Normal map resource question...

Blitz3D Forums/Blitz3D Programming/Normal map resource question...

Liberator(Posted 2006) [#1]
How 'expensive' are the dot3 normal maps in terms of processing power in B3d?

Also, what happens if the user's video card doesn't support it, will it simply not appear, or will it have errors?


Zmatrix(Posted 2006) [#2]
The expense will depend on what your doing with it.

for example:
the blending Operation itself doesnt really take any more processing than any other multitexture OP.
But updating the Normals will , depending on the Geometry.

If the card dosent support it, it will probably display it as a regular texture, so it will look Odd.

Sam
Sam


Pinete(Posted 2006) [#3]
I've been doing a lot of trials with dot3.

As Zmatrix says, is expensive depending on the
stuff you want to do and how you want to achieve it.

For me the key point is the size in polys of your geometry. It will have a great
impact in framerate if you are updating normals all the time in order to achieve a realistic normal mapping effect.
Maybe that's the most slow.
In order to give you an idea, I've managed a scenario with aprox. 90000 polys and a lot of textures (50 aprox. from 256x256 to 512x512) and the lost of framerate when I include
the normalmap_updatenormals() is dramatic. It jumps from 30-32fps to 3fps, taking into account that almost the 90% of the scene are "normal mapped".
Really, the delay comes from updating all the normals of your objects each frame. If you don't do that you will see you don't experience any framerate lost.

If you apply the normal map to less objects, your speed lost will be minor if your function only update the normal mapped objects.

The blending operation, as Zmatrix says, doesn't take more time than any other similar operation.

Be careful of the polygons of your scene and make a lot of trials looking for optimizations in your code.

regards,


Liberator(Posted 2006) [#4]
Thanks for the help guys, gives me some good insight :)