CC3Vector CC3Camera::getProjectLocation( const CC3Vector& a3DLocation )
{
// Convert specified location to a 4D homogeneous location vector
// and transform it using the modelview and projection matrices.
CC3Vector4 hLoc;
hLoc.fromLocation(a3DLocation);
hLoc = getViewMatrix()->transformHomogeneousVector( hLoc );
hLoc = getProjectionMatrix()->transformHomogeneousVector( hLoc );
// Convert projected 4D vector back to 3D.
CC3Vector projectedLoc = hLoc.homogenizedCC3Vector();
// The projected vector is in a projection coordinate space between -1 and +1 on all axes.
// Normalize the vector so that each component is between 0 and 1 by calculating ( v = (v + 1) / 2 ).
projectedLoc = projectedLoc.average( CC3Vector::kCC3VectorUnitCube );
CCAssert(_viewport.h > 0 && _viewport.w > 0, "%CC3Camera does not have a valid viewport");
// Map the X & Y components of the projected location (now between 0 and 1) to display coordinates.
GLfloat g2p = 1.0f / CCDirector::sharedDirector()->getContentScaleFactor();
projectedLoc.x *= ((GLfloat)_viewport.w * g2p);
projectedLoc.y *= ((GLfloat)_viewport.h * g2p);
// Using the vector from the camera to the 3D location, determine whether or not the
// 3D location is in front of the camera by using the dot-product of that vector and
// the direction the camera is pointing. Set the Z-component of the projected location
// to be the signed distance from the camera to the 3D location, with a positive sign
// indicating the location is in front of the camera, and a negative sign indicating
// the location is behind the camera.
CC3Vector camToLocVector = a3DLocation - getGlobalLocation();
GLfloat camToLocDist = camToLocVector.length();
GLfloat frontOrBack = (GLfloat)SIGN( camToLocVector.dot( getGlobalForwardDirection() ) );
projectedLoc.z = frontOrBack * camToLocDist;
//LogTrace(@"%@ projecting location %@ to %@ and orienting with device to %@ using viewport %@",
// self, NSStringFromCC3Vector(a3DLocation), NSStringFromCC3Vector(projectedLoc),
// NSStringFromCC3Vector(orientedLoc), NSStringFromCC3Viewport(_viewport));
return projectedLoc;
}
CC3Vector CC3Camera::calculateLocationToShowAllOf( CC3Node* aNode, const CC3Vector& targLoc, const CC3Vector& aDirection, GLfloat padding, bool checkScene )
{
ensureSceneUpdated( checkScene );
// Complementary unit vectors pointing towards camera from node, and vice versa
CC3Vector camDir = aDirection.normalize();
CC3Vector viewDir = camDir.negate();
// The camera's new forward direction will be viewDir. Use a matrix to detrmine
// the camera's new up and right directions assuming the same scene up direction.
CC3Matrix3x3 rotMtx;
CC3Matrix3x3PopulateToPointTowards(&rotMtx, viewDir, getReferenceUpDirection());
CC3Vector upDir = CC3Matrix3x3ExtractUpDirection(&rotMtx);
CC3Vector rtDir = CC3Matrix3x3ExtractRightDirection(&rotMtx);
// Determine the eight vertices, of the node's bounding box, in the global coordinate system
CC3Box gbb = aNode->getGlobalBoundingBox();
CC3Vector targetLoc = targLoc;
// If a target location has not been specified, use the center of the node's global bounding box
if ( targetLoc.isNull() )
targetLoc = gbb.getCenter();
CC3Vector bbMin = gbb.minimum;
CC3Vector bbMax = gbb.maximum;
CC3Vector bbVertices[8];
bbVertices[0] = cc3v(bbMin.x, bbMin.y, bbMin.z);
bbVertices[1] = cc3v(bbMin.x, bbMin.y, bbMax.z);
bbVertices[2] = cc3v(bbMin.x, bbMax.y, bbMin.z);
bbVertices[3] = cc3v(bbMin.x, bbMax.y, bbMax.z);
bbVertices[4] = cc3v(bbMax.x, bbMin.y, bbMin.z);
bbVertices[5] = cc3v(bbMax.x, bbMin.y, bbMax.z);
bbVertices[6] = cc3v(bbMax.x, bbMax.y, bbMin.z);
bbVertices[7] = cc3v(bbMax.x, bbMax.y, bbMax.z);
// Express the camera's FOV in terms of ratios of the near clip bounds to
// the near clip distance, so we can determine distances using similar triangles.
CCSize fovRatios = getFovRatios();
// Iterate through all eight vertices of the node's bounding box, and calculate
// the largest distance required to place the camera away from the center of the
// node in order to fit all eight vertices within the camera's frustum.
// Simultaneously, calculate the extra distance from the center of the node to
// the vertex that will be farthest from the camera, so we can ensure that all
// vertices will fall within the frustum's far end.
GLfloat maxCtrDist = 0;
GLfloat maxVtxDeltaDist = 0;
GLfloat minVtxDeltaDist = 0;
for (int i = 0; i < 8; i++)
{
// Get a vector from the target location to the vertex
CC3Vector relVtx = bbVertices[i] - targetLoc;
// Project that vector onto each of the camera's new up and right directions,
// and use similar triangles to determine the distance at which to place the
// camera so that the vertex will fit in both the up and right directions.
GLfloat vtxDistUp = fabs(relVtx.dot( upDir ) / fovRatios.height);
GLfloat vtxDistRt = fabs(relVtx.dot( rtDir ) / fovRatios.width);
GLfloat vtxDist = MAX(vtxDistUp, vtxDistRt);
// Calculate how far along the view direction the vertex is from the center
GLfloat vtxDeltaDist = relVtx.dot( viewDir );
GLfloat ctrDist = vtxDist - vtxDeltaDist;
// Accumulate the maximum distance from the node's center to the camera
// required to fit all eight points, and the distance from the node's
// center to the vertex that will be farthest away from the camera.
maxCtrDist = MAX(maxCtrDist, ctrDist);
maxVtxDeltaDist = MAX(maxVtxDeltaDist, vtxDeltaDist);
minVtxDeltaDist = MIN(minVtxDeltaDist, vtxDeltaDist);
}
// Add some padding so we will have a bit of space around the node when it fills the view.
maxCtrDist *= (1 + padding);
// Determine if we need to move the far end of the camera frustum farther away
GLfloat farClip = viewDir.scaleUniform(maxCtrDist + maxVtxDeltaDist).length();
farClip *= (GLfloat)(1 + kCC3FrustumFitPadding); // Include a little bit of padding
if (farClip > getFarClippingDistance())
setFarClippingDistance( farClip );
// Determine if we need to move the near end of the camera frustum closer
GLfloat nearClip = viewDir.scaleUniform(maxCtrDist + minVtxDeltaDist).length();
nearClip *= (GLfloat)(1 - kCC3FrustumFitPadding); // Include a little bit of padding
if (nearClip < getNearClippingDistance())
setNearClippingDistance( nearClip );
//LogTrace(@"%@ moving to %@ to show %@ at %@ within %@ with new farClip: %.3f", self,
// NSStringFromCC3Vector(CC3VectorAdd(targLoc, CC3VectorScaleUniform(camDir, maxCtrDist))),
// aNode, NSStringFromCC3Vector(targLoc), _frustum, self.farClippingDistance);
// Return the new location of the camera,
return targetLoc.add( camDir.scaleUniform( maxCtrDist ) );
}
