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364 lines
14 KiB
C++
364 lines
14 KiB
C++
//
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// AABox.h - Axis Aligned Boxes
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// hifi
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//
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// Added by Brad Hefta-Gaub on 04/11/13.
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// Originally from lighthouse3d. Modified to utilize glm::vec3 and clean up to our coding standards
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//
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// Simple axis aligned box class.
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//
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#include "SharedUtil.h"
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#include "AABox.h"
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#include "GeometryUtil.h"
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void AABox::scale(float scale) {
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_corner = _corner * scale;
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_size = _size * scale;
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_center = _center * scale;
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}
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glm::vec3 AABox::getVertex(BoxVertex vertex) const {
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switch (vertex) {
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case BOTTOM_LEFT_NEAR:
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return _corner + glm::vec3(_size.x, 0, 0);
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case BOTTOM_RIGHT_NEAR:
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return _corner;
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case TOP_RIGHT_NEAR:
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return _corner + glm::vec3(0, _size.y, 0);
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case TOP_LEFT_NEAR:
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return _corner + glm::vec3(_size.x, _size.y, 0);
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case BOTTOM_LEFT_FAR:
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return _corner + glm::vec3(_size.x, 0, _size.z);
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case BOTTOM_RIGHT_FAR:
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return _corner + glm::vec3(0, 0, _size.z);
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case TOP_RIGHT_FAR:
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return _corner + glm::vec3(0, _size.y, _size.z);
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case TOP_LEFT_FAR:
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return _corner + _size;
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}
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}
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void AABox::setBox(const glm::vec3& corner, const glm::vec3& size) {
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_corner = corner;
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_size = size;
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// In the event that the caller gave us negative sizes, fix things up to be reasonable
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if (_size.x < 0.0) {
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_size.x = -size.x;
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_corner.x -= _size.x;
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}
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if (_size.y < 0.0) {
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_size.y = -size.y;
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_corner.y -= _size.y;
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}
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if (_size.z < 0.0) {
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_size.z = -size.z;
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_corner.z -= _size.z;
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}
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_center = _corner + (_size * 0.5f);
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}
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glm::vec3 AABox::getVertexP(const glm::vec3& normal) const {
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glm::vec3 result = _corner;
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if (normal.x > 0) {
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result.x += _size.x;
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}
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if (normal.y > 0) {
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result.y += _size.y;
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}
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if (normal.z > 0) {
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result.z += _size.z;
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}
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return result;
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}
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glm::vec3 AABox::getVertexN(const glm::vec3& normal) const {
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glm::vec3 result = _corner;
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if (normal.x < 0) {
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result.x += _size.x;
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}
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if (normal.y < 0) {
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result.y += _size.y;
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}
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if (normal.z < 0) {
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result.z += _size.z;
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}
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return result;
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}
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// determines whether a value is within the extents
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static bool isWithin(float value, float corner, float size) {
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return value >= corner && value <= corner + size;
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}
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bool AABox::contains(const glm::vec3& point) const {
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return isWithin(point.x, _corner.x, _size.x) &&
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isWithin(point.y, _corner.y, _size.y) &&
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isWithin(point.z, _corner.z, _size.z);
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}
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bool AABox::contains(const AABox& otherBox) const {
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for (int v = BOTTOM_LEFT_NEAR; v < TOP_LEFT_FAR; v++) {
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glm::vec3 vertex = otherBox.getVertex((BoxVertex)v);
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if (!contains(vertex)) {
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return false;
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}
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}
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return true;
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}
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// determines whether a value is within the expanded extents
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static bool isWithinExpanded(float value, float corner, float size, float expansion) {
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return value >= corner - expansion && value <= corner + size + expansion;
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}
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bool AABox::expandedContains(const glm::vec3& point, float expansion) const {
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return isWithinExpanded(point.x, _corner.x, _size.x, expansion) &&
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isWithinExpanded(point.y, _corner.y, _size.y, expansion) &&
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isWithinExpanded(point.z, _corner.z, _size.z, expansion);
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}
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// finds the intersection between a ray and the facing plane on one axis
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static bool findIntersection(float origin, float direction, float corner, float size, float& distance) {
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if (direction > EPSILON) {
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distance = (corner - origin) / direction;
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return true;
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} else if (direction < -EPSILON) {
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distance = (corner + size - origin) / direction;
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return true;
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}
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return false;
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}
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bool AABox::expandedIntersectsSegment(const glm::vec3& start, const glm::vec3& end, float expansion) const {
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// handle the trivial cases where the expanded box contains the start or end
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if (expandedContains(start, expansion) || expandedContains(end, expansion)) {
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return true;
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}
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// check each axis
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glm::vec3 expandedCorner = _corner - glm::vec3(expansion, expansion, expansion);
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glm::vec3 expandedSize = _size + glm::vec3(expansion, expansion, expansion) * 2.0f;
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glm::vec3 direction = end - start;
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float axisDistance;
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return (findIntersection(start.x, direction.x, expandedCorner.x, expandedSize.x, axisDistance) &&
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axisDistance >= 0.0f && axisDistance <= 1.0f &&
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isWithin(start.y + axisDistance*direction.y, expandedCorner.y, expandedSize.y) &&
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isWithin(start.z + axisDistance*direction.z, expandedCorner.z, expandedSize.z)) ||
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(findIntersection(start.y, direction.y, expandedCorner.y, expandedSize.y, axisDistance) &&
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axisDistance >= 0.0f && axisDistance <= 1.0f &&
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isWithin(start.x + axisDistance*direction.x, expandedCorner.x, expandedSize.x) &&
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isWithin(start.z + axisDistance*direction.z, expandedCorner.z, expandedSize.z)) ||
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(findIntersection(start.z, direction.z, expandedCorner.z, expandedSize.z, axisDistance) &&
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axisDistance >= 0.0f && axisDistance <= 1.0f &&
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isWithin(start.y + axisDistance*direction.y, expandedCorner.y, expandedSize.y) &&
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isWithin(start.x + axisDistance*direction.x, expandedCorner.x, expandedSize.x));
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}
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bool AABox::findRayIntersection(const glm::vec3& origin, const glm::vec3& direction, float& distance, BoxFace& face) const {
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// handle the trivial case where the box contains the origin
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if (contains(origin)) {
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distance = 0;
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return true;
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}
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// check each axis
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float axisDistance;
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if ((findIntersection(origin.x, direction.x, _corner.x, _size.x, axisDistance) && axisDistance >= 0 &&
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isWithin(origin.y + axisDistance*direction.y, _corner.y, _size.y) &&
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isWithin(origin.z + axisDistance*direction.z, _corner.z, _size.z))) {
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distance = axisDistance;
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face = direction.x > 0 ? MIN_X_FACE : MAX_X_FACE;
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return true;
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}
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if ((findIntersection(origin.y, direction.y, _corner.y, _size.y, axisDistance) && axisDistance >= 0 &&
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isWithin(origin.x + axisDistance*direction.x, _corner.x, _size.x) &&
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isWithin(origin.z + axisDistance*direction.z, _corner.z, _size.z))) {
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distance = axisDistance;
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face = direction.y > 0 ? MIN_Y_FACE : MAX_Y_FACE;
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return true;
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}
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if ((findIntersection(origin.z, direction.z, _corner.z, _size.z, axisDistance) && axisDistance >= 0 &&
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isWithin(origin.y + axisDistance*direction.y, _corner.y, _size.y) &&
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isWithin(origin.x + axisDistance*direction.x, _corner.x, _size.x))) {
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distance = axisDistance;
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face = direction.z > 0 ? MIN_Z_FACE : MAX_Z_FACE;
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return true;
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}
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return false;
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}
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bool AABox::findSpherePenetration(const glm::vec3& center, float radius, glm::vec3& penetration) const {
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glm::vec4 center4 = glm::vec4(center, 1.0f);
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float minPenetrationLength = FLT_MAX;
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for (int i = 0; i < FACE_COUNT; i++) {
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glm::vec4 facePlane = getPlane((BoxFace)i);
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glm::vec3 vector = getClosestPointOnFace(center, (BoxFace)i) - center;
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if (glm::dot(center4, getPlane((BoxFace)i)) >= 0.0f) {
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// outside this face, so use vector to closest point to determine penetration
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return ::findSpherePenetration(vector, glm::vec3(-facePlane), radius, penetration);
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}
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float vectorLength = glm::length(vector);
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if (vectorLength < minPenetrationLength) {
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// remember the smallest penetration vector; if we're inside all faces, we'll use that
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penetration = (vectorLength < EPSILON) ? glm::vec3(-facePlane) * radius :
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vector * ((vectorLength + radius) / -vectorLength);
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minPenetrationLength = vectorLength;
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}
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}
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return true;
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}
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bool AABox::findCapsulePenetration(const glm::vec3& start, const glm::vec3& end, float radius, glm::vec3& penetration) const {
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glm::vec4 start4 = glm::vec4(start, 1.0f);
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glm::vec4 end4 = glm::vec4(end, 1.0f);
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glm::vec4 startToEnd = glm::vec4(end - start, 0.0f);
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float minPenetrationLength = FLT_MAX;
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for (int i = 0; i < FACE_COUNT; i++) {
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// find the vector from the segment to the closest point on the face (starting from deeper end)
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glm::vec4 facePlane = getPlane((BoxFace)i);
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glm::vec3 closest = (glm::dot(start4, facePlane) <= glm::dot(end4, facePlane)) ?
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getClosestPointOnFace(start4, startToEnd, (BoxFace)i) : getClosestPointOnFace(end4, -startToEnd, (BoxFace)i);
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glm::vec3 vector = -computeVectorFromPointToSegment(closest, start, end);
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if (glm::dot(vector, glm::vec3(facePlane)) < 0.0f) {
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// outside this face, so use vector to closest point to determine penetration
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return ::findSpherePenetration(vector, glm::vec3(-facePlane), radius, penetration);
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}
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float vectorLength = glm::length(vector);
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if (vectorLength < minPenetrationLength) {
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// remember the smallest penetration vector; if we're inside all faces, we'll use that
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penetration = (vectorLength < EPSILON) ? glm::vec3(-facePlane) * radius :
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vector * ((vectorLength + radius) / -vectorLength);
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minPenetrationLength = vectorLength;
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}
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}
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return true;
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}
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glm::vec3 AABox::getClosestPointOnFace(const glm::vec3& point, BoxFace face) const {
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switch (face) {
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case MIN_X_FACE:
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return glm::clamp(point, glm::vec3(_corner.x, _corner.y, _corner.z),
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glm::vec3(_corner.x, _corner.y + _size.y, _corner.z + _size.z));
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case MAX_X_FACE:
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return glm::clamp(point, glm::vec3(_corner.x + _size.x, _corner.y, _corner.z),
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glm::vec3(_corner.x + _size.x, _corner.y + _size.y, _corner.z + _size.z));
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case MIN_Y_FACE:
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return glm::clamp(point, glm::vec3(_corner.x, _corner.y, _corner.z),
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glm::vec3(_corner.x + _size.x, _corner.y, _corner.z + _size.z));
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case MAX_Y_FACE:
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return glm::clamp(point, glm::vec3(_corner.x, _corner.y + _size.y, _corner.z),
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glm::vec3(_corner.x + _size.x, _corner.y + _size.y, _corner.z + _size.z));
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case MIN_Z_FACE:
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return glm::clamp(point, glm::vec3(_corner.x, _corner.y, _corner.z),
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glm::vec3(_corner.x + _size.x, _corner.y + _size.y, _corner.z));
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case MAX_Z_FACE:
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return glm::clamp(point, glm::vec3(_corner.x, _corner.y, _corner.z + _size.z),
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glm::vec3(_corner.x + _size.x, _corner.y + _size.y, _corner.z + _size.z));
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}
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}
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glm::vec3 AABox::getClosestPointOnFace(const glm::vec4& origin, const glm::vec4& direction, BoxFace face) const {
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// check against the four planes that border the face
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BoxFace oppositeFace = getOppositeFace(face);
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bool anyOutside = false;
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for (int i = 0; i < FACE_COUNT; i++) {
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if (i == face || i == oppositeFace) {
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continue;
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}
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glm::vec4 iPlane = getPlane((BoxFace)i);
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float originDistance = glm::dot(origin, iPlane);
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if (originDistance < 0.0f) {
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continue; // inside the border
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}
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anyOutside = true;
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float divisor = glm::dot(direction, iPlane);
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if (fabs(divisor) < EPSILON) {
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continue; // segment is parallel to plane
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}
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// find intersection and see if it lies within face bounds
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float directionalDistance = -originDistance / divisor;
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glm::vec4 intersection = origin + direction * directionalDistance;
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BoxFace iOppositeFace = getOppositeFace((BoxFace)i);
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for (int j = 0; j < FACE_COUNT; j++) {
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if (j == face || j == oppositeFace || j == i || j == iOppositeFace) {
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continue;
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}
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if (glm::dot(intersection, getPlane((BoxFace)j)) > 0.0f) {
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goto outerContinue; // intersection is out of bounds
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}
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}
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return getClosestPointOnFace(glm::vec3(intersection), face);
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outerContinue: ;
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}
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// if we were outside any of the sides, we must check against the diagonals
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if (anyOutside) {
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int faceAxis = face / 2;
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int secondAxis = (faceAxis + 1) % 3;
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int thirdAxis = (faceAxis + 2) % 3;
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glm::vec4 secondAxisMinPlane = getPlane((BoxFace)(secondAxis * 2));
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glm::vec4 secondAxisMaxPlane = getPlane((BoxFace)(secondAxis * 2 + 1));
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glm::vec4 thirdAxisMaxPlane = getPlane((BoxFace)(thirdAxis * 2 + 1));
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glm::vec4 offset = glm::vec4(0.0f, 0.0f, 0.0f,
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glm::dot(glm::vec3(secondAxisMaxPlane + thirdAxisMaxPlane), _size) * 0.5f);
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glm::vec4 diagonals[] = { secondAxisMinPlane + thirdAxisMaxPlane + offset,
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secondAxisMaxPlane + thirdAxisMaxPlane + offset };
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float minDistance = FLT_MAX;
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for (int i = 0; i < sizeof(diagonals) / sizeof(diagonals[0]); i++) {
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float divisor = glm::dot(direction, diagonals[i]);
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if (fabs(divisor) < EPSILON) {
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continue; // segment is parallel to diagonal plane
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}
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minDistance = glm::min(-glm::dot(origin, diagonals[i]) / divisor, minDistance);
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}
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if (minDistance != FLT_MAX) {
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return getClosestPointOnFace(glm::vec3(origin + direction * minDistance), face);
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}
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}
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// last resort or all inside: clamp origin to face
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return getClosestPointOnFace(glm::vec3(origin), face);
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}
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glm::vec4 AABox::getPlane(BoxFace face) const {
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switch (face) {
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case MIN_X_FACE: return glm::vec4(-1.0f, 0.0f, 0.0f, _corner.x);
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case MAX_X_FACE: return glm::vec4(1.0f, 0.0f, 0.0f, -_corner.x - _size.x);
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case MIN_Y_FACE: return glm::vec4(0.0f, -1.0f, 0.0f, _corner.y);
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case MAX_Y_FACE: return glm::vec4(0.0f, 1.0f, 0.0f, -_corner.y - _size.y);
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case MIN_Z_FACE: return glm::vec4(0.0f, 0.0f, -1.0f, _corner.z);
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case MAX_Z_FACE: return glm::vec4(0.0f, 0.0f, 1.0f, -_corner.z - _size.z);
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}
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}
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BoxFace AABox::getOppositeFace(BoxFace face) {
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switch (face) {
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case MIN_X_FACE: return MAX_X_FACE;
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case MAX_X_FACE: return MIN_X_FACE;
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case MIN_Y_FACE: return MAX_Y_FACE;
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case MAX_Y_FACE: return MIN_Y_FACE;
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case MIN_Z_FACE: return MAX_Z_FACE;
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case MAX_Z_FACE: return MIN_Z_FACE;
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}
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}
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