Fix indentation and add full example

vendor/wgpu/examples/sdl2/os_sdl2.odin

@@ -0,0 +1,87 @@
+//+build !js
+package vendor_wgpu_example_triangle
+
+import "core:c"
+import "core:fmt"
+
+import "vendor:sdl2"
+import "vendor:wgpu"
+import "vendor:wgpu/sdl2glue"
+
+OS :: struct {
+	window: ^sdl2.Window,
+}
+
+os_init :: proc(os: ^OS) {
+	sdl_flags := sdl2.InitFlags{.VIDEO, .JOYSTICK, .GAMECONTROLLER, .EVENTS}
+	if res := sdl2.Init(sdl_flags); res != 0 {
+		fmt.eprintfln("ERROR: Failed to initialize SDL: [%s]", sdl2.GetError())
+		return
+	}
+	
+	window_flags: sdl2.WindowFlags = {.SHOWN, .ALLOW_HIGHDPI, .RESIZABLE}
+	os.window = sdl2.CreateWindow(
+		"wgpu triangle",
+		sdl2.WINDOWPOS_CENTERED,
+		sdl2.WINDOWPOS_CENTERED,
+		800,
+		600,
+		window_flags,
+	)
+	if os.window == nil {
+		fmt.eprintfln("ERROR: Failed to create the SDL Window: [%s]", sdl2.GetError())
+		return
+	}
+
+	sdl2.AddEventWatch(size_callback, nil)
+}
+
+os_run :: proc(os: ^OS) {
+	now := sdl2.GetPerformanceCounter()
+	last : u64
+	dt: f32
+	main_loop: for {
+		last = now
+		now = sdl2.GetPerformanceCounter()
+		dt = f32((now - last) * 1000) / f32(sdl2.GetPerformanceFrequency())
+
+		e: sdl2.Event
+
+		for sdl2.PollEvent(&e) {
+			#partial switch (e.type) {
+			case .QUIT:
+				break main_loop
+			}
+		}
+
+		frame(dt)
+	}
+
+	sdl2.DestroyWindow(os.window)
+	sdl2.Quit()
+
+	finish()
+}
+
+
+os_get_render_bounds :: proc(os: ^OS) -> (width, height: u32) {
+	iw, ih: c.int
+	sdl2.GetWindowSize(os.window, &iw, &ih)
+	return u32(iw), u32(ih)
+}
+
+os_get_surface :: proc(os: ^OS, instance: wgpu.Instance) -> wgpu.Surface {
+	return sdl2glue.GetSurface(instance, os.window)
+}
+
+@(private="file")
+size_callback :: proc "c" (userdata: rawptr, event: ^sdl2.Event) -> c.int {
+	
+	if event.type == .WINDOWEVENT {
+		if event.window.event == .SIZE_CHANGED || event.window.event == .RESIZED {
+			resize()
+		}
+	}
+
+	return 0
+}