triangulate_monotone_polygon: removed bug concerning co-linear revers…

…al of

segments
new: test_triangulate_monotone_polygon_colinear,
test_ptNode_colinear_reversal, tests for co-linear vertical lines
removed: test_add_segment_special_5

build/pnltri.js

@@ -2183,7 +2183,17 @@ PNLTRI.MonoTriangulator.prototype = {
 		while ( (frontVert != endVert) || (vertBackLogIdx > 1) ) {
 			if (vertBackLogIdx > 0) {
 				// vertBackLog is not empty
-				if ( PNLTRI.Math.ptsCrossProd( frontVert, vertBackLog[vertBackLogIdx-1], vertBackLog[vertBackLogIdx] ) > 0 ) {		// TODO !!
+				var angle = PNLTRI.Math.ptsCrossProd( frontVert, vertBackLog[vertBackLogIdx-1], vertBackLog[vertBackLogIdx] );		// TODO !!
+				if ( Math.abs(angle) <= PNLTRI.Math.EPSILON_P ) {
+					// co-linear
+					if ( PNLTRI.Math.compare_pts_yx( frontVert, vertBackLog[vertBackLogIdx] ) != PNLTRI.Math.compare_pts_yx( vertBackLog[vertBackLogIdx], vertBackLog[vertBackLogIdx-1] ) ) {
+//						console.log("triangulate_monotone_polygon: colinear", frontVert.x - vertBackLog[vertBackLogIdx].x, frontVert.y - vertBackLog[vertBackLogIdx].y,
+//													vertBackLog[vertBackLogIdx].x - vertBackLog[vertBackLogIdx-1].x, vertBackLog[vertBackLogIdx].y - vertBackLog[vertBackLogIdx-1].y,
+//													frontVert, vertBackLog[vertBackLogIdx], vertBackLog[vertBackLogIdx-1] );
+						angle = 1;		// co-linear-reversal => create triangle
+					}
+				}
+				if ( angle > 0 ) {
 					// convex corner: cut if off
 					this.polyData.addTriangle( vertBackLog[vertBackLogIdx-1], vertBackLog[vertBackLogIdx], frontVert );
 					vertBackLogIdx--;