum. They will still participate in the update pass, but will not be rendered during drawing. If you set the farClippingPlane property of your camera appropriately, you can also automatically cull objects that are farther away from your camera.

...Bill

Posted 9 months ago #

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