I know that there are many other posts about this topic, but i was wondering if anyone knew of a method to create a 3D glow effect using shaders, that doesn''t require rendering to a texture.

Unfortunately no. You''ll need to render the scene to an off-screen texture because you''ll need to blur it.

This may be a really weird idea, but you could try rendering both the plain scene and the blurred regions to the backbuffer one after the other... Might work.

depends, on what kind of glow ya want... there has been billboarded glow around lights forever.

Pretty much the requirements for the glow is that it has to be done with cg shaders, and that it can''t use OGRE''s render to texture, which left me without any ideas on how to do it.

Use yer imagination. It is possible to do a glow effect with only render-to-texture, but your blur effect won''t be as good.

1) Render normal scene;

2) Make everything that is not glowing black, make everything that glows fully self-illuminated. Render to texture;

3) Blur the texture. That can be done by, as example, rendering the texture on top of itself, with a 50% blend, offset to the top, bottom, left and right (four renders). This may cause a performance hit if your texture is too big, so you may try to scale the texture down (the original, no blurred, texture could be drawn at full resolution, and then scaled down into half resolution for blurring).

4) Render the final texture on top of the screen buffer, with additive blending.

Tron 2.0 does more or less that, and it works in cards without pixel shaders.