Update README.md

README.md

@@ -2,20 +2,97 @@
 
 ***Work in progress***
 
-RTGL1 is a library that simplifies the process of porting applications with fixed-function pipeline to *real-time path tracing*
+RTGL1 is a library that simplifies the process of porting applications with fixed-function pipeline to *real-time path tracing*.
 
 It's achievable with hardware accelerated ray tracing, low sample per pixel count and utilizing denoising algorithms to improve the image quality by aggressively reusing spatio-temporal data.
 
-## Screenshots
 
-Test Scene
+## Build
+1. Requirements:
+    * 64-bit CPU
+    * GPU with ray tracing support
+    * [Git](https://github.com/git-for-windows/git/releases)
+    * [CMake](https://cmake.org/download/)
+    * [Vulkan SDK](https://vulkan.lunarg.com/)
+    * [Python 3](https://www.python.org/downloads/) (for building the shaders)
+
+1. Clone the repository
+    * `git clone https://github.com/sultim-t/RayTracedGL1.git`
 
-![Screenshot 00](/Doc/Screenshots/Screenshot_00.png)
-![Screenshot 01](/Doc/Screenshots/Screenshot_01.png)
+1. Configure with CMake
+    * on Windows, with Visual Studio: 
+        * open the folder as CMake project
+    * otherwise:
+        * specify windowing systems to build the library with, by enabling some of the CMake options:
+            * `RG_WITH_SURFACE_WIN32`
+            * `RG_WITH_SURFACE_METAL`
+            * `RG_WITH_SURFACE_WAYLAND`
+            * `RG_WITH_SURFACE_XCB`
+            * `RG_WITH_SURFACE_XLIB`
+        * *(optional)* to build with DLSS: add the environment variable `DLSS_SDK_PATH` that points to a cloned [DLSS repository](https://github.com/NVIDIA/DLSS), and enable `RG_WITH_NVIDIA_DLSS` option    
+        * configure
+        ```
+        mkdir Build
+        cd Build
+        cmake ..
+        ```
+        * but make sure that projects that use RTGL1 can find the compiled dynamic library, as it usually assumed that it's in `Build/x64-Debug` or `Build/x64-Release`
+
+1. Build
+    * `cmake --build .`
+
+1. Build shaders
+    * Run `Source/Shaders/GenerateShaders.py` with Python3, it will generate SPIR-V files to `Build` folder
+
+### Notes:
+* RTGL1 requires a set of blue noise images on start-up: `RgInstanceCreateInfo::pBlueNoiseFilePath`. A ready-to-use resource can be found here: `Tools/BlueNoise_LDR_RGBA_128.ktx2`
+
+
+## Tools
+
+### Shader development
+
+RTGL1 supports shader hot-reloading (a target application sets `RgStartFrameInfo::requestShaderReload=true` in runtime).
 
-Serious Sam TFE: Ray Traced
+But to ease the process of *building* the shaders, instead of running `GenerateShaders.py` from a terminal manually, you can install [Visual Studio Code](https://code.visualstudio.com/) and [Script Runner extension](https://marketplace.visualstudio.com/items?itemName=easterapps.script-runner) to it. Open `Sources/Shaders` folder, add such config to VS Code's `.json` settings file (of courser, it could be better done with VS Code workspaces).
+```
+"script-runner.definitions": {
+        "commands": [
+            {
+                "identifier": "shaderBuild",
+                "description": "Build shaders",
+                "command": "cls; python .\\GenerateShaders.py -ps",
+                "working_directory": "${workspaceFolder}",
+            },
+            {
+                "identifier": "shaderGenAndBuild",
+                "description": "Build shaders with generating common files",
+                "command": "cls; python .\\GenerateShaders.py -ps -g",
+                "working_directory": "${workspaceFolder}",
+            }
+        ],
+    },
+```
+Then assign hotkeys to `shaderBuild` and `shaderGenAndBuild` commands in `File->Preferences->Keyboard Shortcuts`.
 
-![Screenshot 02](/Doc/Screenshots/Screenshot_02.png)
-![Screenshot 03](/Doc/Screenshots/Screenshot_03.png)
-![Screenshot 04](/Doc/Screenshots/Screenshot_04.png)
-![Screenshot 04](/Doc/Screenshots/Screenshot_05.png)
+### Textures
+Some games don't have PBR materials, but to add them, RTGL1 provides 'texture overriding' functionality: application requests to upload an original texture and specifies its name, then RTGL1 tries to find files with such name (appending some suffixes, e.g. `_n` for normal maps, or none for albedo maps) and loads them instead of original ones. These files are in `.ktx2` format with a specific compression and contain image data. 
+
+To generate such textures: 
+1. [Compressonator CLI](https://gpuopen.com/compressonator/) and `Python3` are required
+1. Create a folder, put `Tools/CreateKTX2.py`, create folder named `Raw` and `Compressed`.
+1. The script:
+   1. scans files (with `INPUT_EXTENSIONS`) in `Raw` folder
+   1. generates corresponding `.ktx2` file to `Compressed` folder, preserving the hierarchy
+
+On RTGL1 initialization, `RgInstanceCreateInfo::pOverridenTexturesFolderPath` should contain a path to the `Compressed` folder. 
+
+
+
+# Projects
+* https://github.com/sultim-t/Serious-Engine-RT/releases
+* https://github.com/sultim-t/prboom-plus-rt
+
+## Screenshots
+![Screenshot 00](/Doc/Screenshots/Screenshot_00.png)
+![Screenshot 01](/Doc/Screenshots/Screenshot_01.png)