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collision_check will now return 1 if there is a collision, and write collision data to the new out variables

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Sara 2023-10-07 22:58:15 +02:00
parent f237da1b93
commit b7721baeb7
2 changed files with 63 additions and 25 deletions
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79
src/collision.c
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@ -8,7 +8,7 @@
typedef struct Range {float min; float max; } Range; typedef struct Range {float min; float max; } Range;
static static
Range _shape_get_range_on_axis(PhysicsEntity self, Vector axis) { Range _internal_collision_get_range_on_axis(PhysicsEntity self, Vector axis) {
Vector point = shape_get_point_transformed(self.tc->get_shape(self.data), 0, *self.transformable->get_transform(self.data)); Vector point = shape_get_point_transformed(self.tc->get_shape(self.data), 0, *self.transformable->get_transform(self.data));
float dot = vdotf(axis, point); float dot = vdotf(axis, point);
Range range = {dot, dot}; Range range = {dot, dot};
@ -26,9 +26,9 @@ Range _shape_get_range_on_axis(PhysicsEntity self, Vector axis) {
} }
static static
Vector _shape_overlap_on_axis(PhysicsEntity self, PhysicsEntity other, Vector axis) { Vector _internal_collision_overlap_on_axis(PhysicsEntity self, PhysicsEntity other, Vector axis) {
Range a_range = _shape_get_range_on_axis(self, axis); Range a_range = _internal_collision_get_range_on_axis(self, axis);
Range b_range = _shape_get_range_on_axis(other, axis); Range b_range = _internal_collision_get_range_on_axis(other, axis);
if(a_range.min <= b_range.max && b_range.min <= b_range.max) if(a_range.min <= b_range.max && b_range.min <= b_range.max)
return vmulff(axis, fminf(b_range.max - b_range.min, b_range.min - a_range.max)); return vmulff(axis, fminf(b_range.max - b_range.min, b_range.min - a_range.max));
@ -37,27 +37,31 @@ Vector _shape_overlap_on_axis(PhysicsEntity self, PhysicsEntity other, Vector ax
} }
static static
Collision _shape_get_overlap_internal(PhysicsEntity self, PhysicsEntity other) { int _internal_collision_get_overlap(PhysicsEntity self, PhysicsEntity other, Collision* out) {
// The shortest escape vector found so far // get components used
Shape* self_shape = self.tc->get_shape(self.data);
Transform* self_transform = self.transformable->get_transform(self.data);
// the shortest distance to solve collision found so far
Vector shortest_escape = InfinityVector; Vector shortest_escape = InfinityVector;
// the squared length of the shortest escape vector found so far // the squared length of the shortest escape vector found so far
float shortest_sqrmag = INFINITY; float shortest_sqrmag = INFINITY;
// the first index of the points on the edge // the first index of the points on the edge
size_t shortest_escape_edge = 0; size_t shortest_escape_edge = 0;
// the number of points in the shape of self // the number of points in the shape of self
size_t self_point_count = shape_get_points_count(self.tc->get_shape(self.data)); size_t self_point_count = shape_get_points_count(self_shape);
for(size_t point_index = 0; point_index < self_point_count; ++point_index) { for(size_t point_index = 0; point_index < self_point_count; ++point_index) {
// the next point on the line // the next point on the line
size_t next_index = (point_index + 1) % self_point_count; size_t next_index = (point_index + 1) % self_point_count;
// get the two points defining the collision edge // get the two points defining the collision edge
Vector a = shape_get_point_transformed(self.tc->get_shape(self.data), point_index, *self.transformable->get_transform(self.data)); Vector a = shape_get_point_transformed(self.tc->get_shape(self.data), point_index, *self_transform);
Vector b = shape_get_point_transformed(self.tc->get_shape(self.data), next_index, *self.transformable->get_transform(self.data)); Vector b = shape_get_point_transformed(self.tc->get_shape(self.data), next_index, *self_transform);
// the direction of the line // the direction of the line
Vector diff = vsubf(b, a); Vector diff = vsubf(b, a);
// the smallest escape vector on this axis // the smallest escape vector on this axis
Vector escape = _shape_overlap_on_axis(self, other, vnormalizedf(diff)); Vector escape = _internal_collision_overlap_on_axis(self, other, vnormalizedf(diff));
float sqr_mag = vsqrmagnitudef(escape); float sqr_mag = vsqrmagnitudef(escape);
if(sqr_mag < shortest_sqrmag) { if(sqr_mag < shortest_sqrmag) {
shortest_sqrmag = sqr_mag; shortest_sqrmag = sqr_mag;
@ -69,20 +73,51 @@ Collision _shape_get_overlap_internal(PhysicsEntity self, PhysicsEntity other) {
RigidBody* rba = self.tc->get_rigidbody(self.data); RigidBody* rba = self.tc->get_rigidbody(self.data);
RigidBody* rbb = self.tc->get_rigidbody(self.data); RigidBody* rbb = self.tc->get_rigidbody(self.data);
return (Collision) { *out = (Collision) {
.edge_left = shortest_escape_edge,
.edge_right = (1 + shortest_escape_edge) % self_point_count,
.normal = vnormalizedf(shortest_escape),
.velocity = vsubf(rigidbody_get_velocity(rba), rigidbody_get_velocity(rbb)),
.other = other, .other = other,
.separation_force = shortest_escape
.point = InfinityVector,
.normal = vnormalizedf(shortest_escape),
.velocity = vsubf(rigidbody_get_velocity(rba), rigidbody_get_velocity(rbb)),
.separation_force = shortest_escape,
.edge_left = shape_get_point_transformed(self_shape, shortest_escape_edge, *self_transform),
.edge_right = shape_get_point_transformed(self_shape, (1 + shortest_escape_edge) % self_point_count, *self_transform),
};
return shortest_sqrmag != 0;
}
static
Collision _internal_collision_invert(Collision collision_a, PhysicsEntity a) {
return (Collision){
.other = a,
.point = collision_a.point,
.normal = vinvf(collision_a.normal),
.velocity = vinvf(collision_a.velocity),
.separation_force = vinvf(collision_a.separation_force),
.edge_left = collision_a.edge_left,
.edge_right = collision_a.edge_right,
}; };
} }
Collision get_collision(PhysicsEntity a, PhysicsEntity b) { int collision_check(PhysicsEntity a, PhysicsEntity b, Collision* out_a, Collision* out_b) {
Collision self_first = _shape_get_overlap_internal(a, b); Collision collision_a, collision_b;
Collision other_first = _shape_get_overlap_internal(b, a); int collision_a_overlaps = _internal_collision_get_overlap(a, b, &collision_a);
return vsqrmagnitudef(self_first.separation_force) < vsqrmagnitudef(other_first.separation_force) int collision_b_overlaps = _internal_collision_get_overlap(b, a, &collision_b);
? self_first
: other_first; if(!collision_a_overlaps && !collision_b_overlaps) {
return 0;
}
if(vsqrmagnitudef(collision_a.separation_force) < vsqrmagnitudef(collision_b.separation_force)) {
collision_b = _internal_collision_invert(collision_a, a);
} else {
collision_a = _internal_collision_invert(collision_b, b);
}
*out_a = collision_a;
*out_b = collision_b;
return 1;
} }

9
src/collision.h
View file

@ -7,14 +7,17 @@
typedef struct Collision { typedef struct Collision {
PhysicsEntity other; PhysicsEntity other;
Vector point; Vector point;
Vector normal; Vector normal;
Vector velocity; Vector velocity;
Vector separation_force; Vector separation_force;
size_t edge_left;
size_t edge_right; Vector edge_left;
Vector edge_right;
} Collision; } Collision;
extern Collision get_collision(PhysicsEntity a, PhysicsEntity b); extern int collision_check(PhysicsEntity a, PhysicsEntity b, Collision* out_a, Collision* out_b);
#endif // !_fencer_collision_h #endif // !_fencer_collision_h