openGL向前旋转时旋转0度，向后旋转90度

Question

I am trying to move my world in reference to a character. It works if the degree is zero (the player goes forward) but messes up everywhere else. When it is 90 degrees, the player goes backwards instead of forwards. I feel like I am on the right track and I just messed up something small.

Here is my equation for the goForward() function

   rad = angle * (pi/180)
   world_loc = (world_loc[0] + speed * sin(rad), world_loc[1], world_loc[2] + speed* cos(rad))

Then this is how I display my world

glPushMatrix()
   glRotate(angle, 0,1,0)
   glTranslatef(world_loc[0],world_loc[1],world_loc[2])
   for x in range(len(world)):
      for y in range(len(world[0])):
         for z in range(len(world[0][0])):
            if(world[x][y][z] != None):              
               glPushMatrix()
               glTranslatef(x*2,y*2,z*2)
               glCallList(world[x][y][z])
               glPopMatrix()
   glPopMatrix()

Any thoughts on what it could be?

Answer 1

The formula is incorrect. Here is the correct one:

def moveForward():
   global angle, angle_speed, world_loc, maxSize
   rad = (angle+90) * (pi/180)
   world_loc = (world_loc[0] - speed * cos(rad), world_loc[1], world_loc[2] - speed *    sin(rad))