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#include "engine/physics.hpp"
#include <cstdio>
PhysicsWorld::PhysicsWorld() {
b2WorldDef def = b2DefaultWorldDef();
def.gravity = {0.0f, -10.0f};
world_id_ = b2CreateWorld(&def);
printf("Physics: Box2D world created\n");
}
PhysicsWorld::~PhysicsWorld() {
b2DestroyWorld(world_id_);
}
void PhysicsWorld::step(float dt) {
// High sub-step count for stable distance joint networks
b2World_Step(world_id_, dt, 8);
}
PhysicsBody* PhysicsWorld::add_static_box(b2Vec2 center,
float half_w, float half_h,
float r, float g, float b) {
b2BodyDef body_def = b2DefaultBodyDef();
body_def.type = b2_staticBody;
body_def.position = center;
b2BodyId body_id = b2CreateBody(world_id_, &body_def);
b2ShapeDef shape_def = b2DefaultShapeDef();
b2Polygon box = b2MakeBox(half_w, half_h);
b2CreatePolygonShape(body_id, &shape_def, &box);
PhysicsBody pb;
pb.id = body_id;
pb.size = {half_w, half_h};
pb.red = r;
pb.green = g;
pb.blue = b;
pb.alpha = 1.0f;
pb.is_static = true;
bodies_.push_back(pb);
return &bodies_.back();
}
PhysicsBody* PhysicsWorld::add_dynamic_box(b2Vec2 center,
float half_w, float half_h,
float r, float g, float b) {
b2BodyDef body_def = b2DefaultBodyDef();
body_def.type = b2_dynamicBody;
body_def.position = center;
b2BodyId body_id = b2CreateBody(world_id_, &body_def);
b2ShapeDef shape_def = b2DefaultShapeDef();
shape_def.density = 1.0f;
shape_def.material.friction = 0.3f;
b2Polygon box = b2MakeBox(half_w, half_h);
b2CreatePolygonShape(body_id, &shape_def, &box);
PhysicsBody pb;
pb.id = body_id;
pb.size = {half_w, half_h};
pb.red = r;
pb.green = g;
pb.blue = b;
pb.alpha = 1.0f;
pb.is_static = false;
bodies_.push_back(pb);
return &bodies_.back();
}
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