Added docs/getting_started.md and updated readme

README.md

@@ -12,11 +12,13 @@ This library simplifies the tedious process of:
 
 It also adds several conveniences for:
 
-* enabling validation layers
+* Enabling validation layers
-* setting up a debug callback
+* Adding a debug callback
-* select a gpu based on a set of common criteria like features, extensions, memory, etc.
+* Select a gpu based on a set of criteria like features, extensions, memory, etc.
 
-## Example
+Read the [Getting Started](docs/getting_started.md) guide for a quick start on using `vk-bootstrap`
+
+## Basic Usage
 
 ```cpp
 
@@ -70,7 +72,8 @@ See `example/triangle.cpp` for an example that renders a triangle to the screen.
 
 ### Simple
 
-This library has no external dependencies.
+This library has no external dependencies beyond C++11 and the standard library.
+
 Simply copy the `src/VkBootstrap.h` and `src/VkBootstrap.cpp` files into your project and compile them as you normally would
 
 ### With git-submodule + CMake
@@ -115,10 +118,3 @@ you can force enable tests by adding `-DVK_BOOTSTRAP_TEST` to the cmake command
 ```bash
 cmake ../path/to/your-project/ -DVK_BOOTSTRAP_TEST=ON
 ```
-
-## Todo's
-
-* Package library to be usable
-* More examples
-* Testing
-* Documenting API

docs/getting_started.md

@@ -0,0 +1,144 @@
+# Getting Started
+
+`vk-bootstrap` reduces the complexity of setting up a vulkan application into 3 main steps; instance creation, Physical device selection, and device creation. 
+
+## Instance Creation
+
+Creating an instance with `vk-bootstrap` uses the `vkb::InstanceBuilder` class.
+
+Simply create a builder variable and call the `build()` member function.
+```cpp
+vkb::InstanceBuilder instance_builder;
+auto instance_builder_return = instance_builder.build();
+```
+Because creating an instance may fail, the builder returns an 'Expected' type which can be either a valid `vkb::Instance` struct, containing the `VkInstance` handle, or the builder returns an error.
+```cpp
+if (!instance_builder_return) {
+    printf("Failed to create Vulkan instance. Cause %s\n", 
+        vkb::to_string(instance_builder_return.error().type));
+    return -1;
+} 
+```
+Now that any possible errors have been handled, 
+```cpp
+vkb::Instance vkb_instance = instance_builder_return.value();
+```
+This is enough to create a usable `VkInstance` but most use cases will want to customize it a bit. To do so, simply call the member functions on the `vkb::InstanceBuilder` object before `build()` is called.
+
+The most common customization to instance creation is enabling the "Validation Layers", an invaluable tool for any vulkan application developer. 
+```cpp
+instance_builder.request_validation_layers ();
+```
+The other common customization point is setting up the `Debug Messenger Callback`, the mechanism in which an application can control what and where the "Validation Layers" log its output.
+```cpp
+instance_builder.set_debug_callback (
+    [] (VkDebugUtilsMessageSeverityFlagBitsEXT messageSeverity,
+	    VkDebugUtilsMessageTypeFlagsEXT messageType,
+	    const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData,
+	    void *pUserData) 
+        -> VkBool32 {
+			auto severity = vkb::to_string_message_severity (messageSeverity);
+			auto type = vkb::to_string_message_type (messageType);
+			printf ("[%s: %s] %s\n", severity, type, pCallbackData->pMessage);
+			return VK_FALSE;
+		}
+    );
+```
+Alternatively, `vk-bootstrap` provides a 'default debug messenger' that prints to standard output.
+```cpp
+instance_builder.use_default_debug_messenger();
+```
+Configuration can be chained together and done inline with building, like so.
+```cpp
+auto inst_builder_ret = instance_builder 
+        .set_app_name ("Awesome Vulkan Application")
+        .set_engine_name("Excellent Game Engine")
+        .require_api_version(1,0,0)
+        .build();
+```
+
+The `vkb::Instance` struct is meant to hold all the necessary instance level data to enable proper Physical Device selection. It also is meant for easy destructuring into custom classes if so desired.
+```cpp
+struct CustomVulkanWrapper {
+    VkInstance instance;
+    //...
+};
+CustomVulkanWrapper custom_vk_class;
+custom_vk_class.instance = vkb_instance.instance;
+```
+
+When the application is finished with the vulkan, call `vkb::destroy_instance()` to dispose of the instance and associated data. 
+```cpp
+// cleanup 
+vkb::destroy_instance(vkb_instance);
+```
+### Instance Creation Summary
+```cpp
+vkb::InstanceBuilder instance_builder;
+auto instance_builder_return = instance_builder
+        // Instance creation configuration
+        .request_validation_layers()
+        .use_default_debug_messenger()
+        .build ();
+if (!instance_builder_return) {
+    // Handle error
+} 
+vkb::Instance vkb_instance = instance_builder_return.value ();
+
+// at program end
+vkb::destroy_instance(vkb_instance);
+```
+## Surface Creation
+
+Vulkan requires manually creating a surface, called `VkSurfaceKHR`. Creating a surface is the responsibility of the windowing system, thus is out of scope for `vk-bootstrap`. However, it does try to make the process as painless as possible by automatically enabling the correct windowing extensions in `VkInstance` creation. 
+
+Windowing libraries which support Vulkan usually provide a way of getting the `VkSurfaceKHR` handle for the window. These methods require a valid Vulkan instance, thus must be done after instance creation.
+
+Examples for GLFW and SDL2 are listed below. 
+```cpp
+vkb::Instance vkb_instance; //valid vkb::Instance
+VkSurfaceKHR surface = nullptr;
+// window is a valid library specific Window handle
+
+// GLFW
+VkResult err = glfwCreateWindowSurface (vkb_instance.instance, window, NULL, &surface);
+if (err != VK_SUCCESS) { /* handle error */ }
+
+// SDL2
+SDL_bool err = SDL_Vulkan_CreateSurface(window, vkb_instance.instance, &surface);
+if (!err){ /* handle error */ }
+
+```
+
+## Physical Device Selection
+
+Once a Vulkan instance has been created, the next step is to find a suitable GPU for the application to use. `vk-bootstrap` provide the `vkb::PhysicalDeviceSelector` class to streamline this process.
+
+Creating a `vkb::PhysicalDeviceSelector` requires a valid `vkb::Instance` to construct.
+
+It follows the same pattern laid out by `vkb::InstanceBuilder`.
+```cpp
+vkb::PhysicalDeviceSelector phys_device_selector (vkb_instance); 
+auto physical_device_selector_return = phys_device_selector
+        .set_surface(surface_handle)
+        .select ();
+if (!physical_device_selector_return) {
+    // Handle error
+}
+auto phys_device = phys_device_ret.value ();
+```
+
+To select a physical device, call `select()` on the `vkb::PhysicalDeviceSelector` object.
+By default, this will prefer a discrete GPU.
+
+No cleanup is required for `vkb::PhysicalDevice`.
+
+// TODO -- configuring selection, querying phys device details, explaining why a surface is needed
+
+## Device Creation
+// TODO
+## Swapchain
+// TODO
+## Error Handling
+// TODO
+