/**
 * Example illustrating usage of fog effect.
 *
 * @verbatim
 * gcc -o evas-3d-fog evas-3d-fog.c `pkg-config --libs --cflags evas ecore ecore-evas eo`-lm
 * @endverbatim
 */

#define EFL_EO_API_SUPPORT
#define EFL_BETA_API_SUPPORT

#include <math.h>
#include <Eo.h>
#include <Evas.h>
#include <Ecore.h>
#include <Ecore_Evas.h>

#define  WIDTH          1024
#define  HEIGHT         1024
#define  FOG_COLOR      0.5, 0.5, 0.5
#define  FOG_FACTOR     0.2

static double pi = 3.14159265359;

typedef struct _Scene_Data
{
   Eo     *scene;
   Eo     *root_node;
   Eo     *camera_node;
   Eo     *light_node;
   Eo     *mesh_node;
   Eo     *mesh_node1;

   Eo     *camera;
   Eo     *light;
   Eo     *mesh;
   Eo     *mesh1;
   Eo     *material;
} Scene_Data;

typedef struct _vec3
{
    float   x;
    float   y;
    float   z;
} vec3;

typedef struct _vec4
{
    float   x;
    float   y;
    float   z;
    float   w;
} vec4;

Ecore_Evas       *ecore_evas  = NULL;
Evas             *evas        = NULL;
Eo               *background  = NULL;
Eo               *image       = NULL;


static void
_on_delete(Ecore_Evas *ee EINA_UNUSED)
{
   ecore_main_loop_quit();
}

static void
_on_canvas_resize(Ecore_Evas *ee)
{
   int w, h;

   ecore_evas_geometry_get(ee, NULL, NULL, &w, &h);

   evas_object_resize(background, w, h);
   eo_do(background, evas_obj_size_set(w, h));
   eo_do(image, evas_obj_size_set(w, h));
}

static Eina_Bool
_animate_scene(void *data)
{
   static float angle = 0.0f;
   Scene_Data *scene = (Scene_Data *)data;

   angle += 0.5;

   eo_do(scene->mesh_node,
         evas_3d_node_orientation_angle_axis_set(angle, 0.0, 1.0, 0.0));

   if (angle > 360.0) angle -= 360.0f;

   return EINA_TRUE;
}

static void
_camera_setup(Scene_Data *data)
{
   data->camera = eo_add(EVAS_3D_CAMERA_CLASS, evas);

   eo_do(data->camera,
         evas_3d_camera_projection_perspective_set(60.0, 1.0, 2.0, 50.0));

  data->camera_node =
      eo_add_custom(EVAS_3D_NODE_CLASS, evas,
                    evas_3d_node_constructor(EVAS_3D_NODE_TYPE_CAMERA));

  eo_do(data->camera_node,
         evas_3d_node_camera_set(data->camera),
         evas_3d_node_position_set(0.0, 0.0, 10.0),
         evas_3d_node_look_at_set(EVAS_3D_SPACE_PARENT, 0.0, 0.0, 0.0,
                                  EVAS_3D_SPACE_PARENT, 0.0, 1.0, 0.0));

  eo_do(data->root_node, evas_3d_node_member_add(data->camera_node));
}

static void
_light_setup(Scene_Data *data)
{
   data->light = eo_add(EVAS_3D_LIGHT_CLASS, evas);
   eo_do(data->light,
         evas_3d_light_ambient_set(0.2, 0.2, 0.2, 1.0),
         evas_3d_light_diffuse_set(1.0, 1.0, 1.0, 1.0),
         evas_3d_light_specular_set(1.0, 1.0, 1.0, 1.0));

   data->light_node =
      eo_add_custom(EVAS_3D_NODE_CLASS, evas,
                    evas_3d_node_constructor(EVAS_3D_NODE_TYPE_LIGHT));
   eo_do(data->light_node,
         evas_3d_node_light_set(data->light),
         evas_3d_node_position_set(0.0, 0.0, 10.0),
         evas_3d_node_look_at_set(EVAS_3D_SPACE_PARENT, 0.0, 0.0, 0.0,
                                  EVAS_3D_SPACE_PARENT, 0.0, 1.0, 0.0));
   eo_do(data->root_node, evas_3d_node_member_add(data->light_node));
}

static void
_set_ball(Eo *mesh, double r, double x, double y, double z, int p, Evas_3D_Material *material)
{
   int vcount, icount, vccount, i, j;
   double dtheta, dfi, sinth, costh, fi, theta, sinfi, cosfi;
   unsigned short *indices, *index;

   icount = p * p * 6;
   vccount = p + 1;
   vcount = vccount * vccount;

   dtheta = pi / p;
   dfi = 2 * pi / p;

   vec3 *vertices = malloc(sizeof(vec3) * vcount);
   vec3 *normals = malloc(sizeof(vec3) * vcount);

   for (j = 0; j < vccount; j++)
     {
        theta = j * dtheta;
        sinth = sin(theta);
        costh = cos(theta);
        for (i = 0; i < vccount; i++)
          {
             fi = i * dfi;
             sinfi = sin(fi);
             cosfi = cos(fi);
             vertices[i + j * vccount].x = r * sinth * cosfi + x;
             vertices[i + j * vccount].y = r * sinth * sinfi + y;
             vertices[i + j * vccount].z = r * costh + z;

             normals[i + j * vccount].x = sinth * cosfi;
             normals[i + j * vccount].y = sinth * sinfi;
             normals[i + j * vccount].z = costh;
          }
     }

   indices = malloc(sizeof(short) * icount);
   index = &indices[0];

   for(j = 0; j < p; j++)
     for(i = 0; i < p; i++)
       {
          *index++ = (unsigned short)(i + vccount * j);
          *index++ = i + vccount * (j + 1);
          *index++ = i + 1 + vccount * (j + 1);

          *index++ =  i + vccount * j;
          *index++ =  i + 1 +  vccount * j;
          *index++ =  i + vccount * (j + 1) + 1;
       }

   eo_do(mesh, evas_3d_mesh_vertex_count_set(vcount),
            evas_3d_mesh_frame_add(0);
            evas_3d_mesh_frame_vertex_data_set(0, EVAS_3D_VERTEX_POSITION,
                                       sizeof(vec3), &vertices[0]);
            evas_3d_mesh_frame_vertex_data_set(0, EVAS_3D_VERTEX_NORMAL,
                                       sizeof(vec3), &normals[0]);
            evas_3d_mesh_index_data_set(EVAS_3D_INDEX_FORMAT_UNSIGNED_SHORT,
                                icount , &indices[0]);
            evas_3d_mesh_vertex_assembly_set(EVAS_3D_VERTEX_ASSEMBLY_TRIANGLES);
            evas_3d_mesh_shade_mode_set(EVAS_3D_SHADE_MODE_PHONG);
            evas_3d_mesh_frame_material_set(0, material));
}


static void
_mesh_setup(Scene_Data *data)
{
   data->material = eo_add(EVAS_3D_MATERIAL_CLASS, evas);

   eo_do(data->material,
         evas_3d_material_enable_set(EVAS_3D_MATERIAL_AMBIENT, EINA_TRUE),
         evas_3d_material_enable_set(EVAS_3D_MATERIAL_DIFFUSE, EINA_TRUE),
         evas_3d_material_enable_set(EVAS_3D_MATERIAL_SPECULAR, EINA_TRUE),

         evas_3d_material_color_set(EVAS_3D_MATERIAL_AMBIENT, 0.2, 0.2, 0.2, 1.0),
         evas_3d_material_color_set(EVAS_3D_MATERIAL_DIFFUSE, 0.8, 0.8, 0.8, 1.0),
         evas_3d_material_color_set(EVAS_3D_MATERIAL_SPECULAR, 1.0, 1.0, 1.0, 1.0),
         evas_3d_material_shininess_set(100.0));

   data->mesh = eo_add(EVAS_3D_MESH_CLASS, evas);
   data->mesh1 = eo_add(EVAS_3D_MESH_CLASS, evas);


   _set_ball(data->mesh, 1, 4, 0, 0, 100, data->material);
   _set_ball(data->mesh1, 2, 0, 0, 0, 100, data->material);

   data->mesh_node =
      eo_add_custom(EVAS_3D_NODE_CLASS, evas,
                    evas_3d_node_constructor(EVAS_3D_NODE_TYPE_MESH));

   eo_do(data->root_node, evas_3d_node_member_add(data->mesh_node));
   eo_do(data->mesh_node, evas_3d_node_mesh_add(data->mesh));

   data->mesh_node1 =
      eo_add_custom(EVAS_3D_NODE_CLASS, evas,
                    evas_3d_node_constructor(EVAS_3D_NODE_TYPE_MESH));

   eo_do(data->root_node, evas_3d_node_member_add(data->mesh_node1));
   eo_do(data->mesh_node1, evas_3d_node_mesh_add(data->mesh1));

   eo_do(data->mesh, evas_3d_mesh_fog_enable_set(EINA_TRUE), evas_3d_mesh_fog_color_set(FOG_COLOR, FOG_FACTOR));
   eo_do(data->mesh1, evas_3d_mesh_fog_enable_set(EINA_TRUE), evas_3d_mesh_fog_color_set(FOG_COLOR, FOG_FACTOR));
}

static void
_scene_setup(Scene_Data *data)
{
   data->scene = eo_add(EVAS_3D_SCENE_CLASS, evas);

   eo_do(data->scene,
         evas_3d_scene_size_set(WIDTH, HEIGHT);
         evas_3d_scene_background_color_set(FOG_COLOR, 1));

   data->root_node =
      eo_add_custom(EVAS_3D_NODE_CLASS, evas,
                    evas_3d_node_constructor(EVAS_3D_NODE_TYPE_NODE));

   _camera_setup(data);
   _light_setup(data);
   _mesh_setup(data);

   eo_do(data->scene,
         evas_3d_scene_root_node_set(data->root_node),
         evas_3d_scene_camera_node_set(data->camera_node));
}

int
main(void)
{

   //Unless Evas 3D supports Software renderer, we set gl backened forcely.
   setenv("ECORE_EVAS_ENGINE", "opengl_x11", 1);
   Scene_Data data;
   Ecore_Animator *anim;

   if (!ecore_evas_init()) return 0;

   ecore_evas = ecore_evas_new("opengl_x11", 10, 10, WIDTH, HEIGHT, NULL);

   if (!ecore_evas) return 0;

   ecore_evas_callback_delete_request_set(ecore_evas, _on_delete);
   ecore_evas_callback_resize_set(ecore_evas, _on_canvas_resize);
   ecore_evas_show(ecore_evas);

   evas = ecore_evas_get(ecore_evas);

   _scene_setup(&data);

   /* Add a background rectangle objects. */
   background = eo_add(EVAS_RECTANGLE_CLASS, evas);
   eo_unref(background);
   eo_do(background,
         evas_obj_color_set(0, 0, 0, 255),
         evas_obj_size_set(WIDTH, HEIGHT),
         evas_obj_visibility_set(EINA_TRUE));

   /* Add an image object for 3D scene rendering. */
   image = evas_object_image_filled_add(evas);

   eo_do(image,
         evas_obj_size_set(WIDTH, HEIGHT),
         evas_obj_visibility_set(EINA_TRUE));

   /* Set the image object as render target for 3D scene. */
   eo_do(image, evas_obj_image_scene_set(data.scene));


   /* Add animation timer callback. */
   ecore_animator_frametime_set(0.008);
   anim = ecore_animator_add(_animate_scene, &data);

   /* Enter main loop. */
   ecore_main_loop_begin();

   ecore_evas_free(ecore_evas);
   ecore_evas_shutdown();
   ecore_animator_del(anim);

   return 0;
}