set3DViewingInformation

EXERCISE: Suppose the overall MC bounding box returned from Controller::getOverallMCBoundingBox and passed into set3DViewingInformation is:

For both Viewing Strategy #1 and #2, answer the following:

1. What values would you pass to ModelView::setMCRegionOfInterest?
2. What values would you compute for center, eye, and up?
3. Assuming a perspective projection, what values would you specify for ecZmin, ecZmax, and ecZpp?
4. In ModelView::getMatrices, what would be computed for ecXmin, ecXmax, ecYmin, and ecYmax?

void set3DViewingInformation(double overallMCBB[])
{
	// ENTRY: overallMCBB has the MC xyz limits of the scene you created.

	// IF using Viewing Strategy #1 THEN
	// Tell class ModelView we initially want to see the whole scene:
	// 1. ModelView::setMCRegionOfInterest(overallMCBB);
	// ELSE (Viewing Strategy #2)
	// 1. Adjust the incoming overallMCBB so that all three Δs:
	//    (i) are the same, (ii) reflect the desired field of view, and
	//    (iii) do not alter the midpoint of the overallMCBB.
	// 2. ModelView::setMCRegionOfInterest(modified_overallMCBB);
	// 3. Tell the ModelView class that dynamic rotations are to be done about the eye.
	//
	// In either case, the ROI can be changed interactively at any time.
	// The MC ROI is used in ModelView::getMatrices to compute the eye coordinate
	// x and y extents of the viewing frustum on the projection plane.

	// MC ⇒ EC:

	// Determine an initial view of your scene:
	// Our approach: create the line of sight through the center of the scene:
	// 1. Center of attention should be midpoint of overallMCBB
	// 2. Eye point should be: Eye = Center + vector, for some suitable vector.
	// 3. up vector needs to be set according to your desired MC "up" direction.
	// Our implementation of projection transformation assumes the line of sight
	// is through the center of the scene!
	cryph::AffPoint eye(0, 0, 1), center; // compute values as stated above!
	cryph::AffVector up(0,1,0); // compute a value as stated above!
	ModelView::setEyeCenterUp(eye, center, up);

	// EC ⇒ LDS

	// Specify the projection type desired (initial value; can be changed interactively)
	ModelView::setProjection(PERSPECTIVE);

	// Determine the EC z parameters for the projection you want. (The EC (x, y)
	// limits will be set during display callbacks in getMatrices as we will see.)
	// 1. ecZmin and ecZmax need to be set based on the DISTANCE between the eye
	//    point and the center of attention so as to ensure that unwanted depth
	//    clipping does not occur.
	//    CONSTRAINTS: (i) ecZmin < ecZmax; (ii) if perspective, ecZmax < 0.
	//    (This will be used in ModelView::getMatrices to set the eye coordinate z
	//    extent of the viewing frustum.)
	double ecZmin = -2.0, ecZmax = -0.05; // compute values as stated above!
	ModelView::setECZminZmax(ecZmin, ecZmax);

	// 2. Place the projection plane. One possible initial placement is at the
	//    front of the scene, e.g.: ecZpp = ecZmax. We will discuss in class
	//    other possible projection plane placements and how to decide what you want.
	//    CONSTRAINT: if perspective: ecZpp < 0
	//    (This will be used in ModelView::getMatrices to set the eye coordinate z
	//    location of the projection plane which is perpendicular to the eye
	//    coordinate z-axis.)
	double ecZpp = -1.0; // compute a value as stated above!
	ModelView::setProjectionPlaneZ(ecZpp);
}