Why doesn't the cubemap use the normal map?

#1 Anybody? I'm curious about this too. If you have a shiny, bumpy floor, the cubemap should distort with the bumps in the floor.

#2 Like this?

#3 That image is a little misleading, Steve, as the normal map isn't terribly deep, and so whether or not the cubemap is actually being distorted by the normal is kind of hard to tell. Based on what I've seen in Torque, though, I'd put money down that it's not actually distorting, and what we're seeing here is just a normal map and cubemap being blended on a flat surface.

On a shape that features more flowing, rounded geometry, this bug?/feature? I'm talking about is a lot more apparent. I noticed it while working on my upcoming car pack. On that shape, the cubemap is very noticeably not using the normal map as the source of it's normals/geometry, and instead just using the low poly model. On broad, flat areas like the roof or hood, you can't really tell, but around areas that have creases, like the doors or lights, you can see the telltale stretching/warping of the cubemap. Here are some pictures to explain.

In the image below, part 1 and 2 show the difference the normal map makes on this model. Notice that the door creases, blower/vents, and hood creases are all much sharper in part 1. In part 2, the lack of a normal map allows you to make out the actual topology, and the whole thing looks a lot more "inflatable balloon car". Compare the differences between part 1 and 2 to parts 3 and 4. 3 and 4 don't have the same drastic differences, just a little bit of a difference in lighting down at the bottom edges. The cubemap distorts around the edges and creases in the exact same way in both images, which is what leads me to believe the cubemap doesn't use the normal map to dictate how it gets rendered.


Again, I realize this might be by design. The point of this thread was to get some word from GG or any of the affiliated devs (such as Sickhead) one way or the other. If it's by design, personally I think it's a little wierd, but hey, not a deal breaker; more just an oddity I need to plan ahead for. If it's a bug, though, then noting it is the first step to getting it fixed.

So, anyone in the know care to comment?

#4 It looks like the cube map isn't distorted by a normal map, unlike the diffuse texture.

Just a diffuse map:

Diffuse and Cube

Diffuse and normal

Diffuse, normal and cube

The cube map doesn't look like it changes to me.

#5 Water objects do a pretty good job of distorting a cubemap. In theory, we should be able to make a material look just like water solely using a normal and cube map.

#6 Hang on, thought of this while asleep ... normal maps don't distort anything, they just register how LIGHT displays on a surface.

So ... wouldn't you actually need a displacement map ... which isn't the same thing?

PS: I just woke up and haven't got a nice cuppa tea yet ...

#7 Oh hey, there you go. That sounds right. Nice half-asleep thinking, Steve.

#8 My subconscious is much better at using brain than myself :P

#9 the needed info is there in 3 images; diffuse, normal and cube. The math is merely what is missing. ..adding another map will only eat resource.

#10 I presume what is happening is the diffuse material is applied first, then it is distorted by the normal map, then the cube map is being applied last.

If this is the current order, I would think that rendering the diffuse map, then the cube map and lastly the normal map would give you the effect that you want.

#11 Where on earth is this layered application done? Seems simple enough in theory like that, I can only pray that it IS actually as simple.