/*
 *  imp_heightfield.c: plugin to generated height fields from images
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 *
 *  (C) 2002 Markus Dahms <dahms@fh-brandenburg.de>
 */

#include <stdlib.h>
#include <string.h>

#include <glib.h>

#include <g3dviewer_plugin.h>

int plugin_load(const char *filename, G3DModel *model)
{
	G3DImage *image = g_new0(G3DImage, 1);
	G3DObject *object;
	G3DMaterial *material;
	unsigned int x, y, index;

	if(g3d_plugins_load_image(filename, image) != EXIT_SUCCESS)
	{
		g_free(image);
		return EXIT_FAILURE;
	}

	object = g_new0(G3DObject, 1);
	object->name = g_strdup("height field");
	model->objects = g_slist_append(model->objects, object);

	material = g3d_new_G3DMaterial();
	material->name = g_strdup("default material");
	material->r = 0.2;
	material->g = 1.0;
	material->b = 0.1;
	material->a = 1.0;
	object->materials = g_slist_append(object->materials, material);

	object->vertex_count = image->width * image->height;
	object->vertices = g_malloc0(object->vertex_count * 3 * sizeof(GLfloat));

#if DEBUG > 0
	g_printerr("height field loader: image: %dx%dx%d\n",
		image->width, image->height, image->depth);
#endif

	for(y = 0; y < image->height; y ++)
	{
#if DEBUG > 5
		g_print("Heightfield: line: ");
#endif
		for(x=0; x<image->width; x++)
		{
			index = y*image->width + x;

			object->vertices[index*3+0] = x;
			object->vertices[index*3+1] = y;
			switch(image->depth)
			{
				case 8:
					object->vertices[index*3+2] = 0.0 +
						(float)image->pixeldata[index] / 32.0;
					break;
				case 15:
				case 16:
					object->vertices[index*3+2] = 0.0 +
						*((short int*)&image->pixeldata[index]);
					break;
				case 24:
				case 32:
					object->vertices[index * 3 + 2] = 0.0 +
						image->pixeldata[index * 4] / 32.0;
					break;
				default:
					break;
			}
#if DEBUG > 5
i			g_print(" (%.1f,%.1f,%.1f)",
				object->vertices[index*3+0],
				object->vertices[index*3+1],
				object->vertices[index*3+2]);
#endif
			if((x < (image->width-1)) && (y < (image->height-1)))
			{
				G3DFace *face = g_new0(G3DFace, 1);

				face->material = material;
				face->num_vertices = 3;
				face->index_vertex = g_malloc(3 * sizeof(int));
				face->index_vertex[0] = index;
				face->index_vertex[1] = index + 1;
				face->index_vertex[2] = index + image->width;
				object->faces = g_slist_prepend(object->faces, face);

				face = g_new0(G3DFace, 1);
				face->material = material;
				face->num_vertices = 3;
				face->index_vertex = g_malloc(3 * sizeof(int));
				face->index_vertex[0] = index + 1;
				face->index_vertex[1] = index + image->width + 1;
				face->index_vertex[2] = index + image->width;
				object->faces = g_slist_prepend(object->faces, face);
			}
		} /* for(x) */
#if DEBUG > 4
		g_printerr("loader: line %d ready\n", y+1);
#endif
#if DEBUG > 5
		g_print("\n");
#endif
	} /* for(y) */

	return EXIT_SUCCESS;
}

char *plugin_description(void)
{
	return g_strdup(
		"plugin to generate height fields from images\n"
		"Author: Markus Dahms\n");
}

char **plugin_extensions(void)
{
	return g3d_plugins_get_image_extensions();
}