Fix hctbuild -b -ninja and explain ninja build steps in README. (#238)

README.md

@@ -77,6 +77,20 @@ You can then use the build directory in the `hctstart` script to test the build.
 
     hctstart C:\source\DirectXShaderCompiler %LOCALAPPDATA%\CMakeBuild\DirectXShaderCompiler\build\x64-Debug
 
+### Building with Ninja
+
+To build with Ninja, please make sure that you have `ninja` and `cl` in your `%PATH%`.
+`ninja` can be installed from [here](https://github.com/ninja-build/ninja/releases);
+`cl` should already be installed together with Visual Studio and can be exported to `%PATH%` via the `vcvars*.bat` script in Visual Studio's VC build directory.
+
+To configure cmake with Ninja generator,
+
+    hctbuild -s -ninja
+
+To build with Ninja, go to the binary directory and run `ninja` directly or
+
+    hctbuild -b -ninja
+
 ## Running Tests
 
 To run tests, open the HLSL Console and run this command after a successful build.
@@ -85,6 +99,8 @@ To run tests, open the HLSL Console and run this command after a successful buil
 
 Some tests will run shaders and verify their behavior. These tests also involve a driver that can run these execute these shaders. See the next section on how this should be currently set up.
 
+If you use Ninja to build the project, please make sure to supply `-ninja` to `hcttest` for testing.
+
 ## Running Shaders
 
 To run shaders compiled as DXIL, you will need support from the operating system as well as from the driver for your graphics adapter.

utils/hct/hctbuild.cmd

@@ -255,16 +255,19 @@ if "%DO_SETUP%"=="1" (
 if "%DO_BUILD%"=="1" (
   rem Should add support for the non-x86-qualified programfiles.
   echo Building solution files for %2 with %1 configuration.
-  if "%BUILD_VS_VER%"=="2015" (
-    if exist "%ProgramFiles(x86)%\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" (
-      call :buildvs_x86dir %1 %2 %3
-    ) else (
-      cmake --build . --config %1
+  if "%BUILD_GENERATOR%" NEQ "Ninja" (
+    if "%BUILD_VS_VER%"=="2015" (
+      if exist "%ProgramFiles(x86)%\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" (
+        call :buildvs_x86dir %1 %2 %3
+        goto :donebuild
+      )
     )
-  ) else (
-    rem Just defer to cmake for now.
-    cmake --build . --config %1
   )
+
+  rem Just defer to cmake for now.
+  cmake --build . --config %1
+
+:donebuild
   if errorlevel 1 (
     echo Failed to build projects.
     echo After fixing, run 'cmake --build --config %1 .' in %2