66 lines
3 KiB
Markdown
66 lines
3 KiB
Markdown
#  Documentation
|
|
|
|
The motivation behind this library and more in-depth information about the rendering techniques utilised can be found in [this technical report](media/sdf-2d.pdf).
|
|
|
|
## Links
|
|
|
|
- [Repository](https://github.com/schmelczerandras/sdf-2d)
|
|
- [Demo](https://sdf2d.schmelczer.dev/)
|
|
- [Minimal example](https://github.com/schmelczerandras/sdf-2d-minimal-example)
|
|
- [More complex example](https://github.com/schmelczerandras/sdf-2d-more-complex-example)
|
|
- [Source code of the demo](https://github.com/schmelczerandras/sdf-2d-demo)
|
|
|
|
## Usage
|
|
|
|
- To start using cutting-edge 2D graphics, first you have get a renderer instance. This is possible by calling the [compile function](globals.html#compile).
|
|
- For this, some [DrawableDescriptors](interfaces/drawabledescriptor.html) has to be provided.
|
|
- Optionally, default compile settings can overridden using [StartupSettings](interfaces/startupsettings.html).
|
|
- After acquiring a renderer, the drawing of objects can be started through the [Renderer](interfaces/renderer.html) interface.
|
|
|
|
## Extending drawables
|
|
|
|
> Iñigo Quilez has some great [2D SDF-s](https://iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm)
|
|
|
|
- Subclass [Drawable](classes/drawable.html)
|
|
- Implement its abstract methods
|
|
- Add a static property to your class called `descriptor` of type [DrawableDescriptors](interfaces/drawabledescriptor.html)
|
|
- Follow the instructions given in [Usage](#usage)
|
|
|
|
## Useful to know
|
|
|
|
### Math
|
|
|
|
The `vec2`, `vec3`, and `vec4` types seen in the documentation come from the [glMatrix](http://glmatrix.net/) library and are equivalent to regular JS Arrays or Float32Arrays. So, feel free to give `[x, y]` as an input for functions requiring `vec2`.
|
|
|
|
### Coordinates
|
|
|
|
Anywhere, where positions need to be specified, the `y` values grow upwards. That means, when setting the view area, the origin is at the bottom left corner of the display.
|
|
|
|
### Tile-based rendering
|
|
|
|
For optimising the evaluation of the distance field, the display is divided up into a grid of tiles. The shaders for each tile are compiled to support a fix maximum number of objects on it. When using the built-in drawables it is possible that after a certain number of on-screen objects new ones won't be visible.
|
|
|
|
Mitigating this issue is quite easy. Instead of the following code:
|
|
|
|
```js
|
|
this.renderer = await compile(canvas, [Circle.descriptor, CircleLight.descriptor]);
|
|
```
|
|
|
|
Modify it to something similar:
|
|
|
|
```js
|
|
this.renderer = await compile(canvas, [
|
|
{
|
|
...Circle.descriptor,
|
|
shaderCombinationSteps: [0, 1, 2, 24, 64],
|
|
},
|
|
{
|
|
...CircleLight.descriptor,
|
|
shaderCombinationSteps: [0, 1, 2, 4],
|
|
},
|
|
]);
|
|
```
|
|
|
|
The usage of too large numbers is not advised for compatibility and performance reasons alike.
|
|
|
|
> Steps are very useful for tile-based rendering, because it is possible for one tile (at a given moment) to be empty or contain just a few objects, while others have a large cluster of objects. The compiled shaders only take into account the necessary number of objects on each tile.
|