/// <summary>
/// Computes the ratio between the area of the projected target inside frame, and the area inside viewport
/// </summary>
public float ComputeRatioInsideFrame(CLCameraMan camera, Rectangle frame)
{
if (this.screenArea < 0.00001)
{
// target is outside viewport or too small
return(0.0f);
}
// clip screen representation by provided frame
List <Vector2> partInFrame = new List <Vector2> (10);
TargetUtils.Clip(frame, screenRepresentation, partInFrame);
float framedArea = TargetUtils.ComputeScreenArea(partInFrame);
return(framedArea / this.screenArea);
}
/// <summary>
/// Computes and internally stores a screen representation of the target given the current camera. The screen
/// representation is in turn used to reason about properties like size, framing, ...
/// </summary>
/// <param name="currentCamera">camera from which rendering is performed</param>
/// <param name="performClipping">if true, we clip against the viewport. If not, screenArea can </param>
public void Render(CLCameraMan camera, bool performClipping = true)
{
screenRepresentation.Clear();
visibleBBVertices.Clear();
/**
* ok, so ... using the world-space AABB of the game object is not ideal because it appears it is the world AABB
* of the world-transformed local AABB of the mesh, see http://answers.unity3d.com/questions/292874/renderer-bounds.html
* Also, using the AABB of the colliderMesh does not help (it appears to be identical to the renderer AABB)
*
* Could transform the camera to local space and use the AABB of the mesh ...
*/
// world position of the camera
Vector3 eye = camera.unityCamera.transform.position;
Bounds AABB = boundingBox;
// World-space min-max corners of the target's AABB
Vector3 minCorner = AABB.min;
Vector3 maxCorner = AABB.max;
/** Calculate bit-string position to perform lookup in the table, real
* spatial relationship is not relevant, the relevant information is the
* vertex ordering */
int pos = ((eye.x < minCorner.x ? 1 : 0) << (int)TargetUtils.RelativePositioning.LEFT)
+ ((eye.x > maxCorner.x ? 1 : 0) << (int)TargetUtils.RelativePositioning.RIGHT)
+ ((eye.y < minCorner.y ? 1 : 0) << (int)TargetUtils.RelativePositioning.BOTTOM)
+ ((eye.y > maxCorner.y ? 1 : 0) << (int)TargetUtils.RelativePositioning.TOP)
+ ((eye.z < minCorner.z ? 1 : 0) << (int)TargetUtils.RelativePositioning.FRONT)
+ ((eye.z > maxCorner.z ? 1 : 0) << (int)TargetUtils.RelativePositioning.BACK);
// If camera inside bounding box return 0
numVisibleBBVertices = TargetUtils.Number(pos);
if (numVisibleBBVertices == 0)
{
this.screenArea = 0.0f;
screenAABB = new Rectangle(0.0f, 0.0f, 0.0f, 0.0f);
screenRatio = 0.0f;
return;
}
// Otherwise project vertices on screen
// Array for storing projected vertices
List <Vector2> projectedBBVertices = new List <Vector2> (10);
bool behindCamera = false;
// project each visibile vertex
for (int i = 0; i < numVisibleBBVertices; i++)
{
Vector3 visibleVertex = TargetUtils.ReturnAABBVertex(TargetUtils.Vertex(i, pos), AABB);
Vector3 projectedVertex = camera.unityCamera.WorldToViewportPoint(visibleVertex);
if (projectedVertex.z >= 0)
{
projectedBBVertices.Add(projectedVertex);
visibleBBVertices.Add(visibleVertex);
//Debug.Log ( newPoint.ToString("F5"));
}
else
{
behindCamera = true;
}
}
// clip them by viewport
if (performClipping)
{
TargetUtils.Clip(camera.clipRectangle, projectedBBVertices, screenRepresentation);
}
// if there are less than three vertices on screen, area is zero
if (screenRepresentation.Count < 3)
{
this.screenArea = 0;
screenAABB = new Rectangle(0.0f, 0.0f, 0.0f, 0.0f);
screenRatio = 0.0f;
}
else
{
// compute area
this.screenArea = Mathf.Min(TargetUtils.ComputeScreenArea(screenRepresentation), 1.0f);
// compute min and max vertices
Vector2 minPoint = screenRepresentation [0];
Vector2 maxPoint = screenRepresentation [1];
for (int i = 0; i < screenRepresentation.Count; i++)
{
if (minPoint.x > screenRepresentation [i].x)
{
minPoint.x = screenRepresentation [i].x;
}
if (minPoint.y > screenRepresentation [i].y)
{
minPoint.y = screenRepresentation [i].y;
}
if (maxPoint.x < screenRepresentation [i].x)
{
maxPoint.x = screenRepresentation [i].x;
}
if (maxPoint.y < screenRepresentation [i].y)
{
maxPoint.y = screenRepresentation [i].y;
}
}
screenAABB = new Rectangle(minPoint.x, maxPoint.x, minPoint.y, maxPoint.y);
if (!behindCamera)
{
screenRatio = this.screenArea / TargetUtils.ComputeScreenArea(projectedBBVertices);
}
else
{
screenRatio = 0.5f; // this is just a hack since otherwise bb projected points behind camera
}
// are simply thrown away and the target, while partially on screen,
// could be considered entirely on screen
if (screenRatio > 1.0f && performClipping)
{
screenRatio = 0.0f;
}
else if (screenRatio > 1.0f)
{
// this means we have no clipping and the projected AABB is greater than the viewport
screenRatio = 1.0f;
}
}
}