textures-gen.go

package main 

import (
  "os"
  "log"
  "image/png"
  "image"
  "image/color"
)

func main() {
  s := 256
  img := image.NewGray(image.Rect(0, 0, s*2, s*2))
  for x:=0; x<s; x++ {
    for y:=0; y<s; y++ {
      var c color.Gray
      if x < y {
        c.Y = uint8(x)
      } else {
        c.Y = uint8(y)
      }
      xn := s+(s-x-1)
      yn := s+(s-y-1)
      img.SetGray(x, y, c)
      img.SetGray(xn, y, c)
      img.SetGray(x, yn, c)
      img.SetGray(xn, yn, c)

    }
  }
  f, err := os.Create("forcuse.png")
  if err != nil {
    log.Fatal(err)
  }
  err = png.Encode(f, img)
  if err != nil {
    log.Fatal(err)
  }
}