# sdf2d

**Repository Path**: dashenyjn123/sdf2d

## Basic Information

- **Project Name**: sdf2d
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 1
- **Created**: 2021-07-31
- **Last Updated**: 2021-07-31

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# sdf2d
Create 2D signed distance field (SDF) using points and polygons.

The accuracy is higher than that of [8ssedt](https://github.com/Lisapple/8SSEDT) method.

Inspired by Yuanming Hu's [Taichi](https://github.com/yuanming-hu/taichi).

# Computing gradient
When computing the gradient for a given point,
I use Yuanming Hu's strategy because it performs more smoothly than mine.

![gradient](./res/gradient.png)

The final gradient is `grad = lerp(grad1, grad2, α)` for `x` and `y` direction, respectively.

It means, if the point is close to the left (or bottom) border of the current cell, i.e. `α -> 1`,
we get more gradient of the current cell.
Otherwise, we get more gradient of the `x + 1` (or `y + 1`) cell.

# Reducing computing time
When deal with dynamic objects in a simulating program,
recomputing SDF is necessary.
In this project, I used an expensive one.
But I have refined it in [another project](https://github.com/iamyoukou/sdf2dWithMPM2D).

# Result
Throwing track (like the one in CSGO)

![result](throwingTrack.gif)