Sphere/box collisions for voxels, various utility functions.

interface/src/Avatar.cpp

@@ -615,15 +615,19 @@ void Avatar::updateCollisionWithEnvironment() {
 void Avatar::updateCollisionWithVoxels() {
     float radius = _height * 0.125f;
     glm::vec3 penetration;
-    if (Application::getInstance()->getVoxels()->findCapsulePenetration(
+    //if (Application::getInstance()->getVoxels()->findCapsulePenetration(
-            _position - glm::vec3(0.0f, _pelvisFloatingHeight - radius, 0.0f),
+    //        _position - glm::vec3(0.0f, _pelvisFloatingHeight - radius, 0.0f),
-            _position + glm::vec3(0.0f, _height - _pelvisFloatingHeight - radius, 0.0f), radius, penetration)) {
+    //        _position + glm::vec3(0.0f, _height - _pelvisFloatingHeight - radius, 0.0f), radius, penetration)) {
+    //    applyCollisionWithScene(penetration);
+    //}
+    
+    if (Application::getInstance()->getVoxels()->findSpherePenetration(_position, _height/2, penetration)) {
         applyCollisionWithScene(penetration);
     }
 }
 
 void Avatar::applyCollisionWithScene(const glm::vec3& penetration) {
-    _position += penetration;
+    _position -= penetration;
         
     // reflect the velocity component in the direction of penetration
     glm::vec3 direction = glm::normalize(penetration);

interface/src/Environment.cpp

@@ -101,13 +101,7 @@ const EnvironmentData Environment::getClosestData(const glm::vec3& position) {
 bool Environment::findCapsulePenetration(const glm::vec3& start, const glm::vec3& end,
                                          float radius, glm::vec3& penetration) {
     // collide with the "floor"
-    bool found = false;
+    bool found = findCapsulePlanePenetration(start, end, radius, glm::vec4(0.0f, 1.0f, 0.0f, 0.0f), penetration);
-    penetration = glm::vec3(0.0f, 0.0f, 0.0f);
-    float floorDist = qMin(start.y, end.y) - radius;
-    if (floorDist < 0.0f) {
-        penetration.y = -floorDist;
-        found = true;
-    }
     
     // get the lock for the duration of the call
     QMutexLocker locker(&_mutex);
@@ -117,11 +111,10 @@ bool Environment::findCapsulePenetration(const glm::vec3& start, const glm::vec3
             if (environmentData.getGravity() == 0.0f) {
                 continue; // don't bother colliding with gravity-less environments
             }
-            glm::vec3 vector = computeVectorFromPointToSegment(environmentData.getAtmosphereCenter(), start, end);
+            glm::vec3 environmentPenetration;
-            float vectorLength = glm::length(vector);
+            if (findCapsuleSpherePenetration(start, end, radius, environmentData.getAtmosphereCenter(),
-            float distance = vectorLength - environmentData.getAtmosphereInnerRadius() - radius;
+                    environmentData.getAtmosphereInnerRadius(), environmentPenetration)) {
-            if (distance < 0.0f) {
+                penetration = addPenetrations(penetration, environmentPenetration);
-                penetration += vector * (-distance / vectorLength);
                 found = true;
             }
         }

libraries/voxels/src/AABox.cpp

@@ -11,6 +11,7 @@
 #include "SharedUtil.h"
 
 #include "AABox.h"
+#include "GeometryUtil.h"
 
 
 void AABox::scale(float scale) {
@@ -82,6 +83,17 @@ bool AABox::contains(const glm::vec3& point) const {
         isWithin(point.z, _corner.z, _size.z);
 }
 
+// determines whether a value is within the expanded extents
+static bool isWithinExpanded(float value, float corner, float size, float expansion) {
+    return value >= corner - expansion && value <= corner + size + expansion;
+}
+
+bool AABox::expandedContains(const glm::vec3& point, float expansion) const {
+    return isWithinExpanded(point.x, _corner.x, _size.x, expansion) &&
+        isWithinExpanded(point.y, _corner.y, _size.y, expansion) &&
+        isWithinExpanded(point.z, _corner.z, _size.z, expansion);
+}
+
 // finds the intersection between a ray and the facing plane on one axis
 static bool findIntersection(float origin, float direction, float corner, float size, float& distance) {
     if (direction > EPSILON) {
@@ -126,3 +138,61 @@ bool AABox::findRayIntersection(const glm::vec3& origin, const glm::vec3& direct
     }
     return false;
 }
+
+bool AABox::findSpherePenetration(const glm::vec3& center, float radius, glm::vec3& penetration) const {
+    glm::vec4 center4 = glm::vec4(center, 1.0f);
+    
+    float minPenetrationLength = FLT_MAX;
+    for (int i = 0; i < FACE_COUNT; i++) {
+        glm::vec3 vector = getClosestPointOnFace(center, (BoxFace)i) - center;
+        if (glm::dot(center4, getPlane((BoxFace)i)) >= 0.0f) {
+            return ::findSpherePenetration(vector, radius, penetration);
+        }
+        float vectorLength = glm::length(vector);
+        if (vectorLength < minPenetrationLength) {
+            penetration = vector * ((vectorLength + radius) / -vectorLength);
+            minPenetrationLength = vectorLength;
+        }
+    }
+    
+    return true;
+}
+
+glm::vec3 AABox::getClosestPointOnFace(const glm::vec3& point, BoxFace face) const {
+    switch (face) {
+        case MIN_X_FACE:
+            return glm::clamp(point, glm::vec3(_corner.x, _corner.y, _corner.z),
+                glm::vec3(_corner.x, _corner.y + _size.y, _corner.z + _size.z));
+        
+        case MAX_X_FACE:
+            return glm::clamp(point, glm::vec3(_corner.x + _size.x, _corner.y, _corner.z),
+                glm::vec3(_corner.x + _size.x, _corner.y + _size.y, _corner.z + _size.z));
+        
+        case MIN_Y_FACE:
+            return glm::clamp(point, glm::vec3(_corner.x, _corner.y, _corner.z),
+                glm::vec3(_corner.x + _size.x, _corner.y, _corner.z + _size.z));
+    
+        case MAX_Y_FACE:
+            return glm::clamp(point, glm::vec3(_corner.x, _corner.y + _size.y, _corner.z),
+                glm::vec3(_corner.x + _size.x, _corner.y + _size.y, _corner.z + _size.z));
+    
+        case MIN_Z_FACE:
+            return glm::clamp(point, glm::vec3(_corner.x, _corner.y, _corner.z),
+                glm::vec3(_corner.x + _size.x, _corner.y + _size.y, _corner.z));
+    
+        case MAX_Z_FACE:
+            return glm::clamp(point, glm::vec3(_corner.x, _corner.y, _corner.z + _size.z),
+                glm::vec3(_corner.x + _size.x, _corner.y + _size.y, _corner.z + _size.z));
+    }
+}
+
+glm::vec4 AABox::getPlane(BoxFace face) const {
+    switch (face) {
+        case MIN_X_FACE: return glm::vec4(-1.0f, 0.0f, 0.0f, _corner.x);
+        case MAX_X_FACE: return glm::vec4(1.0f, 0.0f, 0.0f, -_corner.x - _size.x);
+        case MIN_Y_FACE: return glm::vec4(0.0f, -1.0f, 0.0f, _corner.y);
+        case MAX_Y_FACE: return glm::vec4(0.0f, 1.0f, 0.0f, -_corner.y - _size.y);
+        case MIN_Z_FACE: return glm::vec4(0.0f, 0.0f, -1.0f, _corner.z);
+        case MAX_Z_FACE: return glm::vec4(0.0f, 0.0f, 1.0f, -_corner.z - _size.z);
+    }
+}

libraries/voxels/src/AABox.h

@@ -19,7 +19,8 @@ enum BoxFace {
     MIN_Y_FACE,
     MAX_Y_FACE,
     MIN_Z_FACE,
-    MAX_Z_FACE
+    MAX_Z_FACE,
+    FACE_COUNT
 };
 
 class AABox 
@@ -46,9 +47,15 @@ public:
 	const glm::vec3& getCenter() const { return _center; };
 
     bool contains(const glm::vec3& point) const;
+    bool expandedContains(const glm::vec3& point, float expansion) const;
     bool findRayIntersection(const glm::vec3& origin, const glm::vec3& direction, float& distance, BoxFace& face) const;
+    bool findSpherePenetration(const glm::vec3& center, float radius, glm::vec3& penetration) const;
 
 private:
+    
+    glm::vec3 getClosestPointOnFace(const glm::vec3& point, BoxFace face) const;
+    glm::vec4 getPlane(BoxFace face) const;
+    
 	glm::vec3 _corner;
 	glm::vec3 _center;
 	glm::vec3 _size;

libraries/voxels/src/GeometryUtil.cpp

@@ -7,7 +7,36 @@
 
 #include "GeometryUtil.h"
 
-glm::vec3 computeVectorFromPointToSegment(const glm::vec3& point, const glm::vec3& start, const glm::vec3& end) {
+bool findSpherePenetration(const glm::vec3& penetratorToPenetratee, float combinedRadius, glm::vec3& penetration) {
+    float vectorLength = glm::length(penetratorToPenetratee);
+    float distance = vectorLength - combinedRadius;
+    if (distance < 0.0f) {
+        penetration = penetratorToPenetratee * (-distance / vectorLength);
+        return true;
+    }
+    return false;
+}
+
+bool findSpherePointPenetration(const glm::vec3& penetratorCenter, float penetratorRadius,
+                                const glm::vec3& penetrateeLocation, glm::vec3& penetration) {
+    return findSpherePenetration(penetrateeLocation - penetratorCenter, penetratorRadius, penetration);
+}
+
+bool findSphereSpherePenetration(const glm::vec3& penetratorCenter, float penetratorRadius,
+                                 const glm::vec3& penetrateeCenter, float penetrateeRadius, glm::vec3& penetration) {
+    return findSpherePointPenetration(penetratorCenter, penetratorRadius + penetrateeRadius, penetrateeCenter, penetration);
+}
+
+bool findSphereLinePenetration(const glm::vec3& penetratorCenter, float penetratorRadius,
+                               const glm::vec3& penetrateeOrigin, const glm::vec3& penetrateeDirection,
+                               glm::vec3& penetration) {
+    // compute the projection of the penetrator vector onto the line
+    float proj = glm::dot(penetratorCenter - penetrateeOrigin, penetrateeDirection);
+    return findSpherePenetration((penetrateeOrigin + penetrateeDirection*proj) - penetratorCenter,
+        penetratorRadius, penetration);
+}
+
+static glm::vec3 computeVectorFromPointToSegment(const glm::vec3& point, const glm::vec3& start, const glm::vec3& end) {
     // compute the projection of the point vector onto the segment vector
     glm::vec3 segmentVector = end - start;
     float proj = glm::dot(point - start, segmentVector) / glm::dot(segmentVector, segmentVector);
@@ -21,3 +50,74 @@ glm::vec3 computeVectorFromPointToSegment(const glm::vec3& point, const glm::vec
         return start + segmentVector*proj - point;
     }
 }
+
+bool findSphereSegmentPenetration(const glm::vec3& penetratorCenter, float penetratorRadius,
+                                  const glm::vec3& penetrateeStart, const glm::vec3& penetrateeEnd, glm::vec3& penetration) {
+    return findSpherePenetration(computeVectorFromPointToSegment(penetratorCenter, penetrateeStart, penetrateeEnd),
+        penetratorRadius, penetration);
+}
+
+bool findSphereCapsulePenetration(const glm::vec3& penetratorCenter, float penetratorRadius, const glm::vec3& penetrateeStart,
+                                  const glm::vec3& penetrateeEnd, float penetrateeRadius, glm::vec3& penetration) {
+    return findSphereSegmentPenetration(penetratorCenter, penetratorRadius + penetrateeRadius,
+        penetrateeStart, penetrateeEnd, penetration);
+}
+
+bool findSpherePlanePenetration(const glm::vec3& penetratorCenter, float penetratorRadius, 
+                                const glm::vec4& penetrateePlane, glm::vec3& penetration) {
+    float distance = glm::dot(penetrateePlane, glm::vec4(penetratorCenter, 1.0f)) - penetratorRadius;
+    if (distance < 0.0f) {
+        penetration = glm::vec3(penetrateePlane) * distance;
+        return true;
+    }
+    return false;
+}
+
+bool findCapsulePointPenetration(const glm::vec3& penetratorStart, const glm::vec3& penetratorEnd, float penetratorRadius,
+                                 const glm::vec3& penetrateeLocation, glm::vec3& penetration) {
+    if (findSphereSegmentPenetration(penetrateeLocation, penetratorRadius, penetratorStart, penetratorEnd, penetration)) {
+        penetration = -penetration;
+        return true;
+    }
+    return false;
+}
+
+bool findCapsuleSpherePenetration(const glm::vec3& penetratorStart, const glm::vec3& penetratorEnd, float penetratorRadius,
+                                  const glm::vec3& penetrateeCenter, float penetrateeRadius, glm::vec3& penetration) {
+    if (findSphereCapsulePenetration(penetrateeCenter, penetrateeRadius,
+            penetratorStart, penetratorEnd, penetratorRadius, penetration)) {
+        penetration = -penetration;
+        return true;
+    }
+    return false;
+}
+
+bool findCapsulePlanePenetration(const glm::vec3& penetratorStart, const glm::vec3& penetratorEnd, float penetratorRadius,
+                                 const glm::vec4& penetrateePlane, glm::vec3& penetration) {
+    float distance = glm::min(glm::dot(penetrateePlane, glm::vec4(penetratorStart, 1.0f)),
+        glm::dot(penetrateePlane, glm::vec4(penetratorEnd, 1.0f))) - penetratorRadius;
+    if (distance < 0.0f) {
+        penetration = glm::vec3(penetrateePlane) * distance;
+        return true;
+    }
+    return false;
+}
+
+glm::vec3 addPenetrations(const glm::vec3& currentPenetration, const glm::vec3& newPenetration) {
+    // find the component of the new penetration in the direction of the current
+    float currentLength = glm::length(currentPenetration);
+    if (currentLength == 0.0f) {
+        return newPenetration;
+    }
+    glm::vec3 currentDirection = currentPenetration / currentLength;
+    float directionalComponent = glm::dot(newPenetration, currentDirection);
+    
+    // if orthogonal or in the opposite direction, we can simply add
+    if (directionalComponent <= 0.0f) {
+        return currentPenetration + newPenetration;
+    }
+    
+    // otherwise, we need to take the maximum component of current and new
+    return currentDirection * glm::max(directionalComponent, currentLength) +
+        newPenetration - (currentDirection * directionalComponent);
+}

libraries/voxels/src/GeometryUtil.h

@@ -11,6 +11,35 @@
 
 #include <glm/glm.hpp>
 
-glm::vec3 computeVectorFromPointToSegment(const glm::vec3& point, const glm::vec3& start, const glm::vec3& end);
+bool findSpherePenetration(const glm::vec3& penetratorToPenetratee, float combinedRadius, glm::vec3& penetration);
+
+bool findSpherePointPenetration(const glm::vec3& penetratorCenter, float penetratorRadius,
+                                const glm::vec3& penetrateeLocation, glm::vec3& penetration);
+
+bool findSphereSpherePenetration(const glm::vec3& penetratorCenter, float penetratorRadius,
+                                 const glm::vec3& penetrateeCenter, float penetrateeRadius, glm::vec3& penetration);
+                                
+bool findSphereLinePenetration(const glm::vec3& penetratorCenter, float penetratorRadius,
+                               const glm::vec3& penetrateeOrigin, const glm::vec3& penetrateeDirection, glm::vec3& penetration);
+
+bool findSphereSegmentPenetration(const glm::vec3& penetratorCenter, float penetratorRadius,
+                                  const glm::vec3& penetrateeStart, const glm::vec3& penetrateeEnd, glm::vec3& penetration);
+
+bool findSphereCapsulePenetration(const glm::vec3& penetratorCenter, float penetratorRadius, const glm::vec3& penetrateeStart,
+                                  const glm::vec3& penetrateeEnd, float penetrateeRadius, glm::vec3& penetration);
+                                  
+bool findSpherePlanePenetration(const glm::vec3& penetratorCenter, float penetratorRadius, 
+                                const glm::vec4& penetrateePlane, glm::vec3& penetration);
+
+bool findCapsulePointPenetration(const glm::vec3& penetratorStart, const glm::vec3& penetratorEnd, float penetratorRadius,
+                                 const glm::vec3& penetrateeLocation, glm::vec3& penetration);
+                                  
+bool findCapsuleSpherePenetration(const glm::vec3& penetratorStart, const glm::vec3& penetratorEnd, float penetratorRadius,
+                                  const glm::vec3& penetrateeCenter, float penetrateeRadius, glm::vec3& penetration);
+
+bool findCapsulePlanePenetration(const glm::vec3& penetratorStart, const glm::vec3& penetratorEnd, float penetratorRadius,
+                                 const glm::vec4& penetrateePlane, glm::vec3& penetration);
+
+glm::vec3 addPenetrations(const glm::vec3& currentPenetration, const glm::vec3& newPenetration);
 
 #endif /* defined(__interface__GeometryUtil__) */

libraries/voxels/src/VoxelTree.cpp

@@ -716,20 +716,20 @@ public:
 bool findSpherePenetrationOp(VoxelNode* node, void* extraData) {
     SphereArgs* args = static_cast<SphereArgs*>(extraData);
     
-    // currently, we treat each node as a sphere enveloping the box
+    // coarse check against bounds
-    const glm::vec3& nodeCenter = node->getCenter();
+    const AABox& box = node->getAABox();
-    glm::vec3 vector = args->center - nodeCenter;
+    if (!box.expandedContains(args->center, args->radius)) {
-    float vectorLength = glm::length(vector);
-    float distance = vectorLength - node->getEnclosingRadius() - args->radius;
-    if (distance >= 0.0f) {
         return false;
     }
     if (!node->isLeaf()) {
         return true; // recurse on children
     }
     if (node->isColored()) {
-        args->penetration += vector * (-distance * TREE_SCALE / vectorLength);
+        glm::vec3 nodePenetration;
-        args->found = true;
+        if (box.findSpherePenetration(args->center, args->radius, nodePenetration)) {
+            args->penetration = addPenetrations(args->penetration, nodePenetration * (float)TREE_SCALE);
+            args->found = true;
+        }        
     }
     return false;
 }
@@ -754,18 +754,16 @@ bool findCapsulePenetrationOp(VoxelNode* node, void* extraData) {
     CapsuleArgs* args = static_cast<CapsuleArgs*>(extraData);
     
     // currently, we treat each node as a sphere enveloping the box
-    const glm::vec3& nodeCenter = node->getCenter();
+    glm::vec3 nodePenetration;
-    glm::vec3 vector = computeVectorFromPointToSegment(nodeCenter, args->start, args->end);
+    if (!findCapsuleSpherePenetration(args->start, args->end, args->radius, node->getCenter(),
-    float vectorLength = glm::length(vector);
+            node->getEnclosingRadius(), nodePenetration)) {
-    float distance = vectorLength - node->getEnclosingRadius() - args->radius;
-    if (distance >= 0.0f) {
         return false;
     }
     if (!node->isLeaf()) {
         return true; // recurse on children
     }
     if (node->isColored()) {
-        args->penetration += vector * (-distance * TREE_SCALE / vectorLength);
+        args->penetration = addPenetrations(args->penetration, nodePenetration * (float)TREE_SCALE);
         args->found = true;
     }
     return false;