These columns by extending them below and above the line of the object. This information we can visualize depth by drawing a vertical column for each segment of the object. YouĬan see from the picture above that each ray represents a distance from our eye to a segment of the object.

Once we have the ray lengths we can figure out the distance and the shape of the object we are looking at. The more rays we cast the more information we gather about the object in the distance. To get a good idea of that we are looking at, we cast many rays across our field of vision. We can imagine casting a ray as extending a line from our eye across a plane until

Ray casting lets us probe the distance between our eyeĪnd a point in the distance. Where ray casting can help us figure these things out. There is just not enough information to tell. Not, or how many sides do we see, or how far away it is. You can see that when we look at it sideways it’s hard to tell if the thing we are looking at is a square or Lines and wouldn’t be able to tell exactly what they represent, nor how far away a particular objects might be. You wouldn’t see much, in fact you would just see a bunch of Looking from above, but being on that 2D plane. Now imagine actually being on that map and not just Picturing it top down, seeing every object from above. Useful for us to change our point of view for a moment. BasicsĪs you might imagine ray casting has something to do with casting rays, but to figure out exactly what, it’s Neat way to get “cheap” 3D before computers got fast enough to run real 3D engines. The only 3D part of it is the rendering of that 2D data, nothing else. Everything in it happens on a flat grid and all of the game logic is limited The reason why these games can’t beĬalled true 3D is because they are actually 2D games under the covers. Like, which used raycasting in one form or another to draw their scenes. Popular examples of ray casters where the 90’s first person shooters like Wolfenstein 3D, Duke Nukem 3D and the

One could say that ray casting is a form of “fake” 3D, which, I guess, is why it’s sometimes called 2.5D. The concepts described here should be applicable to any language. The demo and the code examples are written in ClojureScript following a (mostly) functional style.

You can play around with the live demo at raycaster-demo or the source

Mmd how to use raycast