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Break up the area/cg test cases and add some documentation describing

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what they are doing.
This commit is contained in:
kruland2607 2012-10-06 21:03:08 -05:00
parent d8edf41355
commit ecac762940
1 changed files with 112 additions and 71 deletions

183
core/test/net/sf/openrocket/rocketcomponent/FinSetTest.java

@ -22,9 +22,10 @@ import org.junit.Test;
public class FinSetTest extends BaseTestCase { public class FinSetTest extends BaseTestCase {
@Test @Test
public void testCGComputation() throws Exception { public void testTrapezoidCGComputation() {
{ {
// This is a simple square fin with sides of 1.0.
TrapezoidFinSet fins = new TrapezoidFinSet(); TrapezoidFinSet fins = new TrapezoidFinSet();
fins.setFinCount(1); fins.setFinCount(1);
fins.setFinShape(1.0, 1.0, 0.0, 1.0, .005); fins.setFinShape(1.0, 1.0, 0.0, 1.0, .005);
@ -36,6 +37,12 @@ public class FinSetTest extends BaseTestCase {
} }
{ {
// This is a trapezoid. Height 1, root 1, tip 1/2 no sweep.
// It can be decomposed into a rectangle followed by a triangle
// +---+
// | \
// | \
// +------+
TrapezoidFinSet fins = new TrapezoidFinSet(); TrapezoidFinSet fins = new TrapezoidFinSet();
fins.setFinCount(1); fins.setFinCount(1);
fins.setFinShape(1.0, 0.5, 0.0, 1.0, .005); fins.setFinShape(1.0, 0.5, 0.0, 1.0, .005);
@ -45,83 +52,117 @@ public class FinSetTest extends BaseTestCase {
assertEquals(0.3889, coords.x, 0.001); assertEquals(0.3889, coords.x, 0.001);
assertEquals(0.4444, coords.y, 0.001); assertEquals(0.4444, coords.y, 0.001);
} }
}
@Test
public void testFreeformCGComputation() throws Exception {
{
// This is a trapezoid. Height 1, root 1, tip 1/2 no sweep.
// It can be decomposed into a rectangle followed by a triangle
// +---+
// | \
// | \
// +------+
FreeformFinSet fins = new FreeformFinSet();
fins.setFinCount(1);
Coordinate[] points = new Coordinate[] {
new Coordinate(0,0),
new Coordinate(0,1),
new Coordinate(.5,1),
new Coordinate(1,0)
};
fins.setPoints(points);
Coordinate coords = fins.getCG();
assertEquals(0.75, fins.getFinArea(), 0.001);
assertEquals(0.3889, coords.x, 0.001);
assertEquals(0.4444, coords.y, 0.001);
}
{
// This is the same trapezoid as previous free form, but it has
// some extra points along the lines.
FreeformFinSet fins = new FreeformFinSet();
fins.setFinCount(1);
Coordinate[] points = new Coordinate[] {
new Coordinate(0,0),
new Coordinate(0,.5),
new Coordinate(0,1),
new Coordinate(.25,1),
new Coordinate(.5,1),
new Coordinate(.75,.5),
new Coordinate(1,0)
};
fins.setPoints(points);
Coordinate coords = fins.getCG();
assertEquals(0.75, fins.getFinArea(), 0.001);
assertEquals(0.3889, coords.x, 0.001);
assertEquals(0.4444, coords.y, 0.001);
}
{
// This is the same trapezoid as previous free form, but it has
// some extra points which are very close to previous points.
// in particular for points 0 & 1,
// y0 + y1 is very small.
FreeformFinSet fins = new FreeformFinSet();
fins.setFinCount(1);
Coordinate[] points = new Coordinate[] {
new Coordinate(0,0),
new Coordinate(0,1E-15),
new Coordinate(0,1),
new Coordinate(1E-15,1),
new Coordinate(.5,1),
new Coordinate(.5,1-1E-15),
new Coordinate(1,1E-15),
new Coordinate(1,0)
};
fins.setPoints(points);
Coordinate coords = fins.getCG();
assertEquals(0.75, fins.getFinArea(), 0.001);
assertEquals(0.3889, coords.x, 0.001);
assertEquals(0.4444, coords.y, 0.001);
}
}
@Test
public void testFreeFormCGWithNegativeY() throws Exception {
// This particular fin shape is currently not allowed in OR since the y values are negative
// however, it is possible to convert RockSim files and end up with fins which
// have negative y values.
{ // A user submitted an ork file which could not be simulated because the fin
// This is the same shape as the previous TrapezoidFinSet. // was constructed on a tail cone. It so happened that for one pair of points
FreeformFinSet fins = new FreeformFinSet(); // y_n = - y_(n+1) which caused a divide by zero and resulted in CGx = NaN.
fins.setFinCount(1);
Coordinate[] points = new Coordinate[] { // This Fin set is constructed to have the same problem. It is a square and rectagle
new Coordinate(0,0), // where the two trailing edge corners of the rectangle satisfy y_0 = -y_1
new Coordinate(0,1), //
new Coordinate(.5,1), // +---------+
new Coordinate(1,0) // | |
}; // | |
fins.setPoints(points); // +----+ |
Coordinate coords = fins.getCG(); // | |
assertEquals(0.75, fins.getFinArea(), 0.001); // | |
assertEquals(0.3889, coords.x, 0.001); // +----+
assertEquals(0.4444, coords.y, 0.001);
} FreeformFinSet fins = new FreeformFinSet();
fins.setFinCount(1);
{ Coordinate[] points = new Coordinate[] {
// Add some superfluous points which are on the outline but "far apart"
FreeformFinSet fins = new FreeformFinSet();
fins.setFinCount(1);
Coordinate[] points = new Coordinate[] {
new Coordinate(0,0),
new Coordinate(0,.5),
new Coordinate(0,1),
new Coordinate(.25,1),
new Coordinate(.5,1),
new Coordinate(.75,.5),
new Coordinate(1,0)
};
fins.setPoints(points);
Coordinate coords = fins.getCG();
assertEquals(0.75, fins.getFinArea(), 0.001);
assertEquals(0.3889, coords.x, 0.001);
assertEquals(0.4444, coords.y, 0.001);
}
{
// add some points which are close
FreeformFinSet fins = new FreeformFinSet();
fins.setFinCount(1);
Coordinate[] points = new Coordinate[] {
new Coordinate(0,0),
new Coordinate(0,1E-15),
new Coordinate(0,1),
new Coordinate(1E-15,1),
new Coordinate(.5,1),
new Coordinate(.5,1-1E-15),
new Coordinate(1,1E-15),
new Coordinate(1,0)
};
fins.setPoints(points);
Coordinate coords = fins.getCG();
assertEquals(0.75, fins.getFinArea(), 0.001);
assertEquals(0.3889, coords.x, 0.001);
assertEquals(0.4444, coords.y, 0.001);
}
{
// Different shaped figure. Two rectangles crafted so two pairs of points y_0 = - y_1
FreeformFinSet fins = new FreeformFinSet();
fins.setFinCount(1);
Coordinate[] points = new Coordinate[] {
new Coordinate(0,0), new Coordinate(0,0),
new Coordinate(0,1), new Coordinate(0,1),
new Coordinate(2,1), new Coordinate(2,1),
new Coordinate(2,-1), new Coordinate(2,-1),
new Coordinate(1,-1), new Coordinate(1,-1),
new Coordinate(1,0) new Coordinate(1,0)
}; };
fins.setPoints(points); fins.setPoints(points);
Coordinate coords = fins.getCG(); Coordinate coords = fins.getCG();
assertEquals(3.0, fins.getFinArea(), 0.001); assertEquals(3.0, fins.getFinArea(), 0.001);
assertEquals(3.5/3.0, coords.x, 0.001); assertEquals(3.5/3.0, coords.x, 0.001);
assertEquals(0.5/3.0, coords.y, 0.001); assertEquals(0.5/3.0, coords.y, 0.001);
}
} }