From 1f8c4c76796ad6faa0d8e65921108426f5d938a6 Mon Sep 17 00:00:00 2001
From: Brandon Dyck <brandon@dyck.us>
Date: Fri, 10 Dec 2021 17:45:53 -0700
Subject: [PATCH] Add OpenGL support to build.zig

---
 build.zig | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/build.zig b/build.zig
index 0225a18..f2c631e 100644
--- a/build.zig
+++ b/build.zig
@@ -1,6 +1,6 @@
 const std = @import("std");
 
-const cflags: []const []const u8 = &.{
+const base_cflags: []const []const u8 = &.{
     "-Wall",
     "-Wextra",
     "-pedantic",
@@ -10,25 +10,38 @@ const cflags: []const []const u8 = &.{
     "-std=c11",
 };
 
-pub fn build(b: *std.build.Builder) void {
-    // Standard release options allow the person running `zig build` to select
-    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall.
+pub fn build(b: *std.build.Builder) !void {
     const mode = b.standardReleaseOptions();
     const target = b.standardTargetOptions(.{});
 
-    const lib = b.addStaticLibrary("minifb-zig-port", null);
-    lib.addCSourceFiles(&.{
+    var c_flags = try std.ArrayList([]const u8).initCapacity(b.allocator, base_cflags.len);
+    defer c_flags.deinit();
+    try c_flags.appendSlice(base_cflags);
+
+    var c_sources = std.ArrayList([]const u8).init(b.allocator);
+    defer c_sources.deinit();
+    try c_sources.appendSlice(&.{
         "src/MiniFB_common.c",
         "src/MiniFB_internal.c",
         "src/MiniFB_timer.c",
         "src/windows/WinMiniFB.c",
-    }, cflags);
+    });
+
+    const use_opengl = b.option(bool, "opengl", "Use OpenGL") orelse false;
+
+    const lib = b.addStaticLibrary("minifb-zig-port", null);
     lib.addIncludeDir("src");
     lib.addIncludeDir("include");
     lib.linkSystemLibraryName("gdi32");
     lib.linkLibC();
     lib.setBuildMode(mode);
     lib.install();
+    if (use_opengl) {
+        try c_flags.append("-DUSE_OPENGL_API");
+        try c_sources.append("src/gl/MiniFB_GL.c");
+        lib.linkSystemLibraryName("Opengl32");
+    }
+    lib.addCSourceFiles(c_sources.items, c_flags.items);
 
     addExample(b, "noise", "tests/noise.c", lib, target, mode);
     addExample(b, "multiple-windows", "tests/multiple_windows.c", lib, target, mode);
@@ -42,7 +55,7 @@ fn addExample(b: *std.build.Builder, comptime name: []const u8, file: []const u8
     exe.setTarget(target);
     exe.linkLibrary(lib);
     exe.addIncludeDir("include");
-    exe.addCSourceFile(file, cflags);
+    exe.addCSourceFile(file, base_cflags);
     exe.install();
 
     const step_name = "run-" ++ name;