Wrap SDL function with sdl.Do() for goroutine thread-safety.

config/sdl.go

@@ -1,27 +0,0 @@
-package config
-
-import (
-	"github.com/veandco/go-sdl2/sdl"
-)
-
-const (
-	SDL_INIT_FLAGS uint32 = sdl.INIT_TIMER | sdl.INIT_AUDIO | sdl.INIT_VIDEO | sdl.INIT_EVENTS | sdl.INIT_JOYSTICK | sdl.INIT_HAPTIC | sdl.INIT_GAMECONTROLLER // ignore sensor subsystem
-
-	SDL_WINDOW_FLAGS            uint32 = sdl.WINDOW_SHOWN | sdl.WINDOW_RESIZABLE
-	SDL_FULLSCREEN_WINDOW_FLAGS uint32 = SDL_WINDOW_FLAGS | sdl.WINDOW_FULLSCREEN_DESKTOP
-	SDL_WINDOW_WIDTH            int32  = 800
-	SDL_WINDOW_HEIGHT           int32  = 600
-)
-
-func SdlSettings() error {
-	// Disable the Linux compositor flicker.
-	// https://github.com/mosra/magnum/issues/184#issuecomment-425952900
-	sdl.SetHint(sdl.HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR, "0")
-
-	sdl.DisableScreenSaver()
-
-	// Capture the mouse for movement
-	sdl.SetRelativeMouseMode(true)
-
-	return nil
-}

internal/game/sdl.go

@@ -0,0 +1,60 @@
+package game
+
+import (
+	"fmt"
+
+	"github.com/veandco/go-sdl2/sdl"
+)
+
+/*
+NOTE: We're using the SDL with goroutines example.
+Every call to an SDL function must be passed through the sdl.Do() function so that it joins the queue of thread-sensitive calls.
+You'll see this a lot below, but basically every SDL function must do something like this:
+	sdl.Do(func() {
+		err = sdl.SomeFunction()
+	})
+This is for thread safety because SDL is not intended to be thread-safe.
+However, the rest of the code can do whatever it wants with threads so long as the SDL calls all use this method.
+*/
+
+const (
+	SDL_INIT_FLAGS uint32 = sdl.INIT_TIMER | sdl.INIT_AUDIO | sdl.INIT_VIDEO | sdl.INIT_EVENTS | sdl.INIT_JOYSTICK | sdl.INIT_HAPTIC | sdl.INIT_GAMECONTROLLER // ignore sensor subsystem
+
+	SDL_WINDOW_FLAGS            uint32 = sdl.WINDOW_SHOWN | sdl.WINDOW_RESIZABLE
+	SDL_FULLSCREEN_WINDOW_FLAGS uint32 = SDL_WINDOW_FLAGS | sdl.WINDOW_FULLSCREEN_DESKTOP
+	SDL_WINDOW_WIDTH            int32  = 800
+	SDL_WINDOW_HEIGHT           int32  = 600
+)
+
+func SdlInit() error {
+	var err error
+
+	// Initialize SDL
+	sdl.Do(func() {
+		err = sdl.Init(SDL_INIT_FLAGS)
+	})
+	if err != nil {
+		err = fmt.Errorf("failed initializing SDL: %w", err)
+		return err
+	}
+
+	// Set some base SDL settings
+	sdl.Do(func() {
+		// Disable the Linux compositor flicker.
+		// https://github.com/mosra/magnum/issues/184#issuecomment-425952900
+		sdl.SetHint(sdl.HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR, "0")
+
+		sdl.DisableScreenSaver()
+
+		// Capture the mouse for movement
+		//sdl.SetRelativeMouseMode(true)
+	})
+
+	return nil
+}
+
+func SdlQuit() {
+	sdl.Do(func() {
+		sdl.Quit()
+	})
+}

internal/game/window.go

@@ -0,0 +1,46 @@
+package game
+
+import (
+	"github.com/veandco/go-sdl2/sdl"
+)
+
+type window struct {
+	SdlWindow *sdl.Window
+	KeyStates map[sdl.Keycode]bool
+}
+
+func NewWindow(title string) (*window, error) {
+	var (
+		err       error
+		sdlWindow *sdl.Window
+	)
+
+	sdl.Do(func() {
+		sdlWindow, err = sdl.CreateWindow(
+			title,
+			sdl.WINDOWPOS_UNDEFINED,
+			sdl.WINDOWPOS_UNDEFINED,
+			SDL_WINDOW_WIDTH,
+			SDL_WINDOW_HEIGHT,
+			SDL_WINDOW_FLAGS)
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	keyStates := make(map[sdl.Keycode]bool)
+	gw := &window{
+		SdlWindow: sdlWindow,
+		KeyStates: keyStates,
+	}
+
+	return gw, nil
+}
+
+func (g *window) Destroy() {
+	if g.SdlWindow != nil {
+		sdl.Do(func() {
+			g.SdlWindow.Destroy()
+		})
+	}
+}

main.go

@@ -3,9 +3,10 @@ package main
 import (
 	"fmt"
 	"log"
-	"runtime"
+	"os"
 
-	"gitea.wisellama.rocks/Project-Ely/project-ely/config"
+	"gitea.wisellama.rocks/Project-Ely/project-ely/internal/config"
+	"gitea.wisellama.rocks/Project-Ely/project-ely/internal/game"
 	"gitea.wisellama.rocks/Wisellama/gosimpleconf"
 	"github.com/veandco/go-sdl2/sdl"
 )
@@ -28,43 +29,50 @@ func main() {
 	}
 	defer logWriter.Cleanup()
 
-	// Start everything
-	log.Printf("=== Starting %v", configMap["game.title"])
-	err = run(configMap)
+	// Start everything with the SDL goroutine context
+	log.Printf("=== Starting %v ===", configMap["game.title"])
+	sdl.Main(func() {
+		err = run(configMap)
+	})
+
+	exitcode := 0
 	if err != nil {
-		log.Fatalf("error running: %v\n", err)
+		log.Printf("ERROR: %v\n", err)
+		exitcode = 1
 	}
+
+	os.Exit(exitcode)
 }
 
 func run(configMap gosimpleconf.ConfigMap) error {
-	runtime.LockOSThread()
+	var err error
 
-	err := sdl.Init(config.SDL_INIT_FLAGS)
+	err = game.SdlInit()
 	if err != nil {
-		err = fmt.Errorf("failed initializing SDL: %w", err)
 		return err
 	}
-	defer sdl.Quit()
+	defer game.SdlQuit()
 
-	err = config.SdlSettings()
+	gameWindow, err := game.NewWindow(configMap["game.title"])
 	if err != nil {
-		err = fmt.Errorf("failed in SDL settings: %w", err)
-		return err
-	}
-
-	gameWindow, err := createWindow(configMap["game.title"])
-	if err != nil {
-		err = fmt.Errorf("failed creating SDL window: %w", err)
+		err = fmt.Errorf("failed creating GameWindow: %w", err)
 		return err
 	}
 	defer gameWindow.Destroy()
 
-	renderer, err := sdl.CreateRenderer(gameWindow, -1, sdl.RENDERER_ACCELERATED)
+	var renderer *sdl.Renderer
+	sdl.Do(func() {
+		renderer, err = sdl.CreateRenderer(gameWindow.SdlWindow, -1, sdl.RENDERER_ACCELERATED)
+	})
 	if err != nil {
 		err = fmt.Errorf("failed creating SDL renderer: %w", err)
 		return err
 	}
-	defer renderer.Destroy()
+	defer func() {
+		sdl.Do(func() {
+			renderer.Destroy()
+		})
+	}()
 
 	var rect *sdl.Rect
 	var x int32 = 0
@@ -74,7 +82,11 @@ func run(configMap gosimpleconf.ConfigMap) error {
 
 	running := true
 	for running {
-		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
+		var event sdl.Event
+		sdl.Do(func() {
+			event = sdl.PollEvent()
+		})
+		for event != nil {
 			switch e := event.(type) {
 			case *sdl.QuitEvent:
 				running = false
@@ -91,6 +103,10 @@ func run(configMap gosimpleconf.ConfigMap) error {
 					keystates[e.Keysym.Sym] = false
 				}
 			}
+
+			sdl.Do(func() {
+				event = sdl.PollEvent()
+			})
 		}
 
 		if keystates[sdl.K_a] {
@@ -101,7 +117,7 @@ func run(configMap gosimpleconf.ConfigMap) error {
 		}
 		if keystates[sdl.K_d] {
 			x += 1
-			w, _ := gameWindow.GetSize()
+			w, _ := gameWindow.SdlWindow.GetSize()
 			if x+rect.W > w {
 				x = w - rect.W
 			}
@@ -115,41 +131,32 @@ func run(configMap gosimpleconf.ConfigMap) error {
 		}
 		if keystates[sdl.K_s] {
 			y += 1
-			_, h := gameWindow.GetSize()
+			_, h := gameWindow.SdlWindow.GetSize()
 			if y+rect.H > h {
 				y = h - rect.H
 			}
 		}
 
 		// Black background
-		renderer.SetDrawColor(0, 0, 0, 255)
-		renderer.Clear()
+		sdl.Do(func() {
+			renderer.SetDrawColor(0, 0, 0, 255)
+			renderer.Clear()
+		})
 
 		// Blue square
-		renderer.SetDrawColor(0, 0, 255, 255)
-		rect = &sdl.Rect{X: x, Y: y, W: 200, H: 200}
-		renderer.DrawRect(rect)
-		renderer.FillRect(rect)
+		sdl.Do(func() {
+			renderer.SetDrawColor(0, 0, 255, 255)
+			rect = &sdl.Rect{X: x, Y: y, W: 200, H: 200}
+			renderer.DrawRect(rect)
+			renderer.FillRect(rect)
+		})
 
-		renderer.Present()
-		sdl.Delay(16)
+		// Draw
+		sdl.Do(func() {
+			renderer.Present()
+			sdl.Delay(16)
+		})
 	}
 
 	return nil
 }
-
-func createWindow(title string) (*sdl.Window, error) {
-	window, err := sdl.CreateWindow(
-		title,
-		sdl.WINDOWPOS_UNDEFINED,
-		sdl.WINDOWPOS_UNDEFINED,
-		config.SDL_WINDOW_WIDTH,
-		config.SDL_WINDOW_HEIGHT,
-		config.SDL_WINDOW_FLAGS)
-	if err != nil {
-		log.Println("Failed creating SDL window")
-		return nil, err
-	}
-
-	return window, nil
-}