XNA creating hole in wall

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3 comments, last by Krohm 12 years ago
Hi im really struggling to get info on how to tell a specific area of geometry not to draw. Basically for a project in looking at creating a hole in a wall via culling to stop a certain area being drawn. i cast a ray from the centre of the screen and i check to see if it has hit geometry e.g my wall model. When this happens i am trying to draw a shape which represents the area of the wall i want to cull. The problem is I have no idea how to tell the are contained within the shape not to draw to create the hole. Can anyone point me in the right direction ?
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Are you trying to do it this way for a reason? If not, why dont you just draw a bullet hole texture wherever you shoot
Yes its for a project that exmaines weather or not punching a hole through a wall through entirely graphical means is a viable alternative to say a fracturing solution in certain situations.
Really want I need to know is does xna have functionality to select an area not to draw, or if I could do it through shaders and attach them to an xna project.
There are a few ways to do that.
I'd be currently inclined to associated each fragment with a world position and issue a clip volume such as a sphere for each hole, calling [font=courier new,courier,monospace]clip/discard/kill[/font] if the fragments ends being in the sphere. Something similar has been done in Left Dead 2 if memory serves.

Messing with alpha maps might also be a possibility. It natively allows for a much higher hole count, I guess it'll also be much faster to render but the machinery required is fairly more involved.

In general, no, XNA/Direct3D does not feature natively this degree of control. You have to build it on top of the provided features.

Previously "Krohm"

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