# Embeds the native renderer HLSL sources (src/native/shaders/*.hlsl) into a
# generated C++ header so the exe stays self-contained. Run as a script:
#   cmake -DSHADER_DIR=<dir> -DOUT=<header> -P EmbedShaders.cmake
# Each shader becomes `inline constexpr char <var>[] = R"__hlsl__(...)__hlsl__";`
# with a leading newline, matching the original in-cpp raw string literals
# (consumers use sizeof(kX) - 1).

set(SHADER_VARS
    kShaderSource
    kShadowBlurSource
    kResolveShaderSource
    kBlurShaderSource
    kOutlineShaderSource
    kShader2dSource
    kShaderSplineSource
    kPhotoFxShaderSource
    kSsaoShaderSource
    kHdrShaderSource
    kSsrShaderSource
)
set(SHADER_FILES
    scene.hlsl
    shadow_blur.hlsl
    resolve.hlsl
    blur.hlsl
    outline.hlsl
    overlay2d.hlsl
    spline.hlsl
    photo_fx.hlsl
    ssao.hlsl
    hdr.hlsl
    ssr.hlsl
)

set(content "// Generated by cmake/EmbedShaders.cmake from src/native/shaders/*.hlsl.\n")
string(APPEND content "// DO NOT EDIT - edit the .hlsl files instead.\n")
string(APPEND content "#pragma once\n\n")

foreach(var file IN ZIP_LISTS SHADER_VARS SHADER_FILES)
    file(READ "${SHADER_DIR}/${file}" src)
    # Inline `#include "x.hlsli"` directives so every embedded shader stays a
    # single self-contained string: the D3D12 backend hands the text to
    # D3DCompile without an include handler, and the shader bytecode cache
    # hashes the full text; pre-expanding means an include edit changes the
    # embedded source and invalidates cached bytecode naturally. The loop
    # rescans after each replacement, so nested includes expand too; the
    # iteration guard catches cycles.
    set(guard 0)
    while(src MATCHES "#include \"([^\"]+)\"")
        set(inc "${CMAKE_MATCH_1}")
        if(NOT EXISTS "${SHADER_DIR}/${inc}")
            message(FATAL_ERROR "${file}: include not found: ${inc}")
        endif()
        file(READ "${SHADER_DIR}/${inc}" inc_src)
        string(REPLACE "#include \"${inc}\"" "${inc_src}" src "${src}")
        math(EXPR guard "${guard} + 1")
        if(guard GREATER 32)
            message(FATAL_ERROR "${file}: include expansion did not converge (cycle?)")
        endif()
    endwhile()
    string(FIND "${src}" ")__hlsl__" collision)
    if(NOT collision EQUAL -1)
        message(FATAL_ERROR "${file} contains the raw-string delimiter )__hlsl__")
    endif()
    string(APPEND content "// ${file}\n")
    string(APPEND content "inline constexpr char ${var}[] = R\"__hlsl__(\n${src})__hlsl__\";\n\n")
endforeach()

file(WRITE "${OUT}" "${content}")