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Help,My puzzle about coordinate value in OpenGL

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Started by scottsong September 01, 2004 04:05 AM

2 comments, last by Thunder_Hawk 19 years, 7 months ago

scottsong

122

Author

September 01, 2004 04:05 AM

In my OpenGL,when I used coordinate value over 1.0,i always failed. for example: glBegin(GL_TRIANGLE) glVertex3f(0.0,0.5,0.0); glVertex3f(-0.5,-0.5,0.0); glVertex3f(0.5,-0.5,0.0); glEnd(); this ok,but glBegin(GL_TRIANGLE) glVertex3f(0.0,20.0,0.0); glVertex3f(-20.0,-20.0,0.0); glVertex3f(20.0,-20.0,0.0); glEnd(); won't work? Could somebody tell me why? thanks ~~~ ^_^

evolutional

1,397

September 01, 2004 05:19 AM

How do you mean 'doesn't work' ?

How is your projection matrix set up?

Q-Parser

168

September 01, 2004 09:09 AM

yeah...you probably have problem with projection matrix or you have n't used glTranslatef() properly...

Thunder_Hawk

314

September 01, 2004 01:45 PM

Most likely, you are drawing too near to the near clipping plane. Try throwing in a:

glLoadIdentity();
glTranslatef (0.0f, 0.0f, -10.0f);

at the beginning of your drawing code.

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