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

* truncate speed to prevent inf result

* code styling

* change truncate() input parameters
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TheTermos committed May 14, 2020
1 parent 836dd4a commit 6ef7ad09bbed9176d0d15f53b5cb14ef6e18a3b2
Showing with 69 additions and 52 deletions.
  1. +69 −52 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
@@ -78,95 +94,94 @@ 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;
}
}

// NO else if here

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;
}

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