Allow Zig build script to change desktop backend (#4358)

src/build.zig

@@ -40,6 +40,17 @@ pub fn addRaylib(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.
  return raylib;
 }
 
+fn setDesktopPlatform(raylib: *std.Build.Step.Compile, platform: PlatformBackend) void {
+ raylib.defineCMacro("PLATFORM_DESKTOP", null);
+
+ switch (platform) {
+ .glfw => raylib.defineCMacro("PLATFORM_DESKTOP_GLFW", null),
+ .rgfw => raylib.defineCMacro("PLATFORM_DESKTOP_RGFW", null),
+ .sdl => raylib.defineCMacro("PLATFORM_DESKTOP_SDL", null),
+ else => {}
+ }
+}
+
 fn compileRaylib(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.builtin.OptimizeMode, options: Options) !*std.Build.Step.Compile {
  raylib_flags_arr.clearRetainingCapacity();
 
@@ -102,7 +113,7 @@ fn compileRaylib(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.
  raylib.linkLibC();
 
  // No GLFW required on PLATFORM_DRM
- if (!options.platform_drm) {
+ if (options.platform != .drm) {
  raylib.addIncludePath(b.path("src/external/glfw/include"));
  }
 
@@ -136,10 +147,10 @@ fn compileRaylib(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.
  raylib.linkSystemLibrary("gdi32");
  raylib.linkSystemLibrary("opengl32");
 
- raylib.defineCMacro("PLATFORM_DESKTOP", null);
+ setDesktopPlatform(raylib, options.platform);
  },
  .linux => {
- if (!options.platform_drm) {
+ if (options.platform != .drm) {
  try c_source_files.append("rglfw.c");
  raylib.linkSystemLibrary("GL");
  raylib.linkSystemLibrary("rt");
@@ -177,7 +188,7 @@ fn compileRaylib(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.
  waylandGenerate(b, raylib, "xdg-activation-v1.xml", "xdg-activation-v1-client-protocol");
  waylandGenerate(b, raylib, "idle-inhibit-unstable-v1.xml", "idle-inhibit-unstable-v1-client-protocol");
  }
- raylib.defineCMacro("PLATFORM_DESKTOP", null);
+ setDesktopPlatform(raylib, options.platform);
  } else {
  if (options.opengl_version == .auto) {
  raylib.linkSystemLibrary("GLESv2");
@@ -211,7 +222,7 @@ fn compileRaylib(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.
  raylib.linkSystemLibrary("Xxf86vm");
  raylib.linkSystemLibrary("Xcursor");
 
- raylib.defineCMacro("PLATFORM_DESKTOP", null);
+ setDesktopPlatform(raylib, options.platform);
  },
  .macos => {
  // On macos rglfw.c include Objective-C files.
@@ -227,7 +238,7 @@ fn compileRaylib(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.
  raylib.linkFramework("AppKit");
  raylib.linkFramework("IOKit");
 
- raylib.defineCMacro("PLATFORM_DESKTOP", null);
+ setDesktopPlatform(raylib, options.platform);
  },
  .emscripten => {
  raylib.defineCMacro("PLATFORM_WEB", null);
@@ -286,7 +297,7 @@ pub const Options = struct {
  rtext: bool = true,
  rtextures: bool = true,
  raygui: bool = false,
- platform_drm: bool = false,
+ platform: PlatformBackend = .glfw,
  shared: bool = false,
  linux_display_backend: LinuxDisplayBackend = .Both,
  opengl_version: OpenglVersion = .auto,
@@ -323,6 +334,13 @@ pub const LinuxDisplayBackend = enum {
  Both,
 };
 
+pub const PlatformBackend = enum {
+ glfw,
+ rgfw,
+ sdl,
+ drm
+};
+
 pub fn build(b: *std.Build) !void {
  // Standard target options allows the person running `zig build` to choose
  // what target to build for. Here we do not override the defaults, which
@@ -336,7 +354,7 @@ pub fn build(b: *std.Build) !void {
 
  const defaults = Options{};
  const options = Options{
- .platform_drm = b.option(bool, "platform_drm", "Compile raylib in native mode (no X11)") orelse defaults.platform_drm,
+ .platform = b.option(PlatformBackend, "platform", "Choose the platform backedn for desktop target") orelse defaults.platform,
  .raudio = b.option(bool, "raudio", "Compile with audio support") orelse defaults.raudio,
  .rmodels = b.option(bool, "rmodels", "Compile with models support") orelse defaults.rmodels,
  .rtext = b.option(bool, "rtext", "Compile with text support") orelse defaults.rtext,