dd_lang2/new_project-catmulrom.dd

# main world
struct world_main : dd_world {

	# test sprite
	struct dd_sprite my_sprite;

	# catmul-rom points
	struct dd_vector2d p1;
	struct dd_vector2d p2;
	struct dd_vector2d p3;
	struct dd_vector2d p4;

	# curve counter
	int counter;

	# current point ( 0 = top left, 1 = top right, 2 = bottom right, 3 = bottom left )
	int point;

	# init sprite
	void init() {

		# start from point 0
		this.point = 0;
		this.counter = 100;

		# first curve has random values
		this.p1.x = 0;
		this.p1.y = DD_GAME_HEIGHT;
		this.p2.x = DD_GAME_WIDTH /2;
		this.p2.y = DD_GAME_HEIGHT/2;
		this.p3.x = DD_GAME_WIDTH *2/3;
		this.p3.y = DD_GAME_HEIGHT*2/3;
		this.p4.x = DD_GAME_WIDTH;
		this.p4.y = DD_GAME_HEIGHT;

		# first sprite is at the top
		this.my_sprite.x = 0;
		this.my_sprite.y = 0;
		this.my_sprite.load("dd_logo.png");

	};

	# update sprite's position
	override void update() {

		# update counter
		this.counter = this.counter +1;

		# counter finished, moved to next curve
		if (this.counter >= 100) {

			# reset counter and move to next point
			this.counter = 1;
			this.point = this.point +1;
			if (this.point >= 4) {
				this.point = 0;
			}

			# calculate the first three points of the curve
			this.p1.x = this.p2.x;
			this.p1.y = this.p2.y;
			this.p2.x = this.my_sprite.x +this.my_sprite.w/2;
			this.p2.y = this.my_sprite.y +this.my_sprite.h/2;

			if (this.point == 0) {
				this.p3.x = 0;
				this.p3.y = 0;
				this.p4.x = DD_GAME_WIDTH;
				this.p4.y = 0;
			}

			if (this.point == 1) {
				this.p3.x = DD_GAME_WIDTH;
				this.p3.y = 0;
				this.p4.x = DD_GAME_WIDTH;
				this.p4.y = DD_GAME_HEIGHT;
			}

			if (this.point == 2) {
				this.p3.x = DD_GAME_WIDTH;
				this.p3.y = DD_GAME_HEIGHT;
				this.p4.x = 0;
				this.p4.y = DD_GAME_HEIGHT;
			}

			if (this.point == 3) {
				this.p3.x = 0;
				this.p3.y = DD_GAME_HEIGHT;
				this.p4.x = 0;
				this.p4.y = 0;
			}

		} # counter finished

		# catmul-rom curve
		float counter_max;
		counter_max = 100;
		int tempx;
		tempx = ( (2 *this.p2.x) +(this.p3.x -this.p1.x) *(this.counter /counter_max)
			+(2 *this.p1.x -5 *this.p2.x +4 *this.p3.x -this.p4.x) *((this.counter /counter_max) *(this.counter /counter_max))
			+(3 *this.p2.x -this.p1.x -3 *this.p3.x +this.p4.x) *((this.counter /counter_max) *(this.counter /counter_max) *(this.counter /counter_max))) /2;
		int tempy;
		tempy = ( (2 *this.p2.y) +(this.p3.y -this.p1.y) *(this.counter /counter_max)
			+(2 *this.p1.y -5 *this.p2.y +4 *this.p3.y -this.p4.y) *((this.counter /counter_max) *(this.counter /counter_max))
			+(3 *this.p2.y -this.p1.y -3 *this.p3.y +this.p4.y) *((this.counter /counter_max) *(this.counter /counter_max) *(this.counter /counter_max))) /2;
		this.my_sprite.x = tempx -this.my_sprite.w/2;
		this.my_sprite.y = tempy -this.my_sprite.h/2;

	}; # update

	# draw sprite
	override void draw() {
		this.my_sprite.draw();
	};

	override void click() {
		this.counter = 100;
	};

}; # world_main