Improved shader conversion custom CMake commands to properly detect changes and not run every build

1 files changed, 16 insertions, 21 deletions

diff --git a/Graphics/HLSL2GLSLConverterLib/CMakeLists.txt b/Graphics/HLSL2GLSLConverterLib/CMakeLists.txt
index 109687df..839d9c20 100644
--- a/Graphics/HLSL2GLSLConverterLib/CMakeLists.txt
+++ b/Graphics/HLSL2GLSLConverterLib/CMakeLists.txt
@@ -18,13 +18,21 @@ set(SOURCE
     src/HLSL2GLSLConverterObject.cpp
 )
 
-add_library(Diligent-HLSL2GLSLConverterLib STATIC ${SOURCE} ${INTERFACE} ${INCLUDE} include/GLSLDefinitions_inc.h)
-set_common_target_properties(Diligent-HLSL2GLSLConverterLib)
+set(GLSL_DEFINITIONS include/GLSLDefinitions.h)
+
+# We must use the full path, otherwise the build system will not be able to properly detect
+# changes and shader conversion custom command will run every time
+set(GLSL_DEFINITIONS_INC ${CMAKE_CURRENT_SOURCE_DIR}/include/GLSLDefinitions_inc.h)
+set_source_files_properties(${GLSL_DEFINITIONS_INC} PROPERTIES GENERATED TRUE)
 
-set_source_files_properties(
-    ${CMAKE_CURRENT_SOURCE_DIR}/include/GLSLDefinitions_inc.h
-    PROPERTIES GENERATED TRUE
+add_library(Diligent-HLSL2GLSLConverterLib STATIC
+    ${SOURCE} ${INTERFACE} ${INCLUDE}
+
+    # A target created in the same directory (CMakeLists.txt file) that specifies any output of the 
+    # custom command as a source file is given a rule to generate the file using the command at build time. 
+    ${GLSL_DEFINITIONS_INC}
 )
+set_common_target_properties(Diligent-HLSL2GLSLConverterLib)
 
 target_include_directories(Diligent-HLSL2GLSLConverterLib 
 PUBLIC 
@@ -44,26 +52,13 @@ PUBLIC
 )
 
 if(NOT FILE2STRING_PATH STREQUAL "")
-    # Create custom target to convert GLSLDefinitions.h to GLSLDefinitions_inc.h
-    add_custom_target(Diligent-ProcessGLSLDefinitions 
-    SOURCES
-        include/GLSLDefinitions.h
-    )
-
-    add_custom_command(TARGET Diligent-ProcessGLSLDefinitions 
-                       # Unfortunately it is not possible to set TARGET directly to HLSL2GLSLConverterLib
-                       # because PRE_BUILD is only supported on Visual Studio 8 or later. For all other generators 
-                       # PRE_BUILD is treated as PRE_LINK.
-                       COMMAND ${FILE2STRING_PATH} include/GLSLDefinitions.h include/GLSLDefinitions_inc.h
+    add_custom_command(OUTPUT ${GLSL_DEFINITIONS_INC} # We must use full path here!
+                       COMMAND ${FILE2STRING_PATH} ${GLSL_DEFINITIONS} include/GLSLDefinitions_inc.h
                        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+                       MAIN_DEPENDENCY ${GLSL_DEFINITIONS}
                        COMMENT "Processing GLSLDefinitions.h"
                        VERBATIM
     )
-
-    add_dependencies(Diligent-HLSL2GLSLConverterLib Diligent-ProcessGLSLDefinitions)
-    set_target_properties(Diligent-ProcessGLSLDefinitions PROPERTIES
-        FOLDER DiligentCore/Graphics/Helper
-    )
 else()
     message(WARNING "File2String utility is currently unavailable on this host system. This is not an issues unless you modify GLSLDefinitions.h file")
 endif()