static const screen_x_t PLAYFIELD_LEFT = 0;
static const screen_y_t PLAYFIELD_TOP = 64;
static const screen_x_t PLAYFIELD_RIGHT = RES_X;
static const screen_y_t PLAYFIELD_BOTTOM = RES_Y;

static const pixel_t PLAYFIELD_W = (PLAYFIELD_RIGHT - PLAYFIELD_LEFT);
static const pixel_t PLAYFIELD_H = (PLAYFIELD_BOTTOM - PLAYFIELD_TOP);

static const screen_x_t PLAYFIELD_CENTER_X = (
	((PLAYFIELD_RIGHT - PLAYFIELD_LEFT) / 2) + PLAYFIELD_LEFT
);

inline pixel_t playfield_fraction_x(float fraction = 1.0f) {
	return ((int)(PLAYFIELD_W * fraction));
}

static inline pixel_t playfield_fraction_y(float fraction = 1.0f) {
	return ((int)(PLAYFIELD_H * fraction));
}

#ifdef rand
// Calculates a random X value that spans the given [fraction] of the
// playfield.
static inline pixel_t playfield_rand_x(float fraction = 1.0f) {
	return (rand() % playfield_fraction_x(fraction));
}

// Calculates a random Y value that spans the given [fraction] of the
// playfield.
static inline pixel_t playfield_rand_y(float fraction = 1.0f) {
	return (rand() % playfield_fraction_y(fraction));
}
#endif