I'd like to draw a triangle and mark a point P in it with barycentric coordinates (3/4,1/6,1/12). How to do this with Maple? Best regards, Rainer Rosenthal r.rosenthal@web.de Perhaps this will do for you. > restart: > with(plots): > P[1],P[2],P[3]:=[3,5],[-1,4],[7,-3]: > B:=[3/4,1/6,1/12]: > C:=add(B[i]*P[i],i=1..3): > > T:=plot([P[1],P[2],P[3],P[1]], style=line, color=red, scaling = constrained,axes=normal): > Pt:=plot([C], style=point,symbol=circle,color=blue): > Text:=textplot([op(C+[-.2,.2]),convert(B,string)],align={ABOVE,RIGHT}): > &...

Peter Shirley's book ("Fundamentals of Computer Graphics") discusses color interpolation via barycentric coordinates. It also says: "we can use the barycentric coordinates to interpolate the depth values of the vertices to each pixel." Is this correct though? I thought some special perspective correct interpolation had to be done. > Peter Shirley's book ("Fundamentals of Computer Graphics") discusses color > interpolation via barycentric coordinates. It also says: "we can use the > barycentric coordinates to interpolate the depth values of the vertices to > each pixel." Is this correct though? I thought some special perspective > correct interpolation had to be done. Yes, it is correct. This has been discussed before, and just recently. In short, the 'depth' values that are used with z-buffer have a special computation formula which has this nice property. Of course, this formula is deliberately chosen such. Quoting myself: "The projected points all lie on a plane, so the notion of depth is added afterwards. What should we qualify as a "depth" value? Distance of the 3d-point to the center of projection? Orthogonal distance of the 3d- point to the projection plane? These are the easy ones that come to mind first. There are an infinity of others. However, all discussion is without a meaning without a purpose to actually use the depth value somewhere. The purpo...

Hello all, I have points P1, P2 lying in a triangle A, B, C. I'm able to compute barycentric coordinates of P1 and P2. Is it possible to interpolate somehow the barycentric coordinates to obtain points which lie on the line segment P1P2? Of course, I could interpolate linearly between P1 and P2, but I would like to interpolate bar. coordinates instead. Is that possible? Thanks. Jindra On Apr 12, 3:39 pm, jindra <jpa...@gmail.com> wrote: > Hello all, > I have points P1, P2 lying in a triangle A, B, C. I'm able to compute > barycentric coordinates of P1 and P2. Is it possible to interpolate > somehow the barycentric coordinates to obtain points which lie on the > line segment P1P2? Of course, I could interpolate linearly between P1 > and P2, but I would like to interpolate bar. coordinates instead. Is > that possible? > It's exactly the same thing. The barycentric coordinates computed from any triangle or generic cartesian coordinates are related to one another by an affine transformation. On Apr 12, 6:36 pm, Lorenzo Gatti <ga...@dsdata.it> wrote: > On Apr 12, 3:39 pm, jindra <jpa...@gmail.com> wrote: > > > Hello all, > > I have points P1, P2 lying in a triangle A, B, C. I'm able to compute > > barycentric coordinates of P1 and P2. Is it possible to interpolate > > somehow the barycentric coordinates to obtain points which lie on the > > line segment P1P2? Of course, I could inter...

How do I transform my values into my coordinate system All values is in pixels In my coordinate system origo is located in (40,495) The display area that I can use is from X=40 to x=750 and from y=495 to y=55 When you go down in the coordinate system the y value is increasing and when you go to the right the x value is increasing. The y-axis is showing time from 12:00 to 20:00 hours and the x-axis is showing from 0 to 800 So I can have values like [13:10, 190] [13:40, 240] [14:25, 390] [15:10, 431] [16:10, 554] [17:10, 643] [18:10, 740] I just wonder if someone has a ...

I think all the algorithms are crap, not useful at all.Old programs on the IBM PC were much faster on a 4.77 Mhz machine than the crap of today. I think we should use ASCII graphics again. And Carl Dau said... > I think all the algorithms are crap, not useful at all.Old programs on the > IBM PC were much faster on a 4.77 Mhz machine than the crap of today. > > I think we should use ASCII graphics again. http://www.jfedor.org/aaquake2/ http://www.catb.org/~esr/jargon/html/T/troll.html > I think all the algorithms are crap, not useful at all. That's why research is done to invent better algorithms to solve real-world problems, you came to the right place if you want to share your knowledge. If the algorithms are so crap, what are you comparing them to, would be interesting to see some real alternatives. > Old programs on the IBM PC were much faster on a 4.77 Mhz machine than the crap of today. Naturally those programs were written for a 4.77 Mhz IBM PC. Put those amazing programs to a modern computer and the comparison is equally brutal the other way (the programs may be fast, but may lack tons of features and quality the applications which would be dead slow on that 4.77 Mhz machine, if they would run at all). On 2004-04-18, joe smith <rapu@ra73727uashduashfh.org> wrote: > >> I think all the algorithms are crap, not useful at all. > > That's why research is done to invent better algorithms to solve real-world > p...

Hi Would you introduce me a good c++ book about computer graphic with actual example, i am currently developing a GUI engine (like QT) for my operating system. A website would be appreciates thanks from Peter (cmk128@hotmail.com) cmk128@hotmail.com =E5=AF=AB=E9=81=93=EF=BC=9A > Hi > Would you introduce me a good c++ book about computer graphic with > actual example, i am currently developing a GUI engine (like QT) for my > operating system. > A website would be appreciates > thanks > from Peter (cmk128@hotmail.com) Hi I want a book that talk about image processing, like this: http://www.jhlabs.com/ip/filters/ thanks AGG http://www.antigrain.com/ ...

Hi everyone, some of you know how fill a quads in 2D using barycentric coordinates?At the present, I'm splitting the quads into 2 triangles, but that way is inefficient because I have to iterate over the second bounding box which repeats pixel that were filled previously (by example, to fill the 2nd triangle I traversed the 1st triangle that belongs at bounding box formed by 2nd triangle) Thanks esmitt Am 01.07.2010 00:50, schrieb esmitt: > Hi everyone, some of you know how fill a quads in 2D using barycentric > coordinates? I think we all know that that's a bad idea, so don't worry about its implementation too much. > At the present, I'm splitting the quads into 2 triangles, > but that way is inefficient because I have to iterate over the second > bounding box which repeats pixel that were filled previously (by > example, to fill the 2nd triangle I traversed the 1st triangle that > belongs at bounding box formed by 2nd triangle) You appear completely confused about the terms you're using. What makes you think that filling using barycentric coordinates would require a bounding box? And while we're at it: what makes you think barycentrics are a useful tool for a polygon into pixels? They have nothing to do with pixels! Thanks for your answer. On Jun 30, 6:55=A0pm, Hans-Bernhard Br=F6ker <HBBroe...@t-online.de> wrote: > Am 01.07.2010 00:50, schrieb esmitt: > > > Hi everyone, some of you know how fill a...

Dear all, I've selected a series of coordinates (x,y) by clicking around an ROI using= the CURSOR and WHILE (!MOUSE.button NE 4)... (as per example in CURSOR doc= umentation). Is there a way to use these coordinates again (e.g. in the nex= t section of a 3D stack) in a way that allows me to modify (e.g. by click a= nd drag) the existing coordinates to better fit the object/ROI (which chang= es ever so slightly in z)? I would like to avoid having to select the ROI again (from scratch) as this= is time-consuming - this is supposed to be an initial look at the data...= =20 Many thanks for your help in advance. Kind regards, Cherrie Cherrie Kong writes: > I've selected a series of coordinates (x,y) by clicking around an ROI using the CURSOR and WHILE (!MOUSE.button NE 4)... (as per example in CURSOR documentation). Is there a way to use these coordinates again (e.g. in the next section of a 3D stack) in a way that allows me to modify (e.g. by click and drag) the existing coordinates to better fit the object/ROI (which changes ever so slightly in z)? You are not going to be able to edit ROI coordinates if you want to continue to use the CURSOR command like this. But, if you wanted to use a draw widget (the normal way to do these kinds of user interactions with the cursor), the world opens up to you. If fact, these kinds of editable ROI widgets have already been built for you in the SelectInteraction object in the Catalyst Libra...

Dear list members, I play around with object graphics and try to build a routine which is able to visualize 3d objects of different sizes in th same way. When I define the viewplane_rect and the zclip of my view, everything works fine before I rotate the view. Then the coordinate system is not the coordinate system of the defined axes anymore. Is there an easy way to calculate the coordinates for viewplane_rect and zclip from the coordinates of the rotated axes ? Thanks for your help in advance ! Klemens > I play around with object graphics and try to build a routine which is &g...

Hi everyone Does anybody know how to insert a graphic inside a graphic?? I mean, to add a small graphic (as a zoom for example) inside a plot. Thanks augusto try axes try axes check out the tool 'imshow()', then try to bring the figure in shape get(gca) and superimpose your graph - 'hold on', 'plot()', 'hold off' (Haven't tried it my self so far) Thorben The example below shows you how to insert a graphic (e.g. photo) into another MATLAB figure. I = imread('peppers.png'); theta = linspace(-pi,pi,200); figure; plot(theta,cos(theta)); gr...

Hello, I am working on 3d graphics using plot3 function. here while running i have to find the 3 coordinates (x-axis, y-axis,z-axis) in this graph where ever i click my mouse icon, for this iam not able to find any suitable function.Like the function ginput( )for 2d graphics i need one for 3d graphics.Please hlep me to find a solution for this problem. Regards Pramod ...

I am trying to create an animation of a piecewise function. I have a graph of a ball rolling and I would like to combine an animation for one equation of motion for the first part with another equation for the second part of the motion. It is easy enough to create the two animations individually, however I am stumped on how to combine them into one continuous animation. Link to the forum page for this post: http://www.mathematica-users.org/webMathematica/wiki/wiki.jsp?pageName=Special:Forum_ViewTopic&pid=10007#p10007 Posted through http://www.mathematica-users.org [[postId=10007]] ...

I came across a limitation in the mechanism for copying coordinates of points in 2D graphics (the Get Coordinates button in the Drawing Tools palette) in V6.03. Consider the following plot of a sine wave Plot[Sin[2 x], {x, 20270, 20275}] When I try to select and paste the coordinates of the two crests of the wave, I typically get two points with the same x-coordinate {{2.027*^4, 0.99}, {2.027*^4, 0.99}} whereas I would expect the two x-coordinates to be around 20270.3 and 20273.5, values which are well separated on the plot. This seems to happen because the Get Coordinate...

I realize this is not truly a LabVIEW question, but I'm hoping for suggestions. I have a digitized image of a sample on a 3 axis stage. The user selects "paths" for a drill to take along the surface of the sample. On the image, 3 reference points are identified. The stage posititions (x, y, and z) corresponding to these points are then identified. I need to now convert the coordinates of the paths to the stage coordinate system. Are there any LabVIEW vi's that are suited to this need? I have IMAQ vi's but not very experience with these yet. Suggestions much apprecia...

Hi=20 I hope I can explain this clearly without getting into too much detail as t= he code in question is a couple of thousand of lines. So to begin, I have = a JPanel to which I add JLabels and JComponents using JPanel's add() method= .. It works fine, but now I would like to print an image ON TOP of the adde= d JLabels and JComponents. For this I manipulate my JPanel's paintComponen= t(Graphics graphics) method. In it I have something of the following sort: paintComponent(Graphics graphics){ Graphics2D g =3D (Graphics2D)graphics.create(); g.drawImage(image, 200, ...

Hello. I've got a tricky problem. I am not experienced with Postscript, but I've read some tutorials and think it's fairly straightforwarded. On my job, we recieve catalogs in postscript format, convert all pages into jpg, and then we create image-maps for them and create online catalogs with them. Since we do quite a lot of catalogs, and some have several hundreds of pages, we want to extract the coordinates from raster graphics in the postscript file automatically. Is there an easy way to do this? What kind of raster graphics are there in postscript? image, colorimage etc.? ...

Hi, just curious if there's a neat way to get the barycentric coordinates (or similar) of the current fragment in a GLSL shader? Only way I could think of it was to render each triangle individually, but that's not too good for performance... - Asbj�rn Lord Crc wrote: > just curious if there's a neat way to get the barycentric coordinates > (or similar) of the current fragment in a GLSL shader? NO, but you can get the same result if you can afford to choose the primitive type to be GL_TRIANGLES and setup the barycentric to each vertex as: A = vec3(1.0, 0.0, 0.0); B = v...

Hiya all. everybody should applicate this type of guidelines This movement builds a strong visual link between the head and shoulders. If you get the correct relationship between the eyes, nose and mouth, you will end up with a good likeness. Our Pencil Portrait lesson explains and illustrates the step by step drawing techniques involved in creating the portrait of a young girl. At this stage, the drawing is no more than a set of carefully measured features that establish the final proportions of the portrait. There are three basic stages in the creation of the image...

Google has failed me again. I don't even know what questions to ask. Pick up any cad program. Clicking on a line segment selects that segment. That's what I want to do. I have a Visual Basic 6/Win98SE program that takes gerber input and translates it to run a pen plotter. It also plots the "toolpath" on the screen. I'd like to be able to select a line segment and see the endpoint coordinates. The only thing I can think to do is try to construct a tiny window, redraw the graphic and somehow use the Windows API clipping functionality to tell me when a line passes thru the box. I'm not even sure this functionality exists. If I have to code it all in VB6, it's gonna be excruciatingly slow. There's gotta be a better way. Can someone point me to a methodology, an algorithm, tutorial, sample code, proper search terms, etc.? Thanks, mike -- Return address is VALID. 500MHz Tek DSOscilloscope TDS540 $2200 http://nm7u.tripod.com/homepage/te.html Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121 Bunch of stuff For Sale and Wanted at the link below. http://www.geocities.com/SiliconValley/Monitor/4710/ mike <spamme0@netscape.net> wrote: > Google has failed me again. I don't even know what questions to ask. The term to search for is "pick correlation" --- the art of correlating a pick (an output position) back to the displayed graphical elements. > The only thing I can think to do is try to construc...

Hi, I'm using the 'algorithm' and 'algorithmic' packages. Some of the numbered lines have a variable-width sized font while other lines have a teletype font. Could someone pls inform me about how to change all the lines to the variable-width sized fonts. thx., glen Am 24.06.2010 14:13, schrieb John Smith: > Hi, > I'm using the 'algorithm' and 'algorithmic' packages. > Some of the numbered lines have a variable-width sized > font while other lines have a teletype font. Could > someone pls inform me about how to change all ...

Hi, In the framework of the algorithmic and algorithm packages, is it possible to "tune" the space between two consecutive lines of the produced algorithm ? Something like itemskip ? Thanks in advance, Vincent Kelner ...

Hello, Who said that lockfree algorithms and waitfree algorithms and scalable algorithms are hard ? as you have noticed i have tried to easy the job for you by inventing scalable algorithms and as you have noticed i have invented today a new algorithm of a very fast concurrent FIFO queue.. Here it is: http://pages.videotron.com/aminer/CQueue1.htm And i am right now thinking about my next invention , so stay tunned ! and enjoy all my programming inventions that you will find at: http://pages.videotron.com/aminer/ Thank you, Amine Moulay Ramdane. ...

Hello... Who said that lockfree algorithms and waitfree algorithms and scalable algorithms are hard ? as you have noticed i have tried to easy the job for you by inventing scalable algorithms and as you have noticed i have invented today a new algorithm of a very fast concurrent FIFO queue.. Here it is: http://pages.videotron.com/aminer/CQueue1.htm And i am right now thinking about my next invention , so stay tunned ! and enjoy all my programming inventions that you will find at: http://pages.videotron.com/aminer/ Thank you, Amine Moulay Ramdane. On Saturday, ...

Hello, Who said that lockfree algorithms and waitfree algorithms and scalable algorithms are hard ? as you have noticed i have tried to easy the job for you by inventing scalable algorithms and as you have noticed i have invented today a new algorithm of a very fast concurrent FIFO queue.. Here it is: http://pages.videotron.com/aminer/CQueue1.htm And i am right now thinking about my next invention , so stay tunned ! and enjoy all my programming inventions that you will find at: http://pages.videotron.com/aminer/ Thank you, Amine Moulay Ramdane. ...

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