Collision detection - #9343 follow-up (#9764)

* truncate speed to prevent inf result

* code styling

* change truncate() input parameters

diff --git a/src/collision.cpp b/src/collision.cpp
index 3b5e79a66cd1c3416049f58ab4c1c5f7ee2cc336..06ef820c5095b3cf8d5118ace2749c23dc34e317 100644 (file)
--- a/src/collision.cpp
+++ b/src/collision.cpp
@@ -66,6 +66,22 @@ struct NearbyCollisionInfo {
        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
@@ -78,70 +94,70 @@ CollisionAxis axisAlignedCollision(
        //TimeTaker tt("axisAlignedCollision");
 
        aabb3f relbox(
-                       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,
+                       (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)
        );
 
        const f32 dtime_max = *dtime;
-       const f32 inner_margin = -1.5f;
+       f32 inner_margin;               // the distance of clipping recovery
        f32 distance;
        f32 time;
 
-       if (speed.X) {
-               distance = relbox.MaxEdge.X - relbox.MinEdge.X;
 
-               *dtime = distance >= 0 ? std::abs(distance / speed.X) : -std::abs(distance / speed.X);
+       if (speed.Y) {
+               distance = relbox.MaxEdge.Y - relbox.MinEdge.Y;
+               *dtime = distance / std::abs(speed.Y);
                time = std::max(*dtime, 0.0f);
 
-               if (distance > inner_margin) {
-                       if (*dtime <= dtime_max) {
-                               if ((speed.X > 0 && staticbox.MaxEdge.X > movingbox.MaxEdge.X) ||
-                                               (speed.X < 0 && staticbox.MinEdge.X < movingbox.MinEdge.X)) {
-                                       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) &&
+               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_X;
-                               }
-                       } else {
-                               return COLLISION_AXIS_NONE;
+                                       )
+                                       return COLLISION_AXIS_Y;
                        }
                }
+               else {
+                       return COLLISION_AXIS_NONE;
+               }
        }
 
        // NO else if here
 
-       if (speed.Y) {
-               distance = relbox.MaxEdge.Y - relbox.MinEdge.Y;
-
-               *dtime = distance >= 0 ? std::abs(distance / speed.Y) : -std::abs(distance / speed.Y);
+       if (speed.X) {
+               distance = relbox.MaxEdge.X - relbox.MinEdge.X;
+               *dtime = distance / std::abs(speed.X);
                time = std::max(*dtime, 0.0f);
 
-               if (distance > inner_margin) {
-                       if (*dtime <= dtime_max) {
-                               if ((speed.Y > 0 && staticbox.MaxEdge.Y > movingbox.MaxEdge.Y) ||
-                                               (speed.Y < 0 && staticbox.MinEdge.Y < movingbox.MinEdge.Y)) {
-                                       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) &&
+               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_Y;
-                               }
-                       } else {
-                               return COLLISION_AXIS_NONE;
+                                       ) 
+                                       return COLLISION_AXIS_X;
                        }
+               } else {
+                       return COLLISION_AXIS_NONE;
                }
        }
 
@@ -149,24 +165,23 @@ CollisionAxis axisAlignedCollision(
 
        if (speed.Z) {
                distance = relbox.MaxEdge.Z - relbox.MinEdge.Z;
-
-               *dtime = distance >= 0 ? std::abs(distance / speed.Z) : -std::abs(distance / speed.Z);
+               *dtime = distance / std::abs(speed.Z);
                time = std::max(*dtime, 0.0f);
 
-               if (distance > inner_margin) {
-                       if (*dtime <= dtime_max) {
-                               if ((speed.Z > 0 && staticbox.MaxEdge.Z > movingbox.MaxEdge.Z) ||
-                                               (speed.Z < 0 && staticbox.MinEdge.Z < movingbox.MinEdge.Z)) {
-                                       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) &&
+               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;
-                               }
+                                       ) 
+                                       return COLLISION_AXIS_Z;
                        }
                }
        }
@@ -245,6 +260,8 @@ 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
        */
@@ -464,7 +481,7 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
 
                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.
@@ -500,7 +517,7 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
                                                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;
                        }