crown-engine/samples/02-animation/main.lua

-- Copyright (c) 2012-2025 Daniele Bartolini et al.
-- SPDX-License-Identifier: MIT

require "core/game/camera"

Game = Game or {
	pw = nil,
	rw = nil,
	sg = nil,
	sm = nil,
	camera = nil,
	player = nil,
	players = {},
	player_i = 1,
	fullscreen = false
}

GameBase.game = Game
GameBase.game_level = "levels/game"

function Game.level_loaded()
	Game.pw = World.physics_world(GameBase.world)
	Game.rw = World.render_world(GameBase.world)
	Game.sg = World.scene_graph(GameBase.world)
	Game.sm = World.animation_state_machine(GameBase.world)

	-- Setup camera.
	local camera = World.camera_instance(GameBase.world, GameBase.camera_unit)
	World.camera_set_orthographic_size(GameBase.world, camera, 540/2/32)
	World.camera_set_projection_type(GameBase.world, camera, "orthographic")
	local camera_transform = SceneGraph.instance(Game.sg, GameBase.camera_unit)
	SceneGraph.set_local_position(Game.sg, camera_transform, Vector3(0, 0, 8))
	SceneGraph.set_local_rotation(Game.sg, camera_transform, Quaternion.from_axis_angle(Vector3.right(), -90*(math.pi/180.0)))

	-- Spawn characters.
	Game.players[1] = World.spawn_unit(GameBase.world, "units/soldier", Vector3(-2, 0, 0))
	Game.players[2] = World.spawn_unit(GameBase.world, "units/princess", Vector3(2, 0, 0))
	Game.player = Game.players[1]
end

function Game.update(dt)
	-- Stop the engine when the 'ESC' key is released.
	if Keyboard.released(Keyboard.button_id("escape")) then
		Device.quit()
	end

	-- Toggle fullscreen.
	if Keyboard.released(Keyboard.button_id("0")) then
		Game.fullscreen = not Game.fullscreen
		Window.set_fullscreen(Game.fullscreen)
	end

	-- Cycle through characters.
	if Pad1.pressed(Pad1.button_id("shoulder_right")) or Keyboard.pressed(Keyboard.button_id("j")) then
		local asm = AnimationStateMachine.instance(Game.sm, Game.player);
		AnimationStateMachine.trigger(Game.sm, asm, "idle")
		Game.player_i = Game.player_i % #Game.players + 1
		Game.player = Game.players[Game.player_i]
	end

	-- Read direction from joypad.
	local pad_dir = Pad1.axis(Pad1.axis_id("left"))
	-- Add keyboard contribution.
	if pad_dir.x == 0.0 and pad_dir.y == 0.0 then
		pad_dir.x = pad_dir.x + Keyboard.button(Keyboard.button_id("d")) - Keyboard.button(Keyboard.button_id("a"))
		pad_dir.y = pad_dir.y + Keyboard.button(Keyboard.button_id("w")) - Keyboard.button(Keyboard.button_id("s"))
		if Vector3.length(pad_dir) > 0.0001 then
			Vector3.normalize(pad_dir)
		end
	end
	-- Compute new player position.
	local player_speed = 4
	local player_tr = SceneGraph.instance(Game.sg, Game.player)
	local player_position = SceneGraph.local_position(Game.sg, player_tr)
	SceneGraph.set_local_position(Game.sg, player_tr, player_position + pad_dir*player_speed*dt)

	-- Sprite depth is proportional to its Z position.
	for i=1, #Game.players do
		local tr = SceneGraph.instance(Game.sg, Game.players[i])
		local pos = SceneGraph.local_position(Game.sg, tr)
		local depth = math.floor(1000 + (1000 - 32*pos.y))
		local sprite = RenderWorld.sprite_instance(Game.rw, Game.players[i])
		RenderWorld.sprite_set_depth(Game.rw, sprite, depth)
	end

	local asm = AnimationStateMachine.instance(Game.sm, Game.player);
	if pad_dir.x ~= 0.0 or pad_dir.y ~= 0.0 then
		local asm = AnimationStateMachine.instance(Game.sm, Game.player);
		local speed_x = AnimationStateMachine.variable_id(Game.sm, asm, "speed_x")
		local speed_y = AnimationStateMachine.variable_id(Game.sm, asm, "speed_y")
		local speed   = AnimationStateMachine.variable_id(Game.sm, asm, "speed")
		AnimationStateMachine.set_variable(Game.sm, asm, speed_x, pad_dir.x)
		AnimationStateMachine.set_variable(Game.sm, asm, speed_y, pad_dir.y)
		AnimationStateMachine.set_variable(Game.sm, asm, speed, math.max(0.2, Vector3.length(pad_dir)))
		AnimationStateMachine.trigger(Game.sm, asm, "run")
	else
		AnimationStateMachine.trigger(Game.sm, asm, "idle")
	end

	-- Toggle help.
	if Keyboard.pressed(Keyboard.button_id("f1")) then
		GameBase.show_help = not GameBase.show_help
	end

	GameBase.draw_help({{ key = "f1", desc = "Toggle help" },
		{ key = "w/a/s/d", desc = "Move" },
		{ key = "j", desc = "Switch characters" },
		{ key = "esc", desc = "Quit" }}
		, "Crown Animation Sample"
		)
end

function Game.render(dt)
end

function Game.shutdown()
end