- added initial support of Vulkan to SDL backend

Removed all platform-specific code from vulkan device

src/win32/win32vulkanvideo.cpp

@@ -0,0 +1,74 @@
+
+#include <assert.h>
+
+#ifdef _WIN32
+#define VK_USE_PLATFORM_WIN32_KHR
+#endif
+
+#include "volk/volk.h"
+
+
+extern HWND Window;
+
+void I_GetVulkanDrawableSize(int *width, int *height)
+{
+	assert(Window);
+
+	RECT clientRect = { 0 };
+	GetClientRect(Window, &clientRect);
+	
+	if (width != nullptr)
+	{
+		*width = clientRect.right;
+	}
+
+	if (height != nullptr)
+	{
+		*height = clientRect.bottom;
+	}
+}
+
+bool I_GetVulkanPlatformExtensions(unsigned int *count, const char **names)
+{
+	static const char* extensions[] = 
+	{
+		VK_KHR_SURFACE_EXTENSION_NAME,
+		VK_KHR_WIN32_SURFACE_EXTENSION_NAME
+	};
+	static const unsigned int extensionCount = static_cast<unsigned int>(sizeof extensions / sizeof extensions[0]);
+
+	if (count == nullptr && names == nullptr)
+	{
+		return false;
+	}
+	else if (names == nullptr)
+	{
+		*count = extensionCount;
+		return true;
+	}
+	else
+	{
+		const bool result = *count >= extensionCount;
+		*count = min(*count, extensionCount);
+
+		for (unsigned int i = 0; i < *count; ++i)
+		{
+			names[i] = extensions[i];
+		}
+
+		return result;
+	}
+}
+
+bool I_CreateVulkanSurface(VkInstance instance, VkSurfaceKHR *surface)
+{
+	VkWin32SurfaceCreateInfoKHR windowCreateInfo;
+	windowCreateInfo.sType = VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR;
+	windowCreateInfo.pNext = nullptr;
+	windowCreateInfo.flags = 0;
+	windowCreateInfo.hwnd = Window;
+	windowCreateInfo.hinstance = GetModuleHandle(nullptr);
+
+	const VkResult result = vkCreateWin32SurfaceKHR(instance, &windowCreateInfo, nullptr, surface);
+	return result == VK_SUCCESS;
+}