Add C language examples alongside C++ in Vulkan tutorials

en/01_Overview.adoc

@@ -28,7 +28,7 @@ with the existing APIs somehow. This resulted in less than ideal abstractions
 Aside from these new features, the past decade also saw an influx of mobile
 and embedded devices with powerful graphics hardware. These mobile GPUs have
  different architectures based on their energy and space requirements.
-One such example is https://en.wikipedia.org/wiki/Tiled_rendering[tiled rendering], 
+One such example is https://en.wikipedia.org/wiki/Tiled_rendering[tiled rendering],
 which would benefit from improved performance by offering the
 programmer more control over this functionality.
 Another limitation originating from the age of these APIs is limited
@@ -261,10 +261,12 @@ developed by LunarG. We'll look into installing this SDK in the next chapter.
 Functions have a lower case `vk` prefix, types like enumerations and structs
  have a `Vk` prefix and enumeration values have a `VK_` prefix.
 The API heavily uses structs to provide parameters to functions.
-For example, object creation generally follows this pattern:
+For example, object creation generally follows this pattern in both the C API and the C++ RAII wrapper:
 
-[,c++]
+[source,multilang,c++,c]
+.Object creation pattern
 ----
+// START c
 VkXXXCreateInfo createInfo{};
 createInfo.sType = VK_STRUCTURE_TYPE_XXX_CREATE_INFO;
 createInfo.pNext = nullptr;
@@ -276,6 +278,12 @@ if (vkCreateXXX(&createInfo, nullptr, &object) != VK_SUCCESS) {
     std::cerr << "failed to create object" << std::endl;
     return false;
 }
+// END c
+
+// START c++
+auto createInfo = vk::xxx();
+auto object = vk::raii::XXX(context, createInfo);
+// END c++
 ----
 
 Many structures in Vulkan require you to explicitly specify the type of
@@ -291,15 +299,6 @@ error code.
 The specification describes which error codes each function can return and
 what they mean.
 
-To help illustrate the utility of using the RAII C++ Vulkan abstraction; this
-is the same code written with our modern API:
-
-[,c++]
-----
-auto createInfo = vk::xxx();
-auto object = vk::raii::XXX(context, createInfo);
-----
-
 Failure of such calls is reported by C++ exceptions. The exception will
 respond with more information about the error including the aforementioned
 vkResult, this enables us to check multiple commands from one call and keep

en/03_Drawing_a_triangle/01_Presentation/00_Window_surface.adoc

@@ -37,9 +37,16 @@ works in this tutorial.
 
 Start by adding a `surface` class member right below the debug callback.
 
-[,c++]
+[source,multilang,c++,c]
+.Surface member
 ----
+// START c++
 vk::raii::SurfaceKHR surface = nullptr;
+// END c++
+
+// START c
+VkSurfaceKHR surface = VK_NULL_HANDLE;
+// END c
 ----
 
 Although the `VkSurfaceKHR` object and its usage is platform-agnostic, its
@@ -72,12 +79,22 @@ Because a window surface is a Vulkan object, it comes with a
 important parameters: `hwnd` and `hinstance`. These are the handles to the
 window and the process.
 
-[,c++]
+[source,multilang,c++,c]
+.Win32 surface create info
 ----
+// START c++
+vk::Win32SurfaceCreateInfoKHR createInfo{
+    .hwnd = glfwGetWin32Window(window),
+    .hinstance = GetModuleHandle(nullptr)
+};
+// END c++
+
+// START c
 VkWin32SurfaceCreateInfoKHR createInfo{};
 createInfo.sType = VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR;
 createInfo.hwnd = glfwGetWin32Window(window);
 createInfo.hinstance = GetModuleHandle(nullptr);
+// END c
 ----
 
 The `glfwGetWin32Window` function is used to get the raw `HWND` from the GLFW
@@ -91,11 +108,18 @@ Technically, this is a WSI extension function, but it is so commonly used
 that the standard Vulkan loader includes it, so unlike other extensions, you
 don't need to explicitly load it.
 
-[,c++]
+[source,multilang,c++,c]
+.Create the Win32 surface
 ----
+// START c++
+surface = vk::raii::SurfaceKHR(instance, createInfo);
+// END c++
+
+// START c
 if (vkCreateWin32SurfaceKHR(instance, &createInfo, nullptr, &surface) != VK_SUCCESS) {
     throw std::runtime_error("failed to create window surface!");
 }
+// END c
 ----
 
 The process is similar for other platforms like Linux, where
@@ -125,15 +149,26 @@ void createSurface() {
 The GLFW call takes simple parameters instead of a struct which makes the
 implementation of the function very straightforward:
 
-[,c++]
+[source,multilang,c++,c]
+.GLFW window surface creation
 ----
+// START c++
 void createSurface() {
-    VkSurfaceKHR       _surface;
+    VkSurfaceKHR _surface;
     if (glfwCreateWindowSurface(*instance, window, nullptr, &_surface) != 0) {
         throw std::runtime_error("failed to create window surface!");
     }
     surface = vk::raii::SurfaceKHR(instance, _surface);
 }
+// END c++
+
+// START c
+void createSurface() {
+    if (glfwCreateWindowSurface(instance, window, nullptr, &surface) != VK_SUCCESS) {
+        throw std::runtime_error("failed to create window surface!");
+    }
+}
+// END c
 ----
 
 However, as you see in the above, GLFW only deals with the Vulkan C API.
@@ -165,9 +200,17 @@ to our window surface. The function to check for that is
 queue family index and surface as parameters. Add a call to it
 in the same loop as the `VK_QUEUE_GRAPHICS_BIT`:
 
-[,c++]
+[source,multilang,c++,c]
+.Presentation support query
 ----
-VkBool32 presentSupport = physicalDevice.getSurfaceSupportKHR( graphicsIndex, *surface );
+// START c++
+VkBool32 presentSupport = physicalDevice.getSurfaceSupportKHR(graphicsIndex, *surface);
+// END c++
+
+// START c
+VkBool32 presentSupport = VK_FALSE;
+vkGetPhysicalDeviceSurfaceSupportKHR(physicalDevice, graphicsIndex, surface, &presentSupport);
+// END c
 ----
 
 Then check the value of the boolean and store the presentation family