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View Full Version : very easy-deleting an object?



01-08-2004, 07:04 AM
So far I can see its all very easy to create objects using simple polygons and vertex's etc...but as each individual object does not have any defining features (ie. a name or reference to that specific object) how can I delete it without having to clear the entire screen and redrawing everything except the object I am trying to delete. For example I have a green square on top of a larger red square. I want to make the green square increase and decrease in size. Increase would be easier...could just draw the bigger one over the top of the old one...but how would I shrink the square again without having to clear the screen and redraw the background red square? Has this got something to do with creating display list objects? I hope that example didnt confuse what I was trying to ask! ...can you delete individual polygons/lines/vertexs etc?

Vlasko
01-08-2004, 07:19 AM
What's wrong with clearing screen and drawing only thigs you want ?You can do it minimaly 30 times per second so it's ok

01-08-2004, 07:50 AM
thought that might be a bit slow...not to clear the screen, but slow to redraw all the other objects that werent supposed to be deleted. Obviously that doesnt matter in my simple case but if I had a really complex scene that would involve a lot of redrawing just to delete one small object?

nexusone
01-08-2004, 08:23 AM
You can't delete an object without redrawing the screen.

This is because your screen image is rendered, from the input data and in order to create a new image the data would have to be processed again with object to be deleted removed from the data.

The is why you need faster CPU's and video cards to play highly detailed 3D games with thousands of triangles.


Originally posted by Mr.JT:
So far I can see its all very easy to create objects using simple polygons and vertex's etc...but as each individual object does not have any defining features (ie. a name or reference to that specific object) how can I delete it without having to clear the entire screen and redrawing everything except the object I am trying to delete. For example I have a green square on top of a larger red square. I want to make the green square increase and decrease in size. Increase would be easier...could just draw the bigger one over the top of the old one...but how would I shrink the square again without having to clear the screen and redraw the background red square? Has this got something to do with creating display list objects? I hope that example didnt confuse what I was trying to ask! ...can you delete individual polygons/lines/vertexs etc?



[This message has been edited by nexusone (edited 01-08-2004).]

01-08-2004, 08:34 AM
makes sense! cheers!