According to Wiki, the first card I was able to find with TrueColor support was the Riva TNT (Source: https://en.wikipedia.org/wiki/RIVA_TNT#Overview:~:text=it%20also%20added%20support%20for%20a%2032%2Dbit%20(truecolor)%20pixel%20format).​ That was in 1998. What confuses me is that 24-bit images are referenced in two books from 1994

Programmer's Guide to the EGA, VGA, and Super VGA Cards by Richard F. Ferraro

Encyclopedia of Graphics File Formats by James D. Murray

What am I missing?

The TARGA card was invented before the Riva TNT.

Uncle Ferraro, yeah… I never checked exactly when I was born. I was told that my parents played around with "extended" VGA capabilities for a while, and thought SuperVGA would be a cute nickname. I guess it just sort of stuck!

As for the 24bit stuff, it's common enough to have specifications before something is utilised in full. Even so, it had many applications before hardware acceleration. There were graphics cards with 24 bit support earlier than TNT though. AGA boards supported 24 bit graphics back in '92, for instance.

In the early 90s, there was a distinction between workstations (running UNIX on custom hardware with non-x86 CPU architectures) and PCs (running Windows on stock x86 hardware). The Riva TNT was a consumer-level 3D accelerator, a relatively recent development, predated by both consumer-level 2D graphics cards and by professional-level 3D workstations.

SuperVGA said:

Even so, it had many applications before hardware acceleration.

Was there ever a software 24-bit?

a light breeze said:

The Riva TNT was a consumer-level 3D accelerator, a relatively recent development, predated by both consumer-level 2D graphics cards and by professional-level 3D workstations.

Are you saying there were 2D-only graphics cards that did support 24 bits? Because even if the AGA board did support 24-bit in the late 80s or early 90s, what about the mid 90s? Did the first Voodoo or NVidia cards support it?

P.S. I think I may not have asked my question clearly. I'm talking about 16 million colors simultaneously. I know that every video card after 1992 could display 256 unique indexed colors which were 24 bit. This way the size of the frame buffer would be kept at 640x480x1 bytes. I'm talking about 3 bytes per pixel, not about indexed color. On one hand I would assume it's just a matter of memory, but if that were the case why wait until 1998 for that. Previous cards had enough memory for 3 byte direct color pixels, even if at a lower, say VGA, resolution.

Endurion said:

Riva TNT is probably the first card to offer 3d acceleration with 24bit. Graphic cards had that before, but then it was only software rendering.

What was it used for back then? It wouldn't have been viable to use it for games, not with the current memory bandwidth. I'm guessing rendering a 640x480@24 frame took maybe 100ms, so maybe just photo browsing? Or movie watching at 320x240?

The ATI Mach 32, released 1992, was a 2D graphics card with 24 bit color support.

a light breeze said:

The ATI Mach 32, released 1992, was a 2D graphics card with 24 bit color support.

I'm beginning to suspect that there is a difference between a 2D and a 3D accelerator, in terms of bit depth. So Riva TNT was the first 3D accelerator with 24 bit color, but 2D accelerators already had 24 bit color? Not just the ATI Mach 32, but most of the 2D cards post 92'?

Borchy said:
Are you saying there were 2D-only graphics cards that did support 24 bits?

Yes, there were 2D-only cards that supported 24-bit direct color. Just as one example, the Diamond Stealth 24, an SVGA card from 1992, supported 24-bit color at 640x480. (As was quite common with hardware of this era though, the 2D accelerator functionality was not usable in 24-bit color mode.)