<?php

// Martin Hozik
// 24.5.2008
// doublethink.cleverweb.cz

class linear_perspective {
    public $cam_location = ['x' => 10, 'y' => 0, 'z' => -240];
    public $cam_rotation = ['x' => -1, 'y' => 0, 'z' => 0];
    public $viewer_position = ['x' => 0, 'y' => -540, 'z' => -65];

    public function get_projection(array $point) {
        $translation = [];
        $projection = [];

        $translation['x'] = cos($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;
    }
}