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### #Actualcaibbor

Posted 18 December 2012 - 11:23 AM

I figured that +1/-1 wouldn't be a unit cube.. it would be a unit*2 cube

and 0.1 to 1.1 because, like I said, if I use +1/-1 on the z, the nature of the perspective matrix continues to project the cube if it goes behind the camera, makign it look like an hour-glass

(my Z axis is up/down)

using +1/-1 on the z:

using -0.1/-1.1 on the z:

all Vec3's when multiplied by a 4x4 matrix assume a w of 1.

But, it seems I am inverting my projection matrix incorrectly, as discussed later in the conversation here: http://www.gamedev.net/topic/635876-bottom-row-of-4x4-matrix/

### #5caibbor

Posted 18 December 2012 - 10:40 AM

I figured that +1/-1 wouldn't be a unit cube.. it would be a unit*2 cube

and 0.1 to 1.1 because, like I said, if I use +1/-1 on the z, the nature of the perspective matrix continues to project the cube if it goes behind the camera, makign it look like an hour-glass

(my Z axis is up/down)

using +1/-1 on the z:

using -0.1/-1.1 on the z:

all Vec3's when multiplied by a 4x4 matrix assume a w of 1.

### #4caibbor

Posted 18 December 2012 - 10:39 AM

I figured that +1/-1 wouldn't be a unit cube.. it would be a unit*2 cube

and 0.1 to 1.1 because, like I said, if I use +1/-1 on the z, the nature of the perspective matrix continues to project the cube if it goes behind the camera, makign it look like an hour-glass, like so:

but if it's -0.1 to -1.1 instead:

all Vec3's when multiplied by a 4x4 matrix assume a w of 1.

### #3caibbor

Posted 18 December 2012 - 10:37 AM

I figured that +1/-1 wouldn't be a unit cube.. it would be a unit*2 cube

and 0.1 to 1.1 because, like I said, if I use +1/-1 on the z, the nature of the perspective matrix continues to project the cube if it goes behind the camera, makign it look like an hour-glass, like so:

all Vec3's when multiplied by a 4x4 matrix assume a w of 1.

### #2caibbor

Posted 18 December 2012 - 10:33 AM

I figured that +1/-1 wouldn't be a unit cube.. it would be a unit*2 cube

and 0.1 to 1.1 because, like I said, if I use +1/-1 on the z, the nature of the perspective matrix continues to project the cube if it goes behind the camera, makign it look like an hour-glass.

all Vec3's when multiplied by a 4x4 matrix assume a w of 1.

### #1caibbor

Posted 18 December 2012 - 10:32 AM

I figured that +1/-1 wouldn't be a unit cube.. it would be a unit*2 cube

all Vec3's when multiplied by a 4x4 matrix assume a w of 1.

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