From guest Fri Jun 17 06:09:05 1994 From: "Marc SIMON Presales support" Message-Id: <9406171514.ZM20930@girl.paris.sgi.com> Date: Fri, 17 Jun 1994 15:14:06 -0600 X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: Fog on RE Cc: mtj@giraffe Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR Testing some customers codes using fog with perforemr 1.2 seems to show a problem with the resolution of the fog table on the RE2. When using FG_PIX_LIN or FG_PIX_EXP or FG_PIX_EXP2 with a far fog of 1000 m for instance and when drawing an object at 1100 m it is still visible. I known that it is of course related to the range of Z value defining by the near and far clipping plane and the lsetdepth value.But it works fine on a Indigo2 Extreme... You can try : - perfly enterprise.flt The model appear at ~ 2600 m from the viewer - fog on (Exponential or linear) - move the far fog to 2500 m . - You could see that the Mister Spoke ears are always visible... Try to do the same on Extreme GFX ... It works fine. Thanks to explain to me what's happend . Is it a bug ?? Is there a way to avoid this ?? My customer is today waiting for an answer to decide to continue or to stop with Performer . Thanks to help me quickly. -- -- Marc -- Marc SIMON Presales support =========================== --------- ////// // // ////// /////// /////// ----------- // // / / // // // / / // --------- ///// // / // ///////// /////// // ----------- // // // // // /// // --------- /////// // // // // / /// /////// ---------- Silicon Graphics France 21 Rue Albert Calmette Jouy-en-Josas 78350 FRANCE Tel (33) 1 34-88-80-00 email : smarc@paris.sgi.com ++++++++++++++++++++++++++++ smarc@paris.sgi.com **************************** From guest Fri Jun 17 08:12:56 1994 From: "Michael Jones" Message-Id: <9406170812.ZM3996@babar.asd.sgi.com> Date: Fri, 17 Jun 1994 08:12:48 -0700 In-Reply-To: "Marc SIMON Presales support" "Fog on RE" (Jun 17, 3:14pm) References: <9406171514.ZM20930@girl.paris.sgi.com> X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: "Marc SIMON Presales support" , info-performer@sgi.sgi.com Subject: Re: Fog on RE Cc: mtj@giraffe Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR On Jun 17, 3:14pm, Marc SIMON Presales support wrote: > Subject: Fog on RE :Testing some customers codes using fog with perforemr 1.2 seems to show a :problem with the resolution of the fog table on the RE2. : :Thanks to explain to me what's happend . Is it a bug ?? Is there a way to :avoid this ?? We'll check into this. :My customer is today waiting for an answer to decide to continue or to :stop with Performer . If your customer thinks the problem is in the RE2, then why would they think that not using Performer (while still using the RE) could make the situation better? Several fog-related questions have come up lately. Perhaps we need to expand the Programming Guide's section on pfFog control and operation in the next release of the manual. -- Be seeing you, Phone:415.390.1455 Fax:415.390.2658 M/S:9U-590 Michael T. Jones Silicon Graphics, Advanced Graphics Division mtj@sgi.com 2011 N. Shoreline Blvd., Mtn. View, CA 94039-7311 From guest Wed Mar 30 08:05:38 1994 From: "pierre VERCRUYSSE" Message-Id: <9403301606.ZM9943@cathy.rennes.sgi.com> Date: Wed, 30 Mar 1994 16:06:22 +0100 X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: fog problem on RE2 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR I, can some body can help? I'm in Performer 1.2a151preMR IRIX 5.2 MR on an Onyx RE2. And when i initialize a fog with EarthSky = pfNewESky(); /* creation du modele horizon/meteo */ pfChanESky(Channel,EarthSky); /* attachement au modele horizon/meteo */ Fog = pfNewFog(NULL); /* creation du modele brume */ pfFogType(Fog,PFFOG_VTX_EXP2);/* attenuation de type expo**2 sur sommets */ /* attachement du modele brouillard au modele horizon/meteo */ pfESkyFog(EarthSky,PFES_GENERAL,Fog); Soleil = pfNewLight(NULL); /* on cree, positionne une nouvelle source */ pfApplyLModel(SoleilModel = pfNewLModel(NULL)); My fog are very cloud, i don't see the scene. In advance thanks for your help, pierre@rennes.sgi.com From guest Wed Jun 8 13:18:20 1994 From: "Drew Hess" Message-Id: <9406081318.ZM7401@airy.arc.nasa.gov> Date: Wed, 8 Jun 1994 13:18:15 -0700 X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: pfFog again Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR When I enable fog in perfly and then take a screen snapshot using the pfuSaveImage function, with readsource() set to SRC_FRONT, the captured image has a much different fog density than the on-screen image. How is fog implemented on the RE2, and what is the proper way to get the same image in a snapshot that I see on the screen? Do I need to readsource() and lrectread() from multiple buffers and somehow blend the images? Thanks -dwh- dhess@vision.arc.nasa.gov dhess@cs.stanford.edu From guest Mon Jun 6 15:44:54 1994 From: "Drew Hess" Message-Id: <9406061346.ZM4341@airy.arc.nasa.gov> Date: Mon, 6 Jun 1994 13:46:20 -0700 X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: pfFog and fog density Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR I need to explicitly set the fog density parameter of Performer fog. As far as I can tell the only way to do this is with PFFOG_PIX_SPLINE, but what I'd actually like to do is use PFFOG_PIX_EXP or PFFOG_VTX_EXP. Basically I need the extra parameter that fogvertex(3G) uses for density, but in looking at the Performer documentation it's not clear how to do this without going to the GL, which I'd like to avoid if possible. It appears that the only controls over fog, besides with the SPLINE type, are color and the near and far fog planes. Am I missing something obvious? How does Performer calculate the density parameter for fog by default? Thanks -dwh- dhess@vision.arc.nasa.gov From guest Mon Jun 6 16:20:58 1994 From: "Michael Jones" Message-Id: <9406061620.ZM4967@babar.asd.sgi.com> Date: Mon, 6 Jun 1994 16:20:46 -0700 In-Reply-To: "Drew Hess" "pfFog and fog density" (Jun 6, 1:46pm) References: <9406061346.ZM4341@airy.arc.nasa.gov> X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: "Drew Hess" , info-performer@sgi.sgi.com Subject: Re: pfFog and fog density Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: O On Jun 6, 1:46pm, Drew Hess wrote: > Subject: pfFog and fog density :I need to explicitly set the fog density parameter of Performer fog. As far as :I can tell the only way to do this is with PFFOG_PIX_SPLINE, but what I'd :actually like to do is use PFFOG_PIX_EXP or PFFOG_VTX_EXP. No problem. To quote from the new IRIS Performer 1.2 Programming Guide: "You can set the near and far edges of the fog with pfFogRange(). For exponential fog functions, the near edge of fog is always zero in eye coordinates. The near edge is where the onset of fog blending occurs, and the far edge is where all pixels are 100% fog color." :Basically I need the extra parameter that fogvertex(3G) uses for density, but :in looking at the Performer documentation it's not clear how to do this without :going to the GL, which I'd like to avoid if possible. The opaque distance is (in a sense) equivalent to the density. Since fog density is a function of distance, it's possible to define fog as a (density, distance) pair. It was decided to use an implied density=1 in the IRIS Performer API such that "at the opaque fog range, the fog density is 1.0". Given this, only the distance need be specified. If f = 1 - e**(-k*d), and you want to specify the general (f,d) pair, just solve for the appropriate f=1 case and use the new d' in your IRIS Performer calls. The only problem here is that you can't really solve for f=1 above and need to accept 255/256th's or so. :It appears that the only controls over fog, besides with the SPLINE type, are :color and the near and far fog planes. Am I missing something obvious? How :does Performer calculate the density parameter for fog by default? The opaque and opaqueOffest parameters are used to define the density in the fogvertex() command as shown in this code extract (from IRIS Performer's fog application code): switch (fog->type) { case PFFOG_VTX_LIN: case PFFOG_PIX_LIN: props[0] = fog->onset + fog->onsetOffset; props[1] = fog->opaque + fog->opaqueOffset; if (props[1] < props[0]) props[1] = props[0]; props[2] = fog->color[0]; props[3] = fog->color[1]; props[4] = fog->color[2]; break; case PFFOG_VTX_EXP: case PFFOG_PIX_EXP: case PFFOG_VTX_EXP2: case PFFOG_PIX_EXP2: props[0] = 1.0f/(fog->opaque + fog->opaqueOffset); props[1] = fog->color[0]; props[2] = fog->color[1]; props[3] = fog->color[2]; break; -- Be seeing you, Phone:415.390.1455 Fax:415.390.2658 M/S:9U-590 Michael T. Jones Silicon Graphics, Advanced Graphics Division mtj@sgi.com 2011 N. Shoreline Blvd., Mtn. View, CA 94039-7311 From guest Wed Jun 8 21:47:57 1994 From: "Drew Hess" Message-Id: <9406082147.ZM8523@airy.arc.nasa.gov> Date: Wed, 8 Jun 1994 21:47:40 -0700 X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: more pfFog fun Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR I've done some playing around since I posted my last message stating that I was having problems with scenes with fog not looking the same as snapshots of those scenes taken using pfuSaveImage(). In case you're actually following along, here's the basic problem: if I render a scene with pfFog turned on, and then take a snapshot of the scene using the Performer pfuSaveImage() function, the snapshot as displayed by imgview(1) is visibly different than the scene rendered by Performer. The difference is that the far fog plane, that is the distance at which all pixels fade to fog color, appears to be missing in the snapshot, and the effect is that you have a much greater visible range in the snapshot than you do in the rendered Performer scene. Here's what I've established so far: a) this problem occurs when running Performer in full-screen GL mode on an Indigo2 with an XL framebuffer as well as on an Onyx with an RE2. b) this problem does *not* occur when a GUI panel is being displayed; that is, both Performer and the snapshot show the GUI, but the scene looks *exactly* the same in Performer as it does when I use imgview(1) to view the snapshot. c) if I create a smaller window, using the -W x,y parameter to perfly, for instance, the snapshot fades to the far fog plane properly, so visible range is the same in both images; but strangely, the fog color in the snapshot is always white (1.0, 1.0, 1.0) despite the fact that the fog color in the Performer scene is, say, grey (0.7, 0.7, 0.7). I don't think this is a gamma correction effect because when I set the fog color in the Performer scene to pure white, the fog colors are identical (both pure white). d) if I create a less-than-fullscreen GLX window (-x in perfly), the snapshot is exactly the same as the Performer scene (except that I need to tweak the window sizes that get passed to lrectread() in pfuSaveImage a bit because it captures part of the window manager border around the GLX window -- note this does not occur in a small window where I don't specify the -x option to perfly). (I also get the overlay plane in my snapshot in this case, evident by the "IRIS Performer" label in the upper right-hand corner of the snapshot.) Anyway, originally I figured that the RE^2 was doing some funky buffering to generate hardware fog that caused readsource(SRC_FRONT) to miss part of the fog layers; now I know that it's not just the RE^2 since the XL produces a similar (though not identical) effect. Still it would be nice if some kind soul at SGI who's bothered to read this far could explain how the RE^2 produces fog :) The pfuSaveImage routine produces a 24-bit RGB image and basically strips off anything but the first 24bits of the pixel, as far as I can tell; but I don't think it's a pixel-depth problem because I'm getting bad results on the XL, which is purely 24-bit, as well as on the variable-depth RE^2. I don't know what mode Performer operates in on such a beast. I've also noticed that playing with the pfESkyMode settings has an effect on the way fog is rendered; I might look into this next if no one has a simple answer for me. Sorry I'm so long-winded, but it's a very curious problem and I thought I should accurately document what I'm talking about. The bottom line is that I want to make snapshots of foggy scenes in any mode I want on any machine (ok, I'll settle for full-screen GL-mode snapshots on the RE^2 only at this point :) ) for image processing, and I want the snapshot to look identical to the rendered scene in Performer. What am I doing wrong? Thanks again to the Performer people, -dwh- dhess@vision.arc.nasa.gov dhess@cs.stanford.edu From guest Tue May 10 08:44:10 1994 From: "pierre VERCRUYSSE" Message-Id: <9405101645.ZM594@cathy.rennes.sgi.com> Date: Tue, 10 May 1994 16:45:05 -0600 X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: (Fwd) Fog implementation Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR Hi I have a customer who have some difficulties to implement the Fog. I have an Onyx RE2 with 2 RM in Irix 5.2 and performer 1.2. He have watch the difference with the his application and perfly and he has conclude this summary and a lot of question ? type of fog Near far status VtxLin,PixLin or [1.0,1000.0] 1000.0 no problem, it'ok spline if > 1000.0 8000.0 Problem why ?? VtxExp/VtxExp2 no variation of the fog when we change the near PixExp/PixExp2 1. We don't seen what kind of value we can put on near ? and what is the minimum distance that i can define for the value "NEAR" of the interval for the fog ? 2. How can i optimise the drawing of the image by manipulating the clipping plan "Far" pfFogRange(fog,1.0f,distance of visibility); pfChanNearFar(channel,1.0f,distance of visibility+alpha); 3. Thus he exist a relation between the distance of visibility, the dynnamic in z of the system and the dynamic about the BDD (step of discretisation) ? My customer goes to the preparation of the ITEC and he told me that during the preparation about the demo of the shared database, He hav'nt seen a demo of performer with fog. Is it true or not ? In advance Thanks for your answerd . pierre@rennes.sgi.com From guest Tue May 10 09:10:32 1994 From: marrou@vsl.ist.ucf.edu (Lance Marrou) Message-Id: <9405101610.AA01612@sg1.vsl.ist.ucf.edu> To: "pierre VERCRUYSSE" , info-performer@sgi.sgi.com Subject: Re: (Fwd) Fog implementation Status: OR I have also had trouble implementing spline fog on RE and RE2 systems, but I had not figured it was worth a lot of trouble (therefore I did not spend a bunch of time with it). I stuck with the regular pix mode on fog and it works fine enough for some neat effects (quick & cheap). We had it running on our demos at I/ITSEC last year. Of course, fog will become a cheap rendition of any fog/cloud simulations currently being developed, but it is a cool source of visual effects; thanks, SGI! :) _______________________________________________________ IST __ E-mail: marrou@vsl.ist.ucf.edu Visual / / ______ /\____ ______ ______ Systems / / / _ / / __ // ____// ____/ Lab / /__ / /_/ / / / / // /___ / __/_ R. Marrou ________/____//____/\\/_/ /_//_____//_____/____________ From guest Fri May 20 09:35:46 1994 From: jrohlf@tubes (John Rohlf) Message-Id: <9405201542.AA01190@tubes.asd.sgi.com> Subject: Re: (Fwd) Fog implementation To: guest (pierre VERCRUYSSE) Date: Fri, 20 May 94 8:42:41 PDT Cc: info-performer@sgi.sgi.com In-Reply-To: <9405101645.ZM594@cathy.rennes.sgi.com>; from "pierre VERCRUYSSE" at May 10, 94 4:45 pm X-Mailer: ELM [version 2.3 PL8] Status: OR > > He have watch the difference with the his application and perfly and he has > conclude this summary and a lot of question ? > > type of fog Near far status > > VtxLin,PixLin or [1.0,1000.0] 1000.0 no problem, it'ok > spline if > 1000.0 8000.0 Problem why ?? > > VtxExp/VtxExp2 no variation of the fog when we change the near > PixExp/PixExp2 > > 1. We don't seen what kind of value we can put on near ? and what is the > minimum distance that i can define for the value "NEAR" of the interval for the > fog ? Only linear and spline fog support a near fog distance. I don't know why near > 1000 causes problems for spline fog. > > 3. Thus he exist a relation between the distance of visibility, the dynnamic in > z of the system and the dynamic about the BDD (step of discretisation) ? > > My customer goes to the preparation of the ITEC and he told me that during the > preparation about the demo of the shared database, He hav'nt seen a demo of > performer with fog. Is it true or not ? perfly uses fog and has sliders for near/far distances and a menu button for fog type. Try it. From guest Thu Mar 10 03:38:21 1994 From: "Ran Yakir" Message-Id: <9403101337.ZM10354@rea1.bvr.co.il> Date: Thu, 10 Mar 1994 13:37:02 +0000 X-Mailer: Z-Mail (3.1b.0 09feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: Fog Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR Hi All I'm using spline fog on Performer 1.2, and have 2 questions 1. The spline fog doesn't work on every RealityEngine machine. Furthermore, on our dual-headed ONYX, it works on the zeroth head but not on the other one. By 'doesn't work' I mean that you set the fog, but see no fog whatsoever. 2. Is it expensive to set the fog ranges and ramp each frame ? Is it better to create several fogs and just switch between them when necesary ? Here is the code fragement that generates the fog : /* * init_fog() is called once at the beginning of time */ void init_fog (nrt_fog *fog) { fog->is_fog = 0; fog->fog = pfNewFog (pfGetSharedArena()); fog->fog_type = PFFOG_PIX_SPLINE; pfFogType (fog->fog, fog->fog_type); pfFogColor (fog->fog, 1.0, 1.0, 1.0); fog->onset_range = 20000.0; fog->opaque_range = 50000.0; pfFogRange (fog->fog, fog->onset_range, fog->opaque_range); pfGetFogRamp (fog->fog, &fog->nof_points, fog->ramp_range, fog->ramp_density, &fog->ramp_bias); } /* * update_env() is called each frame and updates the fog among other things */ void update_env (pfChannel *chan, nrt_environment *env) { /* * do other things */ .... /* * do fog */ pfFogType (env->fog.fog, env->fog.fog_type); pfFogRange (env->fog.fog, env->fog.onset_range, env->fog.opaque_range); pfFogRamp (env->fog.fog, env->fog.nof_points, env->fog.ramp_range, env->fog.ramp_density, env->fog.ramp_bias); if (env->fog.is_fog) pfESkyFog (esky, PFES_GENERAL, env->fog.fog); else pfESkyFog (esky, PFES_GENERAL, NULL); pfChanESky (chan, esky); /* * do more other things */ .... } Thanks Ran Yakir -- __ | Ran Yakir /_) _ __ \ / _ / o __ | Phone : / )_ (_(_) ) \/ (_(_/<_(_)( | Work : 972-3-5715671 _/ | Res. : 972-3-6995364 | E-mail : rany@bvr.co.il From guest Wed Jun 29 09:10:13 1994 From: "Ran Yakir" Message-Id: <9406291909.ZM9676@amcor.bvr.co.il> Date: Wed, 29 Jun 1994 19:09:07 +0000 X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: pfFog Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: O Hi What is the reason for the exsitance of fog-offsets ? Is there any difference (in performance or other) between setting fog-ranges or fog-offsets ? Ran -- __ | Ran Yakir /_) _ __ \ / _ / o __ | Graphics App. Chief Engineer / )_ (_(_) ) \/ (_(_/<_(_)( | BVR Technologies Ltd. _/ | -------------------------------------+-------------------------------- Phone : | E-mail : rany@bvr.co.il Work : 972-3-5715671 | Res. : 972-3-6995364 | Fax : 972-3-5715668 |