Julien Bayle

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About Julien Bayle

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  1. Light sources lighting volumic matter?

    I got the thing to avoid sudden change But I'm still suprised by the strange light effect in the video linked finally, maybe it is a bit more complex (for me)
  2. Light sources lighting volumic matter?

    Hello dpadam450, sorry for the late reply. Thanks for your answer. I got you about that. About the influence of space, I cannot understand how it works. Indeed, these 2D textures are "only" 2D and if I pass through with the camera, how should it behave ? Wouldn't it be only like if you passed through a wall ..?
  3. Hi there, I'd like to understand [url="http://www.youtube.com/watch?v=o5z1wEj3tHk&feature=player_embedded"]how this light diffusion effect is done[/url] Each light seems to influence the "space" It seems there is a kind of diffusion. I firstly thought about a kind of open-cubes based grid with transparent faces but which would reflect or distort those lights or whatever. Not sure. Thought about fog too. Would someone have some leads to dig this ? Any kind of leads would be appreciate.
  4. I understood all the point maybe it means I'm not that a beginner[img]http://public.gamedev.net//public/style_emoticons/default/blink.png[/img] ok for the 2 model per object. I also got it. I also got the pure culling concept you developed. I'm already making azimuth/elevation calculation for all objects because I need these values for sound panning purpose. Does it make sense to cull or not according to these values instead of detecting intersections between objects & view planes ? Indeed, I feel it like more efficient to use these already available values in my system... My objects would/will be almost only primitives like spheres, glowing lines, very light grid of small spheres.. but glowing, lighting, flashing. many thanks for your answer. I'll implement that as soon as I'll be totally ok with that : http://www.gamedev.net/topic/626839-quaternion-rotation-vs-euler-angles-based-rotation/ This also shows you I'm a beginner [img]http://public.gamedev.net//public/style_emoticons/default/wacko.png[/img]
  5. still multiplying quaternions and vectors... #poetry
  6. Quaternion rotation VS Euler angles based rotation

    Alvaro, I got it. and this is directly related to my mistake! I'm using Max6 and I have to implement that. I guess all objects required already exist but I'm a bit confuse with these [i]incremental rotations[/i] (reference post to Max6 forum in order to excite search engines a bit http://cycling74.com/forums/topic.php?id=40633&replies=12#post-197452 )
  7. Quaternion rotation VS Euler angles based rotation

    Hi Radikalizm, I understood it like that too. It is the way to avoid it.. I read this : http://www.gamedev.net/page/resources/_/technical/math-and-physics/quaternion-powers-r1095 In the Demo Avoiding Gimbal Lock section, I read this: [quote][color=#282828][font=helvetica, arial, verdana, tahoma, sans-serif][size=3][left]he main point you should take note (in the while loop) is[/left][/size][/font][/color][list] [*]The orientation of the camera is a quaternion. [*]There are 3 angles corresponding to the keypress. Note the angles are meant to be an on/off switch (not accumulative). I reset them inside the while loop. Of course this is not the best way to do it but as I said, it is a quick job. [*]I convert the 3 angles to a temporary quaternion. [*]I multiply the temporary quaternion to the camera quaternion to obtain the combined orientation. Note the order of multiplication. [*]The camera rotation is then converted to the Axis Angle representation for transforming the final matrix. [/list] [color=#282828][font=helvetica, arial, verdana, tahoma, sans-serif][size=3][left]When a key is pressed, I generate a temporary quaternion corresponding to the key for a small rotation in that particular axis. I then multiply the temporary quaternion into the camera quaternion. This concatenation of rotations in 4D space will avoid gimbal lock. Try it and see for yourself.[/left][/size][/font][/color][/quote] In my system (based on OpenGL in Max6 framework), I'm grabbing the cam quaternion and this is that one I convert to matrix and I apply it to all my objects coordinates. This is that resulting vector I'm taking for my atan2 based azimuth calculation. I don't use the temporary vector at all. Maybe my problem comes from here. I don't use it because my system provides me directly the quaternion from the cam. still stuck ?!
  8. Hi there, If I use quaternion to rotate an object in my 3d space, I won't have any gimbal lock right? I know about the efficiency around calculation (multiplications only and no trigo, less memory for storage etc) but wanted to be sure about the lock. Especially, I'm calculating azimuth and elevation using the coordinates X & Z of the resulting vector of translation+rotation to camera space. The atan2 have singularities and I wanted to know if I used quaternion I would "override" these singularities. My maths seem rusty.. Any help would be appreciate
  9. [color=#000000][font=Arial,]I have a camera quaternion (a,b,c,d) and a cam position (camX, camY, camZ) I have an object with 3d coordinates (x,y,z)[/font][/color] [color=#000000][font=Arial,]I need to calculate azimuth, elevation of objects relatively to the cam view direction & plane.[/font][/color] [color=#000000][font=Arial,][b]First question[/b] If I keep the object in center of my view (I mean, if I aim at it with my cam), even If I rotate the cam, translate it keeping the object in the center, I should have the same azimuth value, right ?? I don't have that.[/font][/color] [color=#000000][font=Arial,][b]Second question, the calculation.[/b] I'm doing (object coordinates - cam position), in order to translate the object to the cam. I'm taking the resulting coordinates and make the sandwich product with the quaternion and its conjugate. (I followed this for the pseudo code :[url="http://fr.wikipedia.org/wiki/Quaternions_et_rotation_dans_l%27espace"]http://fr.wikipedia....ns_l'espace[/url])[/font][/color] [color=#000000][font=Arial,]Then, I have a vector result and I take X & Z component and calculate the atan2.[/font][/color] [color=#000000][font=Arial,]Does it seem right ?[/font][/color] [color=#000000][font=Arial,]any leads or explanation would help me a lot in my struggle[/font][/color]
  10. What is this kind of matter ... fog ?

    Maybe I made a mistake by posting it here instead of openGL category :-/ I don't want to double post btw..
  11. OpenGL Making glowing objects

    [quote name='dpadam450' timestamp='1340319581' post='4951533'] Pretty much looks like a glow texture that has alpha on the edges. Nothing special that it looks like they are doing. [/quote] dpadam450, I especially posted about the influence of those lights in a new specific thread there: http://www.gamedev.net/topic/626795-what-is-this-kind-of-matter-fog If you'd have any leads, I'd be happy to dig them
  12. Hi there, I'd like to understand [url="http://www.youtube.com/watch?v=o5z1wEj3tHk&feature=player_embedded"]how this light diffusion effect is done[/url] Each light seems to influence the "space" It seems there is a kind of diffusion. I firstly thought about a kind of open-cubes based grid with transparent faces but which would reflect or distort those lights or whatever. Not sure. Thought about fog too. Would someone have some leads to dig this ? Any kind of leads would be appreciate.
  13. Hi there, I tried a little presentation of myself here: [url="http://www.gamedev.net/topic/626751-little-hello/"]http://www.gamedev.n...1-little-hello/[/url] I wanted to describe a bit my project before posting some questions. myUniverse is a 3d visual & sound environment for composition and performance. It is all based on Max6 framework. The basic idea is to explore relationship between space & time, between visuals & sounds. I can instantiate objects in this 3d space. Each object have sounds & visuals properties. The camera visit the space and experience sounds & visuals during the travel. A core made using JAVA instantiated inside Max6 is the centralize way to store/load my maps (a map is a set of objects and their properties, plus some global context stuff like fog presence or not etc) I'm at the point when I need to : - consolidate the engine ([url="http://www.gamedev.net/topic/626752-view-frustum-culling-vs-azimuthelevation-for-objects-inactivationactivation/page__p__4951651#entry4951651"]view frustum culling based on azimuth/elevation/distance[/url], improvement of azimuth, elevation & distance calculations..) - finish the small gui which helps me to compose (= create, move objects, change their properties etc) - design my set of objects Beginning to post here, because it seems the appropriate place for me. Feel free to tell me I should post elsewhere. Best
  14. Hi jefferytitan. Many thanks for your answer which is very complete. About culling. Because of calculations constraints in my actual way, I'm already making azimuth/elevation/distance calculations for each object. Can I use these values for culling ? I mean, the usual/classic culling works with the 6 planes intersection detection and a list of object to activate/inactivate. Implementing that in my system would be a cost more, knowing I alread have all A/E/D for all objects. What do you think about the fact I can inactivate/activate about A/E/D ? It would also provide something precious, not all objects would be culled on the same way as you suggest... glowing lighten object could be cull only considering distance, and the others considering distance and position relative to cam. I have to know how to glow like in this video: http://www.youtube.com/watch?feature=player_embedded&v=o5z1wEj3tHk it seems there is like a "matter in the space" (sorry for my newbie words) this would forbid me to cull objects even if they are behind the cam, if I want to have that kind of glowing no? About LOD. I read http://blog.wolfire.com/2010/10/Imposters about that Thanks a lot to have pointed me there. It is an interesting technique, probably classic but totally new for me. I'll dig that for my system, but my system is really much simpler than complex objects to visualize. Those objects would "only" be primitives like spheres, cubes etc. Btw, I'll try to test it. About PVS. god.. 10h I'm here and you already taught me a lot I got it too. in my case, there wouldn't be a predefined path, which means the cam can go everywhere without predictable path. It means it would be hard to use that BUT ... it gives me another idea related to the first answer I had here by BCullis. I could use a global sphere around the cam (I already have it with my distances calculations) (partial) Conclusion if I can cull considering A/E/D, I guess i would already optimize A LOT ! I'll dig LOD for sure.
  15. Little Hello

    [quote name='Tom Sloper' timestamp='1340323141' post='4951545'] This one was moved to the Lounge from For Beginners. [/quote] Got it. Thanks for your answer and tips [quote name='jbadams' timestamp='1340328930' post='4951569'] Welcome Julien, I hope you find our site and community helpful! [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img] [/quote] Hi there, I'm sure I'll find it VERY helpful. Curiously, I thought it would be only for game developers, but in my huge visual & sound project, I'm flirting closely with this world and it is very interesting. And it gives me ideas for my own CMS because http://designthemedia.com uses it too ( I mean IPS Board) Thanks for your "welcome"