animation errors
Author
hello, i have been reading opengl superbible version 4 and im confused about one of the projects. Aside from the colors used my project is almost identical to the code in the book and im getting a weird resault. the yellow square is supposed to bounce around the edges but instead it rapidly flips over the oragin. i have no idea whats wrong and would like some help. ive included the code. thanks for any responces
Almost identical? If you look for what you have done differently that could be your answer!
As far as I can see, what you got looks good... I haven't touched much graphics code in the last 6 months mind you! The only thing I would say that looks out of place is this:
-windowWidth (in a few places). As far as I'm aware, in OpenGL the origin is bottom left, so -windowWidth would be off the screen! I believe this should be 0.
Also it seems that the rect is initially being drawn off the screen with y - rsize: 0 - 25 = -25 which is below the window.
Hope this is helpful!
As far as I can see, what you got looks good... I haven't touched much graphics code in the last 6 months mind you! The only thing I would say that looks out of place is this:
if (x1 > windowWidth - rsize || x1 < -windowWidth)
xstep = -xstep;
-windowWidth (in a few places). As far as I'm aware, in OpenGL the origin is bottom left, so -windowWidth would be off the screen! I believe this should be 0.
Also it seems that the rect is initially being drawn off the screen with y - rsize: 0 - 25 = -25 which is below the window.
Hope this is helpful!
Author
what i ment my almost identical is that i changed the colors of the background and the square
You have to set windowWidth and windowHeight:
That said: I don't think that "windowWidth" and "windowHeight" are proper variable names in this case, because their values represent the limits of your visible coordinate system.
if (w<=h){
windowWidth = 100;
windowHeight = 100 / aspectRatio;
}else{
windowWidth = 100 * aspectRatio;
windowHeight = 100;
}
glOrtho (-windowWidth, windowWidth, -windowHeight, windowHeight, 1.0, -1.0 );
That said: I don't think that "windowWidth" and "windowHeight" are proper variable names in this case, because their values represent the limits of your visible coordinate system.
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