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Comments:
<0> hi yall
<1> Does anyone know where I can find some detailed tutorials on the theories behind metaballs or volumetric lights?
<2> does glut provide real-time input?
<0> define real-time?
<3> you prob. need to rely on other libs for input
<3> i may be wrong, but i've never seen any input related extenions in glut at all
<1> there is a function that recieves input etc
<1> I've seen it :P
<1> http://www.swiftless.com/tutorials/opengl/keyboard.html
<2> thanks alot
<1> :)
<1> Now can anyone tell me where I can find some tutorial on doing volumetric lights? (using GLSL)
<1> Is there anyway in GLSL to check the previous stored Z value in the fragment shader?
<1> ok I'm really going nuts, how are volumetric lights done?
<4> by faking it, obviously
<1> even the ones in HL2?
<1> should I try a billboard approach?
<4> I don't remember how those look :p
<1> 1 sec
<1> http://www.petertorpey.com/tutorials/volume_light/final.jpg
<4> hmm, let's see, I guess you could do it with particle effects, a simple cone or shaders
<4> and probably a ton of other ways that I haven't thought of :p
<1> I don't want the cone to be rendered like a triangular cone obviously
<1> and I want to make the sides faint
<4> and you want it to be visible from within the cone itself?
<1> hmm nah
<1> it won't matter
<4> then I'd probably use a very simple shader for the light
<4> eh, for the cone
<1> how would I make the cone sides faint ...
<4> a blinn-phong shading model, affecting the alpha instead of the intensity maybe?
<1> on screen dot product?
<1> so you're suggesting multiple cones lit up?
<4> eh?
<4> I'm thinking a single cone
<1> ok
<4> I can do a little experiment on it in 45 minutes, if you can wait that long :p
<1> sure :D
<4> see if I can make something that doesn't look like crap, I doubt it though
<1> Damn , so many tutorials on how to do it using various programs, but not a single one explaining how to code it or the theory behind it
<4> well, there's a lot of ways to do it
<1> I just need to know how to do the fall off on the edge
<1> brb in 10 minutes
<4> well, you could do it with vertex colors for a really cheap hackish solution that might not look good, and probably won't look all that good (well, it'll probably look pretty bad I guess)
<1> yeah
<1> Hmm...
<1> dot (normalize (texel screen position-light screen position),normalize (midpoint screen position-light screen position)) ?
<1> midpoint some point in the middle of the cone
<1> whould that work?
<1> determining fall off based on that
<1> and also
<1> One thing's for certain color is based on FragCoord.xy
<4> I wouldn't use the light position at all, I'd simply use vertex colors to determine the falloff from the light, then use a modified blinn-phong shading model to detirmine the falloff to the sides, using the view vector for the light vector, and using the intensity of the light to determine the alpha
<1> Hmm
<4> I'm not sure if that would look good or not, but it seems like a reasonable solution to me
<1> Dude that's brilliant
<1> I totally forgot the eye vector dot reflection
<1> that would be very reasonable
<4> it's really easy to test atleast
<1> because on the sides, the reflect vector would be pointing way out of your view
<4> yeah
<1> or even better
<1> normal dot view
<4> that would be a very effective way of doing it
<1> and texel distance for origin with a cut-off value would be good for normal fall-off
<4> just give it a shot, and see how it looks, shouldn't take more than a few minutes to implement
<1> hmm sure
<1> after I come from the washroom
<1> :D
<4> hehe
<4> how'd it go qman? :p
<1> arrgh
<1> I'm back
<1> well
<1> It needs more polygons for smoother fall off
<1> more 'round' cone results in more smooth fall off on the sides
<1> That brings me to the conclusion that I need a better way to emulate the fall off
<4> use a pixel shader
<1> Even with 100 triangles on the sides of the cone, you can still see the flat shading problem :P
<1> I am :D
<1> both pixel and vertex linked
<1> Maybe ...
<1> I can try this in combination with distance
<1> with*
<1> in**
<1> argh w/e
<4> you still need to generate proper normals, and interpolate them per fragment
<1> proper normals are generated ;)
<1> maybe you're thinking about ... normals different per face?
<4> just like normal per-pixel blinn-phong shading, except the light is the eye, and the intensity controls the alpha
<1> Hmm
<4> you have a working blinn-phong implementation?
<1> I'm using a static mesh right now (a cone I just drew up and exported from 3dsmax)
<1> Yeah but in a more complex shader
<4> hold on, I got something here...
<1> give me a moment let me try something
<4> ok, I got something fairly simple here
<4> it's just a single light, textured, blinn-phon, per-pixel shader
<4> *blinn-phong
<1> my phong shader would look nice if all normals spread out circle-wise
<4> man, I must have been drunk when I wrote this thing, no comments at all :p
<1> so I could interpolate then across the triangle
<1> and normalize
<1> I'm sure this would look superb
<1> damn flat normals
<1> like normals/flat face
<4> http://pastebin.ca/344992
<1> don't worry I need to stop using this static mesh for that purpose X_X
<4> just generate the mesh at runtime
<1> arrgh
<1> I have homework <=(
<4> :p
<4> could you take a screenshot of the results you got now?
<1> argh sure
<1> it's a cone test btw ;P
<1> http://img258.imageshack.us/my.php?image=weqg7.jpg
<1> dot product raised to the 4.0th power
<4> well, there's one big problem with that, the light isn't brightest at the top :p
<1> well I'll use a distance factor too =)
<1> 20/texel_dist_from_light_src
<1> or something like that
<1> if < 1.0 set 0.0
<4> well, if you're doing it linearly, you could just do a simple vertex alpha
<1> smooth interpolated normals across the cone surface would make it look alot better no?
<4> you mean if < 1.0 set 1.0? :p
<4> yeah
<1> that's what I will do after I finish my calc 2 homework =)
<1> factor = 20/texel_dist_from_light_src
<1> if factor < 1.0 factor = 0.0
<1> gl_FragColor = factor + phong_term
<4> won't you get a div by zero error then?
<1> 20 being cut off distance :P
<4> oh, nevermind
<1> if texel_dist_from_light_src == 0.0 texel_dist_from_light_src = 0.001
<1> ./* :D */
<4> yeah
<4> hehe :D
<5> wana know whats even more fun than picking your nose ?
<5> picking your nose scabs with pliers and then chewing on them
<5> its a really tough skin not like regular scabs
<5> dont take my word for it
<5> I incist
<5> momma allways sayd the best things in life r free
<6> You must be a hit with the ladies.
<6> Nothing they like better than a nose-picking geek on IRC.
<7> I want to blend two textures together using a noise map. How should I do this?
<8> the speed of glGetUniformLocation ? is it okay to call it every frame, or should I buffer the locations?
<9> i dont know about the speed, but you can buffer the locations, as they wont change until the next link command
<9> personally, id buffer them, as string parsing needs to be done to figure out which uniform you want to get the location of
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