<?php
# Martin Hozik
# 24.5.2008
# doublethink.cleverweb.cz


class linear_perspective {

	public $cam_location = array('x' => 10, 'y' => 0, 'z' => -240);
	public $cam_rotation = array('x' => -1, 'y' => 0, 'z' => 0);
	public $viewer_position = array('x' => 0, 'y' => -540, 'z' => -65);
	
	public function get_projection(array $point) {

		$translation = array();
		$projection = array();

		$translation['x'] = cos($this->cam_rotation['y']) * (sin($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) + cos($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x'])) - sin($this->cam_rotation['y']) * ($point['z'] - $this->cam_location['z']);
		$translation['y'] = sin($this->cam_rotation['x']) * (cos($this->cam_rotation['y']) * ($point['z'] - $this->cam_location['z']) + sin($this->cam_rotation['y']) * (sin($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) + cos($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x']))) + cos($this->cam_rotation['z']) * (cos($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) - sin($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x']));
		$translation['z'] = cos($this->cam_rotation['x']) * (cos($this->cam_rotation['y']) * ($point['z'] - $this->cam_location['z']) + sin($this->cam_rotation['y']) * (sin($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) + cos($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x']))) - sin($this->cam_rotation['z']) * (cos($this->cam_rotation['z']) * ($point['y'] - $this->cam_location['y']) - sin($this->cam_rotation['z']) * ($point['x'] - $this->cam_location['x']));

		$projection['x'] = ($translation['x'] - $this->viewer_position['x']) * ($this->viewer_position['z'] / $translation['z']);
		$projection['y'] = ($translation['y'] - $this->viewer_position['y']) * ($this->viewer_position['z'] / $translation['z']);

		return $projection;
	}
}
?>