CODEWITHSUNDEEP
pygamekeyboardgravity
Noah
Noah

Reputation: 614

Implementing very basic gravity into pygame

In my program I use key detection to move my player around. Although others have asked how to get working gravity, there is a very specific thing I would like to find out, how would I do this in real code from pseudocode.

if keys 1
    pos[1] ++
unless you just jumped

Basically allowing me to take input from previous loops of my main game loop.

Upvotes: 1

Views: 102

Answers (1)

Chris Zacharias
Chris Zacharias

Reputation: 608

There are a couple of ways you could do this.

1.) You could use global state to track a keypress boolean. Check it is "false" before jump, set it to "true" on jump, set it back to "false" on landing. Some games allow double-jumping, hence you would increment and decrement a keypress counter instead.

global has_jumped = False
if keys 1 and has_jumped is False:
  pos[1] ++
  has_jumped is True

// Apply gravity here.

if pos[1] <= 0: // Presumes ground is at Y = 0
  has_jumped is False

2.) Alternatively, a more robust way to do this is to calculate if the player is standing on the map and use that to decide if the character can jump.

global player_acceleration_y = -10  // Gravity, in delta pixels per loop
global player_velocity_y = 0  // Velocity in pixels per loop

function loop():
   pos[1] += player_velocity_y
   player_velocity_y += player_acceleration_y
   if pos[1] <= 0: // Just using a ground plane of 0 here. You could use more complex collision logic here.
       pos[1] = 0 // Make sure we don't fall through the floor.
       player_velocity_y = 0 // Stop falling.

   if keys 1: // Jump 
      if pos[1] <= 0:
          player_velocity_y = 30  // Jump up at a rate of 30 pixels per loop, which will be offset by gravity over time.

Upvotes: 2

Related Questions