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Ray/capsule intersection test.

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This commit is contained in:
Andrzej Kapolka 2014-01-03 17:48:58 -08:00
parent aa9fc290a5
commit c2af9becba
1 changed files with 45 additions and 11 deletions
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56
libraries/shared/src/GeometryUtil.cpp
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@ -157,12 +157,12 @@ glm::vec3 addPenetrations(const glm::vec3& currentPenetration, const glm::vec3&
bool findRaySphereIntersection(const glm::vec3& origin, const glm::vec3& direction,
const glm::vec3& center, float radius, float& distance) {
glm::vec3 relativeOrigin = origin - center;
float b = glm::dot(direction, relativeOrigin);
float c = glm::dot(relativeOrigin, relativeOrigin) - radius * radius;
if (c < 0.0f) {
distance = 0.0f;
return true; // starts inside the sphere
}
float b = glm::dot(direction, relativeOrigin);
float radicand = b * b - c;
if (radicand < 0.0f) {
return false; // doesn't hit the sphere
@ -177,19 +177,53 @@ bool findRaySphereIntersection(const glm::vec3& origin, const glm::vec3& directi
bool findRayCapsuleIntersection(const glm::vec3& origin, const glm::vec3& direction,
const glm::vec3& start, const glm::vec3& end, float radius, float& distance) {
float minDistance = FLT_MAX;
float sphereDistance;
if (findRaySphereIntersection(origin, direction, start, radius, sphereDistance)) {
minDistance = qMin(minDistance, sphereDistance);
if (start == end) {
return findRaySphereIntersection(origin, direction, start, radius, distance); // handle degenerate case
}
if (findRaySphereIntersection(origin, direction, end, radius, sphereDistance)) {
minDistance = qMin(minDistance, sphereDistance);
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;
}
}
if (minDistance < FLT_MAX) {
distance = minDistance;
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
}
return false;
float b = 2.0f * glm::dot(constant, coefficient);
float divisor = 2.0f * a;
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;
}
// Do line segments (r1p1.x, r1p1.y)--(r1p2.x, r1p2.y) and (r2p1.x, r2p1.y)--(r2p2.x, r2p2.y) intersect?