Jon Muckell assigned as TA. His email is

.

He will hold office hours in the scheduled lab session.

The simple.c program that I discussed in class today needs one more line to run. It's glutInit(&argc,argv); in main. I've added it and called the new file simple2.c .

In order to cover more material, for awhile we'll have lectures also in the labs, on Wed, starting this Wed, Sep 12.

Homework 2 is online.

Homework 3 is online.

redefinition error for exit, then do not include stdlib.h in your program. It is already included by another include file, and it lacks an inclusion guard. Thanks to Julio.

Homework 5 is online.

Final exam is set for Wed Dec 12 at 3-6 pm. Please tell me if you have a conflict (and what that conflict is).

Homework3Solution.doc and Homework4Solution.doc are online.

Summer Opportunity - SIGGRAPH Student Volunteer

is the biggest Computer Graphics conference. In 2008, it's Aug 11 to 15 in Los Angeles.

Everyone who likes graphics should see it once. Student interns can see it cheap. If you work halftime then admission and a place to stay are free, and they might also pay for transportation. Hard deadline: Feb 24.

I strongly recommend this opportunity.

Term project details and Homework 6 online.

It's time to get those project proposals (and even first progress reports) in.

Would anyone be interested in spending a few weeks in Brazil learning to collaborate on research with Brazilian colleagues? This question is to gauge student interest, as I'm considering writing an NSF proposal.

full, so any one who did not sign up is assigned to Monday Dec 3.

Scatterplot of Midterm Grade vs Finish Order

1. Engineering Grounded In Reality
2. Angel powerpoint lecture slide set 1. I'll give the password in class.
3. A little on API philosophy, e.g, PortabilityAndStandards, and submarine patents.
4. Angel powerpoint lecture slide set 2.

1. Angel powerpoint lecture slide set 3 Models and Architectures
2. Angel powerpoint lecture slide set 4 Programming with OpenGL, Part 1: Background. First program: simple.c

1. Reading up to now: Angel chapter 1.
2. OpenGLSummary
3. Angel powerpoint lecture slide set 5 Programming with OpenGL Part 2: Complete Programs
4. Demo, discuss, and modify shape_test.c

1. Angel powerpoint lecture slide set 6 Programming with OpenGL Part 3: Three Dimensions
2. Demo, discuss, and modify gasket2.c
   
3. Demo, discuss, and modify gasket3.c
   
4. Angel powerpoint lecture slide set 7 Input and Interaction
   1. logical input devices
   2. X window input, client-server model. (In X, the client is the machine where the processing is done; the server displays the graphics.)
   3. callbacks, incl idle callback
   4. request vs event mode
   5. post redisplay - use this when you've changed something and so the system has to update the display.
   6. double buffering

1. single_double.c. Shows:
   1. The difference between single and double buffering.
   2. Creating two graphics windows in one program. Note the order:
      1. Set the display mode.
      2. Create the window.
      3. Register the callbacks.
      4. Repeat for each window.
      5. Call MainLoop.
   3. Mouse input.
   4. Changing the idle callback. The new one replaces the previous one. (This answers a question in class a few days ago.)
2. getinfo.c. Shows how to read information about the OpenGL version and how to get internal state variables. This shows just a sample; there are more.
3. showinput.c. Shows how to get input. This also shows the coordinate system used to report mouse events. Units are pixels.

      (0,0) ...... (xmax,0)
      ....
      ....
      ....
      (0,ymax).....(xmax,ymax)  
   
4. Angel powerpoint lecture slide set 8
   1. more on callbacks

1. Here are refs answering a question asked after Monday's class on how to avoid tearing caused by swapping the foreground and background buffers in the middle of refreshing the image and the two buffers have different images.
   1. One solution is to wait until the vertical retrace to swap the buffers. However, if each buffer takes about 1/60 second to recompute, sometimes more and other times less, then the refresh rate will fluctuate between 1/60 and 2/60 second.
   2. Another solution is to use 3 buffers. You display from the 1st, have the 2nd ready to swap with the 1st in the next vertical retrace, and meanwhile compute into the 3rd. This uses 50% more memory.
   3. How to fight tearing
   4. OpenGL Extension WGL_I3D_swap_frame_lock
   5. Smooth Gaming with Triple Buffering
2. square2.c. Demonstrates glutMotionFunc callback. Change glutMotionFunc to glutPassiveMotionFunc to see what happens.
3. manywindows.c. Shows that many top level windows (a new one with each left mouse click) can be dynamically created.
4. paint.c, a simple paint program showing hierarchical menus. Note that is is still using immediate mode graphics; redrawing erases everything.

1. paintxor.c modified by paint.c to write triangles into the color buffer in XOR mode. Everything else is still written in COPY mode. XOR mode is useful for cursors and rubberbanding because XORing the same object twice restores the original buffer.
2. Angel powerpoint lecture slide set 9 Better interactive programs
3. Angel powerpoint lecture slide set 10 Geometry

I will present transformations 3 different ways to help you understand this important topic.

1. Angel powerpoint lecture slide set 11 Representation
2. Angel powerpoint lecture slide set 12 Transformations
3. My note on homogeneous coordinates and projections demoed by Albrecht Durer
   (The following display better in Firefox than Internet Explorer.)
4. Homogeneous matrix examples, p' = M p for
   1. Translate by (1,2,3):
      {$M = \left(\begin{array}{cccc} 1 & 0 & 0 & 1\\ 0 & 1 & 0 & 2\\ 0 & 0 & 1 & 3\\ 0 & 0 & 0 & 1\end{array} \right)$} . This also works: {$M = \left(\begin{array}{cccc} 2 & 0 & 0 & 2 \\ 0 & 2 & 0 & 4 \\ 0 & 0 & 2 & 6 \\ 0 & 0 & 0 & 2 \end{array} \right)$}
   2. Rotate around Z axis by an angle whose cosine is 0.6:
      {$$ M = \left(\begin{array}{cccc} .6 & -.8 & 0 & 0 \\ .8 & .6 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array} \right)$$}

1. My note on 3D rotation
   1. all rigid transformations in 3D that don't move the origin have a line of fixed points, i.e., an axis, that they rotate around.
   2. deriving the vector formula for a rotation given the axis and angle
   3. computing the matrix from a rotation axis and angle
   4. testing whether a matrix is a rotation
   5. if it is, then finding the axis and angle
2. Bill Jacobs' OpenGL video tutorial - excellent

1. Rotations continued
2. Angel powerpoint lecture slide set 13 OpenGL Transformations

Jon Muckell presents OpenDX, an open source visualization software package based on IBM's Visualization Data Explorer.

IBMs Data Explorer - OpenDX tutorial

OpenDX vs OpenGL

OpenGL - fast, portable, close to hardware, event-driven

OpenDX - specifically for data visualization, data should be computed before using openDX. Many default parameters and abstraction allows the user to quickly visualize the data.

Installing OpenDX

The simplest way to install OpenDX is to use YaST or some automated installation tool that will install from an RPM. Installing from source can be unusually tricky.

If you are running Windows you need to have Cygwin installed

Installing on SUSE 10 Linux

1. Open YaST and then Installation Source
2. Add the following URLs

http://download.opensuse.org/distribution/SL-10.1/inst/source

http://ftp.opensuse.org/pub/opensuse/distribution/SL-10.1/non-oss-inst-source/

1. Then open Software Management and search for dx and install all appropriate items
2. The install is successful if you can type dx in the terminal and openDX runs

How To Make a Simple Picture in OpenDX

I'm going to walk you through an example I made of visualizing two protein chains. First you'll need to download my example Protein.tar.gz containing the following files.

• Protein.net - This is the actual OpenDX file
• protein_e.general - This is the header information for file 1acb_e.out
• 1acb_e.out - This is the actual data being fed in

protein_i.general and lacb_i.out is the data relating to the other protein chain, we don't have to worry about that for now.

Describing your Data

The Header File - protein_e.general

First open up the following two files protein_e.general and lacb_e.out

protein_e.general is the header file for lacb_e.out and contains the following information.

The Data - lacb_e.out

Note OpenDX skips one character and then reads in 6, as described in layout in the header file. Therefore there is two spaces between 18.252 and 4.407, and there is only one space between 4.407 and 16.785

Running The Program

1. To run the program you'll need to first change the import path. Double click on one of the Import palettes. Change the path /home/muckellj/Documents/DX/DATA/protein_i.general to your appropriate path. Repeat for the second Import palette.
2. Under the Execute Tab click Execute Once
3. If you have done this correctly you should see an image of one red and one blue protein chain.

Palette Description

A palette only has an effect on the program if there is a path from the palette to the image(or display) palette.

• IMPORT: This palette reads in from the header file (typically a .general file), and imports the data into the program. We require two imports for this program because we are reading in from two different data files, one for each chain. To display only one protein chain, simply disconnect one of the wires leading to COLLECT.
• GLYPH: This palette has the effect of creating each of the different spheres. If you double click on one of the glyphs, you'll notice that the type is "sphere" this can be changed to numerous other geometric types. If you click Expand and look at the other values you can set, you'll notice that both min and max are set to the same value. This is because we want all the sizes of the spheres to be the same size.
• COLOR: Colors each sphere
• COLLECT: Puts the two chains together to be used as a single image
• IMAGE: Displays the image

How To Make a Animation in OpenDX

The file animates two protein chains with the camera moving around the objects. ProteinAnimate.tar.gz

The program is the same as the one above except we added a few more palettes. We needs to use the DISPLAY palette so we can specify where we want the camera to be positioned. We then use the ReadImageWindow palette to read the display window and then output that result to the image palette. The final result needs to reach the image palette because that allows us to save the final frames.

SEQUENCER: This is a crucial palette for creating animations because it allows us to increment numbers. For example, in this program the sequencer increments from 0 to 360 which relates to the current rotation of the protein chains for each of the 361 frames.

1. Under the Execute tab click Execute on Change
2. In the Image window click on the Execute tab and the click on Sequencer.
3. Click the forward Arrows to change between frames
4. To save the frames, under the Image window goto Save Image. We want to have the Format as type MIFF and we want Continuous Saving.
5. Incriminate the Sequencer with the Continuous Saving applied. SaveAnimation.tiff
6. We will use image magick to convert the miff file into an mpeg using the command convert ProteinRotate.miff ProteinRotate.mpeg. NOTE you probably will need to add this file to your bin - mpeg2encode
7. Run your mpeg - I use MPlayer mplayer ProteinRotate.mpeg

Here is the animation: ProteinRotate.mpeg

Some Example MPEGS made using OpenDX

Resources

www.opendx.org

1. Review rotations, including the example just added to My note on 3D rotation.
2. Read relevant parts of Angel, chapter 4.
3. My note on 4D rotation. In 4D, there is no fixed axis, but there is either a fixed plane or no fixed point except the origin.
4. Quaternions. Refs:
   1. my paper paper
   2. Angel, page 224ff.
   3. Quaternion Examples
   4. Sample exam question:
      What rotation does this quaternion represent: {$q = 0.707 + 0.707 j$}
      Answer: a {$90^\circ$} rotation about the axis {$(0,1,0)$}
5. Angel powerpoint lecture slide set 14 Building Models
   This section tells how to draw polyhedra more easily than with many glVertex calls. You can load the vertices into an array and then do a lot with one hi-level call. This may be more efficient and also reduces programming errors.

1. Demonstrate 3D rotations in Maple using Gfiles:rot_maple.code
2. Review slide set 14.

Zero or more of the following:

1. Angel powerpoint lecture slide set 15 Classical Viewing
   The fine distinctions in classical viewing are not relevant to this course.
2. Angel powerpoint lecture slide set 16 Computer Viewing - 1st pass

Review for midterm

Here is some material to help you study for the midterm. This year's topics may be slightly different, but will be mostly the same. Since there are a finite number of electrons in the universe and they say that recycling is good, I'll recycle many of these questions.

I'll discuss answers in the review, or you may figure out answers on your own.

1. Sample questions
2. Fall 2006 midterm
3. Spring 2005 midterm
4. Fall 2005 midterm

Notes:

1. normalizing a vector: divide all components by the vector's length, to make its length 1.
2. questions from F2006 not on tomorrow's exam: 4, 9, 11, 13, 15, 19
3. questions from S2005 not on tomorrow's exam: 4, 12, 22
4. homogeneous matrix to scale by 5:
   {$ \left(\begin{array}{cccc}5&0&0&0\\0&5&0&0\\0&0&5&0\\0&0&0&1\end{array}\right)$}

Midterm F2007. You may bring any printed, copied, or written material, but no computers or calculators.

MidtermSolution.doc

To unwind from the midterm, Jon Muckell will let you play with test the Bluetooth Laser Virtual Keyboard while I'm in St Louis.

Today's big idea is the view normalization transformation. Routines like gluLookAt and gluPerspective really create a viewing transformation matrix so that the original scene when viewed with your desired parameters gives the same image and the transformed image seen with a standard projection and clip volume.

See the OpenGL Reference Manual on viewing.

1. Angel powerpoint lecture slide set 16 Computer Viewing - 2nd pass
2. Angel powerpoint lecture slide set 17 Projection Matrices

Today we switch to a completely different topic.

1. Angel powerpoint lecture slide set 18 Shading I
2. Angel powerpoint lecture slide set 19 Shading II

1. I attempted to email to each student our view of your grades. If you didn't receive this, or there was an error, please tell Jon and me, and sorry about the error.
2. Note this excellent talk The Art and Science of Computer Graphics by Don House today at 4 in JEC3117:
   http://www.cs.rpi.edu/news/colloquia/October22_2007.html
3. Angel powerpoint lecture slide set 20 Shading in OpenGL

1. Computer graphics in the real world
   1. Forma Urbis Romae - reconstruction of a street map of 211AD Rome from 1186 pieces like this one:
      
2. Another OpenGL tutorial The Practical Physicist's OpenGL tutorial Edward S. Boyden
3. Note on GL_MODELVIEW vs GL_PROJECTION.
4. Look at demo programs used for Homework 6.
5. Term project details
6. Angel powerpoint:
   We now change from learning the API to studying how things are implemented under the API.
   1. Angel powerpoint lecture slide set 21 Implementation I - Rasterization, Clipping

1. Angel powerpoint:
   1. Angel powerpoint lecture slide set 22 Implementation II - Clipping, Visibility
   2. Angel powerpoint lecture slide set 23 Implementation III

Advantage of using Cohen-Sutherland:

1. You always have to use the detailed clipping since sometimes the CS algorithm reports that it doesn't know.
2. However often it can classify the line segment (or the box with everything inside) as either completely in or else completely out.
3. In that case, the rest of the pipeline is faster.
4. However you have to write more lines of code.
5. You don't have to know how this works, only what its purpose is.

Bresenham presents the fast line and circle drawing algorithms better than the text.

Chance to ask Jon questions about, and demo, the homework.

Notes:

1. For more info on testing whether a point is in a polygon, see my note. Also see the comp.graphics.algorithms FAQ, question 2.03.
2. The flood fill will fail if the interior is not connected. That happens when two close edges cause adjacent pixels to be set. It will also fail if there is a gap in the perimeter - the color will leak out.
3. The scan line fill must handle special cases like a vertex being on a scan line. My solution is to pretend that any vertex on a scan line is really slightly above. This is a simple case of a serious technique called ''Simulation of Simplicity'' invented by Herbert Edelsbrunner.
4. Angel powerpoint
   1. Angel powerpoint lecture slide set 24 - Buffers

Special guest lecturer! Tobi Saulnier, PhD (EE) RPI, Founder and CEO, 1st Playable Productions talk: realtime-graphics-in-games 11-05-07.ppt

Special guest lecturer! Prof Barb Cutler,

1. Angel powerpoint
   1. Angel powerpoint lecture slide set 25 - Texture mapping
   2. Angel powerpoint lecture slide set 26 - OpenGL texture mapping. As always in engineering, there are more details than you might expect.

1. Angel powerpoint
   1. Angel powerpoint lecture slide set 27 - Compositing and blending. The executive summary would be what this is and a list of applications.
   2. Angel powerpoint lecture slide set 28 - Programmable pipelines
   3. Angel powerpoint lecture slide set 29 - GLSL I.
   4. Angel powerpoint lecture slide set 30 - GLSL II.

1. Smooth Shading 'Gotcha's in OpenGL by Steve Baker.
2. Alpha-blending and the Z-buffer by Steve Baker.
3. [[http://sjbaker.org/steve/omniv/eulers_are_evil.html|\ Euler Angles are Evil]] by Steve Baker.
4. Lesson 4: Lighting by Bill Jacobs.
5. Lesson 5: Textures by Bill Jacobs.
6. Lesson 6: Putting It All Together by Bill Jacobs.
7. Angel powerpoint
   1. Angel powerpoint lecture slide set 31 - Hierarchical modeling II.
   2. Angel powerpoint lecture slide set 32 - Hierarchical modeling II.
   3. Angel powerpoint lecture slide set 33 - Graphical objects and scene graphs.

1. Angel powerpoint
   1. Angel powerpoint lecture slide set 34 - Particle systems.
   2. Angel powerpoint lecture slide set 35 - Curves and surfaces.
   3. Angel powerpoint lecture slide set 36 - Designing parametric cubic curves.
   4. Angel powerpoint lecture slide set 37 - Bezier and spline curves and surfaces.

1. Angel powerpoint
   1. Angel powerpoint lecture slide set 38 - Rendering curves and surfaces.
   2. Angel powerpoint lecture slide set 39 - Curves and surfaces in OpenGL.
   3. Angel powerpoint lecture slide set 40 - Ray tracing.

1. Angel powerpoint
   1. Angel powerpoint lecture slide set 41 - Radiosity.
   2. Angel powerpoint lecture slide set 42 - Parallel rendering.
2. Paper tips:
   1. Make the abstract clear:
      "We describe how to transmute lead into gold. That builds on our earlier successes transmuting lead into copper, tin, and silver. More gold prevents renewed price inflation. Our technique starts by irradiating polywater with N-rays...."
   2. Start with a title, your name, coordinates, date.
   3. Say what you did, how you did it, why it's useful, what earlier work you built on.
   4. Include examples showing what works. If you describe a feature but don't include a screendump or video, then I'll guess that you weren't able fully to debug and get it working.
   5. Have a few references.
   6. Proofread for mispellings and words out.
   7. Don't play games with the formatting --- odd fonts, colors, etc.
   8. Binders are not necessary.
3. Video possibilities:
   1. Create a series of jpeg images, then convert them to a video.
   2. Use a screen capture program.
4. Talk tips:
   1. The hardest part will be keeping to the schedule.
   2. E.g., put your talk online, then use the podium computer.

1. Angel powerpoint
   1. Angel powerpoint lecture slide set E1 - Marching squares: tracing along the zero-surface of an implicit function.
   2. Angel powerpoint lecture slide set E2 - Virtual trackball (very brief)
   3. Angel powerpoint lecture slide set E3 - Display issues: There is a lot of material here. Important vocab includes tristimulus, color gamut, CIE chromaticity diagram, NTSC, YIQ, and CMYK.
2. My note on NTSC And Other TV Formats.

1. 2:00 Melih Ozlem
2. 2:30 Danlester Delarosa & Timothy Herrmann
3. 2:40 Tamara Sobers & Julio Lajara
4. 2:50 Brian Farrell
5. 3:00 Steve Meza
6. 3:30 Samuel Hughes & Thomas Smith
7. 3:40 Peter Littlefield

(In case of no-shows, we will advance the remaining speakers.)

1. 2:00 Zachary Barth & Daniel Hathaway
2. 2:10 John Bungert
3. 2:20 (Taylor) Gregg Lehman
4. 2:30 Daniel Wojcik
5. 2:50 Steven Warner
6. 3:00 Patrick Marion
7. 3:10 Benjamin Consolati
8. 3:20 Jason Anyalebechi
9. 3:30 Venkata Sreekanth Arikatla & Yuan Gao
10. 3:40 Daniel Book

term project presentations in class

1. 2:10 Paul Luong
2. 2:20 Christopher Stuetzle
3. 2:30 William Durr

review for final exam