applying velocity of ground the worst way possible

src/logic/PlayerController.cpp

@@ -229,8 +229,8 @@ PlayerController::PlayerController(
 }
 
 void PlayerController::onFootstep(const Hitbox& hitbox) {
-    auto pos = hitbox.position;
-    auto half = hitbox.halfsize;
+    const auto& pos = hitbox.position;
+    const auto& half = hitbox.getHalfSize();
 
     for (int offsetZ = -1; offsetZ <= 1; offsetZ++) {
         for (int offsetX = -1; offsetX <= 1; offsetX++) {

src/logic/scripting/lua/libs/lib__transform.cpp

@@ -31,7 +31,7 @@ static int l_set_pos(lua::State* L) {
         auto vec = lua::tovec3(L, 2);
         check_valid(vec);
         entity->getTransform().setPos(vec);
-        entity->getRigidbody().hitbox.position = vec;
+        entity->getRigidbody().hitbox.setPos(vec);
     }
     return 0;
 }

src/objects/Entities.cpp

@@ -316,30 +316,36 @@ void Entities::updatePhysics(float delta) {
 
     auto view = registry->view<EntityId, Transform, Rigidbody>();
     auto physics = level.physics.get();
-    for (auto [entity, eid, transform, rigidbody] : view.each()) {
-        if (!rigidbody.enabled || rigidbody.hitbox.type == BodyType::STATIC) {
-            continue;
-        }
-        auto& hitbox = rigidbody.hitbox;
-        auto prevVel = hitbox.velocity;
-        bool grounded = hitbox.grounded;
 
-        float vel = glm::length(prevVel);
-        int substeps = static_cast<int>(delta * vel * 20);
-        substeps = std::min(100, std::max(2, substeps));
-        physics->step(*level.chunks, hitbox, delta, substeps, eid.uid);
-        hitbox.friction = glm::abs(hitbox.gravityScale <= 1e-7f)
-                              ? 8.0f
-                              : (!grounded ? 2.0f : 10.0f);
-        hitbox.scale = transform.size;
-        transform.setPos(hitbox.position);
-        if (hitbox.grounded && !grounded) {
-            scripting::on_entity_grounded(
-                *get(eid.uid), glm::length(prevVel - hitbox.velocity)
-            );
-        }
-        if (!hitbox.grounded && grounded) {
-            scripting::on_entity_fall(*get(eid.uid));
+    for (int solid = false; solid <= true; solid++) {
+        for (auto [entity, eid, transform, rigidbody] : view.each()) {
+            if (!rigidbody.enabled || rigidbody.hitbox.type == BodyType::STATIC) {
+                continue;
+            }
+            if (eid.def.solid == solid) {
+                continue;
+            }
+            auto& hitbox = rigidbody.hitbox;
+            auto prevVel = hitbox.velocity;
+            bool grounded = hitbox.grounded;
+
+            float vel = glm::length(prevVel);
+            int substeps = static_cast<int>(delta * vel * 20);
+            substeps = std::min(100, std::max(2, substeps));
+            physics->step(*level.chunks, hitbox, delta, substeps, eid.uid);
+            hitbox.friction = glm::abs(hitbox.gravityScale <= 1e-7f)
+                                ? 8.0f
+                                : (!grounded ? 2.0f : 10.0f);
+            hitbox.scale = transform.size;
+            transform.setPos(hitbox.position);
+            if (hitbox.grounded && !grounded) {
+                scripting::on_entity_grounded(
+                    *get(eid.uid), glm::length(prevVel - hitbox.velocity)
+                );
+            }
+            if (!hitbox.grounded && grounded) {
+                scripting::on_entity_fall(*get(eid.uid));
+            }
         }
     }
 }

src/objects/Player.cpp

@@ -114,7 +114,7 @@ void Player::teleport(glm::vec3 position) {
     this->position = position;
 
     if (auto entity = level.entities->get(eid)) {
-        entity->getRigidbody().hitbox.position = position;
+        entity->getRigidbody().hitbox.setPos(position);
         entity->getTransform().setPos(position);
         entity->setInterpolatedPosition(position);
     }

src/physics/Hitbox.cpp

@@ -6,5 +6,6 @@ Hitbox::Hitbox(BodyType type, glm::vec3 position, glm::vec3 halfsize)
   : type(type),
     position(position), 
     halfsize(halfsize), 
-    velocity(0.0f,0.0f,0.0f)
+    velocity(0.0f,0.0f,0.0f),
+    prevPosition(position)
 {}

src/physics/Hitbox.hpp

@@ -1,5 +1,7 @@
 #pragma once
 
+#define GLM_ENABLE_EXPERIMENTAL
+
 #include "maths/aabb.hpp"
 #include "typedefs.hpp"
 #include "util/EnumMetadata.hpp"
@@ -8,6 +10,7 @@
 #include <string>
 #include <functional>
 #include <glm/glm.hpp>
+#include <glm/gtx/norm.hpp>
 
 enum class SensorType {
     AABB,
@@ -62,6 +65,13 @@ struct Hitbox {
     bool crouching = false;
     float stepHeight = 0.5f;
     glm::vec3 groundVelocity {};
+    
+    // garbage tbh
+    glm::vec3 prevPosition {};
+    int substeps = 1;
+    float delta = 0.0f;
+
+    static inline constexpr float TELEPORT_THRESOLD_SQR = 0.5f;
 
     Hitbox(BodyType type, glm::vec3 position, glm::vec3 halfsize);
 
@@ -72,4 +82,11 @@ struct Hitbox {
     glm::vec3 getHalfSize() const {
         return halfsize * scale;
     }
+
+    void setPos(const glm::vec3& vec) {
+        position = vec;
+        if (glm::distance2(position, prevPosition) >= TELEPORT_THRESOLD_SQR) {
+            prevPosition = vec;
+        }
+    }
 };

src/physics/PhysicsSolver.cpp

@@ -208,7 +208,7 @@ static bool calc_collision_neg_y(
             if (pos.y < newy && glm::abs(pos.y - newy) < 0.5f) {
                 pos.y = newy;
             }
-            groundVelocty = box->velocity;
+            groundVelocty = (box->position - box->prevPosition) / box->delta;
             if (vel.y < 0.0f) {
                 vel.y = 0.0f;
                 return true;
@@ -362,8 +362,14 @@ void PhysicsSolver::calcSubstep(
     glm::vec3& vel,
     glm::vec3& pos,
     bool prevGrounded,
-    float dt
+    float dt,
+    int substeps
 ) {
+    if (hitbox.grounded) {
+        pos.x += hitbox.groundVelocity.x * dt * substeps;
+        pos.z += hitbox.groundVelocity.z * dt * substeps;
+    }
+
     auto initpos = pos;
     auto half = hitbox.getHalfSize();
     float gravityScale = hitbox.gravityScale;
@@ -434,6 +440,10 @@ void PhysicsSolver::step(
     uint substeps,
     entityid_t entity
 ) {
+    hitbox.prevPosition = hitbox.position;
+    hitbox.substeps = substeps;
+    hitbox.delta = delta;
+    
     float dt = delta / static_cast<float>(substeps);
     float linearDamping = hitbox.linearDamping * hitbox.friction;
 
@@ -443,12 +453,7 @@ void PhysicsSolver::step(
     bool prevGrounded = hitbox.grounded;
     hitbox.grounded = false;
     for (uint i = 0; i < substeps; i++) {
-        calcSubstep(chunks, hitbox, vel, pos, prevGrounded, dt);
-    }
-
-    if (prevGrounded && !hitbox.grounded) {
-        vel += hitbox.groundVelocity;
-        hitbox.groundVelocity = {};
+        calcSubstep(chunks, hitbox, vel, pos, prevGrounded, dt, substeps);
     }
 
     vel.x /= 1.0f + delta * linearDamping;
@@ -456,6 +461,11 @@ void PhysicsSolver::step(
     if (hitbox.verticalDamping > 0.0f) {
         vel.y /= 1.0f + delta * linearDamping * hitbox.verticalDamping;
     }
+    if (prevGrounded && !hitbox.grounded) {
+        auto appliedVelocity = hitbox.groundVelocity;
+        vel += appliedVelocity;
+        hitbox.groundVelocity = {};
+    }
 
     AABB aabb;
     aabb.a = pos - hitbox.getHalfSize();

src/physics/PhysicsSolver.hpp

@@ -53,6 +53,7 @@ private:
         glm::vec3& vel,
         glm::vec3& pos,
         bool prevGrounded,
-        float dt
+        float dt,
+        int substeps
     );
 };