Realtime Cubemap Reflection

[TylerH]

After speaking with Josh, though he is busy, I think I am doing it the proper way (yet it still isn't working)

 

-- Create cubemap camera
cubemapcamera = CreateCamera()

-- Create cubemap
cubemap = CreateCubemap(512,512)

-- Create cubemap 'gbuffer'
cubemapbuffer = CreateBuffer(512,512,1+2+4+8)

-- Create six buffers to render each cube face to
cubemapbufferpx = CreateBuffer(512,512,1+2+4+8)
cubemapbuffernx = CreateBuffer(512,512,1+2+4+8)
cubemapbufferpy = CreateBuffer(512,512,1+2+4+8)
cubemapbufferny = CreateBuffer(512,512,1+2+4+8)
cubemapbufferpz = CreateBuffer(512,512,1+2+4+8)
cubemapbuffernz = CreateBuffer(512,512,1+2+4+8)

-- Bind each buffer to a face of the cubemap
SetColorBuffer(cubemapbufferpx, cubemap, 0, 0) -- positive x
SetColorBuffer(cubemapbuffernx, cubemap, 0, 1) -- negative x
SetColorBuffer(cubemapbufferpy, cubemap, 0, 2) -- positive y
SetColorBuffer(cubemapbufferny, cubemap, 0, 3) -- negative y
SetColorBuffer(cubemapbufferpz, cubemap, 0, 4) -- positive z
SetColorBuffer(cubemapbuffernz, cubemap, 0, 5) -- negative z

Then during rendering:

-- Realtime cubemap
CameraProjMode(camera, 0) -- Disable player cam
PositionEntity(cubecamera,mesh.position) -- Position cubemap camera at the center of the mesh
CameraProjMode(cubecamera, 1) -- Enable cubemap camera

--Render Positive X
SetBuffer(cubemapbuffer)
RotateEntity(cubecamera, Vec3(0, 90, 0))
world:Render()
SetBuffer(cubemapbufferpx)
world:RenderLights(cubemapbuffer)

-- Render Negative X
SetBuffer(cubemapbuffer)
RotateEntity(cubecamera, Vec3(0, -90, 0))
world:Render()
SetBuffer(cubemapbuffernx)
world:RenderLights(cubemapbuffer)

--Render Positive Y
SetBuffer(cubemapbuffer)
RotateEntity(cubecamera, Vec3(-90, 0, 0))
world:Render()
SetBuffer(cubemapbufferpy)
world:RenderLights(cubemapbuffer)

-- Render Negative Y
SetBuffer(cubemapbuffer)
RotateEntity(cubecamera, Vec3(90, 0, 0))
world:Render()
SetBuffer(cubemapbufferny)
world:RenderLights(cubemapbuffer)

--Render Positive Z
SetBuffer(cubemapbuffer)
RotateEntity(cubecamera, Vec3(0, 0, 0))
world:Render()
SetBuffer(cubemapbufferpz)
world:RenderLights(cubemapbuffer)

--Render Negative Z
SetBuffer(cubemapbuffer)
RotateEntity(cubecamera, Vec3(0, -180, 0))
world:Render()
SetBuffer(cubemapbuffernz)
world:RenderLights(cubemapbuffer)

CameraProjMode(cubecamera, 0) -- Disable cubemap camera
CameraProjMode(camera, 1) -- Enable player camera

SetShader(GetMaterialShader(mesh.material))
BindTexture(cubemap,0) -- Bind cubemap to material
SetShader(nil)

-- render world to GBuffer and draw to BackBuffer as usual.

 

This is the result (all 6 individual buffers are rendered to fine, but the cubemap doesn't seem to be getting rendered to):

 

Full script is attached.

cubemap.lua

[flachdrache]

I have no idea - at first glance hide/unhide the entity which uses the cubemap but aint doing nothing so does switching materials from invisible.mat to cubemap.mat.

What i didnt tried is to bind a dummy cubemap in the material and use kind of a FreeTexture before using cubemap.material or a freeBuffer on the cubemap buffers each pass.

 

Cant give anymore time on this currently.

[TylerH]

Josh suggested it may be an nVidia drivers issues, which I researched and found plausible. I need people with ATI cards to test this and see if it works, to determine if the issue lies in the code, or in the GPU drivers.

[macklebee]

In my mind, SetColorBuffer is not doing this:

-- Bind each buffer to a face of the cubemap

but rather is doing this:

-- Set a face of the cubemap to a buffer

 

and then you are rendering the buffer and it shows up as a texture in DrawImage, but I do not see a place where you are assigning the individual textures created from the buffers back into the cubemap itself. You need a way to copy those buffers back to those individual cubemap indexes I suspect for this to work. Something like SetCubeMap(cubemap,texture,index) seems like it would be needed...

[flachdrache]

Hmmm, the cubemap faces are fine. Replace to

 

-- REALTIME CUBE MAP

CameraProjMode(camera, 0)
PositionEntity(cubecamera, camera.position)
CameraProjMode(cubecamera, 1)

 

its the upload through the material pipeline which isnt working as aspected.

i.e. "SetShader(GetMaterialShader(mesh.material))" might be a little to lazy.

 

PS: Hmmm, so we have to sphere map, the opposite direction that we are looking, to the mesh, through the material pipeline and have the cubemap rotate counterclockwise just so that it is not too easy, right ?

[macklebee]

Hmmm, the cubemap faces are fine. Replace to

 

-- REALTIME CUBE MAP

CameraProjMode(camera, 0)
PositionEntity(cubecamera, camera.position)
CameraProjMode(cubecamera, 1)

that sets the position of the cubemap camera to the normal camera's postion... which is fine if he was trying something like a cctv screen, but since he is trying to do a reflection, the cubemap camera needs to look out from the cube not at it.

[Gilmer]

thanks TylerH.. :­)

 

I tested here, and also was without displaying the texture. I tested putting the skybox texture in place of cubemap, and it showed. I think it is related in time to pass the cubemap to shader =/

[macklebee]

I have a realtime "cubemap" (of a sort) as an object scripted model.

except I am hacking it by having a different material on each face, rendering to each face's buffer, and then setting the resulting colorbuffer to each face's material... effectively creating a "cubemap". Using the framework camera for the buffer renders gives it a nice crystal clear reflection and all of the nice framework effects rendered... but its a fps killer doing 6 faces. For actual use in a game, you could just use a normal camera for the render which will give a greater fps boost.

[Gilmer]

Cool your idea macklebee, i think right now would be more appropriate. But how could the normal check that is being presented at the render?

[TylerH]

I have a realtime "cubemap" (of a sort) as an object scripted model.

except I am hacking it by having a different material on each face, rendering to each face's buffer, and then setting the resulting colorbuffer to each face's material... effectively creating a "cubemap". Using the framework camera for the buffer renders gives it a nice crystal clear reflection and all of the nice framework effects rendered... but its a fps killer doing 6 faces. For actual use in a game, you could just use a normal camera for the render which will give a greater fps boost.

 

Very cool. Care to share how you did that?

[macklebee]

Cool your idea macklebee, i think right now would be more appropriate. But how could the normal check that is being presented at the render?

 

Thanks gilmer. I am not sure I understand exactly what you are asking... If its what I think you are asking then right now I am just setting the camera up to a predefined surface normal vector in the object script using a correctly oriented pivot.

 

Very cool. Care to share how you did that?

 

yeah, its pretty straight forward. I was trying to figure out the 3d angle of incidence math to get the reflection right, cause right now it just "reflects" straight out from the cube face... which looks ok but gives more of an impression that its a video screen than an actual reflection. Let me clean up my code and comment it and I will post it.

[TylerH]

Sounds great

[macklebee]

Here is the same concept added to a mirror model. It still suffers from the same problem as the cube as it doesn't use the angle of incidence to calculate the reflected image... but I have to go work out of town for the next three days so I won't be able to work on it. Perhaps someone like Tyler can figure out the proper math needed to get the angle of incidence/reflection?

 

I can upload the cube but it really is a fps killer and I don't want anyone to complain when their editor locks up!

[Masterxilo]

Try calling:

-- Bind each buffer to a face of the cubemap
SetColorBuffer(cubemapbufferpx, cubemap, 0, 0) -- positive x
SetColorBuffer(cubemapbuffernx, cubemap, 0, 1) -- negative x
SetColorBuffer(cubemapbufferpy, cubemap, 0, 2) -- positive y
SetColorBuffer(cubemapbufferny, cubemap, 0, 3) -- negative y
SetColorBuffer(cubemapbufferpz, cubemap, 0, 4) -- positive z
SetColorBuffer(cubemapbuffernz, cubemap, 0, 5) -- negative z

after every render.