Fri, Mar 31, 2006
Here's a 30-second walkthrough:
glClearColor(0.000000,0.000000,0.000000,0.000000) wglGetCurrentContext()=0x10000 wglGetCurrentDC()=0xb70114f8 wglGetCurrentContext()=0x10000 wglGetCurrentDC()=0xb70114f8 glViewport(0,0,600,300) glMatrixMode(GL_PROJECTION) glLoadIdentity() glOrtho(0.000000,2.000000,0.000000,1.000000,-1.000000,1.000000) glMatrixMode(GL_MODELVIEW) glLoadIdentity() glClear(GL_COLOR_BUFFER_BIT) glColor3f(1.000000,1.000000,0.000000) glBegin(GL_LINES) glVertex3f(1.000000,0.000000,0.000000) glVertex3f(1.000000,1.000000,0.000000) glEnd() glViewport(300,0,300,300) glMatrixMode(GL_PROJECTION) glLoadIdentity() glFrustum(-1.500000,1.500000,-1.500000,1.500000,2.000000,8.000000) glMatrixMode(GL_MODELVIEW) glLoadIdentity() glMultMatrixf([1.000000,0.000000,0.000000,0.000000, 0.000000,1.000000,0.000000,0.000000, 0.000000,0.000000,1.000000,0.000000, 0.000000,0.000000,0.000000,1.000000]) glTranslated(0.000000,0.000000,-6.500000) glPushMatrix() glPushMatrix() glColor3f(1.000000,0.000000,0.000000) glBegin(GL_LINE_LOOP) glNormal3fv([0.000000,0.000000,-1.000000]) glVertex3fv([0.500000,0.500000,-0.500000]) glVertex3fv([0.500000,-0.500000,-0.500000]) glVertex3fv([-0.500000,-0.500000,-0.500000]) glVertex3fv([-0.500000,0.500000,-0.500000]) glEnd()Running with gliConfig_FullDebug.ini also makes sure that every call to an OpenGL function is checked with glGetError(), which will catch things like passing bad values to functions or trying to pop the matrix stack more times that it's been pushed.
Note that you don't need access to the source code -- if you have a game at home that uses OpenGL, you can watch what it's doing, too. (Just don't steal their code, and don't tell them I'm the one who told you how.)
GLIntercept has a few more tricks up its sleeve, but I'll leave it up to you to read about them. For Linux people, there's a similar program called BuGLe, but I haven't tried it. And, of course, we smug OS X weenies have the OpenGL Profiler.
For those of you using Igloo, I've put together a new debug package that includes GLIntercept and Windows port of GNU tail. I'm not entirely sure about the legality of all this -- GLIntercept and GNU tail are available under the GNU General Public license, but EiC is still MIA.Sat, Mar 18, 2006
Why Microsoft is not my favorite software company
The HTML file was generated by setting a print area and choosing Save As Web Page from the File menu in Excel 2004 for Mac.
I understand cross-browser differences. I even understand cross-platform differences. But if I can't save a web page from the latest version of one Microsoft product and have it readable from the latest version of another Microsoft product, well...
You should all be using Mozilla Firefox anyway. It looks fine there.
If you turned in an assignment that isn't recorded, or if you didn't get as high a score on an assignment as you think you should have, please e-mail me.Fri, Mar 10, 2006 Tue, Mar 07, 2006
quizzes -- given early and often -- may be a student's best friend when it comes to understanding and retaining information for the long haulSay, that gives me an idea... Mon, Mar 06, 2006
For those of you wondering why I've been making changes to the schedule, I've taught the course two different ways in the past:
I'd originally planned to teach this semester as a lecture course, but when it was scheduled for a single class meeting on Friday nights a couple of things became clear:
Vector Math Tutorial for 3D Computer Graphics
If you compare it with the original screenshot, you'll notice that the original wasn't really a parallel projection.
The problem is that (as you should recall from your reading) OpenGL is a state machine. When you make a function call like
My mistake was to draw the parallel projections (calling
To avoid making silly mistakes like me, do the following whenever you go to render a model (e.g., in your display callback):
Don't cross the streams
By the way, Assignment 4 is available.