Discussion Main / SpritePolygonMix

http://doom.wikia.com/wiki/Doom_rendering_engine#Basic_objects

"The base unit is the vertex, which signifies a single 2D point. In the diagram to the right, each small blue square is a vertex. Vertices (or "vertexes" as they are referred to internally) are then joined to form lines, known as linedefs. Each linedef can have either one or two sides, which are known as sidedefs. Sidedefs are then grouped together to form polygons; these are called sectors."

So yeah, polygons. Doom's mapping system doesn't have a true Z axis, but it does use polygons.

WRONG! Sectors and subsectors do NOT work the same way as 3D polygons; "polygonal rendering" assumes 3D mesh rendering, which Doom is NOT. Doom's walls, for instance, are not polygonal at all, but "extruded" out of a 2D space. Doom's renderer is NOT 3D, it is erroneous to compare it to 3D engines, even if PART of the renderer uses things shaped like polygons. Subsectors alone do not make Polygonal Rendering. There is a difference between a game having things with polygonal shapes and "polygonal rendering". Polygonal rendering means the world is constructed out of 3D meshes, while Doom's engine uses an entirely different method. Only GL ports use polygonal rendering, because the hacks that allow Doom's rendering engine do not work in Open GL. There were absolutely no polygonal First-Person Shooter games before Descent. I've made maps for Wolfenstein and Doom, I know how they work. They do not work anything like Descent, Quake, or a modern game.

Polygonal rendering means polygonal MESHES, not just elements of the maps with polygonal shapes. By your standards Asteroids is polygonal rendering. Sure, it has no 3D, no meshes, and nothing that even resembles a modern renderer, but since there are polygon-shaped things in it, it must be polygonal rendering, right?

Look at what you're actually replying to, though.

"They used various types of simple polygons to create pseudo-3D backgrounds"

This does not exclude the method used in Doom, which uses a type of simple polygon to create a pseudo-3D background (as in one with an illusion of having a third dimension). You seem to be reading that as a comment on rendering when it isn't.

But it's not Polygonal Graphics. It's no more "polygonal" than Asteroids. In that case the whole section should be deleted. In fact, I think I'll delete the whole Doom/Doom clone section right now.

Polygonal Graphics involve entire objects built out of polygons interlocked in 3D space; Doom doesn't even have 3D space, and the "polygons" are just areas defined to pass rendering instructions (this sector is X units tall, has a brightness of Y, and has floor texture Z) to the renderer and facilitate the level's storage as BSP. There is nothing in Doom that is made of polygons (Doom's walls are lines, not polygons). Absolutely nothing.

To call sectors and subsectors "simple polygons" in a page that uses "polygons" as shorthand for 3D polygonal rendering is completely false. They do not have the function of polygons on a 3D model and have nothing to do with Polygonal Graphics.

The Doom section is needed to explain how it worked, and because Doom is one of the games people are likely to think of when they think of this trope; there's not many better examples of 'sprites rotate to face you in an apparently 3D space.' And would you please stop banging your drum about polygons, it doesn't even say that in the Doom example anymore. The section as it is states they have an appearance consistant with this trope, which is true. It's much like the subsection on pre-rendered 2D games, which also look like they have rendered graphics even though the system running them isn't doing anything with polygons at all.

I really don't think this endless nitpicking is really achieving anything.

It's achieving misinforming people about Doom even being remotely related to polygonal rendering. It is not. It is a 2D engine. It is a terrible example of Sprite/Polygon Mix. Just because it "kinda looks like" polygonal rendering doesn't make it so. I already posted an example to replace it in the form of Descent, which does use 3D polygon rendering (alongside sprite-based powerups) and, in 1994, made a huge deal in marketing over how it used polygonal rendering and 'Doom'' did not.

Correctness should not be sacrificed because "it's one of the games people are likely to think of". If they think of it then they are wrong. You're advocating obscuring the truth because it makes ignorant people feel like the article is more complete. I will not accept that. Do not say Quake required an accelerator either, it was written with a software renderer and the GL version did not come out until after Quake was already enormously successful.

Again, I suggest you actually read the example before removing it. It explains they look like they are this trope, but are not in a technical sense. That's not going to confuse anyone, because it is a clarification.

I wonder if anyone can post a image for the page; it's kinda hard to visualise the trope without some assistance...