sdl_2.go

package main

import (
	"fmt"
	"math/rand"
	"github.com/veandco/go-sdl2/sdl"
	"os"
)

var winTitle string = "Go-SDL2 Render"
const (

 winWidth  = 320
 winHeight = 240
)

func run() int {
	var window *sdl.Window
	var renderer *sdl.Renderer
	var event sdl.Event

	window, err := sdl.CreateWindow(winTitle, sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED,
		int32(winWidth), int32(winHeight), sdl.WINDOW_SHOWN)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to create window: %s\n", err)
		return 1
	}
	defer window.Destroy()

	renderer, err = sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to create renderer: %s\n", err)
		return 2
	}
	defer renderer.Destroy()

	texture,_ :=  renderer.CreateTexture(sdl.PIXELFORMAT_ARGB8888,sdl.TEXTUREACCESS_STATIC,winWidth,winHeight)
	
	frames := 0 
	prev_time := sdl.GetTicks()
	current_time := sdl.GetTicks()
	fps := 0
	color := 0
	addr :=0
	var pixels [ winWidth*winHeight ]byte

	for  y:=0;y<int(winHeight);y++ {
		for x:=0;x<int(winWidth);x++ {
			addr = x + y *int(winWidth)
			pixels[addr] = byte( rand.Intn(255))
		}
	}

	running := true
	
	for running {
		
		for event = sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
			switch t := event.(type) {
				case *sdl.QuitEvent:
					running = false
					break
				case *sdl.KeyboardEvent:
					if t.Type == sdl.KEYDOWN {
						if t.Keysym.Sym ==  sdl.K_q  || t.Keysym.Sym ==  sdl.K_ESCAPE {
							running = false	
							break
						}
					}
			}
		}
		
		for y:=0;y<int(winHeight);y++ {
			for x:=0;x<int(winWidth);x++ {
				addr = x + y *int(winWidth)
				color = rand.Int() % 255
				pixels[addr] = byte( color)
			}
		}

		texture.Update(nil,pixels[:],int(winWidth))

		renderer.Clear()
		renderer.Copy(texture, nil,nil)
		renderer.Present()
		
		frames+=1
		current_time = sdl.GetTicks()
		if current_time - prev_time > 10000 {
			fps = frames / 10
			fmt.Println("fps is ",fps)
			frames = 0
			prev_time = current_time
		}
		
	}


	return 0
}

func main() {
	os.Exit(run())
}