I was thinking today about ways to create an explosion in a game. But moreover, I'm trying to stylize this to look like something around the turn of the century, plus or minus a few years. (It's just a thought at this time, but that's the sort of target I'm aiming for.)

I've looked at explosions from a few games around this era. The one that looks the most like what I would want to achieve are the explosions in Goldeneye on the Nintendo 64. They are beautiful, they are firey, and they have volume. You can view them from any angle and you see this magnificent volume of burning destruction. And then they leave these thick clouds in their wake that take a long time to dissipate. (I remember even using them as cover in multiplayer matches.)

When the game was new, I had thought the explosions were made with a series of meshes, overlapping each other and animating in a very controlled manner. One thing in particular that led me to believe this was when I was looking at the smoke, and one time I saw polygonal edges, suggesting to me that it was made out of a bunch of meshes with slight transparencies, all stacked on top of each other and deforming in a manner to simulate smoke. And for some reason I thought the explosions were doing basically the same thing.

Today I was looking at some videos, carefully pausing and examining the images, and I see more tell-tale signs of sprites. When they bleed through a wall, they always cut through at a perpendicular angle. The edges fade a bit into wisps, and that would be hard to do as a mesh without either some advanced shader effects or some exceedingly high poly counts.

But when I think about the logistics of playing a large volume of animated sprites, what I see doesn't quite match what I would expect. I don't see repeating patterns from repeating sprites. If the explosion is viewed from above, I don't see edges of sprites in the middle, but it looks like the same wall of fire seen from other angles.

If this were truly made from a series of animated sprites, it would need to be running a massive collection of different animations in a very high quantity, which I would have a hard time imagining the Nintendo 64 being able to pull off in the middle of an active game.

So one, I am curious about how Goldeneye specifically created their explosions.

Two, I am also just curious about how other games near the turn of the century did their explosions. A lot of games used animated sprites, but they would clip unnaturally with walls and surfaces. Some used animated meshes, but they lacked a realistic pattern and had very clear edges to the explosions. Are there any other good examples to study that show interesting ways to pull off more natural effects?

If the explosion is viewed from above, I don't see edges of sprites in the middle, but it looks like the same wall of fire seen from other angles.

They look like billboards - 2D sprites that are always oriented to face the camera.

However, each explosion seems to be made by placing multiple such billboards close together to create one larger explosion.
Multiple animated sprites in close quarters always oriented to face the player (pivoting on a fixed location). Each billboard is playing different frames.

It looks almost as if multiple billboards are being spawned as the explosion progresses, but it could be that they are pre-spawned and are on a delay before animating off of their initial blank frame.

If this were truly made from a series of animated sprites, it would need to be running a massive collection of different animations in a very high quantity, which I would have a hard time imagining the Nintendo 64 being able to pull off in the middle of an active game.

Maybe seven or so billboards are spawned per explosion - that's not much, and wouldn't be hard to render. The explosions likely use the same animations, so that's no problem. The animations frames, however, would need to be continually available, and that'd take alot of space (which the N64 had little of). However, the N64 did have bilinear filtering, and those explosions look awfully smooth. I also wonder if many of the frames of the explosions is just other frames mirrored, rotated, and scaled. If so, it could really just be a single animation worth of frames, in terms of memory. This is speculation.

If the explosion is viewed from above, I don't see edges of sprites in the middle, but it looks like the same wall of fire seen from other angles.

They look like billboards - 2D sprites that are always oriented to face the camera.

I meant, the edges of the sprite graphic. It would repeat itself much more frequently if you viewed it form the wrong angle, such as from above. For a particular example, some of the explosions have more orange edges. If this was a common edge, when you view it from the wrong angle you would see ribbons of orange ribbing the explosion where the edge of the sprite is repeating.

I'd have to see an example, but probably just their bilinear filtering bleeding over from the next frame in the texture sheet, or from the opposite side of the same texture if they weren't using texture sheets.