Update ray tracing samples to use VK_KHR_ray_tracing (#753)

* Started updating ray tracing samples to KHR extension

* Updated GLSL shaders to use GL_EXT_ray_tracing

* Code cleanup, naming

* Fix include directories to use Vulkan headers from repository instead of NDK for the Android build

* Added new Android function pointers

* Renamed basic ray tracing sample

Added android build files

* Remove unused batch file

* Replaced remaining NV identifiers

* Updating ray tracing shadow sample to KHR extension

* Updated shaders to use KHR instead of NV extension

Fixed shader bindings

* Updating ray tracing reflections sample to KHR extension

* Renamed ray tracing reflections sample

* Renamed ray tracing shadows sample

Added android build files

* Removed no-longer used batch files for shader generation

* Proper alignment for the shader binding table

* Updated readme

* Reworked shader group setup

* Cleanup

* Reworked shader group setup

* Reworked shader group setup

* Code cleanup

README.md

@@ -20,6 +20,7 @@ A comprehensive collection of open source C++ examples for [Vulkan®](https://ww
     + [Compute Shader](#ComputeShader)
     + [Geometry Shader](#GeometryShader)
     + [Tessellation Shader](#TessellationShader)
+    + [Ray tracing](#Raytracing)
     + [Headless](#Headless)
     + [User Interface](#UserInterface)
     + [Effects](#Effects)
@@ -287,6 +288,20 @@ Renders a terrain using tessellation shaders for height displacement (based on a
 
 Uses curved PN-triangles ([paper](http://alex.vlachos.com/graphics/CurvedPNTriangles.pdf)) for adding details to a low-polygon model.
 
+### <a name="Raytracing"></a> Ray Tracing (VK_KHR_ray_tracing)
+
+#### [01 - Basic ray tracing](examples/raytracingbasic)
+
+Basic example for doing hardware accelerated ray tracing using the ```VK_KHR_ray_tracing``` extension. Shows how to setup acceleration structures, ray tracing pipelines and the shaders needed to do the actual ray tracing.
+
+#### [02 - Ray traced shadows](examples/raytracingshadows)
+
+Adds ray traced shadows casting using the new ray tracing extensions to a more complex scene. Shows how to add multiple hit and miss shaders and how to modify existing shaders to add shadow calculations.
+
+#### [03 - Ray traced reflections](examples/raytracingreflections)
+
+Renders a complex scene with reflective surfaces using the new ray tracing extensions. Shows how to do recursion inside of the ray tracing shaders for implementing real time reflections.
+
 ### <a name="Headless"></a> Headless
 
 Examples that run one-time tasks and don't make use of visual output (no window system integration). These can be run in environments where no user interface is available ([blog entry](https://www.saschawillems.de/tutorials/vulkan/headless_examples)).
@@ -363,18 +378,6 @@ An updated version using ```VK_EXT_debug_utils``` along with an in-depth tutoria
 
 Shows how to render a scene using a negative viewport height, making the Vulkan render setup more similar to other APIs like OpenGL. Also has several options for changing relevant pipeline state, and displaying meshes with OpenGL or Vulkan style coordinates. Details can be found in [this tutorial](https://www.saschawillems.de/tutorials/vulkan/flipping-viewport).
 
-#### [08 - Basic ray tracing with VK_NV_ray_tracing](examples/nv_ray_tracing_basic)
-
-Basic example for doing ray tracing using the new Nvidia RTX extensions. Shows how to setup acceleration structures, ray tracing pipelines and the shaders needed to do the actual ray tracing.
-
-#### [09 - Ray traced shadows with VK_NV_ray_tracing](examples/nv_ray_tracing_shadows)
-
-Adds ray traced shadows casting using the new Nvidia RTX extensions to a more complex scene. Shows how to add multiple hit and miss shaders and how to modify existing shaders to add shadow calculations.
-
-#### [10 - Ray traced reflections with VK_NV_ray_tracing](examples/nv_ray_tracing_reflections)
-
-Renders a complex scene with reflective surfaces using the new Nvidia RTX extensions. Shows how to do recursion inside of the ray tracing shaders for implementing real time reflections.
-
 ### <a name="Misc"></a> Misc
 
 #### [01 - Vulkan Gears](examples/gears/)