McBain

11-23-2001, 05:37 PM

i have to do this:

- loadidentity

- lightpos = x

- camera transformations

- lightpos = (10, 10, 10)

now i have to know x

did it like this:

- loadidentity

- camera transformations

- get M and calculate M-1

- light_coord = (10, 10, 10) * M-1

- loadidentity

- draw point at light_coord

this should be the same as:

- loadidentity

- camera transformations

- draw point at light_coord

but this is not the case

if my camera transformation is just a gluLookAt:

works if i draw point at (light_coord.x, light_coord.y, -light_coord.z), notice the -

if my camera transformations also have a rotation the whole thing is flipping

i calcualte M * M-1 in my display routine and it gives Identity every time, so M-1 is calculated correctly.

what the **** am i missing here ???????????????

- loadidentity

- lightpos = x

- camera transformations

- lightpos = (10, 10, 10)

now i have to know x

did it like this:

- loadidentity

- camera transformations

- get M and calculate M-1

- light_coord = (10, 10, 10) * M-1

- loadidentity

- draw point at light_coord

this should be the same as:

- loadidentity

- camera transformations

- draw point at light_coord

but this is not the case

if my camera transformation is just a gluLookAt:

works if i draw point at (light_coord.x, light_coord.y, -light_coord.z), notice the -

if my camera transformations also have a rotation the whole thing is flipping

i calcualte M * M-1 in my display routine and it gives Identity every time, so M-1 is calculated correctly.

what the **** am i missing here ???????????????