Thanks for your reply, but i think you dont understand my problem.
ie, i need draw a rect on my client area, which position at (200, 200, 600, 400).
with opengl i do the following:
glVertex3f(fxRight, fyTop, 0.0f);
glVertex3f(fxLeft, fyTop, 0.0f);
glVertex3f(fxLeft, fyBottom, 0.0f);
glVertex3f(fxRight, fyBottom, 0.0f);
but i dont know what value should i set for the fxRight to represent the 600 pixel(also what values for fxLeft,
fyTop and fyBottom to represent 200, 200 and 400.
I have to try many times in order to find the right position. ie, i first set fxLeft to 1.0f, then i run my
program to see where it position. if it position at left of 200 pixel, i increase fxLeft a little(ie, add 0.1f)
and try again. I do the same with fxRight, fyTop and fyBottom. But this is too complex and i need a simple
Does anybody have good ideas? Thanks a lot!