Advanced Concepts

This chapter covers textured objects, camera control, collision helpers, multiple scenes, and UI text.

Textured Objects and Tint

To use a texture, create the object with has_texture=True and then load the texture:

player = scene.spawn_object((0, 0), (32, 32), has_texture=True)
player.use_texture("res/textures/player.png", 0)

Textured objects use tint instead of color:

player.tint = (255, 0, 0, 0.5)

The fourth component is the tint strength from 0.0 to 1.0.

Camera

Each scene exposes a camera object:

camera = scene.camera
camera.follow(player)
camera.follow_offset = (0, 15)
camera.zoom = 1.1

You can also place the camera manually with camera.pos = (x, y).

Collisions

Attach collision boxes to objects and query the results:

wall = scene.spawn_object((40, 0), (20, 60))
wall.color = (180, 180, 180)
wall.add_collision_box((0, 0), (20, 60))

player.add_collision_box((0, 0), (20, 20))

hit = player.collides_with(wall)
if hit:
    print(hit.direction)

For automatic collision resolution order, set player.auto_collides to an integer priority.

For example, if you want the player to be blocked automatically by many walls:

wall = scene.spawn_object((40, 0), (20, 60))
wall.color = (180, 180, 180)
wall.add_collision_box((0, 0), (20, 60))

wall2 = scene.spawn_object((0, -10), (40, 10))
wall2.color = (180, 180, 180)
wall2.add_collision_box((0, 0), (40, 10))

# wall3 etc.

player.add_collision_box((0, 0), (20, 20))
player.auto_collides = 1 # This will handle collision automatically

Alternatively, if you want multiple objects to collide in a predictable way, you must use higher orders. In grafyte, a higher order object will push the objects with a lower resolution order:

player.auto_collides = 1
# ...
ball.auto_collides = 2

In the above example, the ball will always push back the player when the two objects are colliding. Please note that if two objects have the same order, collision handling order may be less intuitive in code, but remains deterministic at runtime.

UI Text

For screen-space overlays, create a UI manager:

from grafyte import Anchor

ui = app.make_new_ui()
score = ui.add_text((10, 10), "Score: 0", scale=18, anchor=Anchor.TopLeft)
score.color = (255, 255, 255)

UI text stays attached to the screen instead of moving with the world camera.

Multiple Scenes

Grafyte supports more than one scene, which makes it easier to keep gameplay, menus, and transitional states separated. A scene can be created up front and activated when your game needs it, instead of forcing everything into a single world state.

import grafyte
from grafyte import InputTrigger, Key

app = grafyte.Application("Multi Scene Demo", (800, 450))
app.input.create_action("start_game", InputTrigger.Press, Key.Space)

menu_scene = app.make_new_scene()
menu_scene.spawn_text_object((20, 20), "Press Space to Start", 20)

gameplay_scene = app.make_new_scene()
player = gameplay_scene.spawn_object((0, 0), (32, 32))
gameplay_scene.spawn_text_object((20, 20), "Gameplay Scene", 18)

# Start in the menu.
app.scene = menu_scene

while not app.should_close():
    if app.input["start_game"]:
        app.scene = gameplay_scene
    app.render()

In practice, this means you can keep a gameplay scene and a menu scene alive at the same time, then switch the active scene without rebuilding the objects every frame.