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Yes, feel the burn.

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Zed A. Shaw 2025-01-12 22:14:04 -05:00
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shiterator.hpp
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@ -13,20 +13,92 @@
/* /*
* # What is This Shit? * # What is This Shit?
* *
* Announcing the Shape Iterators, or `shiterators` for short. You could also say these are Shaw's Iterators, but * Announcing the Shape Iterators, or "shiterators" for short. The best shite
* either way they are the _shit_. Or are they shit? You decide. Maybe they're "shite"? * for C++ for-loops since that [one youtube
* video](https://www.youtube.com/watch?v=rX0ItVEVjHc) told everyone to
* recreate SQL databases with structs. You could also say these are Shaw's
* Iterators, but either way they are the _shite_. Or are they shit? You decide.
* Maybe they're "shite"?
* *
* A shiterator is a simple generator that converts 2D shapes into a 1D stream of x/y coordinates. You give it a matrix, some parameters like start, end, etc. and each time you call `next()` you the next viable x/y coordinate to complete the shape. * A shiterator is a simple generator that converts 2D shapes into a 1D stream
* of x/y coordinates. You give it a matrix, some parameters like start, end,
* etc. and each time you call `next()` you get the next viable x/y coordinate to
* complete the shape. This makes them far superior to _any_ existing for-loop
* technology because shiterators operate _intelligently_ in shapes. Other
* [programming pundits](https://www.youtube.com/watch?v=tD5NrevFtbU) will say
* their 7000 line "easy to maintain" switch statements are better at drawing
* shapes, but they're wrong. My way of making a for-loop do stuff is vastly
* superior because it doesn't use a switch _or_ a virtual function _or_
* inheritance at all. That means they have to be the _fastest_. Feel free to run
* them 1000 times and bask in the glory of 1 nanosecond difference performance.
* *
* A shiterator tries to ensure a few things: * It's science and shite.
* *
* 1. All x/y values will be within the Matrix you give it. * More importantly, shiterators are simple and easy to use. They're so easy to
* use you _don't even use the 3rd part of the for-loop_. What? You read that right,
* not only have I managed to eliminate _both_ massive horrible to maintain switches,
* and also avoided virtual functions, but I've also _eliminated one entire part
* of the for-loop_. This obviously makes them way faster than other inferior
* three-clause-loop-trash. Just look at this comparison:
*
* ```cpp
* for(it = trash.begin(); it != trash.end(); trash++) {
* std::cout << it << std::endl;
* }
* ```
*
* ```cpp
* for(each_cell it{mat}; it.next();) {
* std::cout << mat[it.y][it.x] << std::endl;
* }
* ```
*
* Obviously this will outperform _any_ iterator invented in the last 30 years, but the best
* thing about shiterators is their composability and ability to work simultaneously across
* multiple matrices in one loop:
*
* ```cpp
* for(line it{start, end}; it.next();) {
* for(compass neighbor{walls, it.x, it.y}; neighbor.next();) {
* if(walls[neighbor.y][neighbor.x] == 1) {
* wall_update[it.y][it.x] = walls[it.y][it.x] + 10;
* }
* }
* }
* ```
*
* This code sample (maybe, because I didn't run it) draws a line from
* `start` to `end` then looks at each neighbor on a compass (north, south, east, west)
* at each point to see if it's set to 1. If it is then it copies that cell over to
* another matrix with +10. Why would you need this? Your Wizard just shot a fireball
* down a corridor and you need to see if anything in the path is within 1 square of it.
*
* You _also_ don't even need to use a for-loop. Yes, you can harken back to the old
* days when we did everything RAW inside a Duff's Device between a while-loop for
* that PERFORMANCE because who cares about maintenance? You're a game developer! Tests?
* Don't need a test if it runs fine on Sony Playstation only. Maintenance? You're moving
* on to the next project in two weeks anyway right?! Use that while-loop and a shiterator
* to really help that next guy:
*
* ```cpp
* box it{walls, center_x, center_y, 20};
* while(it.next()) {
* walls[it.y][it.x] = 1;
* }
* ```
*
* ## Shiterator "Guarantees"
*
* Just like Rust [guarantees no memory leaks](https://github.com/pop-os/cosmic-comp/issues/1133),
* a shiterator tries to ensure a few things, if it can:
*
* 1. All x/y values will be within the Matrix you give it. The `line` shiterator doesn't though.
* 2. They try to not store anything and only calculate the math necessary to linearlize the shape. * 2. They try to not store anything and only calculate the math necessary to linearlize the shape.
* 3. You can store them and incrementally call next to get the next value. * 3. You can store them and incrementally call next to get the next value.
* 4. You should be able to compose them together on the same Matrix or different matrices of the same dimensions. * 4. You should be able to compose them together on the same Matrix or different matrices of the same dimensions.
* 5. Most of them will only require 1 for-loop, the few that require 2 only do this so you can draw the inside of a shape. `circle` is like this. * 5. Most of them will only require 1 for-loop, the few that require 2 only do this so you can draw the inside of a shape. `circle` is like this.
* 6. They don't assume any particular classes or require subclassing. As long as the type given enables `mat[y][x]` (row major) access then it'll work. * 6. They don't assume any particular classes or require subclassing. As long as the type given enables `mat[y][x]` (row major) access then it'll work.
* 7. The matrix given to a shiterator isn't actually attached to it, so you can use one matrix to setup an iterator, then apply the x/y values to any other matrix of the same dimensions. * 7. The matrix given to a shiterator isn't actually attached to it, so you can use one matrix to setup an iterator, then apply the x/y values to any other matrix of the same dimensions. Great for smart copying and transforming.
* 8. More importantly, shiterators _do not return any values from the matrix_. They only do the math for coordinates and leave it to you to work your matrix. * 8. More importantly, shiterators _do not return any values from the matrix_. They only do the math for coordinates and leave it to you to work your matrix.
* *
* These shiterators are used all over the game to do map rendering, randomization, drawing, nearly everything that involves a shape. * These shiterators are used all over the game to do map rendering, randomization, drawing, nearly everything that involves a shape.
@ -47,11 +119,11 @@
* *
* ## Thanks * ## Thanks
* *
* Special thanks for Amit and hirdrac for their help with the math and for * Special thanks to Amit and hirdrac for their help with the math and for
* giving me the initial idea. hirdrac doesn't want to be held responsible for * giving me the initial idea. hirdrac doesn't want to be held responsible for
* this travesty but he showed me that you can do iteration and _not_ use the * this travesty but he showed me that you can do iteration and _not_ use the
* weird C++ iterators. Amit did a lot to show me how to do these calculations * weird C++ iterators. Amit did a lot to show me how to do these calculations
* without branching. Thanks to you both and everyone helping me while I * without branching. Thanks to you both--and to everyone else--for helping me while I
* stream my development. * stream my development.
*/ */
namespace shiterator { using std::vector, std::queue, std::array; using namespace shiterator { using std::vector, std::queue, std::array; using