switch from capy to sokol + imgui

build.zig

@@ -1,30 +1,90 @@
 const std = @import("std");
-const capy = @import("capy");
+const Build = std.Build;
+const OptimizeMode = std.builtin.OptimizeMode;
+const ResolvedTarget = Build.ResolvedTarget;
+const Dependency = Build.Dependency;
+const sokol = @import("sokol");
 
-pub fn build(b: *std.Build) !void {
+pub fn build(b: *Build) !void {
     const target = b.standardTargetOptions(.{});
-    const mode = b.standardOptimizeOption(.{});
+    const optimize = b.standardOptimizeOption(.{});
 
-    const exe = b.addExecutable(.{
-        .name = "doggo",
-        .root_source_file = .{ .path = "src/main.zig" },
+    // note that the sokol dependency is built with `.with_imgui_sokol = true`
+    const dep_sokol = b.dependency("sokol", .{
         .target = target,
-        .optimize = mode,
+        .optimize = optimize,
+        .with_sokol_imgui = true,
+    });
+    const dep_cimgui = b.dependency("cimgui", .{
+        .target = target,
+        .optimize = optimize,
     });
 
-    b.installArtifact(exe);
+    // inject the cimgui header search path into the sokol C library compile step
+    const cimgui_root = dep_cimgui.namedWriteFiles("cimgui").getDirectory();
+    dep_sokol.artifact("sokol_clib").addIncludePath(cimgui_root);
 
-    const run_cmd = try capy.install(exe, .{ .args = b.args });
-
-    const run_step = b.step("run", "Run the app");
-    run_step.dependOn(run_cmd);
-
-    const exe_tests = b.addTest(.{
-        .root_source_file = .{ .path = "src/main.zig" },
-        .target = target,
-        .optimize = mode,
-    });
-
-    const test_step = b.step("test", "Run unit tests");
-    test_step.dependOn(&exe_tests.step);
+    // from here on different handling for native vs wasm builds
+    if (target.result.isWasm()) {
+        try buildWasm(b, target, optimize, dep_sokol, dep_cimgui);
+    } else {
+        try buildNative(b, target, optimize, dep_sokol, dep_cimgui);
+    }
+}
+
+fn buildNative(b: *Build, target: ResolvedTarget, optimize: OptimizeMode, dep_sokol: *Dependency, dep_cimgui: *Dependency) !void {
+    const demo = b.addExecutable(.{
+        .name = "demo",
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+    demo.root_module.addImport("sokol", dep_sokol.module("sokol"));
+    demo.root_module.addImport("cimgui", dep_cimgui.module("cimgui"));
+    b.installArtifact(demo);
+    b.step("run", "Run demo").dependOn(&b.addRunArtifact(demo).step);
+}
+
+fn buildWasm(b: *Build, target: ResolvedTarget, optimize: OptimizeMode, dep_sokol: *Dependency, dep_cimgui: *Dependency) !void {
+    // build the main file into a library, this is because the WASM 'exe'
+    // needs to be linked in a separate build step with the Emscripten linker
+    const demo = b.addStaticLibrary(.{
+        .name = "demo",
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+    demo.root_module.addImport("sokol", dep_sokol.module("sokol"));
+    demo.root_module.addImport("cimgui", dep_cimgui.module("cimgui"));
+
+    // get the Emscripten SDK dependency from the sokol dependency
+    const dep_emsdk = dep_sokol.builder.dependency("emsdk", .{});
+
+    // need to inject the Emscripten system header include path into
+    // the cimgui C library otherwise the C/C++ code won't find
+    // C stdlib headers
+    const emsdk_incl_path = dep_emsdk.path("upstream/emscripten/cache/sysroot/include");
+    dep_cimgui.artifact("cimgui_clib").addSystemIncludePath(emsdk_incl_path);
+
+    // all C libraries need to depend on the sokol library, when building for
+    // WASM this makes sure that the Emscripten SDK has been setup before
+    // C compilation is attempted (since the sokol C library depends on the
+    // Emscripten SDK setup step)
+    dep_cimgui.artifact("cimgui_clib").step.dependOn(&dep_sokol.artifact("sokol_clib").step);
+
+    // create a build step which invokes the Emscripten linker
+    const link_step = try sokol.emLinkStep(b, .{
+        .lib_main = demo,
+        .target = target,
+        .optimize = optimize,
+        .emsdk = dep_emsdk,
+        .use_webgl2 = true,
+        .use_emmalloc = true,
+        .use_filesystem = false,
+        .shell_file_path = dep_sokol.path("src/sokol/web/shell.html").getPath(b),
+    });
+    // ...and a special run step to start the web build output via 'emrun'
+    const run = sokol.emRunStep(b, .{ .name = "demo", .emsdk = dep_emsdk });
+    run.step.dependOn(&link_step.step);
+    b.step("run", "Run demo").dependOn(&run.step);
 }