Switch shader storage to char arrays

CMakeModules/BuildSteps/CreateShaderCpp.cmake

@@ -1,54 +1,83 @@
-file( READ ${SOURCE} SOURCE_TEXT )
+#
-file( SIZE ${SOURCE} SOURCE_FILESIZE )
+# Converts provided shader files into the gal namespaced shaders
+#
+# The goal here is to convert the contents of shaders in the source tree
+# into strings to embed into the binaries rather than loading from disk.
+#
+# We convert the shaders to binary form in the header due limitations of string literal
+# lengths and also because future development options such as moving to bgfx
+# results in precompiled binary shaders we need to store
+#
+# This file is structured to be invoked from add_custom_command in order
+# to have GENERATED marked output files that can be rebuilt on change.
+#
+# Required Arguments:
+# SOURCE_FILE - Path to source shader file
+# OUT_CPP_DIR - Destination path for cpp file
+# OUT_HEADER_DIR - Destination path for header file
+# OUT_CPP_FILENAME - cpp filename
+# OUT_HEADER_FILENAME - header filename
+# OUT_VAR_NAME - Name of variable containing shader to be created
+#
+# Parts taken from https://github.com/sivachandran/cmake-bin2h
+# Copyright 2020 Sivachandran Paramasivam
+#
 
-set( MAX_BYTES_PER_LITERAL 16000 )
+# Function to wrap a given string into multiple lines at the given column position.
+# Parameters:
+#   VARIABLE    - The name of the CMake variable holding the string.
+#   AT_COLUMN   - The column position at which string will be wrapped.
+function(WRAP_STRING)
+    set(oneValueArgs VARIABLE AT_COLUMN)
+    cmake_parse_arguments(WRAP_STRING "${options}" "${oneValueArgs}" "" ${ARGN})
 
-math(EXPR NUMBER_LITERALS "${SOURCE_FILESIZE}/${MAX_BYTES_PER_LITERAL}")
+    string(LENGTH ${${WRAP_STRING_VARIABLE}} stringLength)
+    math(EXPR offset "0")
+
+    while(stringLength GREATER 0)
+
+        if(stringLength GREATER ${WRAP_STRING_AT_COLUMN})
+            math(EXPR length "${WRAP_STRING_AT_COLUMN}")
+        else()
+            math(EXPR length "${stringLength}")
+        endif()
+
+        string(SUBSTRING ${${WRAP_STRING_VARIABLE}} ${offset} ${length} line)
+        set(lines "${lines}\n${line}")
+
+        math(EXPR stringLength "${stringLength} - ${length}")
+        math(EXPR offset "${offset} + ${length}")
+    endwhile()
+
+    set(${WRAP_STRING_VARIABLE} "${lines}" PARENT_SCOPE)
+endfunction()
 
 
-set( outCppTextStdString "std::string ${OUTVARNAME} = ")
+file( READ ${SOURCE_FILE} _SOURCE_BINARY HEX )
+string(LENGTH ${_SOURCE_BINARY} _SOURCE_BINARY_LENGTH)
+
+set(SOURCE_BINARY "${_SOURCE_BINARY}00") # null terminate for the sake of it
+
+wrap_string(VARIABLE _SOURCE_BINARY AT_COLUMN 32)
+math(EXPR _ARRAY_SIZE "${_SOURCE_BINARY_LENGTH} / 2")
+
+
+# adds '0x' prefix and comma suffix before and after every byte respectively
+string(REGEX REPLACE "([0-9a-f][0-9a-f])" "0x\\1, " _ARRAY_VALUES ${_SOURCE_BINARY})
+# removes trailing comma
+string(REGEX REPLACE ", $" "" _ARRAY_VALUES ${_ARRAY_VALUES})
+
+set( outCppTextByteArray "unsigned char ${OUT_VAR_NAME}_bytes[] = { ${_ARRAY_VALUES} };")
+set( outCppTextStdString "std::string ${OUT_VAR_NAME} = std::string( reinterpret_cast<char const*>(${OUT_VAR_NAME}_bytes), ${_ARRAY_SIZE} ) ;")
 
 set( outCppText
 "
 #include <string>
-#include <${OUTHEADERFILE}>
+#include <${OUT_HEADER_FILENAME}>
 
 namespace KIGFX {
 namespace BUILTIN_SHADERS {
-")
+${outCppTextByteArray}
-
-
-MATH(EXPR LAST_LITERAL_ITER "${NUMBER_LITERALS}-1")
-
-foreach(LITERAL_ITER RANGE 0 ${NUMBER_LITERALS} 1)
-    set( CHUNK_TEXT "" )
-
-    MATH(EXPR TEXT_OFFSET "${LITERAL_ITER}*${MAX_BYTES_PER_LITERAL}")
-
-    string(SUBSTRING "${SOURCE_TEXT}" ${TEXT_OFFSET} ${MAX_BYTES_PER_LITERAL} CHUNK_TEXT)
-
-
-    set( outCppText
-    "
-${outCppText}
-
-const char ${OUTVARNAME}_p${LITERAL_ITER}[] = R\"SHADER_SOURCE(
-${CHUNK_TEXT}
-)SHADER_SOURCE\";
-
-    " )
-
-    set( outCppTextStdString "${outCppTextStdString} std::string(${OUTVARNAME}_p${LITERAL_ITER})")
-    if( ${LITERAL_ITER} LESS_EQUAL ${LAST_LITERAL_ITER})
-        set( outCppTextStdString " ${outCppTextStdString} +")
-    endif()
-endforeach()
-
-set( outCppTextStdString "${outCppTextStdString};")
-
-set( outCppText
-"
-${outCppText}
 
 ${outCppTextStdString}
 }
@@ -56,7 +85,7 @@ ${outCppTextStdString}
 " )
 
 file(
-    WRITE ${DESTINATION_SOURCE_DIR}/${OUTCPPFILE}
+    WRITE ${OUT_CPP_DIR}/${OUT_CPP_FILENAME}
     "${outCppText}"
 )
 
@@ -64,14 +93,14 @@ file(
 set( outHeaderText
 "namespace KIGFX {
     namespace BUILTIN_SHADERS {
-        extern std::string ${OUTVARNAME};
+        extern std::string ${OUT_VAR_NAME};
     }
 }"
 )
 
 file(
-    WRITE ${DESTINATION_HEADER_DIR}/${OUTHEADERFILE}
+    WRITE ${OUT_HEADER_DIR}/${OUT_HEADER_FILENAME}
     "${outHeaderText}"
 )
 
-message(STATUS "Shader ${SOURCE} converted to ${DESTINATION_SOURCE_DIR}/${OUTCPPFILE}")
+message(STATUS "Shader ${SOURCE_FILE} converted to ${OUT_CPP_DIR}/${OUT_CPP_FILENAME}")

common/gal/CMakeLists.txt

@@ -65,12 +65,12 @@ function( add_shader outTarget inFile shaderName )
         OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${outCppName}
                 ${CMAKE_BINARY_DIR}/include/gal/shaders/${outHeaderName}
         COMMAND ${CMAKE_COMMAND}
-            -DSOURCE="${CMAKE_CURRENT_SOURCE_DIR}/shaders/${inFile}"
+            -DSOURCE_FILE="${CMAKE_CURRENT_SOURCE_DIR}/shaders/${inFile}"
-            -DDESTINATION_SOURCE_DIR="${CMAKE_CURRENT_BINARY_DIR}/"
+            -DOUT_CPP_DIR="${CMAKE_CURRENT_BINARY_DIR}/"
-            -DDESTINATION_HEADER_DIR="${CMAKE_BINARY_DIR}/include/gal/shaders/"
+            -DOUT_HEADER_DIR="${CMAKE_BINARY_DIR}/include/gal/shaders/"
-            -DOUTCPPFILE="${outCppName}"
+            -DOUT_CPP_FILENAME="${outCppName}"
-            -DOUTHEADERFILE="${outHeaderName}"
+            -DOUT_HEADER_FILENAME="${outHeaderName}"
-            -DOUTVARNAME="${shaderName}"
+            -DOUT_VAR_NAME="${shaderName}"
             -P ${CMAKE_MODULE_PATH}/BuildSteps/CreateShaderCpp.cmake
         DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/shaders/${inFile}
                 ${CMAKE_MODULE_PATH}/BuildSteps/CreateShaderCpp.cmake