/vr/ - Retro Games

>>3075078
OP here. I meant the original image to be rhetorical, but >>3075052 >>3075043 don't give the effect enough credit.

The SNES has 8 different background graphics settings, modes 0-7. You have surely heard of mode 7. What you might not know much about the other modes. In this case mode 1 is used, in which the programmers had access to 2 16-color/tile backgrounds and 1 4-color/tile background layer. SNES games are composed of building up layers on top of each other to make a full screen image.

Super Metroid uses mode 2 where BG1=foreground, BG2=background, BG3=overlay (water,lava,mist,etc). When the X-ray scope is used, BG2 is set to a copy of a computed "revealed" foreground layer. To cut a wedge shaped area simulating the scope, a technique called windowing is used to throw out the foreground within the wedge, while the shape of the wedge is modulated per scanline using a technique called Horizontal Direct Memory Access (HDMA), which is just a fancy way of saying they updated some memory (here the window) every scanline. The effect is further refined by a constant color subtraction to darken the atmosphere using HDMA too.

It's actually a really clever use of the tools they had available, and in no way is trivial.

I wish I had an animated picture of this image because it took me a while to figure out how they did it...