app: [Vulkan] keep VkSurfaceKHR ownership to platforms

Before this change, it was unclear who owned the platform specific
VkSurfaceKHR object, leading to a double-free in the error path for
devices with no Vulkan support. This change moves the ownership to the
platform specific code.

Add vk.EnumeratePhysicalDevices while here (refactor was part of
debugging of the double-free).

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/vulkan_android.go

@@ -15,6 +15,7 @@ import (
 type wlVkContext struct {
 	win  *window
 	inst vk.Instance
+	surf vk.Surface
 	ctx  *vkContext
 }
 
@@ -39,6 +40,7 @@ func init() {
 		c := &wlVkContext{
 			win:  w,
 			inst: inst,
+			surf: surf,
 			ctx:  ctx,
 		}
 		return c, nil
@@ -55,6 +57,7 @@ func (c *wlVkContext) API() gpu.API {
 
 func (c *wlVkContext) Release() {
 	c.ctx.release()
+	vk.DestroySurface(c.inst, c.surf)
 	vk.DestroyInstance(c.inst)
 	*c = wlVkContext{}
 }
@@ -71,11 +74,13 @@ func (c *wlVkContext) Unlock() {}
 
 func (c *wlVkContext) Refresh() error {
 	win, w, h := c.win.nativeWindow()
-	c.ctx.destroySurface()
+	if c.surf != 0 {
+		c.ctx.destroySwapchain()
+		vk.DestroySurface(c.inst, c.surf)
+	}
 	surf, err := vk.CreateAndroidSurface(c.inst, unsafe.Pointer(win))
 	if err != nil {
 		return err
 	}
-	c.ctx.setSurface(surf)
-	return c.ctx.refresh(w, h)
+	return c.ctx.refresh(surf, w, h)
 }