The construction of 3D graphics - Official support forum | RGraph.net
The construction of 3D graphics
Posted by evan at 16:38 on Tuesday 10th May 2022[link]
Do you have any recommendations for geometry generation? How are 3D pie charts constructed
Posted by Richard at 18:00 on Tuesday 10th May 2022[link]
There's not really any 3D geometry generation - canvas (without webGL) is a 2d environment so the 3D looks have to be "hacked together".
The 3D Pie chart canvas is stretched horizontally, the chart is then centered and drawn multiple times moving the center coordinate up by one each time. This gives the correct perspective and the thickness of the chart.
Unfortunately, it's not the most efficient drawing process (the Pie chart is drawn multiple times per frame) but it's passable.
Oh, and canvas text looks slightly thicker due to it being stretched too.