diff --git a/src/kekengine/cpp/common/defaults.cpp b/src/kekengine/cpp/common/defaults.cpp
index a9e2e49..9f92cfe 100644
--- a/src/kekengine/cpp/common/defaults.cpp
+++ b/src/kekengine/cpp/common/defaults.cpp
@@ -5,8 +5,6 @@
 #include "internal/ui.h"
 #include "internal/physics.h"
 
-#include <BulletCollision/CollisionDispatch/btGhostObject.h>
-
 namespace kek::Defaults {
 
 static KeyBinding
@@ -47,7 +45,7 @@ static void defaultInput(GLFWwindow *window, void *data) {
 	bool jump = false;
 	if(Input::getKeyState(keyUp) == GLFW_PRESS) {
 		direction += glm::vec3(0,1,0);
-		jump = true;
+		jump = kekData.player->onGround;
 	}
 
 	if(Input::getKeyState(keyDown) == GLFW_PRESS) {
@@ -63,7 +61,7 @@ static void defaultInput(GLFWwindow *window, void *data) {
 			btVector3 vel = kekData.player->physics->body->getLinearVelocity();
 			glm::vec3 newVel = glm::normalize(direction) * 6.0f;
 			newVel.y = vel.y();
-			if(jump) newVel.y = 6.0f;
+			if(jump) newVel.y = 2.7f;
 			kekData.player->physics->body->setLinearVelocity(Physics::fromGLM(newVel));
 		}
 	}
@@ -180,13 +178,14 @@ void init() {
 	btRigidBody *body = new btRigidBody(KEK_PLAYER_MASS, nullptr, shape);
 	body->setFriction(3);
 	body->setActivationState(DISABLE_DEACTIVATION);
-	kekData.physics->world->addRigidBody(body, KEK_PLAYER_COLLISION_GROUP, KEK_OBJECT_COLLISION_GROUP);
+	kekData.physics->world->addRigidBody(body);
 
-	btCollisionShape *jumpShape = new btBoxShape(btVector3(KEK_PLAYER_RADIUS, 0.1, KEK_PLAYER_RADIUS));
-	btCollisionObject *jumpCollider = new btGhostObject();
+	btCollisionShape *jumpShape = new btSphereShape(KEK_PLAYER_RADIUS / 2);
+	btGhostObject *jumpCollider = new btGhostObject();
 	jumpCollider->setCollisionShape(jumpShape);
+	jumpCollider->setCollisionFlags(jumpCollider->getCollisionFlags() | btCollisionObject::CF_NO_CONTACT_RESPONSE);
 	jumpCollider->setActivationState(DISABLE_DEACTIVATION);
-	kekData.physics->world->addCollisionObject(jumpCollider, KEK_PLAYER_COLLISION_GROUP, KEK_OBJECT_COLLISION_GROUP);
+	kekData.physics->world->addCollisionObject(jumpCollider);
 
 	kekData.player->physics = new PlayerPhysicsObjectData();
 	kekData.player->physics->body = body;
diff --git a/src/kekengine/cpp/object/gameobject.cpp b/src/kekengine/cpp/object/gameobject.cpp
index 52e0a34..58b8bf0 100644
--- a/src/kekengine/cpp/object/gameobject.cpp
+++ b/src/kekengine/cpp/object/gameobject.cpp
@@ -38,7 +38,7 @@ void GameObject::addPhysics(btCollisionShape *shape, float mass, int collisionFl
 	shape->calculateLocalInertia(mass, inertia);
 	btRigidBody *body = new btRigidBody(mass, new btDefaultMotionState(), shape, inertia);
 	body->setFriction(1);
-	kekData.physics->world->addRigidBody(body, KEK_OBJECT_COLLISION_GROUP, KEK_OBJECT_COLLISION_GROUP | KEK_PLAYER_COLLISION_GROUP);
+	kekData.physics->world->addRigidBody(body);
 	body->setCollisionFlags(body->getCollisionFlags() | collisionFlags);
 	this->physics->body = body;
 }
diff --git a/src/kekengine/cpp/object/player.cpp b/src/kekengine/cpp/object/player.cpp
index bf5daa0..f9224dc 100644
--- a/src/kekengine/cpp/object/player.cpp
+++ b/src/kekengine/cpp/object/player.cpp
@@ -6,6 +6,7 @@ namespace kek {
 
 Player::Player(): RotateableObject() {
 	this->noclip = false;
+	this->onGround = false;
 }
 
 void Player::rotateTo(glm::quat rotation) {
diff --git a/src/kekengine/cpp/physics/physics.cpp b/src/kekengine/cpp/physics/physics.cpp
index 1d28ea3..6973b58 100644
--- a/src/kekengine/cpp/physics/physics.cpp
+++ b/src/kekengine/cpp/physics/physics.cpp
@@ -15,6 +15,7 @@ void init() {
 	btBroadphaseInterface *overlappingPairCache = new btDbvtBroadphase();
 	btSequentialImpulseConstraintSolver *solver = new btSequentialImpulseConstraintSolver();
 	kekData.physics->world = new btDiscreteDynamicsWorld(dispatcher, overlappingPairCache, solver, collisionConf);
+	kekData.physics->world->getBroadphase()->getOverlappingPairCache()->setInternalGhostPairCallback(new btGhostPairCallback());
 	kekData.physics->world->setGravity(btVector3(0, -10, 0));
 }
 
@@ -37,8 +38,12 @@ void step(float deltaT) {
 		}
 	}
 
+	kekData.player->physics->jumpCollider->getWorldTransform().setOrigin(Physics::fromGLM(kekData.player->getFootPosition() + glm::vec3(0, KEK_PLAYER_RADIUS / 2, 0)));
+
 	kekData.physics->world->stepSimulation(deltaT, 100);
 
+	kekData.player->onGround = kekData.player->physics->jumpCollider->getNumOverlappingObjects() > 1; // TODO: improve
+
 	if(!kekData.player->noclip) {
 		kekData.activeCamera->moveTo(kekData.player->getEyePosition());
 	}
diff --git a/src/kekengine/include/constants.h b/src/kekengine/include/constants.h
index 33d8100..e2d36fb 100644
--- a/src/kekengine/include/constants.h
+++ b/src/kekengine/include/constants.h
@@ -47,5 +47,3 @@
 #define KEK_PLAYER_RADIUS 0.5f
 #define KEK_PLAYER_EYE_OFFSET (KEK_PLAYER_HEIGHT / 2 - KEK_PLAYER_RADIUS)
 #define KEK_PLAYER_MASS 50
-#define KEK_OBJECT_COLLISION_GROUP 1
-#define KEK_PLAYER_COLLISION_GROUP 2
diff --git a/src/kekengine/include/internal/physics.h b/src/kekengine/include/internal/physics.h
index 6a211bf..077c190 100644
--- a/src/kekengine/include/internal/physics.h
+++ b/src/kekengine/include/internal/physics.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <btBulletDynamicsCommon.h>
+#include <BulletCollision/CollisionDispatch/btGhostObject.h>
 
 namespace kek {
 
@@ -13,7 +14,7 @@ struct PhysicsObjectData {
 };
 
 struct PlayerPhysicsObjectData: public PhysicsObjectData {
-	btCollisionObject *jumpCollider;
+	btGhostObject *jumpCollider;
 };
 
 namespace Physics {
diff --git a/src/kekengine/include/player.h b/src/kekengine/include/player.h
index 5e997d3..24a79ef 100644
--- a/src/kekengine/include/player.h
+++ b/src/kekengine/include/player.h
@@ -9,6 +9,7 @@ class Player: public RotateableObject {
 public:
 	PlayerPhysicsObjectData *physics;
 	bool noclip;
+	bool onGround;
 
 	Player();