package main

import (
	"fmt"

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

const winWith, winHight int = 800, 600

type color struct {
	r, g, b byte
}

func setPixel(x, y int, c color, pixels []byte) {

	index := (y*winWith + x) * 4

	if index < len(pixels)-4 && index >= 0 {
		pixels[index] = c.r
		pixels[index+1] = c.g
		pixels[index+2] = c.b
	}
}

func main() {

	err := sdl.Init(sdl.INIT_EVERYTHING)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer sdl.Quit()

	window, err := sdl.CreateWindow(
		"test", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, int32(winWith), int32(winHight), sdl.WINDOW_SHOWN)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer window.Destroy()

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

	texture, err := renderer.CreateTexture(sdl.PIXELFORMAT_ABGR8888, sdl.TEXTUREACCESS_STREAMING, int32(winWith), int32(winHight))
	if err != nil {
		fmt.Println(err)
		return
	}
	defer texture.Destroy()

	pixels := make([]byte, winWith*winHight*4)

	for y := 0; y < winHight; y++ {
		for x := 0; x < winWith; x++ {
			setPixel(x, y, color{255, 0, 0}, pixels)
		}
	}

	texture.Update(nil, pixels, winWith*4)
	renderer.Copy(texture, nil, nil)
	renderer.Present()
	for {
		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
			switch event.(type) {
			case *sdl.QuitEvent:
				return
			}
		}
		sdl.Delay(16)
	}

}