#jogamp @ irc.freenode.net - 20141214 05:06:33 (UTC)

20141214 05:06:33 -jogamp- Previous @ http://jogamp.org/log/irc/jogamp_20141213050632.html
20141214 05:06:33 -jogamp- This channel is logged @ http://jogamp.org/log/irc/jogamp_20141214050633.html
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20141214 13:39:53 <Eclesia> good afternoon
20141214 13:43:54 <Eclesia> to save a bit of time, does someone have the classic interpolation functions code ? nearest,bilinear,trilinear,bicubic ? (and would agree to make those public domain)
20141214 13:49:40 <Eclesia> rmk0: o/
20141214 13:54:22 <rmk0> .o.
20141214 13:54:26 <rmk0> lo
20141214 13:54:30 <rmk0> if i had them, i would!
20141214 13:54:57 * rmk0 nudges Eclesia ^^
20141214 13:55:27 <Eclesia> :( ok no problem. I'll rewrite them
20141214 13:56:44 <rmk0> unless i'm mistaken, you can write them as 1D interpolation functions and just evaluate them twice
20141214 13:59:03 <Eclesia> for bilinear yes, but for the others I'm not sure
20141214 14:13:14 <Eclesia> rmk0: you are right +1
20141214 14:13:32 <Eclesia> they can be generalize to N dimensions
20141214 14:13:34 <rmk0> convenient
20141214 14:16:03 <Eclesia> yeah first one made. Neareast. that was hard.
20141214 15:19:33 <Eclesia> hm the hard part is to make a clean api, to allow a stack of image + extrapolator + interpolator
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20141214 20:05:23 <Eclesia> rmk0: have you worked with seeds ? I mean like, placing tree, flowers, grass with only a texture as input
20141214 20:06:26 <rmk0> not sure which way to interpret that...
20141214 20:06:34 <rmk0> how do you mean placing?
20141214 20:06:37 <rmk0> and... placing into what?
20141214 20:06:52 <Eclesia> let's say I want to render some grass
20141214 20:07:06 <Eclesia> I won't make a mesh for each grass blade
20141214 20:07:31 <Eclesia> I would use a texture containing the grass density
20141214 20:08:10 <rmk0> hm
20141214 20:08:11 <Eclesia> and from that generate more or less grass blades.
20141214 20:08:27 <rmk0> am sort of inclined to use transform feedback for this
20141214 20:08:46 <rmk0> any sort of "particle" system like this, really
20141214 20:09:10 <Eclesia> is that what is also called 'autofeed buffers' ?
20141214 20:09:17 <rmk0> not heard that term before...
20141214 20:09:20 * rmk0 looks it up
20141214 20:09:52 <rmk0> .. possibly
20141214 20:10:13 <rmk0> you render n copies of a mesh, transformed to world space, into one large VBO
20141214 20:10:48 <Eclesia> for each frame ?
20141214 20:10:56 <rmk0> you'd only need to do it once
20141214 20:11:32 <Eclesia> but I'm moving on the map, that would become an enormous vbo
20141214 20:12:15 <rmk0> it depends on what you're doing, but when i've seen it done in most modern engines, they draw grass with decreasing density out to a fixed radius
20141214 20:12:42 <rmk0> i think this problem is something that both opengl and directx really struggle with... e.g, "draw lots of copies of something really fast"
20141214 20:12:54 <rmk0> is an acknowledged major problem with both APIs
20141214 20:13:10 <rmk0> has led to extensions like bindless drawing, direct state access, etc
20141214 20:13:20 <Eclesia> hm ...
20141214 20:13:50 <rmk0> i'd use transform feedback because it works everywhere, but there's also instanced drawing
20141214 20:14:51 <Eclesia> ok thanks, I'll take a look at both
20141214 20:14:53 <rmk0> you more or less supply an array of n transforms to a shader, and then tell opengl to draw n copies of the VBO you've got currently bound
20141214 20:15:57 <rmk0> the api makes it pretty error-prone
20141214 20:16:27 <rmk0> i can't use it, personally, as i've got to support 3.1
20141214 20:16:32 <Eclesia> It won't be Opengl if it was not :D
20141214 20:16:35 <rmk0> you really need 3.3 and greater
20141214 20:16:43 <Eclesia> wouldn't*
20141214 20:37:33 <Eclesia> that's going to be some work to add instancing and transform feedback in an easy way into the engine
20141214 20:38:07 <Eclesia> well, we'll see what I can do in one week ^^
20141214 20:38:07 <rmk0> transform feedback is easier in the sense that the engine doesn't really need to know about it
20141214 20:38:13 <rmk0> it just sees a VBO that you produced by some other means
20141214 20:38:16 <rmk0> instancing is definitely intrusive
20141214 20:38:59 <Eclesia> yeah seems like transform feedback can be something completly separate, like a GL utility class
20141214 20:39:30 <Eclesia> instancing, i think it could be a special scene node, which repeats N times it's children
20141214 21:07:29 <Eclesia> good night ++
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20141215 05:06:33 -jogamp- Continue @ http://jogamp.org/log/irc/jogamp_20141215050633.html