| 1539 |  |  | 
| 1540 |  | Added rtcontrib -fo option to write over existing files, which it now | 
| 1541 |  | refuses to do without this option. | 
| 1542 | + |  | 
| 1543 | + | Made rtcontrib flush output when handed a zero-length ray vector, | 
| 1544 | + | to match behavior of rtrace. | 
| 1545 | + |  | 
| 1546 | + | Improved color scale for falsecolor output. | 
| 1547 | + |  | 
| 1548 | + | Added threshold test for Fresnel approximation to prevent its use | 
| 1549 | + | on smooth surfaces with unrealistically low specularities (less than 1.8%). | 
| 1550 | + | Water has a specular reflectance of 2.1% at room temperture. |