равномерный гардиент в окне 800 на 600 с использованием sdl2 и go

sdl_gradient_slice.go

package main

import (
	"unsafe"

	"github.com/veandco/go-sdl2/sdl"
)

const (
	winWidth  int32 = 800
	winHeight int32 = 600
)

type Color struct {
	r, g, b byte
}

func setPixel(x, y int, color Color, pixels []byte) {
	index := (y*int(winWidth) + x) * 4
	if index > len(pixels)-4 || index < 0 {
		return
	}
	pixels[index+3] = color.r
	pixels[index+2] = color.g
	pixels[index+1] = color.b
}

func main() {

	window, err := sdl.CreateWindow("ИГРА!", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, winWidth, winHeight, sdl.WINDOW_SHOWN)
	if err != nil {
		panic(err)
	}
	defer window.Destroy()

	renderer, err := sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED)
	if err != nil {
		panic(err)
	}
	defer renderer.Destroy()

	tex, err := renderer.CreateTexture(sdl.PIXELFORMAT_RGBA8888, sdl.TEXTUREACCESS_STREAMING, winWidth, winHeight)
	if err != nil {
		panic(err)
	}
	defer tex.Destroy()
	pixels := make([]byte, winWidth*winHeight*4)
	yScaleFactor := (int(winHeight) + 255) / 255
	xScaleFactor := (int(winWidth) + 255) / 255
	for yFrame := 0; yFrame < int(winHeight); yFrame += yScaleFactor {
		for y := 0; y < yScaleFactor; y++ {
			for xFrame := 0; xFrame < int(winWidth); xFrame += xScaleFactor {
				for x := 0; x < xScaleFactor; x++ {
					setPixel(xFrame+x, yFrame+y, Color{r: byte(xFrame / xScaleFactor % 255), g: byte(yFrame / yScaleFactor % 255), b: byte(0)}, pixels)
				}
			}
		}
	}

	tex.Update(nil, unsafe.Pointer(&pixels[0]), int(winWidth)*4)
	renderer.Copy(tex, nil, nil)
	renderer.Present()
	sdl.Delay(20 * 1000)
}