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Author Topic: Order of drawing vertices in vertexarray  (Read 1897 times)

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FRex

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Order of drawing vertices in vertexarray
« on: December 06, 2012, 04:41:04 am »
Can there be any assumption about order of drawing primitives in vertexarray? For example 8 vertices, two quads, first one is big rectangle, other is smaller one with it's area completely contained in the area of first one. Will both always show, first in array getting drawn first or is it (implementation /un)defined?
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cire

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Re: Order of drawing vertices in vertexarray
« Reply #1 on: December 06, 2012, 05:51:39 am »
OpenGL draws them in order and I didn't see any reordering in the source for sf::RenderTarget.  Seems like a safe assumption.

Laurent

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Re: Order of drawing vertices in vertexarray
« Reply #2 on: December 06, 2012, 07:50:41 am »
Yes it should be safe, however I don't know if it's explicitely written in the OpenGL spec.
Laurent Gomila - SFML developer

cire

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Re: Order of drawing vertices in vertexarray
« Reply #3 on: December 06, 2012, 08:15:46 am »
Quote
When glDrawArrays is called, it uses count sequential elements from each enabled array to construct a sequence of geometric primitives, beginning with element first.

Found here.

Laurent

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Re: Order of drawing vertices in vertexarray
« Reply #4 on: December 06, 2012, 08:32:06 am »
Thanks :)
Laurent Gomila - SFML developer

FRex

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Re: Order of drawing vertices in vertexarray
« Reply #5 on: December 06, 2012, 11:42:09 pm »
Thanks too.
Err... by construct it means render, right?  ;D
« Last Edit: December 06, 2012, 11:44:48 pm by FRex »
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Laurent

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Re: Order of drawing vertices in vertexarray
« Reply #6 on: December 07, 2012, 12:00:12 am »
Quote
Err... by construct it means render, right?
Of course :P
Laurent Gomila - SFML developer

FRex

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Re: Order of drawing vertices in vertexarray
« Reply #7 on: December 07, 2012, 12:05:21 am »
Ah.. obviously it does.. ::)
Thanks. ;)
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