/* *****************************************************************************
 * update.c -- update the scene.
 * Copyright (C) 2017 Olivier "Ninestars" Lanneau
 * Copyright (C) 2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 *
 * This file is part of libwindmill.
 * libwindmill is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3.0 of the License,
 * or (at your option) any later version.
 *
 * libwindmill is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libwindmill; if not, see <http://www.gnu.org/licenses/>.
 * ************************************************************************** */
#include <libwindmill/internals.h>

/**
 *	wml_update_camera:
 *	Update the camera.
 *
 *	@arg	scene		the scene to update.
 */

void wml_update_camera(wml_scene_t *scene)
{
	scene->camera_yaw = (int)(scene->camera_yaw + 360) % 360;
	float camera_yaw_rad = M_PI * scene->camera_yaw / 180.0;

	/* calculate intermediate value */
	float camera_pitch_rad = M_PI * scene->camera_pitch / 180.0;
	float cos_yaw = cosf(camera_yaw_rad), sin_yaw = sinf(camera_yaw_rad);
	float cos_pitch = cosf(camera_pitch_rad);
	float sin_pitch = sinf(camera_pitch_rad);

	/* set final values */
	scene->a1 = 128.0 * cos_yaw;
	scene->a2 = 128.0 * -sin_yaw;
	scene->a3 = 0.0;
	scene->a4 = 128.0 * cos_pitch * sin_yaw;
	scene->a5 = 128.0 * cos_pitch * cos_yaw;
	scene->a6 = 128.0 * -sin_pitch;
	scene->a7 = 128.0 * sin_pitch * sin_yaw;
	scene->a8 = 128.0 * sin_pitch * cos_yaw;
	scene->a9 = 128.0 * cos_pitch;
}

/**
 *	wml_update_viewport:
 *	Update the viewport.
 *
 *	@arg	scene		the scene to update.
 */

void wml_update_viewport(wml_scene_t *scene)
{
	free(scene->z_buffer);
	scene->shift_x = (scene->viewport_x1 + scene->viewport_x2 - 128) / 2;
	scene->shift_y = (scene->viewport_y1 + scene->viewport_y2 - 64) / 2;

	scene->z_buffer_size = (scene->viewport_x2 - scene->viewport_x1)
		* (scene->viewport_y2 -scene->viewport_y2);
	scene->z_buffer = (unsigned short*)calloc(scene->z_buffer_size, 2);
	scene->z_buffer_width = scene->viewport_x2 - scene->viewport_x1;
	scene->z_buffer_offset = 64 - scene->viewport_x1
		+ scene->z_buffer_width * (32 - scene->viewport_y1);
	memset(scene->z_buffer, 0xFF, scene->z_buffer_size * 2);
}