/* CompactModel.java Representation of a 3D model as a wire frame of line
segments tailored for use in a AWT drawing environment.
History:
10 Jun 2008 Extracted and adapted from Model3D class in ThreeD.java.
*/
/**
The representation of a 3D model. Used by ThreeD.
@see ThreeD
*/
public class CompactModel extends Model3D {
/**
A vertex index was used which is too large to fit in
the bitfield reserved for it.
@param s description of the situation
@see CompactModel#addLine
@see CompactModel#M_INDEX_MASK
@see CompactModel#M_INDEX_NBITS
*/
public class VertexOverflowException extends ModelException {
public VertexOverflowException(String s) {
super(s);
}
}
/**
Average x value (in model coordinates) for the figure.
*/
float m_xmean;
/**
Average y value (in model coordinates) for the figure.
*/
float m_ymean;
/**
Average z value (in model coordinates) for the figure.
*/
float m_zmean;
/**
Radius (in model coordinates) of the figure's bounding sphere.
*/
float m_radius;
/**
Untransformed (model) coordinates for all points.
*/
private float m_verts[];
/**
Size of used portion of vertex array.
*/
private int m_nverts;
/**
Minimum size of vertex and line arrays.
*/
static final int M_MIN_BUFFSIZE = 50;
/**
One integer for each line. There are two bitfields indicating
the indices of the endpoint vertices (0 based index), and a third bitfield
indicating a type. The latter value is used when the line is
painted to indicate how it should be rendered.
@see #M_INDEX_MASK
@see #M_INDEX_NBITS
@see #M_TYPE_MASK
@see #M_TYPE_NBITS
*/
private int m_lines[];
/**
Indicates how many of the values in m_lines are valid.
Incremented by addLine().
@see #m_lines
@see #addLine
*/
private int m_nlines;
/**
Mask used to extract the index bitfields from an integer containing
a line's description. Used by p1(), p2() and type() to decode
the integers in m_lines.
@see #m_lines
@see #p1
@see #p2
@see #type
*/
private static final int M_INDEX_MASK = 0x7FFF;
/**
Bit count used to extract the index and type
bitfields from an integer containing
a line's description. Used by addLine() to encode
and p1(), p2() and type() to decode the integers in m_lines.
It should be set to the number of set bits in M_INDEX_MASK.
@see #M_INDEX_MASK
@see #m_lines
@see #addLine
@see #p1
@see #p2
@see #type
*/
private static final int M_INDEX_NBITS = 15;
/**
Mask used to extract the type bitfield from an integer containing
a line's description. Used by addLine() to encode
and p1(), p2() and type() to decode the integers in m_lines.
@see #m_lines
@see #addLine
@see #p1
@see #p2
@see #type
*/
private static final int M_TYPE_MASK = 0x0003;
/**
Bit count used to extract the index and type
bitfields from an integer containing
a line's description. Used by addLine() to encode
and p1(), p2() and type() to decode the integers in m_lines.
It should be set to the number of set bits in M_TYPE_MASK.
@see #M_TYPE_MASK
@see #m_lines
@see #addLine
@see #p1
@see #p2
@see #type
*/
private static final int M_TYPE_NBITS = 2;
CompactModel() { }
/**
Initialize the model to the empty state.
*/
public void reset()
{
m_nverts = 0;
m_nlines = 0;
}
/**
See how many vertices are in the current model -- can also be
used to check if a model has been loaded.
*/
int nverts() { return m_nverts; }
/**
Get vertices for the current model.
*/
float[] verts() { return m_verts; }
/**
See how many lines are in the current model.
*/
int nlines() { return m_nlines; }
/**
Index of first end point for given line.
*/
int p1(int index)
{
return
((m_lines[index] >> (M_INDEX_NBITS + M_TYPE_NBITS)) & M_INDEX_MASK) * 3;
}
/**
Index of second end point for given line.
*/
int p2(int index)
{
return ((m_lines[index] >> M_TYPE_NBITS) & M_INDEX_MASK) * 3;
}
/**
Type value for given line.
*/
int type(int index) { return m_lines[index] & M_TYPE_MASK; }
/**
Add a vertex to this model.
Implements abstract method.
@param x x coordinate of point
@param y y coordinate of point
@param z z coordinate of point
@exception ModelException See exception documentation for reason.
*/
void addPoint(double x, double y, double z)
throws ModelException {
int i = m_nverts;
if (i >= M_INDEX_MASK) throw new VertexOverflowException(toString());
if (m_verts == null) m_verts = new float[M_MIN_BUFFSIZE * 3];
else if ((i + 1)*3 > m_verts.length) {
float nv[] = new float[m_verts.length*2];
System.arraycopy(m_verts, 0, nv, 0, m_verts.length);
m_verts = nv;
}
i *= 3;
m_verts[i] = (float)x;
m_verts[i + 1] = (float)y;
m_verts[i + 2] = (float)z;
m_nverts++;
}
/**
Add a line from vertex p1 to vertex p2 to the model's geometry.
Implements abstract method.
@param p1 zero-based index of first endpoint
@param p2 zero-based index of second endpoint
@param type type value for this line segment
@exception ModelException See exception documentation for reason.
*/
void addLineSegment(int p1, int p2, int val) {
val = val % 8;
int type = 0;
if (val == 0) return;
else if (val == 1) type = 1;
else if (val == 2 || val == 4 || val == 6) type = 2;
else if (val == 3 || val == 5) type = 3 ;
else type = 0 ;
if (p1 >= m_nverts || p2 >= m_nverts) return;
if (m_lines == null) m_lines = new int[M_MIN_BUFFSIZE];
else if (m_nlines >= m_lines.length) {
int nl[] = new int[m_lines.length*2];
System.arraycopy(m_lines, 0, nl, 0, m_lines.length);
m_lines = nl;
}
m_lines[m_nlines] = (p1 << (M_INDEX_NBITS + M_TYPE_NBITS)) |
(p2 << M_TYPE_NBITS) | (type & M_TYPE_MASK);
m_nlines++;
}
/**
Compute the bounding sphere (in model coordinates) of this model.
Implements abstract method.
@see #m_xmean
@see #m_ymean
@see #m_zmean
@see #m_radius
*/
void computeBoundingSphere() {
if (m_nverts <= 0) return;
// find center
m_xmean = 0;
m_ymean = 0;
m_zmean = 0;
for (int i = (m_nverts - 1)* 3; i >= 0; i -= 3) {
m_xmean += m_verts[i];
m_ymean += m_verts[i + 1];
m_zmean += m_verts[i + 2];
}
m_xmean /= m_nverts;
m_ymean /= m_nverts;
m_zmean /= m_nverts;
// find radius
m_radius = 0;
for (int i = (m_nverts - 1)* 3; i >= 0; i -= 3) {
float dx = m_verts[i] - m_xmean;
float dy = m_verts[i + 1] - m_ymean;
float dz = m_verts[i + 2] - m_zmean;
float radius = dx*dx + dy*dy + dz*dz;
if (radius > m_radius) m_radius = radius;
}
m_radius = (float)Math.sqrt(m_radius);
}
}