Noise flow field using Ebiten and GFX

ebiten-gfx-noise-flow-field.go

package main

import (
	"image"

	"github.com/hajimehoshi/ebiten/v2"
	"github.com/peterhellberg/gfx"
)

func main() {
	ff := newFlowField(200, 200, 2, 4, gfx.PaletteEDG36, 789)

	ebiten.SetWindowSize(ff.width*ff.scale, ff.height*ff.scale)
	ebiten.SetWindowDecorated(false)
	ebiten.RunGame(ff)
}

type FlowField struct {
	frame   int
	width   int
	height  int
	pixels  int
	scale   int
	size    int
	palette gfx.Palette
	*gfx.SimplexNoise
	*image.RGBA
}

func newFlowField(width, height, scale, size int, palette gfx.Palette, seed int64) *FlowField {
	return &FlowField{
		width:        width,
		height:       height,
		pixels:       width * height,
		scale:        scale,
		size:         size,
		palette:      palette,
		SimplexNoise: gfx.NewSimplexNoise(seed),
		RGBA:         gfx.NewImage(width, height),
	}
}

func (ff *FlowField) Update() error {
	if ebiten.IsKeyPressed(ebiten.KeyEscape) {
		return gfx.ErrDone
	}

	for x := 0; x < ff.width; x += ff.size {
		for y := 0; y < ff.height; y += ff.size {
			r := gfx.IR(x, y, x+ff.size, y+ff.size)
			n := ff.Noise3D(float64(x)/100, float64(y)/100, float64(ff.frame)/100) * 100
			t := (100 + n) / 200
			c := ff.palette.At(t)

			gfx.DrawColor(ff, r, c)
		}
	}

	ff.frame++

	return nil
}

func (ff *FlowField) Draw(screen *ebiten.Image) {
	screen.ReplacePixels(ff.Pix)
}

func (ff *FlowField) Layout(w, h int) (int, int) {
	return ff.width, ff.height
}