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SceneState and rendering to texture

by Kyle Goodwin · in Torque Game Engine · 09/25/2004 (1:59 pm) · 11 replies

I'm attempting to duplicate SceneState::RenderCurrentImages so that I can render the entire scene to a texture (with some matrix differences and a clip plane etc.) and then use said texture. After digging on this for a while I'm no longer certain that this is the best way to do such a thing, so I have a twofold question: is this the right way to go about rendering the scene to a texture and if it is, what's the right way to go about getting the SceneState upon which to call my new RenderCurrentImagesToTexture method from within the rendering of something else (right now in the fluid rendering code for a planar reflection)? Also, has anyone else done this or is there a good refernce anywhere? I don't want to be reinventing the wheel if it's not necessary... ;) This is the last aspect that's giving me trouble and preventing my having a fully functional real-time reflective bump-mapped water implementation (I'm using CG for my shaders).

Thanks! :)
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Torque Owner Brian Richardson
#1
09/27/2004 (6:25 am)
The only reference that I can see is engine/interior/mirrorSubObject.cc which manipulates the SceneState to do mirrors on interior poly's.

You could probably use the same ideas to manipulate and render a scene from the water's pov.

Torque Owner Kyle Goodwin
#2
09/27/2004 (8:37 am)
Actually that works by manipulating portals and rendering what is basically a backwards facing portal back into the room you're in. In short: this will only work on interiors. At least that's how I understand it.

Torque Owner Kyle Goodwin
#3
09/28/2004 (9:36 pm)
I've made a lot of progress on this and am very close to having it done, but a few snags remain. My rendered to texture buffer is coming out all black, I must not be using it correctly or something, and for some reason whenever I have rendering to texture enabled I end up with random textures getting put on my terrain in spots, quite odd. It also corrupts the mouse cursor and text in places. Anyone have any ideas about that or agl help with the pbuffers and using them as textures?

Associate Matt Fairfax
PopCap
#4
09/28/2004 (9:38 pm)
Are you in 16 bit or 32 bit mode?

Torque 3D Owner Steven Chiu
#5
09/28/2004 (11:23 pm)
@Kyle:

Check the glBase web site below:

http://www.futurenation.net/glbase/reflect.htm

It has a demo source using the pbuffers for rendering to textures, hope this helps!

Torque Owner Kyle Goodwin
#6
09/29/2004 (5:29 am)
I'm rendering the texture in RGBA 32-bit mode.

Torque 3D Owner Steven Chiu
#7
10/06/2004 (7:55 am)
@Kyle:

Just wondering what's the modelview matrix you use to mirror the terrain about the clip plane?

Torque Owner Kyle Goodwin
#8
10/06/2004 (2:38 pm)
@Steven:

Assuming an xy-plane clip plane, multiply your current MV matrix by the identity (4x4) matrix and the z component negative. If your clip clane is parallel to the xy-plane but does not pass through the origin, add 2*h (the signed distance from the xy-plane to your plane) to the z-component of the homogenous column vector of the matrix (column 4). This is a standard rotation matrix, the only tricky part is the homogenous bit and the confusion that sometimes arises when not understanding the need for a w component/a fourth column vector.

Torque 3D Owner Steven Chiu
#9
10/25/2004 (10:12 am)
Almost finish the planar reflection part of it and I can see the reflection now. But the texture coordinates seems not always correct, sometimes I can see it reflect the clippped portion of the rendered texture. So what's the texture matrix you use to project the rendered texture? Thanks.

BTW The terrain still not fully show up in the reflection, I'll check if it's the camera lead to this problem. I use the advanced camera resource.

Torque Owner Kyle Goodwin
#10
12/03/2004 (9:46 am)
Will you be releasing any of this code? This is still something I'm working on, but I haven't really had time to finish.

Torque 3D Owner Steven Chiu
#11
12/04/2004 (1:24 am)
@Kyle:
No problem! I'll mail the code and some screenshots to you asap, hope we can work together to finish the cool planar reflection and maybe for TSE also!