Rotation problems
Author
I know I''m doing something wrong, and it''s probably pretty damn obvious, but i can''t figure it out.
I''m knew to openGL so it''s pretty basic:
void render()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) ;
glLoadIdentity() ;
glEnable(GL_POINT_SMOOTH) ;
angle += 0.1f ;
if (angle >= 360.0f)
{
angle = 0.0f ;
}
glRotatef(angle, 0.0f, 1.0f, 0.0f) ;
glTranslatef(0.0f, 0.0f, -5.0f) ;
glColor3f(1.0f, 0.0f, 0.0f) ;
glBegin(GL_TRIANGLE_STRIP) ;
glVertex3f(0.0f, 1.0f, 0.0f) ;
glVertex3f(1.0f, 0.0f, 0.0f) ;
glVertex3f(-1.0f, 0.0f, 0.0f) ;
glVertex3f(0.0f, 0.0f, -1.0f) ;
glVertex3f(0.0f, 1.0f, 0.0f) ;
glVertex3f(1.0f, 0.0f, 0.0f) ;
glEnd();
glFlush() ;
SwapBuffers(ghDC) ;
return ;
}
I''m trying to rotate the triangle around the y axis, but instead it seems to translate it along the negative x axis.....
I know it''s something stupid, but, any ideas?
Thanks a lot.
MelvinElvin.
Hello Melvin,
The reason why it looks like it is going just across the negative x-axis is because of two things:
1: You have your translation after your rotation, so first it rotates and then it translates. Switch your rotatef and translatef, so translatef comes first.
2: After you do step 1, your triangle will not move, but it will not look like it is rotating because the rotation angle increments are so small: 0.1, increase this to something higher if u want to see your triangle rotating around the y-axis.
Good Luck, saisoft
The reason why it looks like it is going just across the negative x-axis is because of two things:
1: You have your translation after your rotation, so first it rotates and then it translates. Switch your rotatef and translatef, so translatef comes first.
2: After you do step 1, your triangle will not move, but it will not look like it is rotating because the rotation angle increments are so small: 0.1, increase this to something higher if u want to see your triangle rotating around the y-axis.
Good Luck, saisoft
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