SDL package

internal/sdl/sdl.go

@@ -0,0 +1,115 @@
+package sdl
+
+import (
+	"fmt"
+	"runtime"
+	"unsafe"
+
+	"github.com/ebitengine/purego"
+)
+
+const (
+	InitVideo       uint32 = 0x00000020
+	WindowVulkan    uint64 = 0x0000000010000000
+	WindowResizable uint64 = 0x0000000000000020
+
+	EventQuit             uint32 = 0x100
+	EventWindowResized    uint32 = 0x206
+	EventPixelSizeChanged uint32 = 0x207
+	EventKeyDown          uint32 = 0x300
+
+	KeyEscape uint32 = 0x1B
+	KeyF      uint32 = 0x66
+)
+
+var (
+	sdlInit                        func(flags uint32) bool
+	sdlQuit                        func()
+	sdlGetError                    func() uintptr
+	sdlCreateWindow                func(title *byte, w, h int32, flags uint64) uintptr
+	sdlDestroyWindow               func(window uintptr)
+	sdlVulkanGetInstanceExtensions func(count *uint32) uintptr
+	sdlVulkanCreateSurface         func(window, instance, allocator uintptr, surface *uint64) bool
+	sdlPollEvent                   func(event unsafe.Pointer) bool
+	sdlGetWindowSizeInPixels       func(window uintptr, w, h *int32) bool
+	sdlSetWindowFullscreen         func(window uintptr, fullscreen bool) bool
+)
+
+var loaded = false
+
+func Load() error {
+	if loaded {
+		return nil
+	}
+	h, err := purego.Dlopen("libSDL3.so.0", purego.RTLD_NOW|purego.RTLD_GLOBAL)
+	if err != nil {
+		return fmt.Errorf("win: load SDL3: %w", err)
+	}
+	purego.RegisterLibFunc(&sdlInit, h, "SDL_Init")
+	purego.RegisterLibFunc(&sdlQuit, h, "SDL_Quit")
+	purego.RegisterLibFunc(&sdlGetError, h, "SDL_GetError")
+	purego.RegisterLibFunc(&sdlCreateWindow, h, "SDL_CreateWindow")
+	purego.RegisterLibFunc(&sdlDestroyWindow, h, "SDL_DestroyWindow")
+	purego.RegisterLibFunc(&sdlVulkanGetInstanceExtensions, h, "SDL_Vulkan_GetInstanceExtensions")
+	purego.RegisterLibFunc(&sdlVulkanCreateSurface, h, "SDL_Vulkan_CreateSurface")
+	purego.RegisterLibFunc(&sdlPollEvent, h, "SDL_PollEvent")
+	purego.RegisterLibFunc(&sdlGetWindowSizeInPixels, h, "SDL_GetWindowSizeInPixels")
+	purego.RegisterLibFunc(&sdlSetWindowFullscreen, h, "SDL_SetWindowFullscreen")
+	loaded = true
+	return nil
+}
+
+func Init(flags uint32) bool { return sdlInit(flags) }
+func Quit()                  { sdlQuit() }
+func GetError() string       { return cstr(sdlGetError()) }
+
+func CreateWindow(title string, w, h int32, flags uint64) uintptr {
+	return sdlCreateWindow(cbytes(title), w, h, flags)
+}
+func DestroyWindow(window uintptr) { sdlDestroyWindow(window) }
+
+func VulkanGetInstanceExtensions() []string {
+	var count uint32
+	vkExts := sdlVulkanGetInstanceExtensions(&count)
+	if vkExts == 0 {
+		return nil
+	}
+	exts := make([]string, count)
+	for i := uint32(0); i < count; i++ {
+		p := *(*uintptr)(unsafe.Pointer(vkExts + uintptr(i)*unsafe.Sizeof(uintptr(0))))
+		exts[i] = cstr(p)
+	}
+	return exts
+}
+func VulkanCreateSurface(window, instance, allocator uintptr, surface *uint64) bool {
+	return sdlVulkanCreateSurface(window, instance, allocator, surface)
+}
+
+func PollEvent(event unsafe.Pointer) bool { return sdlPollEvent(event) }
+
+func GetWindowSizeInPixels(window uintptr, w, h *int32) bool {
+	return sdlGetWindowSizeInPixels(window, w, h)
+}
+func SetWindowFullscreen(window uintptr, fullscreen bool) bool {
+	return sdlSetWindowFullscreen(window, fullscreen)
+}
+
+// cstr reads a NUL-terminated C string at p.
+func cstr(p uintptr) string {
+	if p == 0 {
+		return ""
+	}
+	var n int
+	for *(*byte)(unsafe.Pointer(p + uintptr(n))) != 0 {
+		n++
+	}
+	return string(unsafe.Slice((*byte)(unsafe.Pointer(p)), n))
+}
+
+// cbytes returns a NUL-terminated copy of s as *byte, kept alive by the caller.
+func cbytes(s string) *byte {
+	b := make([]byte, len(s)+1)
+	copy(b, s)
+	runtime.KeepAlive(b)
+	return &b[0]
+}