Adding raytesting for physics.

Rays collide with IBoundingObjects. Cameras can also ray test.
Material.String() and Animation.String() now print readably.
IBoundingObject now implements iNode as well.
collisionPlanes are now non-pointer referenced.
Broadphase.TrianglesFromBounding() now returns a pre-populated set of all triangles if the grid size is less than or equal to 1.
Camera Projection matrix is now cached when possible; camera alteration is now done using functions (SetPerspective(), SetFieldOfView(), etc).
Altering Matrix4.Inverted() to use a faster system from stackoverflow.
Adding NewCylinderMesh() function to make cylinder mesh.
Adding Camera.ScreenToWorld().

animation.go

@@ -1,6 +1,7 @@
 package tetra3d
 
 import (
+	"fmt"
 	"log"
 	"math"
 	"time"
@@ -213,6 +214,14 @@ func (animation *Animation) Library() *Library {
 	return animation.library
 }
 
+func (animation *Animation) String() string {
+	if ReadableReferences {
+		return "<" + animation.Name + ">"
+	} else {
+		return fmt.Sprintf("%p", animation)
+	}
+}
+
 // AnimationValues indicate the current position, scale, and rotation for a Node.
 type AnimationValues struct {
 	Position       Vector

bounds.go

@@ -175,6 +175,7 @@ type CollisionTestSettings struct {
 // concerning whether an object that implements IBoundingObject is colliding with another IBoundingObject, and
 // if so, by how much.
 type IBoundingObject interface {
+	INode
 	// Colliding returns true if the BoundingObject is intersecting the other BoundingObject.
 	Colliding(other IBoundingObject) bool
 	// Collision returns a Collision if the BoundingObject is intersecting another BoundingObject. If

boundsTriangles.go

@@ -147,8 +147,8 @@ type collisionPlane struct {
 	Distance float64
 }
 
-func newCollisionPlane() *collisionPlane {
-	return &collisionPlane{}
+func newCollisionPlane() collisionPlane {
+	return collisionPlane{}
 }
 
 func (plane *collisionPlane) Set(v0, v1, v2 Vector) {
@@ -170,6 +170,27 @@ func (plane *collisionPlane) ClosestPoint(point Vector) Vector {
 
 }
 
+func (plane *collisionPlane) RayAgainstPlane(from, to Vector) (Vector, bool) {
+
+	dir := to.Sub(from).Unit()
+
+	nd := dir.Dot(plane.Normal)
+	pn := from.Dot(plane.Normal)
+
+	if nd >= 0 {
+		return Vector{}, false
+	}
+
+	t := (plane.Distance - pn) / nd
+
+	if t >= 0 {
+		return from.Add(dir.Scale(t)), true
+	}
+
+	return Vector{}, false
+
+}
+
 var colPlane = newCollisionPlane()
 
 func closestPointOnTri(point, v0, v1, v2 Vector) Vector {

broadphase.go

@@ -15,6 +15,7 @@ type Broadphase struct {
 	Center            *Node
 	aabb              *BoundingAABB
 	TriSets           [][][][]uint16
+	allTriSet         map[uint16]bool
 	BoundingTriangles *BoundingTriangles
 }
 
@@ -57,6 +58,7 @@ func (bp *Broadphase) Clone() *Broadphase {
 	}
 
 	newBroadphase.TriSets = ts
+	newBroadphase.allTriSet = bp.allTriSet
 
 	return newBroadphase
 }
@@ -79,6 +81,7 @@ func (bp *Broadphase) Resize(gridSize int) {
 	bp.aabb.updateSize()
 
 	bp.TriSets = make([][][][]uint16, gridSize)
+	bp.allTriSet = make(map[uint16]bool)
 
 	hg := float64(bp.GridSize) / 2
 
@@ -108,6 +111,7 @@ func (bp *Broadphase) Resize(gridSize int) {
 					if bp.aabb.PointInside(closestOnTri) {
 						bp.TriSets[i][j][k] = append(bp.TriSets[i][j][k], tri.ID)
 					}
+					bp.allTriSet[tri.ID] = true
 
 				}
 
@@ -124,12 +128,8 @@ func (bp *Broadphase) Resize(gridSize int) {
 // once, of course.
 func (bp *Broadphase) TrianglesFromBounding(boundingObject IBoundingObject) map[uint16]bool {
 
-	if bp.GridSize <= 0 {
-		trianglesSet := make(map[uint16]bool, len(bp.BoundingTriangles.Mesh.Triangles))
-		for _, tri := range bp.BoundingTriangles.Mesh.Triangles {
-			trianglesSet[tri.ID] = true
-		}
-		return trianglesSet
+	if bp.GridSize <= 1 {
+		return bp.allTriSet
 	}
 
 	trianglesSet := make(map[uint16]bool, len(bp.TriSets))