Frustum culling question

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1 comment, last by JohnBolton 18 years, 6 months ago
whats the space does my frustum is located? is it in world space or in object space. Im confused on how to check the bounding boxes of the 3d object in the scene if i need to transform these boxes in world space to check with the frusutm or i need to inverse its coordinate to return to world space. i computed the frustum by using the view and the projection matrix as most of u did
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The frustum is defined with a set of 6 planes. These planes (their equations) could be described relative to the world coordinate system (world space) or relative to the view coordinate system (view space). So, if your bounding boxes were defined in the world space, you must check them with a frustum described in the world space. If the BB were defined in the view space, use a frustum described in the view space.
The frustum can exist in any space. Except for projection/clip space the only difference is the location and orientation. But in projection/clip space, the frustum is a "cube".

One way to get the view frustum in world space is to transform the sides of the "cube" into view space using the inverse of the projection transform, and then tranform that into world space using the inverse of the view transform(which is the camera's model/world transform).
John BoltonLocomotive Games (THQ)Current Project: Destroy All Humans (Wii). IN STORES NOW!

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