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package com.jme3.scene.plugins.blender.curves;
import com.jme3.math.Vector3f;
import com.jme3.scene.plugins.blender.file.DynamicArray;
import com.jme3.scene.plugins.blender.file.Structure;
import java.util.ArrayList;
import java.util.List;
/**
* A class that helps to calculate the bezier curves calues. It uses doubles for performing calculations to minimize
* floating point operations errors.
* @author Marcin Roguski
*/
public class BezierCurve {
public static final int X_VALUE = 0;
public static final int Y_VALUE = 1;
public static final int Z_VALUE = 2;
/**
* The type of the curve. Describes the data it modifies.
* Used in ipos calculations.
*/
private int type;
/** The dimension of the curve. */
private int dimension;
/** A table of the bezier points. */
private float[][][] bezierPoints;
@SuppressWarnings("unchecked")
public BezierCurve(final int type, final List<Structure> bezTriples, final int dimension) {
if (dimension != 2 && dimension != 3) {
throw new IllegalArgumentException("The dimension of the curve should be 2 or 3!");
}
this.type = type;
this.dimension = dimension;
//first index of the bezierPoints table has the length of triples amount
//the second index points to a table od three points of a bezier triple (handle, point, handle)
//the third index specifies the coordinates of the specific point in a bezier triple
bezierPoints = new float[bezTriples.size()][3][dimension];
int i = 0, j, k;
for (Structure bezTriple : bezTriples) {
DynamicArray<Number> vec = (DynamicArray<Number>) bezTriple.getFieldValue("vec");
for (j = 0; j < 3; ++j) {
for (k = 0; k < dimension; ++k) {
bezierPoints[i][j][k] = vec.get(j, k).floatValue();
}
}
++i;
}
}
/**
* This method evaluates the data for the specified frame. The Y value is returned.
* @param frame
* the frame for which the value is being calculated
* @param valuePart
* this param specifies wheather we should return the X, Y or Z part of the result value; it should have
* one of the following values: X_VALUE - the X factor of the result Y_VALUE - the Y factor of the result
* Z_VALUE - the Z factor of the result
* @return the value of the curve
*/
public float evaluate(int frame, int valuePart) {
for (int i = 0; i < bezierPoints.length - 1; ++i) {
if (frame >= bezierPoints[i][1][0] && frame <= bezierPoints[i + 1][1][0]) {
float t = (frame - bezierPoints[i][1][0]) / (bezierPoints[i + 1][1][0] - bezierPoints[i][1][0]);
float oneMinusT = 1.0f - t;
float oneMinusT2 = oneMinusT * oneMinusT;
float t2 = t * t;
return bezierPoints[i][1][valuePart] * oneMinusT2 * oneMinusT + 3.0f * bezierPoints[i][2][valuePart] * t * oneMinusT2 + 3.0f * bezierPoints[i + 1][0][valuePart] * t2 * oneMinusT + bezierPoints[i + 1][1][valuePart] * t2 * t;
}
}
if (frame < bezierPoints[0][1][0]) {
return bezierPoints[0][1][1];
} else { //frame>bezierPoints[bezierPoints.length-1][1][0]
return bezierPoints[bezierPoints.length - 1][1][1];
}
}
/**
* This method returns the frame where last bezier triple center point of the bezier curve is located.
* @return the frame number of the last defined bezier triple point for the curve
*/
public int getLastFrame() {
return (int) bezierPoints[bezierPoints.length - 1][1][0];
}
/**
* This method returns the type of the bezier curve. The type describes the parameter that this curve modifies
* (ie. LocationX or rotationW of the feature).
* @return the type of the bezier curve
*/
public int getType() {
return type;
}
/**
* This method returns a list of control points for this curve.
* @return a list of control points for this curve.
*/
public List<Vector3f> getControlPoints() {
List<Vector3f> controlPoints = new ArrayList<Vector3f>(bezierPoints.length * 3);
for (int i = 0; i < bezierPoints.length; ++i) {
controlPoints.add(new Vector3f(bezierPoints[i][0][0], bezierPoints[i][0][1], bezierPoints[i][0][2]));
controlPoints.add(new Vector3f(bezierPoints[i][1][0], bezierPoints[i][1][1], bezierPoints[i][1][2]));
controlPoints.add(new Vector3f(bezierPoints[i][2][0], bezierPoints[i][2][1], bezierPoints[i][2][2]));
}
return controlPoints;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("Bezier curve: ").append(type).append('\n');
for (int i = 0; i < bezierPoints.length; ++i) {
sb.append(this.toStringBezTriple(i)).append('\n');
}
return sb.toString();
}
/**
* This method converts the bezier triple of a specified index into text.
* @param tripleIndex
* index of the triple
* @return text representation of the triple
*/
private String toStringBezTriple(int tripleIndex) {
if (this.dimension == 2) {
return "[(" + bezierPoints[tripleIndex][0][0] + ", " + bezierPoints[tripleIndex][0][1] + ") ("
+ bezierPoints[tripleIndex][1][0] + ", " + bezierPoints[tripleIndex][1][1] + ") ("
+ bezierPoints[tripleIndex][2][0] + ", " + bezierPoints[tripleIndex][2][1] + ")]";
} else {
return "[(" + bezierPoints[tripleIndex][0][0] + ", " + bezierPoints[tripleIndex][0][1] + ", " + bezierPoints[tripleIndex][0][2] + ") ("
+ bezierPoints[tripleIndex][1][0] + ", " + bezierPoints[tripleIndex][1][1] + ", " + bezierPoints[tripleIndex][1][2] + ") ("
+ bezierPoints[tripleIndex][2][0] + ", " + bezierPoints[tripleIndex][2][1] + ", " + bezierPoints[tripleIndex][2][2] + ")]";
}
}
}
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