kmBool kmRay2IntersectTriangle(const kmRay2* ray, const kmVec2* p1, const kmVec2* p2, const kmVec2* p3, kmVec2* intersection, kmVec2* normal_out) {
kmVec2 intersect;
kmVec2 final_intersect;
kmVec2 normal;
kmScalar distance = 10000.0f;
kmBool intersected = KM_FALSE;
if(kmRay2IntersectLineSegment(ray, p1, p2, &intersect)) {
intersected = KM_TRUE;
kmVec2 tmp;
kmScalar this_distance = kmVec2Length(kmVec2Subtract(&tmp, &intersect, &ray->start));
if(this_distance < distance) {
final_intersect.x = intersect.x;
final_intersect.y = intersect.y;
distance = this_distance;
calculate_line_normal(*p1, *p2, &normal);
}
}
if(kmRay2IntersectLineSegment(ray, p2, p3, &intersect)) {
intersected = KM_TRUE;
kmVec2 tmp;
kmScalar this_distance = kmVec2Length(kmVec2Subtract(&tmp, &intersect, &ray->start));
if(this_distance < distance) {
final_intersect.x = intersect.x;
final_intersect.y = intersect.y;
distance = this_distance;
calculate_line_normal(*p2, *p3, &normal);
}
}
if(kmRay2IntersectLineSegment(ray, p3, p1, &intersect)) {
intersected = KM_TRUE;
kmVec2 tmp;
kmScalar this_distance = kmVec2Length(kmVec2Subtract(&tmp, &intersect, &ray->start));
if(this_distance < distance) {
final_intersect.x = intersect.x;
final_intersect.y = intersect.y;
distance = this_distance;
calculate_line_normal(*p3, *p1, &normal);
}
}
if(intersected) {
intersection->x = final_intersect.x;
intersection->y = final_intersect.y;
if(normal_out) {
normal_out->x = normal.x;
normal_out->y = normal.y;
}
}
return intersected;
}
kmBool kmRay2IntersectBox(const kmRay2* ray, const kmVec2* p1, const kmVec2* p2, const kmVec2* p3, const kmVec2* p4,
kmVec2* intersection, kmVec2* normal_out) {
kmBool intersected = KM_FALSE;
kmVec2 intersect, final_intersect, normal;
kmScalar distance = 10000.0f;
const kmVec2* points[4];
points[0] = p1;
points[1] = p2;
points[2] = p3;
points[3] = p4;
unsigned int i = 0;
for(; i < 4; ++i) {
const kmVec2* this_point = points[i];
const kmVec2* next_point = (i == 3) ? points[0] : points[i+1];
const kmVec2* other_point = (i == 3 || i == 0) ? points[1] : points[0];
if(kmRay2IntersectLineSegment(ray, this_point, next_point, &intersect)) {
kmVec2 tmp;
kmScalar this_distance = kmVec2Length(kmVec2Subtract(&tmp, &intersect, &ray->start));
kmVec2 this_normal;
calculate_line_normal(*this_point, *next_point, *other_point, &this_normal);
if(this_distance < distance && kmVec2Dot(&this_normal, &ray->dir) < 0.0f) {
kmVec2Assign(&final_intersect, &intersect);
distance = this_distance;
intersected = KM_TRUE;
kmVec2Assign(&normal, &this_normal);
}
}
}
if(intersected) {
intersection->x = final_intersect.x;
intersection->y = final_intersect.y;
if(normal_out) {
normal_out->x = normal.x;
normal_out->y = normal.y;
}
}
return intersected;
}
