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Special Effects

Started by Zealot Jul 30, 2002 at 6:56 AM 0 replies 550+ views

Original Post

Jul 30, 2002 at 6:56 AM

I have a few questions concerning special effects: 1. I never really understood those shadowing tutorials, so I thought up this idea on how to create shadows (if you use animations, then this method [assuming it works] would allow deformable shadows, depending on the model''s state): Render the object to cast shadows Render it again, but multiple times (sorta like this -) [- is the object, and ) shows the multiple renderings]) into the stencil buffer Draw the objects to be shadowed upon Draw the objects to be shadowed upon again, but limited by the stencil buffer, and modified by glColor3f(R, G, B) to make it darker, and possibly add some blending I just wanted to know if this has any chance of working, and if it does, will it be able to at a reasonable speed? 2. Does fog work better if you specify normals? I added fog to a scene, but it do much, but I didn''t specify normals. 3. What does GL_AUTO_NORMAL do? 4. How do you make realistic smoke and fire without a serious drain on the cpu? I thought you might be able to use the stencil buffer and fog for smoke, but I realized that probably wouldn''t work well. 5. Lastly, does light attenuation drain the cpu a lot? En taro Adun! Doom to all who threaten the homeworld! *Protoss Zealot - Starcraft*

_the_phantom_

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_the_phantom_

Jul 30, 2002 at 10:11 AM

quote:
Original post by Zealot
I have a few questions concerning special effects:

1. I never really understood those shadowing tutorials, so I thought up this idea on how to create shadows (if you use animations, then this method [assuming it works] would allow deformable shadows, depending on the model''s state):
Render the object to cast shadows
Render it again, but multiple times (sorta like this -) [- is the object, and ) shows the multiple renderings]) into the stencil buffer
Draw the objects to be shadowed upon
Draw the objects to be shadowed upon again, but limited by the stencil buffer, and modified by glColor3f(R, G, B) to make it darker, and possibly add some blending
I just wanted to know if this has any chance of working, and if it does, will it be able to at a reasonable speed?

Thats very close to the ''Carmack''s reverse'' way of doing things (but his can be descibed on two lines and uses the z-buffer), you might want to take a look at an artical on Nvidia''s dev pages about shadow mapping, as i belive it has a link to an email from John Carmack about his method.

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