pandemonium_demo_projects/2d/physics_platformer/player/player.gd

231 lines
5.7 KiB
GDScript

class_name Player
extends RigidBody2D
# Character Demo, written by Juan Linietsky.
#
# Implementation of a 2D Character controller.
# This implementation uses the physics engine for
# controlling a character, in a very similar way
# than a 3D character controller would be implemented.
#
# Using the physics engine for this has the main advantages:
# - Easy to write.
# - Interaction with other physics-based objects is free
# - Only have to deal with the object linear velocity, not position
# - All collision/area framework available
#
# But also has the following disadvantages:
# - Objects may bounce a little bit sometimes
# - Going up ramps sends the chracter flying up, small hack is needed.
# - A ray collider is needed to avoid sliding down on ramps and
# undesiderd bumps, small steps and rare numerical precision errors.
# (another alternative may be to turn on friction when the character is not moving).
# - Friction cant be used, so floor velocity must be considered
# for moving platforms.
const WALK_ACCEL = 500.0
const WALK_DEACCEL = 500.0
const WALK_MAX_VELOCITY = 140.0
const AIR_ACCEL = 100.0
const AIR_DEACCEL = 100.0
const JUMP_VELOCITY = 380
const STOP_JUMP_FORCE = 450.0
const MAX_SHOOT_POSE_TIME = 0.3
const MAX_FLOOR_AIRBORNE_TIME = 0.15
var anim = ""
var siding_left = false
var jumping = false
var stopping_jump = false
var shooting = false
var floor_h_velocity = 0.0
var airborne_time = 1e20
var shoot_time = 1e20
var Bullet = preload("res://player/Bullet.tscn")
var Enemy = preload("res://enemy/Enemy.tscn")
onready var sound_jump = $SoundJump
onready var sound_shoot = $SoundShoot
onready var sprite = $Sprite
onready var sprite_smoke = sprite.get_node("Smoke")
onready var animation_player = $AnimationPlayer
onready var bullet_shoot = $BulletShoot
func _integrate_forces(s):
var lv = s.get_linear_velocity()
var step = s.get_step()
var new_anim = anim
var new_siding_left = siding_left
# Get player input.
var move_left = Input.is_action_pressed("move_left")
var move_right = Input.is_action_pressed("move_right")
var jump = Input.is_action_pressed("jump")
var shoot = Input.is_action_pressed("shoot")
var spawn = Input.is_action_pressed("spawn")
if spawn:
call_deferred("_spawn_enemy_above")
# Deapply prev floor velocity.
lv.x -= floor_h_velocity
floor_h_velocity = 0.0
# Find the floor (a contact with upwards facing collision normal).
var found_floor = false
var floor_index = -1
for x in range(s.get_contact_count()):
var ci = s.get_contact_local_normal(x)
if ci.dot(Vector2(0, -1)) > 0.6:
found_floor = true
floor_index = x
# A good idea when implementing characters of all kinds,
# compensates for physics imprecision, as well as human reaction delay.
if shoot and not shooting:
call_deferred("_shot_bullet")
else:
shoot_time += step
if found_floor:
airborne_time = 0.0
else:
airborne_time += step # Time it spent in the air.
var on_floor = airborne_time < MAX_FLOOR_AIRBORNE_TIME
# Process jump.
if jumping:
if lv.y > 0:
# Set off the jumping flag if going down.
jumping = false
elif not jump:
stopping_jump = true
if stopping_jump:
lv.y += STOP_JUMP_FORCE * step
if on_floor:
# Process logic when character is on floor.
if move_left and not move_right:
if lv.x > -WALK_MAX_VELOCITY:
lv.x -= WALK_ACCEL * step
elif move_right and not move_left:
if lv.x < WALK_MAX_VELOCITY:
lv.x += WALK_ACCEL * step
else:
var xv = abs(lv.x)
xv -= WALK_DEACCEL * step
if xv < 0:
xv = 0
lv.x = sign(lv.x) * xv
# Check jump.
if not jumping and jump:
lv.y = -JUMP_VELOCITY
jumping = true
stopping_jump = false
sound_jump.play()
# Check siding.
if lv.x < 0 and move_left:
new_siding_left = true
elif lv.x > 0 and move_right:
new_siding_left = false
if jumping:
new_anim = "jumping"
elif abs(lv.x) < 0.1:
if shoot_time < MAX_SHOOT_POSE_TIME:
new_anim = "idle_weapon"
else:
new_anim = "idle"
else:
if shoot_time < MAX_SHOOT_POSE_TIME:
new_anim = "run_weapon"
else:
new_anim = "run"
else:
# Process logic when the character is in the air.
if move_left and not move_right:
if lv.x > -WALK_MAX_VELOCITY:
lv.x -= AIR_ACCEL * step
elif move_right and not move_left:
if lv.x < WALK_MAX_VELOCITY:
lv.x += AIR_ACCEL * step
else:
var xv = abs(lv.x)
xv -= AIR_DEACCEL * step
if xv < 0:
xv = 0
lv.x = sign(lv.x) * xv
if lv.y < 0:
if shoot_time < MAX_SHOOT_POSE_TIME:
new_anim = "jumping_weapon"
else:
new_anim = "jumping"
else:
if shoot_time < MAX_SHOOT_POSE_TIME:
new_anim = "falling_weapon"
else:
new_anim = "falling"
# Update siding.
if new_siding_left != siding_left:
if new_siding_left:
sprite.scale.x = -1
else:
sprite.scale.x = 1
siding_left = new_siding_left
# Change animation.
if new_anim != anim:
anim = new_anim
animation_player.play(anim)
shooting = shoot
# Apply floor velocity.
if found_floor:
floor_h_velocity = s.get_contact_collider_velocity_at_position(floor_index).x
lv.x += floor_h_velocity
# Finally, apply gravity and set back the linear velocity.
lv += s.get_total_gravity() * step
s.set_linear_velocity(lv)
func _shot_bullet():
shoot_time = 0
var bi = Bullet.instance()
var ss
if siding_left:
ss = -1.0
else:
ss = 1.0
var pos = position + bullet_shoot.position * Vector2(ss, 1.0)
bi.position = pos
get_parent().add_child(bi)
bi.linear_velocity = Vector2(400.0 * ss, -40)
sprite_smoke.restart()
sound_shoot.play()
add_collision_exception_with(bi) # Make bullet and this not collide.
func _spawn_enemy_above():
var e = Enemy.instance()
e.position = position + 50 * Vector2.UP
get_parent().add_child(e)