Details
Description
1) The ch14.pdf file has some empty triangles on p. 20, because two points of the triangle are identical. These empty triangles result in divide by zeroes, which can result in black raster coloring of a whole page at resolutions that I didn't use before.
Bugfix: detect and delete empty triangles, and added code to detect an empty list and no background in GouraudShadingContext.getRaster().
2) One statement (raster.setPixels) in GouraudShadingContext was accidentally moved one line up in the past which could result in lower performance.