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Bloom / glow

Started by patrrr Aug 12, 2006 at 9:27 AM 2 replies 1.5k views

Original Post

Aug 12, 2006 at 9:27 AM

Hello, I've got a question about implementating a glow or "bloom" effect, I know that you basically render the scene as usual, then you render it again but with different textures which tell where there should be glow. ("glowmaps"?) The second pass is rendered onto a texture and a blur effect is applied. But how do you apply that texture to the scene? Using an orthonormal projection? And how would you do this in shaders? Thanks.

m4gnus

Aug 12, 2006 at 11:38 AM

you render a fullscreen quad and combine the bloom texture and the scene without bloom with a pixelshader.

OrangyTang

Aug 12, 2006 at 12:00 PM

Quote:
Original post by m4gnus
you render a fullscreen quad and combine the bloom texture and the scene without bloom with a pixelshader.

Typically you don't even need a shader, the final result is usually just done as finalScene = originalScene + blurResult. This can be done with simple additive blending or multitexturing (depending on what you've already got in the framebuffer to work with).

superpig

Aug 13, 2006 at 8:40 AM

Quote:
Original post by patrrr
But how do you apply that texture to the scene?
Using an orthonormal projection?

When you render the second pass, all geometry is projected into screenspace already. You don't need to project the result again, you just render it in screenspace.

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