From guest Tue Feb 1 14:14:40 1994 Return-Path: From: abramsh@maestro.MITRE.ORG (Howard Abrams) Message-Id: <9402011714.ZM15902@maestro> Date: Tue, 1 Feb 1994 17:14:08 -0500 X-Mailer: Z-Mail (2.1.0 10/27/92) To: info-performer@sgi.sgi.com Subject: Snow/Rain Cc: plevy@maestro.mitre.org Status: O I was planing on creating a snow/rain effect on performer. Has anyone had any success in doing this? I had planed on making several texture mapped polygons, and moving the texture or polygons to animate the snow/rain. Does anyone know if this would be a good approach, and if so, can I move the texture instead of the polygon? Also, I had heard that 1.2 will have smoke and dust effects. Will it also have rain? --Howard From guest Fri Feb 4 00:45:22 1994 From: "Dennis Pierce" Message-Id: <9402040344.ZM21670@sgimco.orlando.sgi.com> Date: Fri, 4 Feb 1994 03:44:54 -0500 In-Reply-To: abramsh@maestro.MITRE.ORG (Howard Abrams) "Snow/Rain" (Feb 1, 5:14pm) References: <9402011714.ZM15902@maestro> X-Mailer: Z-Mail-SGI (3.0S.1026 26oct93 MediaMail) To: abramsh@maestro.MITRE.ORG (Howard Abrams), info-performer@sgi.sgi.com Subject: Re: Snow/Rain Cc: plevy@maestro.mitre.org Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR On Feb 1, 5:14pm, Howard Abrams wrote: > Subject: Snow/Rain > > I was planing on creating a snow/rain effect on performer. Has >anyone had any success in doing this? I had planed on making several >texture mapped polygons, and moving the texture or polygons to animate >the snow/rain. Does anyone know if this would be a good approach, and if >so, can I move the texture instead of the polygon? > > Also, I had heard that 1.2 will have smoke and dust effects. Will >it also have rain? > >--Howard > >-- End of excerpt from Howard Abrams let's talk... I built this function into an IG in a former life and since we never patented the approach, it's now yours... the main issue with rain is that unless its really heavy, at night, or you're looking through binoculars, rain is pretty much invisible - not so for snow unless you're in whiteout conditions so, the basic issue is to present enough of an illusion to fool the eye into thinking that it is seeing some obstruction - this means that very muted colors should be used for rain and snow the approach taken was to place pseudorandom numbers into a top array and side array, and to draw some occulting object where the row, column indicated that the object should be drawn - each frame, the rows are marched downward by shifting a starting index into the column, and the columns can be shifted sideways (for blowing rain or snow) by shifting the starting index into the top row - this approach takes absolutely trivial storage (two linear arrays) and works amazingly well now, the speed with which the rows are shifted gives the speed of the rain - likewise for the blowing rain side shifts - plus, you can "dance" the rain or snow by shifting both directions in the row the number pattern and interpretation of this pattern gives the density of the rain or snow - I used 1's and 0's as the numeric values, but you could expand the approach with higher valued digits and build feathered edge objects by building some sort of guassian ramp at various points in the arrays hard rain is set by something like the following: 0 0 0 1 0 0 1 1 0 0 0 1 0 0 1 1 1 0 0 if you interpret this to mean that every 1,1 is drawn, the resulting pattern is something like 1 1 1 1 1 1 1 1 1 1 1 1 which, when moved at the correct vertical velocity (which is controlled by the amount you change the column offset with each frame), gives a nice set of streaks moving down the screen snow is less streaky, and, possibly, wider - definately slower if you use numbers other than 0 and 1, you can intepret the addition range as colors and have light and dim drops or flakes as I said earlier, the real magic here is the correct generation of the row and column values, and the speed at which the items move on the screen as for implementation, the overlay planes are good, but instead of clearing the entire plane, just erase the current pattern and draw the new pattern during the vertical retrace interval - if you're doing the entire screen, there may not be enough time in the 1.7 ms to accomplish this, so you may be forced into doing that double buffer thing couple this with a few wider blobs and you've got a pretty convincing windshield I've been wanting to put this into practice but just have not had the time to play the way I should - maybe soon I know this is skeletal, but if it seems like something that will help and if you want to pursue it further, let me know and I'll be more than happy to cobble a quickie or just present better details seeee ya... -- Dennis Pierce, SGI, 900 Winderley Place, Ste 130, Maitland, FL 32751 email: dpierce@sgi.com vmail: 8548 tel : 407.660.0073 late : 407.660.2789 fax : 407.660.8981 cell : 407.256.8447 From guest Fri Feb 4 14:39:17 1994 From: "Dennis Pierce" Message-Id: <9402041739.ZM7726@sgimco.orlando.sgi.com> Date: Fri, 4 Feb 1994 17:39:02 -0500 In-Reply-To: steveh@k2.mss.ctaeng.com (Steve Hurt) "Snow and Rain" (Feb 4, 7:01am) References: <9402041401.AA03171@k2.mss.ctaeng.com> X-Mailer: Z-Mail-SGI (3.0S.1026 26oct93 MediaMail) To: steveh@k2.mss.ctaeng.com (Steve Hurt), dpierce@sgi.sgi.com Subject: Re: Snow and Rain Cc: info-performer@sgi.sgi.com Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR On Feb 4, 7:01am, Steve Hurt wrote: > Subject: Snow and Rain > >I just red your message on snow and rain fx. In it you present >some really good ideas, what kind of "occulting object" would >you recommend? > >Thx. >-------------------------------------------- >Steve Hurt CTA Incorporated. >5670 Greenwood Plaza Blvd Suite 200 >Englewood, Colorado 80111 > >303) 889-1286 >steveh@ctaeng.com >-------------------------------------------- > >-- End of excerpt from Steve Hurt an occulting object is just a blob - in its most simple form, the object is just a screen dot (pixel) - a more advanced form would be an alpha blended gaussian distributed circle where the outer edges are nearly transparent and the center is opaque - I didn't want to sound so pedestrian by saying "pixel" because my old system didn't have any transparency features and I think that it would be quite beneficial to explore a more "correct" presentation with this new fancy RE hardware but... please understand that ANY additional use of transformation and fill hardware will be difficult to justify, so the simpler, the better - and I think you'll find that a few streaks (for rain) or a few floating pixel clusters (for snow) will be sufficient to convey a reasonable presentation of precepitation - also, be aware that the successful implementation of this will probably be largely based on "fooling" the eye into thinking that more is being shown than is actually being presented - I don't think there is sufficient bandwidth in the RE to draw a physical model of rain or snow PLUS do the real task of terrain, culture and models the real novelty of the approach presented is that it solves the problem of having dots fall in a controlled manner with two simple linear arrays - contrast this with a full-up 1280x1024 array this pseudo-random approach can also be used to generate random, but repeatable ground features such as roads, tree patterns, bush clutter, and the like - for some applications, the rapid generation of "good enough" terrain and culture can be done procedurally instead of actually modeling the features - this gives an "infinite" scape to play on without having to actually build the model first - I'm sure the approach has been implemented a couple of hundred times by the real IG folks hope this helps... bye. -- Dennis Pierce, SGI, 900 Winderley Place, Ste 130, Maitland, FL 32751 email: dpierce@sgi.com vmail: 8548 tel : 407.660.0073 late : 407.660.2789 fax : 407.660.8981 cell : 407.256.8447 From guest Thu Jan 6 09:31:13 1994 From: "Marc SIMON Presales support" Message-Id: <9401061755.ZM7241@girl.paris.sgi.com> Date: Thu, 6 Jan 1994 17:55:48 +0100 X-Mailer: Z-Mail-SGI (3.0S.1026 26oct93 MediaMail) To: info-performer@sgi.sgi.com Subject: smoke simulation Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR Hi all, It's not really a Performer question but i hope somebody could help me. I would like to simulate an explosion and "dynamic" smoke . I think one way will be to use texture (with alpha ) and change the projection parameters ( mmode(MTEXTURE) ) to "animate" the smoke , but i'm sure there is other ways to do that , so thanks in advance for any suggestions. Marc SIMON smarc@paris.sgi.com From guest Thu Jan 6 10:19:18 1994 Date: Thu, 6 Jan 94 09:46:13 -0800 From: ib@ivan (Ivan Bach) Message-Id: <9401061746.AA07406@ivan.asd.sgi.com> To: "Marc SIMON Presales support" , info-performer@sgi.sgi.com Subject: Re: smoke simulation Status: O > Marc SIMON writes: I would like to simulate an explosion and "dynamic" smoke. ------------------- copies of old articles ---------------------------- From guest Thu Jan 6 10:25:34 1994 Message-Id: <9401061825.AA05457@surreal.asd.sgi.com> To: "Marc SIMON Presales support" Cc: info-performer@sgi.sgi.com Subject: Re: smoke simulation In-Reply-To: Your message of "Thu, 06 Jan 94 17:55:48 +0100." <9401061755.ZM7241@girl.paris.sgi.com> Date: Thu, 06 Jan 94 10:25:27 -0800 From: Jim Helman Status: O In 1.2, libpfutil will have a simple smoke simulator which uses its own point-rotate billboards and multiple, moving and spinning polygons with transparent smoke and flame textures on them. -jim From guest Thu Jan 6 11:23:26 1994 Message-Id: <9401061924.AA08756@Crazypete.AI.SRI.COM> To: "Marc SIMON Presales support" Cc: info-performer@sgi.sgi.com Subject: Re: smoke simulation In-Reply-To: Your message of "Thu, 06 Jan 1994 17:55:48 +0100." <9401061755.ZM7241@girl.paris.sgi.com> Date: Thu, 06 Jan 1994 11:24:36 -0800 From: Stephen Lau Status: O Some people from the Naval Postgraduate School have done some 3-D textures for animating smoke that looks pretty good. It's not "photo-realistic" but it get's the message across and is inexpensive in terms of rendering and CPU time. I can put you in touch with them if you want. Steve ------------------------------------------------------------------------------- Stephen Lau lau@ai.sri.com| "No, no, not Orwellian, HUXLEY! SRI International | Brave New World." 333 Ravenswood Ave., Menlo Park, CA. 94025| - George Coates, "Box Conspiracy: (415) 859-2925 (415) 326-6200| An Interactive Sho" ------------------------------------------------------------------------------- From guest Wed Jun 8 13:03:07 1994 From: "Darin C. Partridge" Message-Id: <9406081402.ZM15794@paradox.idec.sdl.usu.edu> Date: Wed, 8 Jun 1994 14:02:48 -0600 X-Mailer: Z-Mail (3.1.0 22feb94 MediaMail) To: info-performer@sgi.sgi.com Subject: Clouds?...Sounds easy enough. Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Status: OR I'm a beginner with performer, however, I've imported several satellite terrain data sets. I usually hack on the Wavefront loader and perfly to accomplish this. It's worked good so far but now I would like to have clouds over the terrain. Since clouds are not included in the environment menu used in perfly I tried to add it. I realize I could be out to lunch since I still haven't got my man pages installed correctly, but here is the perfly module I modified: perfly/gui.c: static pfuGUIString ESky_strs[] = {"Sky/Clear","Overcast","Sky/Grnd","Sky", "Clear","PFES_SKY","Tag"}; static long ESky_vals[] = { PFES_SKY_CLEAR,PFES_OVERCAST,PFES_SKY_GRND,PFES_SKY, PFES_FAST, PFES_SKY, PFES_TAG}; common/env.c: void updateEnvironment(void) { pfEarthSky *es = ViewState->eSky; static long eSkyMode = -1; static long fogType = -1; static float fogNear = 0.0f, fogFar = 0.0f; if ((eSkyMode == ViewState->earthSkyMode) && (fogType == ViewState->fog) && (fogNear == ViewState->nearFogRange) && (fogFar == ViewState->farFogRange)) return; if (ViewState->fog != PFFOG_OFF) { pfFogType(fog, ViewState->fog); pfFogRange(fog, ViewState->nearFogRange, ViewState->farFogRange); pfESkyFog(es, PFES_GENERAL, fog); } else pfESkyFog(es, PFES_GENERAL, NULL); if( ViewState->earthSkyMode == PFES_OVERCAST ) { pfESkyMode(es, PFES_CLOUDS, ViewState->earthSkyMode); pfESkyAttr(es, PFES_CLOUD_TOP, 30.0f ); pfESkyAttr(es, PFES_CLOUD_BOT, 20.0f ); pfESkyColor(es, PFES_CLOUD_TOP, 0.1f, 0.1f, 0.2f, 1.0f); pfESkyColor(es, PFES_CLOUD_BOT, 0.2f, 0.2f, 0.1f, 1.0f); } else pfESkyMode(es, PFES_BUFFER_CLEAR, ViewState->earthSkyMode); /* update static values */ fogType = ViewState->fog; fogFar = ViewState->farFogRange; eSkyMode = ViewState->earthSkyMode; } Thanks for any help, Darin (darin@paradox.idec.sdl.usu.edu)