EPhysics

Date
  2012 (created)

# Table of Contents

- Introduction
- How to compile
- Next Steps
- Introductory Example

# Introduction

EPhysics is a library that makes it easy to use Ecore, Evas and Bullet Physics together. It's a kind of wrapper, a glue, between these libraries. It's not intended to be a physics library (we already have many out there).

# How to compile

Ephysics is a library your application links to. The procedure for this is very simple. You simply have to compile your application with the appropriate compiler flags that the `pkg-config` script outputs. For example:

Compiling C or C++ files into object files:

    gcc -c -o main.o main.c `pkg-config --cflags ephysics`

Linking object files into a binary executable:

    gcc -o my_application main.o `pkg-config --libs ephysics`

See pkgconfig

# Next Steps

After you understood what EPhysics is and installed it in your system you should proceed understanding the programming interface.

Recommended reading:

- EPhysics
- EPhysics World
- EPhysics Body
- EPhysics Camera
- EPhysics Constraint
- EPhysics Quaternion
- EPhysics Shape

# Introductory Example

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "ephysics_test.h"
static Eina_Bool
_on_keydown(void *data, Evas_Object *obj __UNUSED__, Evas_Object *src __UNUSED__, Evas_Callback_Type type, void *event_info)
{
Evas_Event_Key_Down *ev = event_info;
EPhysics_Body *body = data;
if (type != EVAS_CALLBACK_KEY_UP)
return EINA_FALSE;
if (strcmp(ev->key, "Up") == 0)
ephysics_body_central_impulse_apply(body, 0, -300, 0);
else if (strcmp(ev->key, "Down") == 0)
ephysics_body_central_impulse_apply(body, 0, 300, 0);
else if (strcmp(ev->key, "Right") == 0)
ephysics_body_central_impulse_apply(body, 300, 0, 0);
else if (strcmp(ev->key, "Left") == 0)
ephysics_body_central_impulse_apply(body, -300, 0, 0);
return EINA_TRUE;
}
static void
_world_populate(Test_Data *test_data)
{
Evas_Object *sphere, *shadow;
EPhysics_Body *fall_body;
shadow = elm_layout_add(test_data->win);
elm_layout_file_set(
shadow, PACKAGE_DATA_DIR "/" EPHYSICS_TEST_THEME ".edj", "shadow-ball");
evas_object_move(shadow, WIDTH / 3, FLOOR_Y);
evas_object_resize(shadow, 70, 3);
evas_object_show(shadow);
test_data->evas_objs = eina_list_append(test_data->evas_objs, shadow);
sphere = elm_image_add(test_data->win);
elm_image_file_set(
sphere, PACKAGE_DATA_DIR "/" EPHYSICS_TEST_THEME ".edj", "big-blue-ball");
evas_object_move(sphere, WIDTH / 3, HEIGHT / 8);
evas_object_resize(sphere, 70, 70);
evas_object_show(sphere);
test_data->evas_objs = eina_list_append(test_data->evas_objs, sphere);
fall_body = ephysics_body_sphere_add(test_data->world);
ephysics_body_evas_object_set(fall_body, sphere, EINA_TRUE);
ephysics_body_restitution_set(fall_body, 0.95);
ephysics_body_friction_set(fall_body, 0.1);
ephysics_body_event_callback_add(fall_body, EPHYSICS_CALLBACK_BODY_UPDATE,
update_object_cb, shadow);
test_data->bodies = eina_list_append(test_data->bodies, fall_body);
test_data->data = fall_body;
}
static void
_restart(void *data, Evas_Object *obj __UNUSED__, const char *emission __UNUSED__, const char *source __UNUSED__)
{
Test_Data *test_data = data;
DBG("Restart pressed");
elm_object_event_callback_del(test_data->win, _on_keydown, test_data->data);
test_clean(test_data);
_world_populate(test_data);
elm_object_event_callback_add(test_data->win, _on_keydown, test_data->data);
}
void
test_bouncing_ball(void *data __UNUSED__, Evas_Object *obj __UNUSED__, void *event_info __UNUSED__)
{
EPhysics_Body *boundary;
EPhysics_World *world;
Test_Data *test_data;
if (!ephysics_init())
return;
test_data = test_data_new();
test_win_add(test_data, "Bouncing Ball", EINA_TRUE);
elm_layout_signal_callback_add(test_data->layout, "restart", "test-theme",
_restart, test_data);
elm_object_signal_emit(test_data->layout, "borders,show", "ephysics_test");
elm_object_signal_emit(test_data->layout, "arrows,show", "ephysics_test");
world = ephysics_world_new();
ephysics_world_light_all_bodies_set(world, EINA_TRUE);
ephysics_world_render_geometry_set(world, 50, 40, -50,
WIDTH - 100, FLOOR_Y - 40, DEPTH);
test_data->world = world;
boundary = ephysics_body_bottom_boundary_add(test_data->world);
ephysics_body_restitution_set(boundary, 0.65);
ephysics_body_friction_set(boundary, 4);
boundary = ephysics_body_right_boundary_add(test_data->world);
ephysics_body_restitution_set(boundary, 0.4);
ephysics_body_friction_set(boundary, 3);
boundary = ephysics_body_left_boundary_add(test_data->world);
ephysics_body_restitution_set(boundary, 0.4);
ephysics_body_friction_set(boundary, 3);
ephysics_body_top_boundary_add(test_data->world);
_world_populate(test_data);
elm_object_event_callback_add(test_data->win, _on_keydown, test_data->data);
}

More examples can be found at EPhysics Examples.