pygame.comp

/**
Pygame chimp tutorial example
Punch a monkey to win prizes.

Demonstrates event dispatch, animation, and game loop
using shape-based function overloading.

- Game state is an immutable shape, each frame produces a new state rather than
  mutating in place
- Event handlers are overloaded on `~pg.event` shape with different type
  constraints, dispatch replaces the typical event type switch statement
- `@update` on handlers means each one only returns the fields that changed, the
  engine merges them onto the existing state
- `pick` maps a boolean to one of two values, replaces ternary operators

*/

!import pg comp "pygame-comp-spectacular@1.0.4"


!shape state ~{
    bgd~pg.card
    fist~pg.card
    chimp~pg.card
}


!startup game (
    !my window [
	pg.display
	| window {1280 480} scaled
	| caption "Monkey Fever"
	| mouse-visible false
	]

    !my state {
        bgd = [{window.size fill={0.7 0.9 0.7}} | card]
        fist = [{res.fist pivot={235 80}} | card]
        chimp = [{res.chimp pivot=center} | card]
    }

    [pg.loop window quit-on={event.quit key.escape} :(
		!param state ~state // loop sets this up as context?
        [$.events | each handle]
		[$.draw
        | clear {0.7 0.9 0.7}
        | draw-cards {state.chimp state.fist}]
	)]
)


/// Handle mouse down: punch and check for hit
!func down.handle ~pg.event<type=mouse.up> @update (
    !param state ~state
    [if [state.fist state.chimp | intersect overlap=5] :{
        chimp.rotate = [state.chimp.rotate | spin 360 0.5 ease-out]
        chimp.translate.x = [state.chimp.translate.x | update after=chimp.rotate]
        commands = [audio.play res.punch]
    } 
    | else :{
        commands = [audio.play res.whiff]
    }]
)


/// Handle mouse up: retract fist
!func up.handle ~pg.event<type=mouse.up> @update (     //x this isn't a legal way to do equality of fields
	!param state ~state
	[state.fist | move {-10 -90}]
)


/// Handle mouse move: track fist position
!func move.handle ~pg.event<type=mouse.move> @update (   //x this isn't a legal way to do equality of fields
	!param state ~state
	[state.fist | position $.position]
)