bring back pre-0.30 player controls

src/physics/Hitbox.hpp

@@ -58,7 +58,6 @@ struct Hitbox {
     glm::vec3 velocity;
     glm::vec3 scale {1.0f, 1.0f, 1.0f};
     float linearDamping = 0.5;
-    float friction = 1.0f;
     float verticalDamping = 1.0f;
     bool grounded = false;
     float gravityScale = 1.0f;
@@ -68,7 +67,10 @@ struct Hitbox {
     float elasticity = 0.0f;
     std::string material;
     std::string groundMaterial;
+
+    // FIXME: only one must survive
     glm::vec3 groundVelocity {};
+    glm::vec3 actualGroundVelocity {};
     
     glm::vec3 prevPosition {};
     glm::vec3 prevVelocity {};
@@ -94,4 +96,8 @@ struct Hitbox {
             prevPosition = vec;
         }
     }
+
+    glm::vec3 getSurfaceVelocity() const {
+        return velocity - actualGroundVelocity;
+    }
 };

src/physics/PhysicsSolver.cpp

@@ -396,10 +396,11 @@ void PhysicsSolver::step(
     }
 
     for (auto hitbox : hitboxes) {
-        float linearDamping = hitbox->linearDamping * hitbox->friction;
+        float linearDamping = hitbox->linearDamping;
 
         glm::vec3& vel = hitbox->velocity;
-        auto diff = hitbox->groundVelocity / dt - vel;
+        hitbox->actualGroundVelocity = hitbox->groundVelocity / dt;
+        auto diff = hitbox->actualGroundVelocity - vel;
         vel.x += diff.x * delta * linearDamping;
         vel.z += diff.z * delta * linearDamping;
 
@@ -411,9 +412,6 @@ void PhysicsSolver::step(
         }
         
         updateSensors(*hitbox);
-        hitbox->friction = glm::abs(hitbox->gravityScale <= 1e-7f)
-                        ? 8.0f
-                        : (!hitbox->prevGrounded ? 2.0f : 10.0f);
     }
 }