Images, memory and padding to x^2
by baylor wetzel · in iTorque 2D · 07/19/2009 (8:15 pm) · 1 replies
i want to understand a little more about what the graphics chip needs from art
If an image is 150x60, it gets padded out to 256x256 to make it a square power of 2. This is because the graphics chip needs art to be a square with dimensions a power of 2. Suppose i use a cell sheet with 4 cells, 150x240. That also gets padded to 256x256. *If* nothing else is needed, i can quadruple the number of images i can load in the same amount of memory
When iTGB and PowerVR draw an image from a cell sheet, do the individual images in the cell sheet get split into their own images which are then padded to the square power of 2? Or is the cell sheet potentially saving me a ton of memory?
(note: i know you can't use cell sheets with pvrtc4s iTGB 1.2 and 1.3 probably won't be out for another couple of months but in my case, the quality is so bad that i can't use PVRTCs anyawy)
(note 2: assuming cell sheets are the way to go, a neat, if low-priority, feature might be if iTGB automatically assembled cell sheets from individual images)
If an image is 150x60, it gets padded out to 256x256 to make it a square power of 2. This is because the graphics chip needs art to be a square with dimensions a power of 2. Suppose i use a cell sheet with 4 cells, 150x240. That also gets padded to 256x256. *If* nothing else is needed, i can quadruple the number of images i can load in the same amount of memory
When iTGB and PowerVR draw an image from a cell sheet, do the individual images in the cell sheet get split into their own images which are then padded to the square power of 2? Or is the cell sheet potentially saving me a ton of memory?
(note: i know you can't use cell sheets with pvrtc4s iTGB 1.2 and 1.3 probably won't be out for another couple of months but in my case, the quality is so bad that i can't use PVRTCs anyawy)
(note 2: assuming cell sheets are the way to go, a neat, if low-priority, feature might be if iTGB automatically assembled cell sheets from individual images)
About the author
Torque 3D Owner Marc Dreamora Schaerer
Gayasoft
If you have wasted space you don't use, the image is likely recombined with other textures to get a somewhere acceptable texture space usage again.
And I really hope that 1.3 is approaching. Another couple of months would be completely inacceptable due to the state of iTGB <= 1.2