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build.zig: allow to pass extra args to the emscripten linker step, an…
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…d some code cleanup
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@floooh
floooh committed Jan 15, 2024
1 parent a2e4b46 commit 575294b
Showing 1 changed file with 83 additions and 74 deletions.
157 changes: 83 additions & 74 deletions build.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,15 @@ const builtin = @import("builtin");
const Build = std.Build;
const OptimizeMode = std.builtin.OptimizeMode;

pub const SokolBackend = enum {
auto, // Windows: D3D11, macOS/iOS: Metal, otherwise: GL
d3d11,
metal,
gl,
gles3,
wgpu,
};

pub fn build(b: *Build) !void {
const opt_use_gl = b.option(bool, "gl", "Force OpenGL (default: false)") orelse false;
const opt_use_wgpu = b.option(bool, "wgpu", "Force WebGPU (default: false, web only)") orelse false;
Expand Down Expand Up @@ -64,14 +73,58 @@ pub fn build(b: *Build) !void {
buildShaders(b);
}

pub const SokolBackend = enum {
auto, // Windows: D3D11, macOS/iOS: Metal, otherwise: GL
d3d11,
metal,
gl,
gles3,
wgpu,
// build one of the examples
const ExampleOptions = struct {
target: Build.ResolvedTarget,
optimize: OptimizeMode,
backend: SokolBackend,
mod_sokol: *Build.Module,
emsdk: *Build.Dependency,
};
fn buildExample(b: *Build, comptime name: []const u8, options: ExampleOptions) !void {
const main_src = "src/examples/" ++ name ++ ".zig";
var run: ?*Build.Step.Run = null;
if (!options.target.result.isWasm()) {
// for native platforms, build into a regular executable
const example = b.addExecutable(.{
.name = name,
.root_source_file = .{ .path = main_src },
.target = options.target,
.optimize = options.optimize,
});
example.root_module.addImport("sokol", options.mod_sokol);
b.installArtifact(example);
run = b.addRunArtifact(example);
} else {
// for WASM, need to build the Zig code as static library, since linking happens via emcc
const example = b.addStaticLibrary(.{
.name = name,
.root_source_file = .{ .path = main_src },
.target = options.target,
.optimize = options.optimize,
});
example.root_module.addImport("sokol", options.mod_sokol);

// create a special emcc linker run step
const backend = resolveSokolBackend(options.backend, options.target.result);
const link_step = try emLinkStep(b, .{
.lib_main = example,
.target = options.target,
.optimize = options.optimize,
.emsdk = options.emsdk,
.use_webgpu = backend == .wgpu,
.use_webgl2 = backend != .wgpu,
.use_emmalloc = true,
.use_filesystem = false,
// NOTE: when sokol-zig is used as package, this path needs to be absolute!
.shell_file_path = "src/sokol/web/shell.html",
});
// ...and a special run step to run the build result via emrun
run = emRunStep(b, .{ .name = name, .emsdk = options.emsdk });
run.?.step.dependOn(&link_step.step);
}
b.step("run-" ++ name, "Run " ++ name).dependOn(&run.?.step);
}

// helper function to resolve .auto backend based on target platform
pub fn resolveSokolBackend(backend: SokolBackend, target: std.Target) SokolBackend {
Expand All @@ -90,6 +143,7 @@ pub fn resolveSokolBackend(backend: SokolBackend, target: std.Target) SokolBacke
}
}

// build the sokol C headers into a static library
pub const LibSokolOptions = struct {
target: Build.ResolvedTarget,
optimize: OptimizeMode,
Expand All @@ -99,8 +153,6 @@ pub const LibSokolOptions = struct {
use_wayland: bool = false,
emsdk: ?*Build.Dependency = null,
};

// build the sokol C headers into a static library
pub fn buildLibSokol(b: *Build, options: LibSokolOptions) !*Build.Step.Compile {
const lib = b.addStaticLibrary(.{
.name = "sokol",
Expand Down Expand Up @@ -221,74 +273,21 @@ pub fn buildLibSokol(b: *Build, options: LibSokolOptions) !*Build.Step.Compile {
return lib;
}

// build one of the examples
const ExampleOptions = struct {
target: Build.ResolvedTarget,
optimize: OptimizeMode,
backend: SokolBackend,
mod_sokol: *Build.Module,
emsdk: *Build.Dependency,
};

fn buildExample(b: *Build, comptime name: []const u8, options: ExampleOptions) !void {
const main_src = "src/examples/" ++ name ++ ".zig";
var run: ?*Build.Step.Run = null;
if (!options.target.result.isWasm()) {
// for native platforms, build into a regular executable
const example = b.addExecutable(.{
.name = name,
.root_source_file = .{ .path = main_src },
.target = options.target,
.optimize = options.optimize,
});
example.root_module.addImport("sokol", options.mod_sokol);
b.installArtifact(example);
run = b.addRunArtifact(example);
} else {
// for WASM, need to build the Zig code as static library, since linking happens via emcc
const example = b.addStaticLibrary(.{
.name = name,
.root_source_file = .{ .path = main_src },
.target = options.target,
.optimize = options.optimize,
});
example.root_module.addImport("sokol", options.mod_sokol);

// create a special emcc linker run step
const backend = resolveSokolBackend(options.backend, options.target.result);
const link_step = try emLinkStep(b, .{
.target = options.target,
.optimize = options.optimize,
.run_closure_in_release = true,
.use_webgpu = backend == .wgpu,
.use_webgl2 = backend != .wgpu,
.use_emmalloc = true,
.no_filesystem = true,
// NOTE: when sokol-zig is used as package, this path needs to be absolute!
.shell_file_path = "src/sokol/web/shell.html",
.lib_main = example,
.emsdk = options.emsdk,
});
// ...and a special run step to run the build result via emrun
run = emRunStep(b, .{ .name = name, .emsdk = options.emsdk });
run.?.step.dependOn(&link_step.step);
}
b.step("run-" ++ name, "Run " ++ name).dependOn(&run.?.step);
}

// for wasm32-emscripten, need to run the Emscripten linker from the Emscripten SDK
// NOTE: ideally this would go into a separate emsdk-zig package
pub const EmLinkOptions = struct {
target: Build.ResolvedTarget,
optimize: OptimizeMode,
emsdk: *Build.Dependency,
lib_main: *Build.Step.Compile, // the actual Zig code must be compiled to a static link library
run_closure_in_release: bool = true,
emsdk: *Build.Dependency,
release_use_closure: bool = true,
release_use_lto: bool = true,
use_webgpu: bool = false,
use_webgl2: bool = false,
use_emmalloc: bool = true,
no_filesystem: bool = true,
use_emmalloc: bool = false,
use_filesystem: bool = true,
shell_file_path: ?[]const u8 = null,
extra_args: []const []const u8 = &.{},
};
pub fn emLinkStep(b: *Build, options: EmLinkOptions) !*Build.Step.Run {
const emcc_path = b.findProgram(&.{"emcc"}, &.{}) catch b.pathJoin(&.{ emSdkPath(b, options.emsdk), "upstream", "emscripten", "emcc" });
Expand All @@ -300,23 +299,30 @@ pub fn emLinkStep(b: *Build, options: EmLinkOptions) !*Build.Step.Run {
defer emcc_cmd.deinit();

try emcc_cmd.append(emcc_path);
if (options.optimize != .Debug) {
try emcc_cmd.append("-Oz");
if (options.optimize == .Debug) {
try emcc_cmd.append("-Og");
} else {
try emcc_cmd.append("-sASSERTIONS=0");
if (options.run_closure_in_release) {
if (options.optimize == .ReleaseSmall) {
try emcc_cmd.append("-Oz");
} else {
try emcc_cmd.append("-O3");
}
if (options.release_use_lto) {
try emcc_cmd.append("-flto");
}
if (options.release_use_closure) {
try emcc_cmd.append("--closure");
try emcc_cmd.append("1");
}
} else {
try emcc_cmd.append("-Og");
}
if (options.use_webgpu) {
try emcc_cmd.append("-sUSE_WEBGPU=1");
}
if (options.use_webgl2) {
try emcc_cmd.append("-sUSE_WEBGL2=1");
}
if (options.no_filesystem) {
if (!options.use_filesystem) {
try emcc_cmd.append("-sNO_FILESYSTEM=1");
}
if (options.use_emmalloc) {
Expand All @@ -326,6 +332,9 @@ pub fn emLinkStep(b: *Build, options: EmLinkOptions) !*Build.Step.Run {
try emcc_cmd.append(b.fmt("--shell-file={s}", .{shell_file_path}));
}
try emcc_cmd.append(b.fmt("-o{s}/web/{s}.html", .{ b.install_path, options.lib_main.name }));
for (options.extra_args) |arg| {
try emcc_cmd.append(arg);
}

const emcc = b.addSystemCommand(emcc_cmd.items);
emcc.setName("emcc"); // hide emcc path
Expand Down

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