bool findRayCapsuleIntersection(const glm::vec3& origin, const glm::vec3& direction,
const glm::vec3& start, const glm::vec3& end, float radius, float& distance) {
if (start == end) {
return findRaySphereIntersection(origin, direction, start, radius, distance); // handle degenerate case
}
glm::vec3 relativeOrigin = origin - start;
glm::vec3 relativeEnd = end - start;
float capsuleLength = glm::length(relativeEnd);
relativeEnd /= capsuleLength;
float originProjection = glm::dot(relativeEnd, relativeOrigin);
glm::vec3 constant = relativeOrigin - relativeEnd * originProjection;
float c = glm::dot(constant, constant) - radius * radius;
if (c < 0.0f) { // starts inside cylinder
if (originProjection < 0.0f) { // below start
return findRaySphereIntersection(origin, direction, start, radius, distance);
} else if (originProjection > capsuleLength) { // above end
return findRaySphereIntersection(origin, direction, end, radius, distance);
} else { // between start and end
distance = 0.0f;
return true;
}
}
glm::vec3 coefficient = direction - relativeEnd * glm::dot(relativeEnd, direction);
float a = glm::dot(coefficient, coefficient);
if (a == 0.0f) {
return false; // parallel to enclosing cylinder
}
float b = 2.0f * glm::dot(constant, coefficient);
float radicand = b * b - 4.0f * a * c;
if (radicand < 0.0f) {
return false; // doesn't hit the enclosing cylinder
}
float t = (-b - sqrtf(radicand)) / (2.0f * a);
if (t < 0.0f) {
return false; // doesn't hit the enclosing cylinder
}
glm::vec3 intersection = relativeOrigin + direction * t;
float intersectionProjection = glm::dot(relativeEnd, intersection);
if (intersectionProjection < 0.0f) { // below start
return findRaySphereIntersection(origin, direction, start, radius, distance);
} else if (intersectionProjection > capsuleLength) { // above end
return findRaySphereIntersection(origin, direction, end, radius, distance);
}
distance = t; // between start and end
return true;
}
bool SphereEntityItem::findDetailedRayIntersection(const glm::vec3& origin, const glm::vec3& direction,
bool& keepSearching, OctreeElement*& element, float& distance, BoxFace& face,
void** intersectedObject, bool precisionPicking) const {
// determine the ray in the frame of the entity transformed from a unit sphere
glm::mat4 translation = glm::translate(getPosition());
glm::mat4 rotation = glm::mat4_cast(getRotation());
glm::mat4 scale = glm::scale(getDimensions());
glm::mat4 registration = glm::translate(glm::vec3(0.5f, 0.5f, 0.5f) - getRegistrationPoint());
glm::mat4 entityToWorldMatrix = translation * rotation * scale * registration;
glm::mat4 worldToEntityMatrix = glm::inverse(entityToWorldMatrix);
glm::vec3 entityFrameOrigin = glm::vec3(worldToEntityMatrix * glm::vec4(origin, 1.0f));
glm::vec3 entityFrameDirection = glm::normalize(glm::vec3(worldToEntityMatrix * glm::vec4(direction, 0.0f)));
float localDistance;
// NOTE: unit sphere has center of 0,0,0 and radius of 0.5
if (findRaySphereIntersection(entityFrameOrigin, entityFrameDirection, glm::vec3(0.0f), 0.5f, localDistance)) {
// determine where on the unit sphere the hit point occured
glm::vec3 entityFrameHitAt = entityFrameOrigin + (entityFrameDirection * localDistance);
// then translate back to work coordinates
glm::vec3 hitAt = glm::vec3(entityToWorldMatrix * glm::vec4(entityFrameHitAt, 1.0f));
distance = glm::distance(origin,hitAt);
return true;
}
return false;
}
bool ShapeEntityItem::findDetailedRayIntersection(const glm::vec3& origin, const glm::vec3& direction,
bool& keepSearching, OctreeElementPointer& element,
float& distance, BoxFace& face, glm::vec3& surfaceNormal,
void** intersectedObject, bool precisionPicking) const {
// determine the ray in the frame of the entity transformed from a unit sphere
glm::mat4 entityToWorldMatrix = getEntityToWorldMatrix();
glm::mat4 worldToEntityMatrix = glm::inverse(entityToWorldMatrix);
glm::vec3 entityFrameOrigin = glm::vec3(worldToEntityMatrix * glm::vec4(origin, 1.0f));
glm::vec3 entityFrameDirection = glm::normalize(glm::vec3(worldToEntityMatrix * glm::vec4(direction, 0.0f)));
float localDistance;
// NOTE: unit sphere has center of 0,0,0 and radius of 0.5
if (findRaySphereIntersection(entityFrameOrigin, entityFrameDirection, glm::vec3(0.0f), 0.5f, localDistance)) {
// determine where on the unit sphere the hit point occured
glm::vec3 entityFrameHitAt = entityFrameOrigin + (entityFrameDirection * localDistance);
// then translate back to work coordinates
glm::vec3 hitAt = glm::vec3(entityToWorldMatrix * glm::vec4(entityFrameHitAt, 1.0f));
distance = glm::distance(origin, hitAt);
bool success;
surfaceNormal = glm::normalize(hitAt - getCenterPosition(success));
if (!success) {
return false;
}
return true;
}
return false;
}
