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### #Actualrocklobster

Posted 11 June 2012 - 03:07 AM

Found a good visual description of the problem of not using the normal matrix to convert the normals into eye space

http://www.lighthouse3d.com/tutorials/glsl-tutorial/the-normal-matrix/

### #5rocklobster

Posted 10 June 2012 - 01:13 PM

Thanks, and i know you've stated before that

If the modelview matrix does not scale, or only has uniform scale, a separate inverse-transposed version of the modelview matrix is not needed

but why would the model view matrix only have uniform scale or does not scale? What leads to this to make me use the normal matrix? The model view contains the up, forward and right vectors which would be the normal matrix that is extracted (i think) but this should generally be unit vectors so it should always be uniform scale?

Maybe i'm overcomplicating things, is it really just converting the normal into camera view space without the translation component?

### #4rocklobster

Posted 10 June 2012 - 01:13 PM

Thanks, and i know you've stated before that

If the modelview matrix does not scale, or only has uniform scale, a separate inverse-transposed version of the modelview matrix is not needed

but why would the model view matrix only have uniform scale or does not scale? What leads to this to make me use the normal matrix? The model view contains the up, forward and right vectors which would be the normal matrix that is extracted (i think) but this should generally be unit vectors so it should always be uniform scale?

Maybe i'm overcomplicating things, is it really just converting the normal into camera view space without the translation component?

### #3rocklobster

Posted 10 June 2012 - 01:11 PM

Thanks, and i know you've stated before that

If the modelview matrix does not scale, or only has uniform scale, a separate inverse-transposed version of the modelview matrix is not needed

but why would the model view matrix only have uniform scale or does not scale? What leads to this to make me use the normal matrix? The model view contains the up, forward and right vectors which would be the normal matrix that is extracted (i think) but this should generally be unit vectors so it should always be uniform scale?

### #2rocklobster

Posted 10 June 2012 - 01:07 PM

Thanks, and i know you've stated before that

If the modelview matrix does not scale, or only has uniform scale, a separate inverse-transposed version of the modelview matrix is not needed

but why would the model view matrix only have uniform scale or does not scale? What leads to this to make me use the normal matrix?

### #1rocklobster

Posted 10 June 2012 - 12:38 PM

Thanks, and i know you've stated before that

If the modelview matrix does not scale, or only has uniform scale, a separate inverse-transposed version of the modelview matrix is not needed

but why would the model view matrix only have uniform scale or does not scale? What leads to this to make me use the normal matrix?

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