From a12dd916fafe29cdc532c267af84e169c1392ab0 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Thu, 10 Apr 2014 11:24:45 -0700
Subject: [PATCH] More plane intersection bits.

---
 interface/src/renderer/Model.cpp       |  2 +-
 libraries/shared/src/PlaneShape.h      | 10 ++----
 libraries/shared/src/ShapeCollider.cpp | 43 +++++++++++++++++++++++++-
 3 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/interface/src/renderer/Model.cpp b/interface/src/renderer/Model.cpp
index a317ddc07a..2d47a077b7 100644
--- a/interface/src/renderer/Model.cpp
+++ b/interface/src/renderer/Model.cpp
@@ -638,7 +638,7 @@ bool Model::findPlaneCollisions(const glm::vec4& plane, CollisionList& collision
     bool collided = false;
     PlaneShape planeShape(plane);
     for (int i = 0; i < _jointShapes.size(); i++) {
-        if (ShapeCollider::shapeShape(&planeShape, _jointShapes[i], collisions)) {
+        if (ShapeCollider::collideShapes(&planeShape, _jointShapes[i], collisions)) {
             CollisionInfo* collision = collisions.getLastCollision();
             collision->_type = MODEL_COLLISION;
             collision->_data = (void*)(this);
diff --git a/libraries/shared/src/PlaneShape.h b/libraries/shared/src/PlaneShape.h
index 11823da701..524d53ec73 100644
--- a/libraries/shared/src/PlaneShape.h
+++ b/libraries/shared/src/PlaneShape.h
@@ -16,15 +16,9 @@
 
 class PlaneShape : public Shape {
 public:
-    PlaneShape() : Shape(Shape::PLANE_SHAPE) {}
-
-    PlaneShape(const glm::vec4& coefficients) : Shape(Shape::PLANE_SHAPE), _coefficients(coefficients) { }
+    PlaneShape(const glm::vec4& coefficients = glm::vec4(0.0f, 1.0f, 0.0f, 0.0f));
     
-    const glm::vec4& getCoefficients() const { return _coefficients; }
-
-private:
-    
-    glm::vec4 _coefficients;
+    glm::vec4 getCoefficients() const;
 };
 
 #endif // hifi_PlaneShape_h
diff --git a/libraries/shared/src/ShapeCollider.cpp b/libraries/shared/src/ShapeCollider.cpp
index 10211f1d78..c53c7fab7d 100644
--- a/libraries/shared/src/ShapeCollider.cpp
+++ b/libraries/shared/src/ShapeCollider.cpp
@@ -191,7 +191,7 @@ bool spherePlane(const SphereShape* sphereA, const PlaneShape* planeB, Collision
             return false; // collision list is full
         }
         collision->_penetration = penetration;
-        collision->_contactPoint = glm::vec3();
+        collision->_contactPoint = sphereA->getPosition() + sphereA->getRadius() * glm::normalize(penetration);
         return true;
     }
     return false;
@@ -404,18 +404,59 @@ bool capsuleCapsule(const CapsuleShape* capsuleA, const CapsuleShape* capsuleB,
 }
 
 bool capsulePlane(const CapsuleShape* capsuleA, const PlaneShape* planeB, CollisionList& collisions) {
+    glm::vec3 start, end, penetration;
+    capsuleA->getStartPoint(start);
+    capsuleA->getEndPoint(end);
+    glm::vec4 plane = planeB->getCoefficients();
+    if (findCapsulePlanePenetration(start, end, capsuleA->getRadius(), plane, penetration)) {
+        CollisionInfo* collision = collisions.getNewCollision();
+        if (!collision) {
+            return false; // collision list is full
+        }
+        collision->_penetration = penetration;
+        glm::vec3 deepestEnd = (glm::dot(start, glm::vec3(plane)) < glm::dot(end, glm::vec3(plane))) ? start : end;
+        collision->_contactPoint = deepestEnd + capsuleA->getRadius() * glm::normalize(penetration);
+        return true;
+    }
     return false;
 }
 
 bool planeSphere(const PlaneShape* planeA, const SphereShape* sphereB, CollisionList& collisions) {
+    glm::vec3 penetration;
+    if (findSpherePlanePenetration(sphereB->getPosition(), sphereB->getRadius(), planeA->getCoefficients(), penetration)) {
+        CollisionInfo* collision = collisions.getNewCollision();
+        if (!collision) {
+            return false; // collision list is full
+        }
+        collision->_penetration = -penetration;
+        collision->_contactPoint = sphereB->getPosition() +
+            (sphereB->getRadius() / glm::length(penetration) - 1.0f) * penetration;
+        return true;
+    }
     return false;
 }
 
 bool planeCapsule(const PlaneShape* planeA, const CapsuleShape* capsuleB, CollisionList& collisions) {
+    glm::vec3 start, end, penetration;
+    capsuleB->getStartPoint(start);
+    capsuleB->getEndPoint(end);
+    glm::vec4 plane = planeA->getCoefficients();
+    if (findCapsulePlanePenetration(start, end, capsuleB->getRadius(), plane, penetration)) {
+        CollisionInfo* collision = collisions.getNewCollision();
+        if (!collision) {
+            return false; // collision list is full
+        }
+        collision->_penetration = -penetration;
+        glm::vec3 deepestEnd = (glm::dot(start, glm::vec3(plane)) < glm::dot(end, glm::vec3(plane))) ? start : end;
+        collision->_contactPoint = deepestEnd + (capsuleB->getRadius() / glm::length(penetration) - 1.0f) * penetration;
+        return true;
+    }
     return false;
 }
 
 bool planePlane(const PlaneShape* planeA, const PlaneShape* planeB, CollisionList& collisions) {
+    // technically, planes always collide unless they're parallel and not coincident; however, that's
+    // not going to give us any useful information
     return false;
 }