Ok, I guess I'll have to explain each of these claims..
1) Multiple Light Sources - G400
The only reason that EMBM can handle multiple light sources is because it
uses the environment map (which represents a render of the whole scene
including all light sources). It is equivalent to saying lets take a
picture of the whole scene with the lights around and then map it to a
texture. Naturally you'll have the light sources on the final texture.
DOT3 is not using environment mapping but just the regular per-pixel bump
mapping, so it won't calculate all the lights but just one. IF you include
an environment map, then you will have the multiple light sources on your
texture.
2) Polychromatic Light Color - G400
Again, the bump map is created by the environment map (which is in color) so
the bump map will be in color. Again, the P3 can use a blend of the bump
map ( monochrome ) and the environment map to achieve polychromatic light
color. Keep in mind that the G400 is blending 3 textures whereas the P3 is
only blending 2 since it isn't using an environment map.
3) Light FallOff Control - G400
I'm not sure what they mean by this.
4) Per Pixel Luminance control - G400
I think they are trying to say that the P3 doesn't use specular highlights
for the bump. This is false since specular highlights can be calculated per
pixel once the interpolated normal has been calculated.
5) Distortion - G400
Agreed.
6) How about moving light sources? Since the G400 can't build the
environment map on the fly, moving a light source in front of the bump
mapped texture will yield no changing specular highlight. This is an
important issue since most games use dynamic lights. This is a big fall
back of using environment maps.
I'm not trying to say that EMBM is not a good feature at all. It is. But
programming with the original DOT3 bump mapping has allowed me to really
understand what is going on underneath the hood.
--Marlin
1) Multiple Light Sources - G400
The only reason that EMBM can handle multiple light sources is because it
uses the environment map (which represents a render of the whole scene
including all light sources). It is equivalent to saying lets take a
picture of the whole scene with the lights around and then map it to a
texture. Naturally you'll have the light sources on the final texture.
DOT3 is not using environment mapping but just the regular per-pixel bump
mapping, so it won't calculate all the lights but just one. IF you include
an environment map, then you will have the multiple light sources on your
texture.
2) Polychromatic Light Color - G400
Again, the bump map is created by the environment map (which is in color) so
the bump map will be in color. Again, the P3 can use a blend of the bump
map ( monochrome ) and the environment map to achieve polychromatic light
color. Keep in mind that the G400 is blending 3 textures whereas the P3 is
only blending 2 since it isn't using an environment map.
3) Light FallOff Control - G400
I'm not sure what they mean by this.
4) Per Pixel Luminance control - G400
I think they are trying to say that the P3 doesn't use specular highlights
for the bump. This is false since specular highlights can be calculated per
pixel once the interpolated normal has been calculated.
5) Distortion - G400
Agreed.
6) How about moving light sources? Since the G400 can't build the
environment map on the fly, moving a light source in front of the bump
mapped texture will yield no changing specular highlight. This is an
important issue since most games use dynamic lights. This is a big fall
back of using environment maps.
I'm not trying to say that EMBM is not a good feature at all. It is. But
programming with the original DOT3 bump mapping has allowed me to really
understand what is going on underneath the hood.
--Marlin
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