[CMAKE] Add shader compile function: ax_add_shader [skip ci]

- ax_add_shader(${FILE}): output compiled shader to ${CMAKE_BINARY_DIR}/runtime/shaders/${SC_LANG}/xxx_fs.bin
- ax_add_shader(${FILE} CUSTOM): output compiled shader to ${CMAKE_BINARY_DIR}/runtime/shaders/${SC_LANG}/xxx_fs.bin
- ax_add_shader(${FILE} CVAR): the shader will compiled to c hex header for embed include by C/C++ use

cmake/Modules/AXBuildHelpers.cmake

@@ -588,3 +588,84 @@ macro(ax_config_pred target_name pred)
         target_compile_definitions(${target_name} PUBLIC ${pred}=1)
     endif()
 endmacro()
+
+# glslcc
+find_program(GLSLCC_EXE NAMES glslcc
+    PATHS ${_AX_ROOT_PATH}/tools/external/glslcc
+)
+
+if (NOT GLSLCC_EXE)
+    message("glslcc not found.")
+    message(FATAL_ERROR "Please run setup.ps1 again to download glslcc, and run CMake again.")
+endif()
+
+# This function allow make shader files (.frag, .vert) compiled with glslcc
+# usage:
+# - ax_add_shader(${FILE}): output compiled shader to ${CMAKE_BINARY_DIR}/runtime/shaders/${SC_LANG}/xxx_fs.bin
+# - ax_add_shader(${FILE} CUSTOM): output compiled shader to ${CMAKE_BINARY_DIR}/runtime/shaders/${SC_LANG}/xxx_fs.bin
+# - ax_add_shader(${FILE} CVAR): the shader will compiled to c hex header for embed include by C/C++ use
+function (ax_add_shader FILE)
+    set(options CUSTOM CVAR)
+    cmake_parse_arguments(opt "${options}" "" "" ${ARGN})
+
+    get_filename_component(FILE_EXT ${FILE} LAST_EXT)
+    get_filename_component(FILE_NAME ${FILE} NAME_WE)
+    string(TOLOWER "${FILE_EXT}" FILE_EXT)
+
+     # silent when compile shader success
+    set(SC_FLAGS "--silent")
+    
+    # shader lang
+    if(NOT opt_CUSTOM)
+        set(SHADER_CATALOG "runtime")
+    else()
+        set(SHADER_CATALOG "custom")
+    endif()
+    if(ANDROID OR WINRT OR AX_USE_ANGLE)
+        # version 300 es
+        set(OUT_DIR "${CMAKE_BINARY_DIR}/${SHADER_CATALOG}/shaders/essl")
+        set(OUT_LANG "ESSL")
+        list(APPEND SC_FLAGS  "--lang=gles" "--profile=300")
+    elseif (WIN32 OR LINUX)
+         # version 330
+         set(OUT_DIR "${CMAKE_BINARY_DIR}/${SHADER_CATALOG}/shaders/glsl")
+         set(OUT_LANG "GLSL")
+         list(APPEND SC_FLAGS  "--lang=glsl" "--profile=330")
+    elseif (APPLE) 
+        set(OUT_DIR "${CMAKE_BINARY_DIR}/${SHADER_CATALOG}/shaders/msl")
+        set(OUT_LANG "MSL")
+        list(APPEND SC_FLAGS  "--lang=msl" "--defines=METAL")
+    endif()
+
+    # input
+    if (FILE_EXT STREQUAL ".frag")
+        list(APPEND SC_FLAGS "--frag=${FILE}")
+        set(TYPE "fs")
+    elseif(FILE_EXT STREQUAL ".vert")
+        set(TYPE "vs")
+        list(APPEND SC_FLAGS "--vert=${FILE}")
+    else()
+        message(FATAL_ERROR "Invalid shader source, the file extesion must be one of .frag;.vert")
+    endif()
+
+    # output
+    file(MAKE_DIRECTORY ${OUT_DIR})
+    if (NOT opt_CVAR)
+        list(APPEND SC_FLAGS "--output=${OUT_DIR}/${FILE_NAME}.bin" )
+
+        # glscc will auto insert ${FILE_NAME}_vs.bin or ${FILE_NAME}_fs.bin
+        # so we set OUTPUT to match with it, otherwise will cause cause incremental build to work incorrectly.
+        set(OUTPUT_FILE "${OUT_DIR}/${FILE_NAME}_${TYPE}.bin")
+    else()
+        set(OUTPUT_FILE "${OUT_DIR}/${FILE_NAME}_${TYPE}.bin.h")
+        list(APPEND SC_FLAGS "${OUT_FILE}" "--cvar=shader_rt_${FILE_NAME}" "--output=${OUTPUT_FILE}")
+    endif()
+
+    # "Compiling ${SHADER_CATALOG} shader ${FILE} for ${OUT_LANG} ..."
+    set(compileCmdLine ${GLSLCC_EXE} ${SC_FLAGS})
+    string(REPLACE ";" " " SC_COMMENT "${compileCmdLine} ...")
+    add_custom_command(
+			MAIN_DEPENDENCY ${FILE} OUTPUT ${OUTPUT_FILE} COMMAND ${compileCmdLine}
+			COMMENT "${SC_COMMENT}"
+		)
+endfunction()