]> git.lizzy.rs Git - minetest.git/blobdiff - src/collision.cpp
Report collisionMoveSimple for client and server. (#13105)
[minetest.git] / src / collision.cpp
index 24d22e8252ab44a3d1a75d40d079bfd936c85b11..575e70ff9375f263d1eab1ad6357dfd11d4acda7 100644 (file)
@@ -18,163 +18,175 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "collision.h"
+#include <cmath>
 #include "mapblock.h"
 #include "map.h"
 #include "nodedef.h"
 #include "gamedef.h"
 #ifndef SERVER
-#include "clientenvironment.h"
+#include "client/clientenvironment.h"
+#include "client/localplayer.h"
 #endif
 #include "serverenvironment.h"
-#include "serverobject.h"
+#include "server/serveractiveobject.h"
 #include "util/timetaker.h"
 #include "profiler.h"
 
-// float error is 10 - 9.96875 = 0.03125
-//#define COLL_ZERO 0.032 // broken unit tests
-#define COLL_ZERO 0
-
+#ifdef __FAST_MATH__
+#warning "-ffast-math is known to cause bugs in collision code, do not use!"
+#endif
 
 struct NearbyCollisionInfo {
-       NearbyCollisionInfo(bool is_ul, bool is_obj, int bouncy,
-                       const v3s16 &pos, const aabb3f &box) :
+       // node
+       NearbyCollisionInfo(bool is_ul, int bouncy, const v3s16 &pos,
+                       const aabb3f &box) :
                is_unloaded(is_ul),
-               is_object(is_obj),
+               obj(nullptr),
                bouncy(bouncy),
                position(pos),
                box(box)
        {}
 
+       // object
+       NearbyCollisionInfo(ActiveObject *obj, int bouncy,
+                       const aabb3f &box) :
+               is_unloaded(false),
+               obj(obj),
+               bouncy(bouncy),
+               box(box)
+       {}
+
+       inline bool isObject() const { return obj != nullptr; }
+
        bool is_unloaded;
        bool is_step_up = false;
-       bool is_object;
+       ActiveObject *obj;
        int bouncy;
        v3s16 position;
        aabb3f box;
 };
 
+// Helper functions:
+// Truncate floating point numbers to specified number of decimal places
+// in order to move all the floating point error to one side of the correct value
+static inline f32 truncate(const f32 val, const f32 factor)
+{
+       return truncf(val * factor) / factor;
+}
+
+static inline v3f truncate(const v3f& vec, const f32 factor)
+{
+       return v3f(
+               truncate(vec.X, factor),
+               truncate(vec.Y, factor),
+               truncate(vec.Z, factor)
+       );
+}
 
 // Helper function:
 // Checks for collision of a moving aabbox with a static aabbox
 // Returns -1 if no collision, 0 if X collision, 1 if Y collision, 2 if Z collision
 // The time after which the collision occurs is stored in dtime.
-int axisAlignedCollision(
+CollisionAxis axisAlignedCollision(
                const aabb3f &staticbox, const aabb3f &movingbox,
-               const v3f &speed, f32 d, f32 *dtime)
+               const v3f &speed, f32 *dtime)
 {
        //TimeTaker tt("axisAlignedCollision");
 
-       f32 xsize = (staticbox.MaxEdge.X - staticbox.MinEdge.X) - COLL_ZERO;     // reduce box size for solve collision stuck (flying sand)
-       f32 ysize = (staticbox.MaxEdge.Y - staticbox.MinEdge.Y); // - COLL_ZERO; // Y - no sense for falling, but maybe try later
-       f32 zsize = (staticbox.MaxEdge.Z - staticbox.MinEdge.Z) - COLL_ZERO;
-
        aabb3f relbox(
-                       movingbox.MinEdge.X - staticbox.MinEdge.X,
-                       movingbox.MinEdge.Y - staticbox.MinEdge.Y,
-                       movingbox.MinEdge.Z - staticbox.MinEdge.Z,
-                       movingbox.MaxEdge.X - staticbox.MinEdge.X,
-                       movingbox.MaxEdge.Y - staticbox.MinEdge.Y,
-                       movingbox.MaxEdge.Z - staticbox.MinEdge.Z
+                       (movingbox.MaxEdge.X - movingbox.MinEdge.X) + (staticbox.MaxEdge.X - staticbox.MinEdge.X),                                              // sum of the widths
+                       (movingbox.MaxEdge.Y - movingbox.MinEdge.Y) + (staticbox.MaxEdge.Y - staticbox.MinEdge.Y),
+                       (movingbox.MaxEdge.Z - movingbox.MinEdge.Z) + (staticbox.MaxEdge.Z - staticbox.MinEdge.Z),
+                       std::max(movingbox.MaxEdge.X, staticbox.MaxEdge.X) - std::min(movingbox.MinEdge.X, staticbox.MinEdge.X),        //outer bounding 'box' dimensions
+                       std::max(movingbox.MaxEdge.Y, staticbox.MaxEdge.Y) - std::min(movingbox.MinEdge.Y, staticbox.MinEdge.Y),
+                       std::max(movingbox.MaxEdge.Z, staticbox.MaxEdge.Z) - std::min(movingbox.MinEdge.Z, staticbox.MinEdge.Z)
        );
 
-       if(speed.X > 0) // Check for collision with X- plane
-       {
-               if (relbox.MaxEdge.X <= d) {
-                       *dtime = -relbox.MaxEdge.X / speed.X;
-                       if ((relbox.MinEdge.Y + speed.Y * (*dtime) < ysize) &&
-                                       (relbox.MaxEdge.Y + speed.Y * (*dtime) > COLL_ZERO) &&
-                                       (relbox.MinEdge.Z + speed.Z * (*dtime) < zsize) &&
-                                       (relbox.MaxEdge.Z + speed.Z * (*dtime) > COLL_ZERO))
-                               return 0;
-               }
-               else if(relbox.MinEdge.X > xsize)
-               {
-                       return -1;
-               }
-       }
-       else if(speed.X < 0) // Check for collision with X+ plane
-       {
-               if (relbox.MinEdge.X >= xsize - d) {
-                       *dtime = (xsize - relbox.MinEdge.X) / speed.X;
-                       if ((relbox.MinEdge.Y + speed.Y * (*dtime) < ysize) &&
-                                       (relbox.MaxEdge.Y + speed.Y * (*dtime) > COLL_ZERO) &&
-                                       (relbox.MinEdge.Z + speed.Z * (*dtime) < zsize) &&
-                                       (relbox.MaxEdge.Z + speed.Z * (*dtime) > COLL_ZERO))
-                               return 0;
+       const f32 dtime_max = *dtime;
+       f32 inner_margin;               // the distance of clipping recovery
+       f32 distance;
+       f32 time;
+
+
+       if (speed.Y) {
+               distance = relbox.MaxEdge.Y - relbox.MinEdge.Y;
+               *dtime = distance / std::abs(speed.Y);
+               time = std::max(*dtime, 0.0f);
+
+               if (*dtime <= dtime_max) {
+                       inner_margin = std::max(-0.5f * (staticbox.MaxEdge.Y - staticbox.MinEdge.Y), -2.0f);
+
+                       if ((speed.Y > 0 && staticbox.MinEdge.Y - movingbox.MaxEdge.Y > inner_margin) ||
+                               (speed.Y < 0 && movingbox.MinEdge.Y - staticbox.MaxEdge.Y > inner_margin)) {
+                               if (
+                                       (std::max(movingbox.MaxEdge.X + speed.X * time, staticbox.MaxEdge.X)
+                                               - std::min(movingbox.MinEdge.X + speed.X * time, staticbox.MinEdge.X)
+                                               - relbox.MinEdge.X < 0) &&
+                                               (std::max(movingbox.MaxEdge.Z + speed.Z * time, staticbox.MaxEdge.Z)
+                                                       - std::min(movingbox.MinEdge.Z + speed.Z * time, staticbox.MinEdge.Z)
+                                                       - relbox.MinEdge.Z < 0)
+                                       )
+                                       return COLLISION_AXIS_Y;
+                       }
                }
-               else if(relbox.MaxEdge.X < 0)
-               {
-                       return -1;
+               else {
+                       return COLLISION_AXIS_NONE;
                }
        }
 
        // NO else if here
 
-       if(speed.Y > 0) // Check for collision with Y- plane
-       {
-               if (relbox.MaxEdge.Y <= d) {
-                       *dtime = -relbox.MaxEdge.Y / speed.Y;
-                       if ((relbox.MinEdge.X + speed.X * (*dtime) < xsize) &&
-                                       (relbox.MaxEdge.X + speed.X * (*dtime) > COLL_ZERO) &&
-                                       (relbox.MinEdge.Z + speed.Z * (*dtime) < zsize) &&
-                                       (relbox.MaxEdge.Z + speed.Z * (*dtime) > COLL_ZERO))
-                               return 1;
-               }
-               else if(relbox.MinEdge.Y > ysize)
-               {
-                       return -1;
-               }
-       }
-       else if(speed.Y < 0) // Check for collision with Y+ plane
-       {
-               if (relbox.MinEdge.Y >= ysize - d) {
-                       *dtime = (ysize - relbox.MinEdge.Y) / speed.Y;
-                       if ((relbox.MinEdge.X + speed.X * (*dtime) < xsize) &&
-                                       (relbox.MaxEdge.X + speed.X * (*dtime) > COLL_ZERO) &&
-                                       (relbox.MinEdge.Z + speed.Z * (*dtime) < zsize) &&
-                                       (relbox.MaxEdge.Z + speed.Z * (*dtime) > COLL_ZERO))
-                               return 1;
-               }
-               else if(relbox.MaxEdge.Y < 0)
-               {
-                       return -1;
+       if (speed.X) {
+               distance = relbox.MaxEdge.X - relbox.MinEdge.X;
+               *dtime = distance / std::abs(speed.X);
+               time = std::max(*dtime, 0.0f);
+
+               if (*dtime <= dtime_max) {
+                       inner_margin = std::max(-0.5f * (staticbox.MaxEdge.X - staticbox.MinEdge.X), -2.0f);
+
+                       if ((speed.X > 0 && staticbox.MinEdge.X - movingbox.MaxEdge.X > inner_margin) ||
+                               (speed.X < 0 && movingbox.MinEdge.X - staticbox.MaxEdge.X > inner_margin)) {
+                               if (
+                                       (std::max(movingbox.MaxEdge.Y + speed.Y * time, staticbox.MaxEdge.Y)
+                                               - std::min(movingbox.MinEdge.Y + speed.Y * time, staticbox.MinEdge.Y)
+                                               - relbox.MinEdge.Y < 0) &&
+                                               (std::max(movingbox.MaxEdge.Z + speed.Z * time, staticbox.MaxEdge.Z)
+                                                       - std::min(movingbox.MinEdge.Z + speed.Z * time, staticbox.MinEdge.Z)
+                                                       - relbox.MinEdge.Z < 0)
+                                       )
+                                       return COLLISION_AXIS_X;
+                       }
+               } else {
+                       return COLLISION_AXIS_NONE;
                }
        }
 
        // NO else if here
 
-       if(speed.Z > 0) // Check for collision with Z- plane
-       {
-               if (relbox.MaxEdge.Z <= d) {
-                       *dtime = -relbox.MaxEdge.Z / speed.Z;
-                       if ((relbox.MinEdge.X + speed.X * (*dtime) < xsize) &&
-                                       (relbox.MaxEdge.X + speed.X * (*dtime) > COLL_ZERO) &&
-                                       (relbox.MinEdge.Y + speed.Y * (*dtime) < ysize) &&
-                                       (relbox.MaxEdge.Y + speed.Y * (*dtime) > COLL_ZERO))
-                               return 2;
-               }
-               //else if(relbox.MinEdge.Z > zsize)
-               //{
-               //      return -1;
-               //}
-       }
-       else if(speed.Z < 0) // Check for collision with Z+ plane
-       {
-               if (relbox.MinEdge.Z >= zsize - d) {
-                       *dtime = (zsize - relbox.MinEdge.Z) / speed.Z;
-                       if ((relbox.MinEdge.X + speed.X * (*dtime) < xsize) &&
-                                       (relbox.MaxEdge.X + speed.X * (*dtime) > COLL_ZERO) &&
-                                       (relbox.MinEdge.Y + speed.Y * (*dtime) < ysize) &&
-                                       (relbox.MaxEdge.Y + speed.Y * (*dtime) > COLL_ZERO))
-                               return 2;
+       if (speed.Z) {
+               distance = relbox.MaxEdge.Z - relbox.MinEdge.Z;
+               *dtime = distance / std::abs(speed.Z);
+               time = std::max(*dtime, 0.0f);
+
+               if (*dtime <= dtime_max) {
+                       inner_margin = std::max(-0.5f * (staticbox.MaxEdge.Z - staticbox.MinEdge.Z), -2.0f);
+
+                       if ((speed.Z > 0 && staticbox.MinEdge.Z - movingbox.MaxEdge.Z > inner_margin) ||
+                               (speed.Z < 0 && movingbox.MinEdge.Z - staticbox.MaxEdge.Z > inner_margin)) {
+                               if (
+                                       (std::max(movingbox.MaxEdge.X + speed.X * time, staticbox.MaxEdge.X)
+                                               - std::min(movingbox.MinEdge.X + speed.X * time, staticbox.MinEdge.X)
+                                               - relbox.MinEdge.X < 0) &&
+                                               (std::max(movingbox.MaxEdge.Y + speed.Y * time, staticbox.MaxEdge.Y)
+                                                       - std::min(movingbox.MinEdge.Y + speed.Y * time, staticbox.MinEdge.Y)
+                                                       - relbox.MinEdge.Y < 0)
+                                       )
+                                       return COLLISION_AXIS_Z;
+                       }
                }
-               //else if(relbox.MaxEdge.Z < 0)
-               //{
-               //      return -1;
-               //}
        }
 
-       return -1;
+       return COLLISION_AXIS_NONE;
 }
 
 // Helper function:
@@ -205,7 +217,7 @@ bool wouldCollideWithCeiling(
 static inline void getNeighborConnectingFace(const v3s16 &p,
        const NodeDefManager *nodedef, Map *map, MapNode n, int v, int *neighbors)
 {
-       MapNode n2 = map->getNodeNoEx(p);
+       MapNode n2 = map->getNode(p);
        if (nodedef->nodeboxConnects(n, n2, v))
                *neighbors |= v;
 }
@@ -217,10 +229,12 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                v3f accel_f, ActiveObject *self,
                bool collideWithObjects)
 {
+       #define PROFILER_NAME(text) (s_env ? ("Server: " text) : ("Client: " text))
        static bool time_notification_done = false;
        Map *map = &env->getMap();
-       //TimeTaker tt("collisionMoveSimple");
-       ScopeProfiler sp(g_profiler, "collisionMoveSimple avg", SPT_AVG);
+       ServerEnvironment *s_env = dynamic_cast<ServerEnvironment*>(env);
+
+       ScopeProfiler sp(g_profiler, PROFILER_NAME("collisionMoveSimple()"), SPT_AVG);
 
        collisionMoveResult result;
 
@@ -237,10 +251,13 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
        } else {
                time_notification_done = false;
        }
+
+       v3f dpos_f = (*speed_f + accel_f * 0.5f * dtime) * dtime;
+       v3f newpos_f = *pos_f + dpos_f;
        *speed_f += accel_f * dtime;
 
-       // If there is no speed, there are no collisions
-       if (speed_f->getLength() == 0)
+       // If the object is static, there are no collisions
+       if (dpos_f == v3f())
                return result;
 
        // Limit speed for avoiding hangs
@@ -248,15 +265,16 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
        speed_f->X = rangelim(speed_f->X, -5000, 5000);
        speed_f->Z = rangelim(speed_f->Z, -5000, 5000);
 
+       *speed_f = truncate(*speed_f, 10000.0f);
+
        /*
                Collect node boxes in movement range
        */
        std::vector<NearbyCollisionInfo> cinfo;
        {
        //TimeTaker tt2("collisionMoveSimple collect boxes");
-       ScopeProfiler sp2(g_profiler, "collisionMoveSimple collect boxes avg", SPT_AVG);
+       ScopeProfiler sp2(g_profiler, PROFILER_NAME("collisionMoveSimple(): collect boxes"), SPT_AVG);
 
-       v3f newpos_f = *pos_f + *speed_f * dtime;
        v3f minpos_f(
                MYMIN(pos_f->X, newpos_f.X),
                MYMIN(pos_f->Y, newpos_f.Y) + 0.01f * BS, // bias rounding, player often at +/-n.5
@@ -277,7 +295,7 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
        for (p.Y = min.Y; p.Y <= max.Y; p.Y++)
        for (p.Z = min.Z; p.Z <= max.Z; p.Z++) {
                bool is_position_valid;
-               MapNode n = map->getNodeNoEx(p, &is_position_valid);
+               MapNode n = map->getNode(p, &is_position_valid);
 
                if (is_position_valid && n.getContent() != CONTENT_IGNORE) {
                        // Object collides into walkable nodes
@@ -289,7 +307,8 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                        if (!f.walkable)
                                continue;
 
-                       int n_bouncy_value = itemgroup_get(f.groups, "bouncy");
+                       // Negative bouncy may have a meaning, but we need +value here.
+                       int n_bouncy_value = abs(itemgroup_get(f.groups, "bouncy"));
 
                        int neighbors = 0;
                        if (f.drawtype == NDT_NODEBOX &&
@@ -321,16 +340,19 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                        }
                        std::vector<aabb3f> nodeboxes;
                        n.getCollisionBoxes(gamedef->ndef(), &nodeboxes, neighbors);
+
+                       // Calculate float position only once
+                       v3f posf = intToFloat(p, BS);
                        for (auto box : nodeboxes) {
-                               box.MinEdge += intToFloat(p, BS);
-                               box.MaxEdge += intToFloat(p, BS);
-                               cinfo.emplace_back(false, false, n_bouncy_value, p, box);
+                               box.MinEdge += posf;
+                               box.MaxEdge += posf;
+                               cinfo.emplace_back(false, n_bouncy_value, p, box);
                        }
                } else {
                        // Collide with unloaded nodes (position invalid) and loaded
                        // CONTENT_IGNORE nodes (position valid)
                        aabb3f box = getNodeBox(p, BS);
-                       cinfo.emplace_back(true, false, 0, p, box);
+                       cinfo.emplace_back(true, 0, p, box);
                }
        }
 
@@ -347,20 +369,22 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
 
        if(collideWithObjects)
        {
-               ScopeProfiler sp2(g_profiler, "collisionMoveSimple objects avg", SPT_AVG);
-               //TimeTaker tt3("collisionMoveSimple collect object boxes");
-
                /* add object boxes to cinfo */
 
                std::vector<ActiveObject*> objects;
 #ifndef SERVER
                ClientEnvironment *c_env = dynamic_cast<ClientEnvironment*>(env);
                if (c_env != 0) {
-                       f32 distance = speed_f->getLength();
+                       // Calculate distance by speed, add own extent and 1.5m of tolerance
+                       f32 distance = speed_f->getLength() * dtime +
+                               box_0.getExtent().getLength() + 1.5f * BS;
                        std::vector<DistanceSortedActiveObject> clientobjects;
-                       c_env->getActiveObjects(*pos_f, distance * 1.5f, clientobjects);
+                       c_env->getActiveObjects(*pos_f, distance, clientobjects);
+
                        for (auto &clientobject : clientobjects) {
-                               if (!self || (self != clientobject.obj)) {
+                               // Do collide with everything but itself and the parent CAO
+                               if (!self || (self != clientobject.obj &&
+                                               self != clientobject.obj->getParent())) {
                                        objects.push_back((ActiveObject*) clientobject.obj);
                                }
                        }
@@ -368,17 +392,24 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                else
 #endif
                {
-                       ServerEnvironment *s_env = dynamic_cast<ServerEnvironment*>(env);
                        if (s_env != NULL) {
-                               f32 distance = speed_f->getLength();
-                               std::vector<u16> s_objects;
-                               s_env->getObjectsInsideRadius(s_objects, *pos_f, distance * 1.5f);
-                               for (u16 obj_id : s_objects) {
-                                       ServerActiveObject *current = s_env->getActiveObject(obj_id);
-                                       if (!self || (self != current)) {
-                                               objects.push_back((ActiveObject*)current);
+                               // Calculate distance by speed, add own extent and 1.5m of tolerance
+                               f32 distance = speed_f->getLength() * dtime +
+                                       box_0.getExtent().getLength() + 1.5f * BS;
+
+                               // search for objects which are not us, or we are not its parent
+                               // we directly use the callback to populate the result to prevent
+                               // a useless result loop here
+                               auto include_obj_cb = [self, &objects] (ServerActiveObject *obj) {
+                                       if (!obj->isGone() &&
+                                               (!self || (self != obj && self != obj->getParent()))) {
+                                               objects.push_back((ActiveObject *)obj);
                                        }
-                               }
+                                       return false;
+                               };
+
+                               std::vector<ServerActiveObject *> s_objects;
+                               s_env->getObjectsInsideRadius(s_objects, *pos_f, distance, include_obj_cb);
                        }
                }
 
@@ -386,37 +417,36 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                                iter != objects.end(); ++iter) {
                        ActiveObject *object = *iter;
 
-                       if (object) {
+                       if (object && object->collideWithObjects()) {
                                aabb3f object_collisionbox;
-                               if (object->getCollisionBox(&object_collisionbox) &&
-                                               object->collideWithObjects()) {
-                                       cinfo.emplace_back(false, true, 0, v3s16(), object_collisionbox);
-                               }
+                               if (object->getCollisionBox(&object_collisionbox))
+                                       cinfo.emplace_back(object, 0, object_collisionbox);
                        }
                }
+#ifndef SERVER
+               if (self && c_env) {
+                       LocalPlayer *lplayer = c_env->getLocalPlayer();
+                       if (lplayer->getParent() == nullptr) {
+                               aabb3f lplayer_collisionbox = lplayer->getCollisionbox();
+                               v3f lplayer_pos = lplayer->getPosition();
+                               lplayer_collisionbox.MinEdge += lplayer_pos;
+                               lplayer_collisionbox.MaxEdge += lplayer_pos;
+                               ActiveObject *obj = (ActiveObject*) lplayer->getCAO();
+                               cinfo.emplace_back(obj, 0, lplayer_collisionbox);
+                       }
+               }
+#endif
        } //tt3
 
        /*
                Collision detection
        */
 
-       /*
-               Collision uncertainty radius
-               Make it a bit larger than the maximum distance of movement
-       */
-       f32 d = pos_max_d * 1.1f;
-       // A fairly large value in here makes moving smoother
-       //f32 d = 0.15*BS;
-
-       // This should always apply, otherwise there are glitches
-       assert(d > pos_max_d);  // invariant
+       f32 d = 0.0f;
 
        int loopcount = 0;
 
        while(dtime > BS * 1e-10f) {
-               //TimeTaker tt3("collisionMoveSimple dtime loop");
-               ScopeProfiler sp2(g_profiler, "collisionMoveSimple dtime loop avg", SPT_AVG);
-
                // Avoid infinite loop
                loopcount++;
                if (loopcount >= 100) {
@@ -428,7 +458,7 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                movingbox.MinEdge += *pos_f;
                movingbox.MaxEdge += *pos_f;
 
-               int nearest_collided = -1;
+               CollisionAxis nearest_collided = COLLISION_AXIS_NONE;
                f32 nearest_dtime = dtime;
                int nearest_boxindex = -1;
 
@@ -436,15 +466,15 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                        Go through every nodebox, find nearest collision
                */
                for (u32 boxindex = 0; boxindex < cinfo.size(); boxindex++) {
-                       NearbyCollisionInfo box_info = cinfo[boxindex];
+                       const NearbyCollisionInfo &box_info = cinfo[boxindex];
                        // Ignore if already stepped up this nodebox.
                        if (box_info.is_step_up)
                                continue;
 
                        // Find nearest collision of the two boxes (raytracing-like)
-                       f32 dtime_tmp;
-                       int collided = axisAlignedCollision(box_info.box,
-                                       movingbox, *speed_f, d, &dtime_tmp);
+                       f32 dtime_tmp = nearest_dtime;
+                       CollisionAxis collided = axisAlignedCollision(box_info.box,
+                                       movingbox, *speed_f, &dtime_tmp);
 
                        if (collided == -1 || dtime_tmp >= nearest_dtime)
                                continue;
@@ -454,19 +484,26 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                        nearest_boxindex = boxindex;
                }
 
-               if (nearest_collided == -1) {
+               if (nearest_collided == COLLISION_AXIS_NONE) {
                        // No collision with any collision box.
-                       *pos_f += *speed_f * dtime;
+                       *pos_f += truncate(*speed_f * dtime, 100.0f);
                        dtime = 0;  // Set to 0 to avoid "infinite" loop due to small FP numbers
                } else {
                        // Otherwise, a collision occurred.
                        NearbyCollisionInfo &nearest_info = cinfo[nearest_boxindex];
                        const aabb3f& cbox = nearest_info.box;
+
+                       //movingbox except moved to the horizontal position it would be after step up
+                       aabb3f stepbox = movingbox;
+                       stepbox.MinEdge.X += speed_f->X * dtime;
+                       stepbox.MinEdge.Z += speed_f->Z * dtime;
+                       stepbox.MaxEdge.X += speed_f->X * dtime;
+                       stepbox.MaxEdge.Z += speed_f->Z * dtime;
                        // Check for stairs.
-                       bool step_up = (nearest_collided != 1) && // must not be Y direction
+                       bool step_up = (nearest_collided != COLLISION_AXIS_Y) && // must not be Y direction
                                        (movingbox.MinEdge.Y < cbox.MaxEdge.Y) &&
                                        (movingbox.MinEdge.Y + stepheight > cbox.MaxEdge.Y) &&
-                                       (!wouldCollideWithCeiling(cinfo, movingbox,
+                                       (!wouldCollideWithCeiling(cinfo, stepbox,
                                                        cbox.MaxEdge.Y - movingbox.MinEdge.Y,
                                                        d));
 
@@ -475,17 +512,17 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
 
                        // Move to the point of collision and reduce dtime by nearest_dtime
                        if (nearest_dtime < 0) {
-                               // Handle negative nearest_dtime (can be caused by the d allowance)
+                               // Handle negative nearest_dtime
                                if (!step_up) {
-                                       if (nearest_collided == 0)
+                                       if (nearest_collided == COLLISION_AXIS_X)
                                                pos_f->X += speed_f->X * nearest_dtime;
-                                       if (nearest_collided == 1)
+                                       if (nearest_collided == COLLISION_AXIS_Y)
                                                pos_f->Y += speed_f->Y * nearest_dtime;
-                                       if (nearest_collided == 2)
+                                       if (nearest_collided == COLLISION_AXIS_Z)
                                                pos_f->Z += speed_f->Z * nearest_dtime;
                                }
                        } else {
-                               *pos_f += *speed_f * nearest_dtime;
+                               *pos_f += truncate(*speed_f * nearest_dtime, 100.0f);
                                dtime -= nearest_dtime;
                        }
 
@@ -494,32 +531,34 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                                is_collision = false;
 
                        CollisionInfo info;
-                       if (nearest_info.is_object)
+                       if (nearest_info.isObject())
                                info.type = COLLISION_OBJECT;
                        else
                                info.type = COLLISION_NODE;
 
                        info.node_p = nearest_info.position;
+                       info.object = nearest_info.obj;
                        info.old_speed = *speed_f;
+                       info.plane = nearest_collided;
 
                        // Set the speed component that caused the collision to zero
                        if (step_up) {
                                // Special case: Handle stairs
                                nearest_info.is_step_up = true;
                                is_collision = false;
-                       } else if (nearest_collided == 0) { // X
+                       } else if (nearest_collided == COLLISION_AXIS_X) {
                                if (fabs(speed_f->X) > BS * 3)
                                        speed_f->X *= bounce;
                                else
                                        speed_f->X = 0;
                                result.collides = true;
-                       } else if (nearest_collided == 1) { // Y
+                       } else if (nearest_collided == COLLISION_AXIS_Y) {
                                if(fabs(speed_f->Y) > BS * 3)
                                        speed_f->Y *= bounce;
                                else
                                        speed_f->Y = 0;
                                result.collides = true;
-                       } else if (nearest_collided == 2) { // Z
+                       } else if (nearest_collided == COLLISION_AXIS_Z) {
                                if (fabs(speed_f->Z) > BS * 3)
                                        speed_f->Z *= bounce;
                                else
@@ -532,6 +571,7 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                                is_collision = false;
 
                        if (is_collision) {
+                               info.axis = nearest_collided;
                                result.collisions.push_back(info);
                        }
                }
@@ -552,9 +592,8 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                        Object touches ground if object's minimum Y is near node's
                        maximum Y and object's X-Z-area overlaps with the node's
                        X-Z-area.
-
-                       Use 0.15*BS so that it is easier to get on a node.
                */
+
                if (cbox.MaxEdge.X - d > box.MinEdge.X && cbox.MinEdge.X + d < box.MaxEdge.X &&
                                cbox.MaxEdge.Z - d > box.MinEdge.Z &&
                                cbox.MinEdge.Z + d < box.MaxEdge.Z) {
@@ -564,10 +603,10 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                                box.MinEdge += *pos_f;
                                box.MaxEdge += *pos_f;
                        }
-                       if (fabs(cbox.MaxEdge.Y - box.MinEdge.Y) < 0.15f * BS) {
+                       if (std::fabs(cbox.MaxEdge.Y - box.MinEdge.Y) < 0.05f) {
                                result.touching_ground = true;
 
-                               if (box_info.is_object)
+                               if (box_info.isObject())
                                        result.standing_on_object = true;
                        }
                }