Mini-Map Defender¶
This example shows how to create a ‘mini-map’ using frame buffers. Frame buffers allow us to draw off-screen. We can then take that image and draw it elsewhere.
Section 1 - Define Constants¶
Lines 26-32
At the start of our code, define some constants that specify how large your mini-map is. In this case, our mini-map is at the top of the screen, and the main playing field is below.
Section 2 - Create Frame Buffer¶
Lines 172-189
As our window opens up, we need to define a frame buffer that will hold our mini-map.
Figure out the size and position.
Create an OpenGL shader program. This is a simple pre-defined shader that just passes through vertex and texture data.
Create a color attachment, which holds what color each pixel is.
Create a frame buffer, and tell it to use the color attachment to hold data.
Create a rectangle that defines where we will draw the mini-map.
Section 3 - Draw to Mini-Map¶
Lines 226-238
Any time we want to draw to the frame buffer instead of the screen, there’s a
use method in the frame buffer. So in this case, we can do:
self.mini_map_screen.use()
To switch back to the screen, use the windows use method:
self.use()
Once we select the frame buffer, we set the viewport to encompass our entire playing field. Then we draw the sprites we want in the mini-map. Note that this example doesn’t draw the background stars or bullets to the mini-map. The program can easily select what should appear in the mini-map this way.
Section 4 - Draw Mini-Map to Screen¶
Lines 263-280
While we’ve drawn the mini-map, it is off-screen and we can’t see it. In this case, we render it to the pre-defined location with:
self.mini_map_color_attachment.use(0)
self.mini_map_rect.render(self.program)
The rest of the code in this section calculates a rectangle on the mini-map that outlines what the user can see on the mini-map.
mini_map_defender.py¶
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Defender Clone.
.. note:: This uses features from the upcoming version 2.4. The API for these
functions may still change. To use, you will need to install one of the
pre-release packages, or install via GitHub.
This example shows how to create a mini-map
If Python and Arcade are installed, this example can be run from the command line with:
python -m arcade.examples.minimap_defender
"""
import arcade
import random
# --- Minimap Related ---
from arcade.gl import geometry
# Size/title of the window
SCREEN_WIDTH = 1280
SCREEN_HEIGHT = 800
SCREEN_TITLE = "Defender Clone"
# Size of the playing field
PLAYING_FIELD_WIDTH = 5000
PLAYING_FIELD_HEIGHT = 1000
# --- Mini-map related ---
# Size of the minimap
MINIMAP_HEIGHT = 200
# Size of the playing field.
# This, plus the mini-map height, should add up to the height of the screen.
MAIN_SCREEN_HEIGHT = SCREEN_HEIGHT - MINIMAP_HEIGHT
# How far away from the edges do we get before scrolling?
VIEWPORT_MARGIN = SCREEN_WIDTH / 2 - 50
TOP_VIEWPORT_MARGIN = 30
DEFAULT_BOTTOM_VIEWPORT = -10
# Control the physics of how the player moves
MAX_HORIZONTAL_MOVEMENT_SPEED = 10
MAX_VERTICAL_MOVEMENT_SPEED = 5
HORIZONTAL_ACCELERATION = 0.5
VERTICAL_ACCELERATION = 0.2
MOVEMENT_DRAG = 0.08
# How far the bullet travels before disappearing
BULLET_MAX_DISTANCE = SCREEN_WIDTH * 0.75
class Player(arcade.SpriteSolidColor):
""" Player ship """
def __init__(self):
""" Set up player """
super().__init__(40, 10, arcade.color.SLATE_GRAY)
self.face_right = True
def accelerate_up(self):
""" Accelerate player up """
self.change_y += VERTICAL_ACCELERATION
if self.change_y > MAX_VERTICAL_MOVEMENT_SPEED:
self.change_y = MAX_VERTICAL_MOVEMENT_SPEED
def accelerate_down(self):
""" Accelerate player down """
self.change_y -= VERTICAL_ACCELERATION
if self.change_y < -MAX_VERTICAL_MOVEMENT_SPEED:
self.change_y = -MAX_VERTICAL_MOVEMENT_SPEED
def accelerate_right(self):
""" Accelerate player right """
self.face_right = True
self.change_x += HORIZONTAL_ACCELERATION
if self.change_x > MAX_HORIZONTAL_MOVEMENT_SPEED:
self.change_x = MAX_HORIZONTAL_MOVEMENT_SPEED
def accelerate_left(self):
""" Accelerate player left """
self.face_right = False
self.change_x -= HORIZONTAL_ACCELERATION
if self.change_x < -MAX_HORIZONTAL_MOVEMENT_SPEED:
self.change_x = -MAX_HORIZONTAL_MOVEMENT_SPEED
def update(self):
""" Move the player """
# Move
self.center_x += self.change_x
self.center_y += self.change_y
# Drag
if self.change_x > 0:
self.change_x -= MOVEMENT_DRAG
if self.change_x < 0:
self.change_x += MOVEMENT_DRAG
if abs(self.change_x) < MOVEMENT_DRAG:
self.change_x = 0
if self.change_y > 0:
self.change_y -= MOVEMENT_DRAG
if self.change_y < 0:
self.change_y += MOVEMENT_DRAG
if abs(self.change_y) < MOVEMENT_DRAG:
self.change_y = 0
# Check bounds
if self.left < 0:
self.left = 0
elif self.right > PLAYING_FIELD_WIDTH - 1:
self.right = PLAYING_FIELD_WIDTH - 1
if self.bottom < 0:
self.bottom = 0
elif self.top > PLAYING_FIELD_HEIGHT - 1:
self.top = PLAYING_FIELD_HEIGHT - 1
class Bullet(arcade.SpriteSolidColor):
""" Bullet """
def __init__(self, width, height, color):
super().__init__(width, height, color)
self.distance = 0
def update(self):
""" Move the particle, and fade out """
# Move
self.center_x += self.change_x
self.center_y += self.change_y
self.distance += self.change_x
if self.distance > BULLET_MAX_DISTANCE:
self.remove_from_sprite_lists()
class Particle(arcade.SpriteSolidColor):
""" Particle from explosion """
def update(self):
""" Move the particle, and fade out """
# Move
self.center_x += self.change_x
self.center_y += self.change_y
# Fade
self.alpha -= 5
if self.alpha <= 0:
self.remove_from_sprite_lists()
class MyGame(arcade.Window):
""" Main application class. """
def __init__(self, width, height, title):
""" Initializer """
# Call the parent class initializer
super().__init__(width, height, title)
# Variables that will hold sprite lists
self.player_list = None
self.star_sprite_list = None
self.enemy_sprite_list = None
self.bullet_sprite_list = None
# Set up the player info
self.player_sprite = None
# Track the current state of what key is pressed
self.left_pressed = False
self.right_pressed = False
self.up_pressed = False
self.down_pressed = False
self.view_bottom = 0
self.view_left = 0
# Set the background color
arcade.set_background_color(arcade.color.BLACK)
# --- Mini-map related ---
# How big is our screen?
screen_size = (SCREEN_WIDTH, SCREEN_HEIGHT)
# How big is the mini-map?
mini_map_size = (SCREEN_WIDTH, MINIMAP_HEIGHT)
# Where is the mini-map to be drawn?
mini_map_pos = (SCREEN_WIDTH / 2, SCREEN_HEIGHT - MINIMAP_HEIGHT / 2)
# Load a vertex and fragment shader
self.program = self.ctx.load_program(
vertex_shader=arcade.resources.shaders.vertex.default_projection,
fragment_shader=arcade.resources.shaders.fragment.texture)
# Add a color attachment to store pixel colors
self.mini_map_color_attachment = self.ctx.texture(screen_size)
# Create a frame buffer with the needed color attachment
self.mini_map_screen = self.ctx.framebuffer(color_attachments=[self.mini_map_color_attachment])
# Create a rectangle that will hold where the mini-map goes
self.mini_map_rect = geometry.screen_rectangle(0, SCREEN_WIDTH, MINIMAP_HEIGHT, SCREEN_HEIGHT)
def setup(self):
""" Set up the game and initialize the variables. """
# Sprite lists
self.player_list = arcade.SpriteList()
self.star_sprite_list = arcade.SpriteList()
self.enemy_sprite_list = arcade.SpriteList()
self.bullet_sprite_list = arcade.SpriteList()
# Set up the player
self.player_sprite = Player()
self.player_sprite.center_x = 50
self.player_sprite.center_y = 50
self.player_list.append(self.player_sprite)
# Add stars
for i in range(100):
sprite = arcade.SpriteSolidColor(4, 4, arcade.color.WHITE)
sprite.center_x = random.randrange(PLAYING_FIELD_WIDTH)
sprite.center_y = random.randrange(PLAYING_FIELD_HEIGHT)
self.star_sprite_list.append(sprite)
# Add enemies
for i in range(30):
sprite = arcade.SpriteSolidColor(20, 20, arcade.csscolor.LIGHT_SALMON)
sprite.center_x = random.randrange(PLAYING_FIELD_WIDTH)
sprite.center_y = random.randrange(PLAYING_FIELD_HEIGHT)
self.enemy_sprite_list.append(sprite)
def on_draw(self):
""" Render the screen. """
# This command has to happen before we start drawing
arcade.start_render()
# --- Mini-map related ---
# Draw to the frame buffer used in the mini-map
self.mini_map_screen.use()
self.mini_map_screen.clear()
arcade.set_viewport(0,
PLAYING_FIELD_WIDTH,
0,
PLAYING_FIELD_HEIGHT)
self.enemy_sprite_list.draw()
self.player_list.draw()
# Now draw to the actual screen
self.use()
arcade.set_viewport(self.view_left,
SCREEN_WIDTH + self.view_left,
self.view_bottom,
SCREEN_HEIGHT + self.view_bottom)
self.star_sprite_list.draw()
self.enemy_sprite_list.draw()
self.bullet_sprite_list.draw()
self.player_list.draw()
# Draw the ground
arcade.draw_line(0, 0, PLAYING_FIELD_WIDTH, 0, arcade.color.WHITE)
# Draw a background for the minimap
arcade.draw_rectangle_filled(SCREEN_WIDTH - SCREEN_WIDTH / 2 + self.view_left,
SCREEN_HEIGHT - MINIMAP_HEIGHT + MINIMAP_HEIGHT / 2 + self.view_bottom,
SCREEN_WIDTH,
MINIMAP_HEIGHT,
arcade.color.DARK_GREEN)
# --- Mini-map related ---
# Draw the minimap
self.mini_map_color_attachment.use(0)
self.mini_map_rect.render(self.program)
# Draw a rectangle showing where the screen is
width_ratio = SCREEN_WIDTH / PLAYING_FIELD_WIDTH
height_ratio = MINIMAP_HEIGHT / PLAYING_FIELD_HEIGHT
width = width_ratio * SCREEN_WIDTH
height = height_ratio * MAIN_SCREEN_HEIGHT
x = (self.view_left + SCREEN_WIDTH / 2) * width_ratio + self.view_left
y = (SCREEN_HEIGHT - MINIMAP_HEIGHT) + self.view_bottom + height / 2 + (MAIN_SCREEN_HEIGHT / PLAYING_FIELD_HEIGHT) * self.view_bottom
arcade.draw_rectangle_outline(center_x=x, center_y=y,
width=width, height=height,
color=arcade.color.WHITE)
def on_update(self, delta_time):
""" Movement and game logic """
# Calculate speed based on the keys pressed
if self.up_pressed and not self.down_pressed:
self.player_sprite.accelerate_up()
elif self.down_pressed and not self.up_pressed:
self.player_sprite.accelerate_down()
if self.left_pressed and not self.right_pressed:
self.player_sprite.accelerate_left()
elif self.right_pressed and not self.left_pressed:
self.player_sprite.accelerate_right()
# Call update to move the sprite
self.player_list.update()
self.bullet_sprite_list.update()
for bullet in self.bullet_sprite_list:
enemy_hit_list = arcade.check_for_collision_with_list(bullet, self.enemy_sprite_list)
for enemy in enemy_hit_list:
enemy.remove_from_sprite_lists()
for i in range(10):
particle = Particle(4, 4, arcade.color.RED)
while particle.change_y == 0 and particle.change_x == 0:
particle.change_y = random.randrange(-2, 3)
particle.change_x = random.randrange(-2, 3)
particle.center_x = enemy.center_x
particle.center_y = enemy.center_y
self.bullet_sprite_list.append(particle)
# Scroll left
left_boundary = self.view_left + VIEWPORT_MARGIN
if self.player_sprite.left < left_boundary:
self.view_left -= left_boundary - self.player_sprite.left
# Scroll right
right_boundary = self.view_left + SCREEN_WIDTH - VIEWPORT_MARGIN
if self.player_sprite.right > right_boundary:
self.view_left += self.player_sprite.right - right_boundary
# Scroll up
self.view_bottom = DEFAULT_BOTTOM_VIEWPORT
top_boundary = self.view_bottom + SCREEN_HEIGHT - TOP_VIEWPORT_MARGIN - MINIMAP_HEIGHT
if self.player_sprite.top > top_boundary:
self.view_bottom += self.player_sprite.top - top_boundary
self.view_left = int(self.view_left)
self.view_bottom = int(self.view_bottom)
def on_key_press(self, key, modifiers):
"""Called whenever a key is pressed. """
if key == arcade.key.UP:
self.up_pressed = True
elif key == arcade.key.DOWN:
self.down_pressed = True
elif key == arcade.key.LEFT:
self.left_pressed = True
elif key == arcade.key.RIGHT:
self.right_pressed = True
elif key == arcade.key.SPACE:
# Shoot out a bullet/laser
bullet = arcade.SpriteSolidColor(35, 3, arcade.color.WHITE)
bullet.center_x = self.player_sprite.center_x
bullet.center_y = self.player_sprite.center_y
bullet.change_x = max(12, abs(self.player_sprite.change_x) + 10)
if not self.player_sprite.face_right:
bullet.change_x *= -1
self.bullet_sprite_list.append(bullet)
def on_key_release(self, key, modifiers):
"""Called when the user releases a key. """
if key == arcade.key.UP:
self.up_pressed = False
elif key == arcade.key.DOWN:
self.down_pressed = False
elif key == arcade.key.LEFT:
self.left_pressed = False
elif key == arcade.key.RIGHT:
self.right_pressed = False
def main():
""" Main method """
window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
window.setup()
arcade.run()
if __name__ == "__main__":
main()
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