Start API Overview

Author: guillaume-haerinck

_toc.yml

@@ -4,4 +4,4 @@
   chapters:
   - file: doc/getting-started/the-forge
   - file: doc/getting-started/building
-  - file: doc/getting-started/triangle
+  - file: doc/getting-started/api-overview

doc/getting-started/api-overview.md

@@ -0,0 +1,112 @@
+# API Overview
+
+## The application interface
+
+Needed to use their windowing system
+
+Talk about the macro `DEFINE_APPLICATION_MAIN` at the bottom of this file
+
+Defined in the `OS` project
+
+Not mandatory, possible to use SDL2 or GLFW, but latest game consoles not handled by these libs while they are with TheForge  
+
+```c++
+class IApp
+{
+public:
+    // this pair of functions initializes and exits once during start-up and shut-down of the application
+    // we open and close all the resources that will never change during the live span of an application
+    // in other words, they are independent from any user changes to the device and quality settings
+    // typically this is restricted to for example to loading and unloading geometry
+	virtual bool Init() = 0;
+	virtual void Exit() = 0;
+
+    // this pair of functions loads and unloads everything that need to be re-loaded in case of a device change.
+    // device changes can come from a user switching from hardware to Warp rendering support or switching on and off MSAA 
+    // and other quality settings
+    // typically shaders, textures, render targets and buffers are loaded here
+	virtual bool Load() = 0;
+	virtual void Unload() = 0;
+
+    // this is input / math update -> everything CPU only ... no Graphics API calls
+	virtual void Update(float deltaTime) = 0;
+    
+    // only Graphics API draw calls and command buffer generation
+	virtual void Draw() = 0;
+
+	virtual const char* GetName() = 0;
+}
+```
+
+## Init
+
+Need to create the renderer
+
+### Queue families
+
+### Command Pool
+
+### Synchronisation primitives
+
+#### Fences
+
+#### Semaphores
+
+### Samplers
+
+### Resources
+
+#### Textures
+
+#### Models
+
+### Shaders
+
+#### Root Signature
+
+#### Buffer Load Description
+
+#### Descriptor sets
+
+### UI
+
+### User Inputs
+
+## Load
+
+### SwapChain
+
+### DepthBuffer
+
+### Graphics Pipeline Description
+
+#### Vertex layout
+
+#### Rasterizer State Description
+
+#### Depth State Description
+
+## Update
+
+### Camera
+
+### User inputs
+
+### Uniforms local values
+
+## Draw
+
+### Swapchain
+
+### Render target
+
+### Synchronisation primitives
+
+### Uniform buffers update
+
+### Command generation
+
+### Microprofiler markers
+
+### Queue Submit
+