Keeping the tiles small allow smart phones with limited memory to still be able to show the panorama.
To determine cube sizes:
- divide by 3.14 to preserve a 1:1 ratio of pixels in the center of the cube but overcompensate at the edge.
- divide by 3.45 to keep the same number of pixels
- divide by 4 to preserve a 1:1 ratio of pixels at the edges of the cube but loose a little resolution at the center.
- Keep dividing by 2 until you are between 256 and 512.
- Round down to nearest even number (I like divisible by 4)
- Keep multiplied by 2 until back to or just under the original cube size.
- Keep adding new levels until you are around 400 to 600 to accommodate the smallest screens zoomed all the way out.
Pano 30000 X 15000
30000 / 3.45 = ~8695 pixel cube face.
8695 / 2 = 4348
4347 / 2 = 2174
2174 / 2 = 1087
1087 / 2 = 543
543 / 2 = 271
271 rounded down to nearest number divisible by 4 is 268
Tile size 268
The top level become 268 * 2 * 2 * 2 * 2 * 2 = 8576
The levels are 8576, 4288, 2144, 1072, 536