diff --git a/examples/gameloop/pollevent.go b/examples/gameloop/pollevent.go new file mode 100644 index 0000000..b16dc81 --- /dev/null +++ b/examples/gameloop/pollevent.go @@ -0,0 +1,101 @@ +package main + +import "github.com/veandco/go-sdl2/sdl" + +const ( + TITLE = "README" + WIDTH = 800 + HEIGHT = 600 + FRAMERATE = 60 +) + +var ( + playerX, playerY = int32(WIDTH / 2), int32(HEIGHT / 2) + playerVX, playerVY = int32(0), int32(0) + running = true +) + +func main() { + if err := sdl.Init(sdl.INIT_EVERYTHING); err != nil { + panic(err) + } + defer sdl.Quit() + + window, err := sdl.CreateWindow(TITLE, sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, WIDTH, HEIGHT, sdl.WINDOW_SHOWN) + if err != nil { + panic(err) + } + defer window.Destroy() + + surface, err := window.GetSurface() + if err != nil { + panic(err) + } + + for running { + for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() { + handleEvent(event) + } + + loopTime := loop(surface) + window.UpdateSurface() + + delay := (1000 / FRAMERATE) - loopTime + sdl.Delay(delay) + } +} + +func handleEvent(event sdl.Event) { + switch t := event.(type) { + case sdl.QuitEvent: // NOTE: Please use `*sdl.QuitEvent` for `v0.4.x` (current version). + println("Quitting..") + running = false + break + case sdl.KeyboardEvent: + if t.State == sdl.RELEASED { + if t.Keysym.Sym == sdl.K_LEFT { + playerVX -= 1 + } else if t.Keysym.Sym == sdl.K_RIGHT { + playerVX += 1 + } + if t.Keysym.Sym == sdl.K_UP { + playerVY -= 1 + } else if t.Keysym.Sym == sdl.K_DOWN { + playerVY += 1 + } + } + break + } +} + +func loop(surface *sdl.Surface) (loopTime uint32) { + // Get time at the start of the function + startTime := sdl.GetTicks() + + // Update player position + playerX += playerVX + playerY += playerVY + if playerX < 0 { + playerX = WIDTH + } else if playerX > WIDTH { + playerX = 0 + } + if playerY < 0 { + playerY = HEIGHT + } else if playerY > HEIGHT { + playerY = 0 + } + + // Clear surface + surface.FillRect(nil, 0) + + // Draw on the surface + rect := sdl.Rect{playerX, playerY, 4, 4} + colour := sdl.Color{R: 255, G: 0, B: 255, A: 255} // purple + pixel := sdl.MapRGBA(surface.Format, colour.R, colour.G, colour.B, colour.A) + surface.FillRect(&rect, pixel) + + // Calculate time passed since start of the function + endTime := sdl.GetTicks() + return endTime - startTime +} diff --git a/examples/gameloop/waitevent.go b/examples/gameloop/waitevent.go new file mode 100644 index 0000000..7516c46 --- /dev/null +++ b/examples/gameloop/waitevent.go @@ -0,0 +1,82 @@ +package main + +import "github.com/veandco/go-sdl2/sdl" + +const ( + TITLE = "README" + WIDTH = 800 + HEIGHT = 600 +) + +var ( + playerX, playerY = int32(WIDTH / 2), int32(HEIGHT / 2) + running = true +) + +func main() { + if err := sdl.Init(sdl.INIT_EVERYTHING); err != nil { + panic(err) + } + defer sdl.Quit() + + window, err := sdl.CreateWindow(TITLE, sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, WIDTH, HEIGHT, sdl.WINDOW_SHOWN) + if err != nil { + panic(err) + } + defer window.Destroy() + + surface, err := window.GetSurface() + if err != nil { + panic(err) + } + + // Draw initial frame + draw(window, surface) + + // Event loop + for event := sdl.WaitEvent(); event != nil; event = sdl.WaitEvent() { + switch t := event.(type) { + case sdl.QuitEvent: // NOTE: Please use `*sdl.QuitEvent` for `v0.4.x` (current version). + println("Quitting..") + return + case sdl.KeyboardEvent: + if t.State == sdl.RELEASED { + if t.Keysym.Sym == sdl.K_LEFT { + playerX -= 4 + } else if t.Keysym.Sym == sdl.K_RIGHT { + playerX += 4 + } + if t.Keysym.Sym == sdl.K_UP { + playerY -= 4 + } else if t.Keysym.Sym == sdl.K_DOWN { + playerY += 4 + } + if playerX < 0 { + playerX = WIDTH + } else if playerX > WIDTH { + playerX = 0 + } + if playerY < 0 { + playerY = HEIGHT + } else if playerY > HEIGHT { + playerY = 0 + } + draw(window, surface) + } + break + } + } +} + +func draw(window *sdl.Window, surface *sdl.Surface) { + // Clear surface + surface.FillRect(nil, 0) + + // Draw on the surface + rect := sdl.Rect{playerX, playerY, 4, 4} + colour := sdl.Color{R: 255, G: 0, B: 255, A: 255} // purple + pixel := sdl.MapRGBA(surface.Format, colour.R, colour.G, colour.B, colour.A) + surface.FillRect(&rect, pixel) + + window.UpdateSurface() +}