| allked |
Posted - Oct 30 2005 : 04:51:08 AM
"rhw"
ps:what do you ofen say when you people getting angry?
like f***,mother f***er , is there anything else?
i am interesting in your way of bad speaking.(clear?idon'tthinkso) |
| Threshold |
Posted - Nov 26 2005 : 9:51:25 PM
I remember reading the meaning of that acronym in the DX8 SDK and saying to myself, "Yeah, just pretend that's not there." |
| cbx |
Posted - Nov 11 2005 : 05:48:10 AM
quote:
Originally posted by Eric Coleman
What does "rhw" mean?
In the context of game programming it meants the "reciprocal homogenous W-coordinate."
In 3D mathematics it can be helpfull to use a "homogenous" coordinate system to make certain mathmatical equations easier to combine. A homogenous system, for game programming, is achieved by using an extra number explicitly defined to be either 1 or 0 depending on the mathematical context of the vector. The W coordinate is not a coordinate at all because it is dependent on the X, Y and Z coordinates. W is really f(X,Y,Z), thus a 4D vector is really only 3D.
If given a vector of (0.5, 2, 1, .25), then the "rhw" is simply 1/.25 because if you multiply the vector by 1/w you normalize it. The vector then becomes (2, 8, 4, 1), where W is normalized to 1. When W = 0 then rhw is undefined, and that has the special meaning that the values for X,Y,Z represent a point or coordinate, which is not the same meaning as a vector.
Zing! Over my head. 
Geeze Eric your head is just as filled up with usless information as mine! Note to allked, forget the mysteriously mysticle "W" and use the matrix.OrthoOffCenterLH found in DirectX (I'm assuming you are using DX) Trust me it just makes life simpler.  |
| hotrodx |
Posted - Nov 02 2005 : 12:53:44 AM
Ha! This is why I love visiting these forums. You always learn something new. |
| Eric Coleman |
Posted - Oct 30 2005 : 9:31:32 PM
What does "rhw" mean?
In the context of game programming it meants the "reciprocal homogenous W-coordinate."
In 3D mathematics it can be helpfull to use a "homogenous" coordinate system to make certain mathmatical equations easier to combine. A homogenous system, for game programming, is achieved by using an extra number explicitly defined to be either 1 or 0 depending on the mathematical context of the vector. The W coordinate is not a coordinate at all because it is dependent on the X, Y and Z coordinates. W is really f(X,Y,Z), thus a 4D vector is really only 3D.
If given a vector of (0.5, 2, 1, .25), then the "rhw" is simply 1/.25 because if you multiply the vector by 1/w you normalize it. The vector then becomes (2, 8, 4, 1), where W is normalized to 1. When W = 0 then rhw is undefined, and that has the special meaning that the values for X,Y,Z represent a point or coordinate, which is not the same meaning as a vector. |
| Walrus |
Posted - Oct 30 2005 : 12:27:15 PM
Yeah, it is a very unusual question, to say the least... |
| Scorpion_Blood |
Posted - Oct 30 2005 : 12:04:15 PM
i have a anti-stress ball so i dont get hungry to often LOOOL kidding :P
anyway why u wanna know that? confusing |
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