Reflection map question (Spherical map)

Game Engine Game Engine Support and Discussion
#1

Greetings. I have a slight issue with spherical reflection maps (issue probably is just my brains which can’t wrap around the thing).

Issue .blend: reflection.blend (1.09 MB)

As In example file I have a sphere and a cube mapped with exact same reflection map texture.
My questions are:

  1. Why on sphere, the reflection follows the camera and doesn’t change according to the angle (Realtime optimizing?)

  2. But on Cube, the reflection changes or rotates when I rotate view, why is this different?

  3. Ok so it has something to do with shading (smooth/flat), but why does it affect so much on reflection behavior?

#2

Make the cube smooth and it will work :).

#3

Actually the cube’s reflection map is closer to right to me than the sphere which is “static”.

#4

Well,i dont know…it works better if the sphere is solid.Though,i dont think thats what you want.

#5

Solid = flat shaded? I hope someone could give me pointers as to why reflection doesn’t work as I would like with Smooth shade.

#6

The reflection mapping is a fake. It isn’t truly a reflection but a computer projected spherical map on the object, as I understand. I can’t explain exactly why the look different, but if you subdivide the cube, you can see that it’s still a fake.

#7

in almost every single big budget game they use false reflections if you pay attention to a big budget game close enough you can tell that the reflection is not exactly the same as the environment this is to make the game faster due to the less processing of the texture to map out the environment in real time.

and the problem with the “sphere map” is that you have to mess with the mapping size of the reflection image(Textures/Mapping/Size:/)

#8

I do know it’s fake as you can see in my example file I am using a reflection texture map.
My main issue is that why, if you have flat-shade on the object, the reflection changes if you rotate the view (as it should in my opinion).
However if you have smooth-shade on, the reflection doesn’t change and is static if you rotate the view (why is that?).

I’m not talking about subdividing or using subdivision surface or anything, I’m just talking about the shading (smooth/flat shade).

#9

idk… it must have something to do with the shader when it smooths the verts it probably smooths the texture too…