fixing overlap

src/main/java/com/elphel/imagej/tileprocessor/TwoQuadCLT.java

@@ -8694,13 +8694,11 @@ if (debugLevel > -100) return true; // temporarily !
 						System.out.println("testing half-step: start_ref_pointers[0]="+start_ref_pointers[0]+
 								", start_ref_pointers[1]="+start_ref_pointers[1]+", start_ref_pointers[2]="+start_ref_pointers[2]+", ref_index="+ref_index);
 						int offset1 = (int) (overlap_scale * (start_ref_pointers[1] - start_ref_pointers[0]));
-						int offset2 = (start_ref_pointers[1] - start_ref_pointers[0]) - offset1;
+						int offset2 = (int) (overlap_scale * (start_ref_pointers[2] - start_ref_pointers[1]));
 						System.out.println("testing half-step:  offset1="+offset1+
 								",  offset2="+offset2+" overlap_scale="+overlap_scale);
 						start_ref_pointers[0] = Math.max ( start_ref_pointers[0] , start_ref_pointers[1]  - offset1);
-						// incorrect, fix  "-1" to actual last scene
-//						start_ref_pointers[1] += offset2;
-						start_ref_pointers[1] = Math.max (start_ref_pointers[2],  start_ref_pointers[1]  - offset1);
+						start_ref_pointers[1] = Math.max (start_ref_pointers[1],  start_ref_pointers[2]  - offset2);
 						System.out.println("testing half-step: start_ref_pointers[0]="+start_ref_pointers[0]+
 								", start_ref_pointers[1]="+start_ref_pointers[1]+", start_ref_pointers[2]="+start_ref_pointers[2]+", ref_index="+ref_index);
 					}