X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fqfat%2Fgeom%2FMatrix.java;h=31fe6e0ef849ab0037a99f3c084085542de6a590;hb=42acb5af8ff15b7af9fa8f34c071ee58e24faf98;hp=93032334622e1a474ae6985ed0ecf7f86261ffe9;hpb=468b086402bb0ccae7ce4dda8b009d61bfc37a71;p=anneal.git

diff --git a/src/edu/berkeley/qfat/geom/Matrix.java b/src/edu/berkeley/qfat/geom/Matrix.java
index 9303233..31fe6e0 100644
--- a/src/edu/berkeley/qfat/geom/Matrix.java
+++ b/src/edu/berkeley/qfat/geom/Matrix.java
@@ -71,6 +71,22 @@ public class Matrix {
                           0, 0, 0, 1);
     }
 
+    public static Matrix reflect(Vec v) {
+        Vec reflectionPlaneNormal = v.norm();
+        float a = reflectionPlaneNormal.x;
+        float b = reflectionPlaneNormal.y;
+        float c = reflectionPlaneNormal.z;
+        return
+                new Matrix( 1-2*a*a,  -2*a*b,  -2*a*c, 0,
+                            -2*a*b,  1-2*b*b,  -2*b*c, 0,
+                            -2*a*c,   -2*b*c, 1-2*c*c, 0,
+                            0,       0,       0,       1);
+    }
+
+    public Vec getTranslationalComponent() {
+        return new Vec(d, h, l);
+    }
+
     public Matrix plus(Matrix x) {
         return new Matrix(a+x.a, b+x.b, c+x.c, d+x.d, e+x.e, f+x.f, g+x.g, h+x.h, i+x.i, j+x.j, k+x.k, l+x.l, m+x.m, n+x.n, o+x.o, p+x.p);
     }
@@ -106,6 +122,14 @@ public class Matrix {
                        i*p.x + j*p.y + k*p.z + l);
     }
 
+    public Matrix preMultiplyTranslationalComponentBy(Matrix mm) {
+        Vec v = mm.times(getTranslationalComponent());
+        return new Matrix(a, b, c, v.x,
+                          e, f, g, v.y,
+                          i, j, k, v.z,
+                          m, n, o, 1);
+    }
+
     /** multiply by another matrix */
     public Matrix times(Matrix z) {
         float t00 = a;
@@ -238,23 +262,25 @@ public class Matrix {
         if (!(oo instanceof Matrix)) return false;
         Matrix z = (Matrix)oo;
         return
-            a==z.a && 
-            b==z.b && 
-            c==z.c && 
-            d==z.d && 
-            e==z.e && 
-            f==z.f && 
-            g==z.g && 
-            h==z.h && 
-            i==z.i && 
-            j==z.j && 
-            k==z.k && 
-            l==z.l && 
-            m==z.m && 
-            n==z.n && 
-            o==z.o && 
-            p==z.p;
+            near(a,z.a) && 
+            near(b,z.b) && 
+            near(c,z.c) && 
+            near(d,z.d) && 
+            near(e,z.e) && 
+            near(f,z.f) && 
+            near(g,z.g) && 
+            near(h,z.h) && 
+            near(i,z.i) && 
+            near(j,z.j) && 
+            near(k,z.k) && 
+            near(l,z.l) && 
+            near(m,z.m) && 
+            near(n,z.n) && 
+            near(o,z.o) && 
+            near(p,z.p);
     }
+    private static final float EPSILON = 0.001f;
+    private static boolean near(float a, float b) { return Math.abs(a-b)<EPSILON; }
 
     public int hashCode() {
         return