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View Full Version : How to make a jump movement?

nosae81
03-16-2002, 08:07 AM
How do i implement a jumping movement when i hit the SPACE. i want to make it in such a way tat the eyey point is raise over a sequence of steps and lowered again when it reach certain limit.

void keyboard(unsigned char key, int x, int y)
{
switch(key)
{
case ' ':
jumping = TRUE;
break;
}
}

int main(int argc, char** argv)
{
glutInit (&argc, argv);
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
glutInitWindowSize (width, height);
glutInitWindowPosition (100, 100);
glutCreateWindow ("Jumping");
init ();
glutDisplayFunc (display);
glutIdleFunc (s);
glutReshapeFunc (reshape);
glutKeyboardFunc (keyboard);
glutSpecialFunc (cursor_keys);
glutPassiveMotionFunc (mouse_motion);
glutMainLoop ();
return 0;
}

void s(void)
{
jumplimit = 1.5;
}

void display(void)
{
if(jumping == TRUE)
{
num = eyey + 0.1;
if(num < jumpLimit)
{
eyey = eyey+ 0.1;
centery =centery +0.1;
}
}

glClear(GL_COLOR_BUFFER_BIT);
calculate_lookpoint(); /* Compute the centre of interest */
gluLookAt(eyex, eyey, eyez, centerx, centery, centerz, upx, upy, upz);
glutSwapBuffers();
}

This code just cant work? may i know where is the problem?

nemesis
03-17-2002, 05:11 AM
Yeah, this will make you jump but, if I'm not wrong, you will never return to the ground...
You could do something more or less like this:

if (state == JUMPING_UP)
{

eyey = eyey + 0.1;
centery = centery + 0.1;
if(eyey > jumpLimit) { state = JUMPING_DOWN; }

}
else if (state == JUMPING_DOWN)
{

eyey = eyey - 0.1;
centery = centery - 0.1;
if(eyey < 0.1) { state = WALKING; }

}

To make the jump more realistic, do not add/substract a constant value. Remeber that physics classes and use those easy formulas to make gravity affect the movement.

Hope it helps,
-nemesis-

Binqay
03-21-2002, 04:50 AM
What those easy formulas (for gravity)?

richardve
03-21-2002, 05:56 AM