config: Factor out crosscompile tool search

Add search for shaderc, texturec, texturev and geometryv

README.md

@@ -1,13 +1,11 @@
-bgfx.cmake
-==========
+# bgfx.cmake
 [![Build Status](https://github.com/bkaradzic/bgfx.cmake/workflows/Release/badge.svg)](https://github.com/bkaradzic/bgfx.cmake/workflows/Release/badge.svg)
 
 **NOTE: This port only made to be used as C++ library, some features (such as bindings) might not work! For those features, please use original repo with GENie instead.**
 
 This repo contains cmake configuration files that can be used to build bgfx with CMake.
 
-Building
----
+## Building
 
 ```bash
 git clone https://github.com/bkaradzic/bgfx.cmake.git
@@ -20,12 +18,10 @@ cmake --build cmake-build
 
 If downloading via zip (instead of using git submodules) manually download bx, bimg and bgfx and copy them into the root directory, or locate them via `BX_DIR`, `BIMG_DIR` and `BGFX_DIR` CMake variables.
 
-How To Use
-----------
+## How To Use
 This project is setup to be included a few different ways. To include bgfx source code in your project simply use add_subdirectory to include this project. To build bgfx binaries build the `INSTALL` target (or `make install`). The installed files will be in the directory specified by `CMAKE_INSTALL_PREFIX` which we recommend you set to `./install` so it will export to your build directory. Note you may want to build install on both `Release` and `Debug` configurations.
 
-Features
---------
+## Features
 * No outside dependencies besides bx, bimg, bgfx, and CMake.
 * Tested on
     * Windows, OSX, Linux, Android, UWP, Emscripten (experimental)
@@ -33,6 +29,66 @@ Features
 * Compiles bgfx, tools & examples.
 * Detects shader modifications and automatically rebuilds them for all examples.
 
-Does this work with latest bx/bgfx/bimg?
-----------------------------------------
+## Added cmake commands
+bgfx.cmake will install `bgfxToolUtils.cmake` which has useful cmake functions for using bgfx's tools:
+
+### `bgfx_compile_shader_to_header`
+Add a build rule for a `*.sc` shader to the generated build system using shaderc.
+```cmake
+bgfx_compile_shader_to_header(
+	TYPE VERTEX|FRAGMENT|COMPUTE
+	SHADERS filenames
+	VARYING_DEF filename
+	OUTPUT_DIR directory
+)
+```
+This defines a shaderc command to generate headers for a number of `TYPE` shaders with `SHADERS` files and `VARYING_DEF` file in the `OUTPUT_DIR` directory. There will be one generated shader for each supported rendering API on this current platform according to the `BGFX_EMBEDDED_SHADER` macro in `bgfx/embedded_shader.h`.
+
+The generated headers will have names in the format of `${SHADERS}.${RENDERING_API}.bin.h` where `RENDERING_API` can be `glsl`, `essl`, `spv`, `dx9`, `dx11` and `mtl` depending on the availability of the platform.
+
+Adding these `SHADERS` as source files to a target will run `shaderc` at build time and they will rebuild if either the contents of the `SHADERS` or the `VARYING_DEF` change.
+
+#### Examples: Generating shaders as headers
+```cmake
+bgfx_compile_shader_to_header(
+  TYPE VERTEX
+  SHADERS vs.sc
+  VARYING_DEF varying.def.sc
+  OUTPUT_DIR ${CMAKE_BINARY_DIR}/include/generated/shaders
+)
+bgfx_compile_shader_to_header(
+  TYPE FRAGMENT
+  SHADERS fs.sc
+  VARYING_DEF ${CMAKE_SOURCE_DIR}/varying.def.sc
+  OUTPUT_DIR ${CMAKE_BINARY_DIR}/include/generated/shaders
+)
+
+add_library(myLib main.cpp vs.sc fs.sc)
+target_include_directories(myLib ${CMAKE_BINARY_DIR}/include/generated/shaders)
+```
+
+```cpp
+// main.cpp
+#include <vs.sc.glsl.bin.h>
+#include <vs.sc.essl.bin.h>
+#include <vs.sc.spv.bin.h>
+#include <fs.sc.glsl.bin.h>
+#include <fs.sc.essl.bin.h>
+#include <fs.sc.spv.bin.h>
+#if defined(_WIN32)
+#include <vs.sc.dx9.bin.h>
+#include <vs.sc.dx11.bin.h>
+#include <fs.sc.dx9.bin.h>
+#include <fs.sc.dx11.bin.h>
+#endif //  defined(_WIN32)
+#if __APPLE__
+#include <vs.sc.mtl.bin.h>
+#include <fs.sc.mtl.bin.h>
+#endif // __APPLE__
+
+const bgfx::EmbeddedShader k_vs = BGFX_EMBEDDED_SHADER(vs);
+const bgfx::EmbeddedShader k_fs = BGFX_EMBEDDED_SHADER(fs);
+```
+
+## Does this work with latest bx/bgfx/bimg?
 Probably! This project needs to be updated if a dependency is added or the bgfx build system changes. The bgfx repository is very active but these types of changes are rare. New examples have to be added manually as well, but not doing so will merely result in that example not showing up and won't break anything else. If pulling latest causes issues, be sure to manually reconfigure CMake as the glob patterns may need to be refreshed (the use of glob patterns in CMake is generally discouraged but in this project it helps to ensure upwards compatibilty with newer bgfx updates).