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/** CSci-4611 Assignment 6: Harold
*/
#ifndef BILLBOARDS_H_
#define BILLBOARDS_H_
#include <mingfx.h>
using namespace mingfx;
#include "ground.h"
/** Billboards are strokes planted in the ground that rotate automatically to
face the viewer. This class holds the entire collection of billboard strokes.
*/
class Billboards {
public:
Billboards();
virtual ~Billboards();
void Init(ShaderProgram *stroke3d_shaderprog);
/// Projects a 2D normalized screen point (e.g., the mouse position in normalized
/// device coordinates) to a 3D point on a plane defined by an "origin", which can
/// really be any point coincident with the plane, and the plane normal. Returns
/// true if the screen point projects onto the plane and stores the result in
/// plane_point. Returns false if the screen point does not project onto the plane.
bool ScreenPtHitsPlane(const Matrix4 &view_matrix, const Matrix4 &proj_matrix,
const Point3 &plane_origin, const Vector3 &plane_normal,
const Point2 &normalized_screen_pt, Point3 *plane_point);
/// Checks to see if a ray starting at the eye point and passing through 2D
/// normalized screen point projects onto any of the billboards in the scene. If
/// so, returns the id of the closest billboard intersected. If not, returns -1.
int IntersectBillboard(const Matrix4 &view_matrix, const Matrix4 &proj_matrix,
const Point2 &normalized_screen_pt);
/// Adds a new stroke as a billboard by projecting it onto a plane parallel
/// to the filmplane that intersects with the anchor point, which should lie
/// on the ground.
void AddBillboardStroke(const Matrix4 &view_matrix, const Matrix4 &proj_matrix,
const std::vector<Point2> &stroke2d, const Mesh &stroke2d_mesh,
const Color &stroke_color, Ground *ground_ptr);
/// Edits an existing billboard by adding an additional stroke to it.
void AddToBillboard(const Matrix4 &view_matrix, const Matrix4 &proj_matrix,
int billboard_id, const Mesh &stroke2d_mesh,
const Color &stroke_color);
/// Adjusts the transformation matrix used to draw each billboard so that the
/// billboard will face the camera. Needs to be called each time the camera
/// is moved within the scene.
void UpdateBillboardRotations(const Point3 ¤t_eye_point);
/// Draws all of the billboards
void Draw(const Matrix4 &view_matrix, const Matrix4 &proj_matrix);
private:
// each billboard stores the following
struct Billboard {
Mesh mesh;
Color color;
Point3 anchor_pt;
AABB bounding_box;
Matrix4 transform;
};
// the array of all active billboards
std::vector<Billboard> billboards_;
ShaderProgram *stroke3d_shaderprog_;
};
#endif
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