3Dgs Box2D wrapper

//////////////////////////////
// @file
// Test - using box2D with entities
//
// Entity movement is constrained in y, z axis - Corresponding to box2D x, y
//////////////////////////////

#include <acknex.h>
#include <default.c>

#include "ackb2d.h"

#define PI 3.14159265
#define INV_PI 0.318309886

// Variables
b2World *world = NULL;
VECTOR gravity;
var phys_scale = 30;

// Box update function
void box_update()
{
	// The current entity body
	b2Body *box_body = NULL;
	
	// Create a box2D representation for the entity
	b2BodyDef *bodyDef = NULL;
	bodyDef = b2BodyDef_Create();
	b2BodyDef_SetType(bodyDef, B2_DYNAMICBODY);
	b2BodyDef_SetPosition(bodyDef, vector(-my->y / phys_scale, my->z / phys_scale, 0.0));
	// Body
	box_body = b2World_CreateBody(world, bodyDef);
	
	/// Box Polygon
	b2PolygonShape *dynamicBox = NULL;
	dynamicBox = b2PolygonShape_Create();
	b2PolygonShape_SetAsBox1(dynamicBox, 8 / phys_scale, 8 / phys_scale);
	
	// Fixture
	b2FixtureDef *fixtureDef = NULL;
	fixtureDef = b2FixtureDef_Create();
	b2FixtureDef_SetShape(fixtureDef, dynamicBox);
	b2FixtureDef_SetDensity(fixtureDef, 1.0);
	b2FixtureDef_SetRestitution(fixtureDef, 0.2);
	b2FixtureDef_SetFriction(fixtureDef, 0.3);
	
	b2Body_CreateFixture(box_body, fixtureDef);
	
	// Destroy unused objects
	b2BodyDef_Destroy(bodyDef);
	b2PolygonShape_Destroy(dynamicBox);
	b2FixtureDef_Destroy(fixtureDef);
		
	// Color entity
	set(my, LIGHT);
	vec_set(my->blue, vector(10+random(150), random(10), random(150)));
	
	// Display shadow
	set(my, SHADOW);
	
	VECTOR position;
	var angle;
	
	while(1)
	{
		// Get properties from physics engine
		b2Body_GetPosition(box_body, &position);
		angle = b2Body_GetAngle(box_body);
		
		// Copy changes into shape objects
		vec_set(my.x, vector(0, position.x * phys_scale, position.y * phys_scale));
		my->roll = 180 * angle * INV_PI;
		
		wait(1);
	}
}

// Sphere update function
void sphere_update()
{
	// The current entity body
	b2Body *box_body = NULL;
	
	// Create a box2D representation for the entity
	b2BodyDef *bodyDef = NULL;
	bodyDef = b2BodyDef_Create();
	b2BodyDef_SetType(bodyDef, B2_DYNAMICBODY);
	b2BodyDef_SetPosition(bodyDef, vector(-my->y / phys_scale, my->z / phys_scale, 0.0));
	// Body
	box_body = b2World_CreateBody(world, bodyDef);
	
	/// Box circle
	b2CircleShape *dynamicCircle = b2CircleShape_Create();
	b2CircleShape_SetRadius(dynamicCircle, 8 / phys_scale);
	
	// Fixture
	b2FixtureDef *fixtureDef = NULL;
	fixtureDef = b2FixtureDef_Create();
	b2FixtureDef_SetShape(fixtureDef, dynamicCircle);
	b2FixtureDef_SetDensity(fixtureDef, 1.0);
	b2FixtureDef_SetRestitution(fixtureDef, 0.6);
	b2FixtureDef_SetFriction(fixtureDef, 0.3);
	
	b2Body_CreateFixture(box_body, fixtureDef);
	
	// Destroy unused objects
	b2BodyDef_Destroy(bodyDef);
	b2CircleShape_Destroy(dynamicCircle);
	b2FixtureDef_Destroy(fixtureDef);
		
	// Color entity
	set(my, LIGHT);
	vec_set(my->blue, vector(10+random(150), random(10), random(150)));
	
	// Display shadow
	set(my, SHADOW);
	
	VECTOR position;
	var angle;
	
	while(1)
	{
		// Get properties from physics engine
		b2Body_GetPosition(box_body, &position);
		angle = b2Body_GetAngle(box_body);
		
		// Copy changes into shape objects
		vec_set(my.x, vector(0, position.x * phys_scale, position.y * phys_scale));
		my->roll = 180 * angle * INV_PI;
		
		wait(1);
	}
}

//////////////////////////////
// Close engine on escape
//////////////////////////////
void esc_handler()
{
	//////////////////////////////
	// Destroy world
	//////////////////////////////	
	b2World_Destroy(world);
	sys_exit("");
}

// Main test
void main()
{
	// Set video mode
	video_mode = 4;
	// limit fps to be in sync with box2D timestep
	fps_max = 60;
	
	// Randomize
	random_seed(0);
	
	// Shadow type
	shadow_stencil = 2;
	
	// Wait for graphics to be ready
	// Wait for the execution of startup functions
	wait(1);
	
	// Set key handler
	on_esc = esc_handler;
	
	// load empty level
	level_load(NULL);
	
	vec_set(&gravity, vector(0.0, -10.0, 0.0));
	var do_sleep = 1;
	
	world = b2World_Create(&gravity, do_sleep);
	
	// Set debug draw to default
	ackDebugDraw *debug = ackDebugDraw_Create(phys_scale);
	ackDebugDraw_SetFlags(debug, E_SHAPEBIT | E_JOINTBIT);
	b2World_SetDebugDraw(world, debug);
	
	// Create entities
	ent_create("cube.mdl", vector(0, -8, 120), box_update);
	ent_create("cube.mdl", vector(0, 8, 150), box_update);
	ent_create("sphere.mdl", vector(0, -8, 200), sphere_update);
	ent_create("sphere.mdl", vector(0, 8, 200), sphere_update);
	
	// position camera
	vec_set(camera.x, vector(-212, -3, 56));
	//set(camera, ISOMETRIC);
	
	/// Body def
	b2BodyDef *groundBodyDef = NULL;
	groundBodyDef = b2BodyDef_Create();
	b2BodyDef_SetPosition(groundBodyDef, vector(0.0, -10.0, 0.0));
	
	/// Body
	b2Body *groundBody = b2World_CreateBody(world, groundBodyDef);
	// Create ground entity
	ENTITY *ground_ent = ent_create("cube.mdl", nullvector, NULL);
	//set(ground_ent, LIGHT);
	vec_set(ground_ent->blue, vector(0, 255, 255));
	
	ground_ent->scale_x = 20;
	ground_ent->scale_y = 40;
	c_updatehull(ground_ent, 1);
	ground_ent->z -= 8;
	
	/// Ground Polygon
	b2PolygonShape *groundBox = NULL;
	groundBox = b2PolygonShape_Create();
	b2PolygonShape_SetAsBox1(groundBox, 50.0, 10.0);
	
	b2Body_CreateFixture2(groundBody, groundBox, 0);
		
	var velocity_iterations = 6;
	var position_iteration = 2;
	var timeStep = 1.0 / 60.0;
	
	while(1)
	{
		// Step in 2d world
		b2World_Step(world, timeStep, velocity_iterations, position_iteration);
		b2World_ClearForces(world);
				
		wait(1);
	}
}