Why TGAs Will Always Rule over PNGs
While working in Max today I ran into a funny issue with a bitmap texture that I was applying as a decal. For some reason the bitmap wasn't working as a decal even though the material settings (which is just telling max to use the alpha channel in the diffuse map slot) were setup right. Well it turns out that its due to the half baked file format that we know as PNG and switching the images to TGAs works just fine.
Now I don't want to get worked up into one of my infamous rants about PNGs, but PNGs have to be the most screwed up file format on the face of this Earth and IMHO need to be corrected and standardized or replaced, enough is enough already! So to help illustrate my points of why TGAs are better than PNGs here are some of my reasons for hating PNGs and loving TGAs:
1) Alpha Channels. With a TGA an alpha channel is an alpha channel plain and simple. With a PNG how ever the screwballs who designed this file spec call it a "transparency channel" and leave it up to the image editing programs who to read and write this data... which 9 times out of 10 isn't the way you need it written or read.
2) Layers. TGA has them, PNG doesn't and as any image editing guru knows, having multiple layers to work with and manipulate is great. Sure it's extra data but since when was having too much of something a bad thing?
3) Versatility. TGA can be used for a wide range of purposes since it can technicly store more than RGBA data with its ability to have multiple layers.
4) Compression. Did you know that TGA can be compressed too and its usually just as small if not smaller than PNGs? Pretty cool huh?
5) Bit Depth. Can you guess which file format can do 16 bits per channel? Its certainly not PNG but that old crusty format that people look down upon, the TGA format!
6) Universal viewing and writing. When you generate a TGA its generated the same each and every time and read back and displayed the same each and every time. With a PNG well its a crap shoot what it will do, but there is nothing like losing pixel data that you didn't want to lose or losing the alpha channel completely. My personal favorite though is when image applications write a bunch of garbage data into the background of the PNG where the pixels will be transparent. Now this doesn't sound like a big thing until you factor in what happens when a pixel isnt completely transparent, say at the edge of a curved shape, you get this wierd color information mixing through and causing funny things like unwanted white outlines on the edges of your curved shape which causes a major visual distortion... gee that's not right now is it, but yet its another lovely thing you have to deal with when working with a PNG.
If anyone has any other reasons why TGA is better than that crappy PNG format lets hear them and let the world know that PNG should be abbolished!
