diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..9e37a10
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,68 @@
+name: Build (ubuntu, macos)
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      # Set fail-fast to false to ensure that feedback is delivered for all matrix combinations. Consider changing this to true when your workflow is stable.
+      fail-fast: false
+
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        # build_type: [Release]
+        c_compiler: [gcc, clang]
+        include:
+          - os: macos-latest
+            c_compiler: clang
+            cpp_compiler: clang++
+          - os: ubuntu-latest
+            c_compiler: gcc
+            cpp_compiler: g++
+          - os: ubuntu-latest
+            c_compiler: clang
+            cpp_compiler: clang++
+        exclude:
+          - os: macos-latest
+            c_compiler: gcc
+
+    steps:
+    - uses: actions/checkout@v7
+
+    - name: Set reusable strings
+      # Turn repeated input strings (such as the build output directory) into step outputs. These step outputs can be used throughout the workflow file.
+      id: strings
+      shell: bash
+      run: |
+        echo "build-output-dir=${{ github.workspace }}/build" >> "$GITHUB_OUTPUT"
+
+    - name: Install dependencies
+      run: |
+        ([[ $OSTYPE == 'darwin'* ]] && brew update && brew install sdl2 boost) ||
+        ([[ $OSTYPE == 'linux'* ]] && sudo apt-get update && sudo apt-get install -y libsdl2-dev libboost-all-dev)
+
+    - name: Configure CMake
+      # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
+      # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
+      run: >
+        cmake -B ${{ steps.strings.outputs.build-output-dir }}
+        -DCMAKE_CXX_COMPILER=${{ matrix.cpp_compiler }}
+        -DCMAKE_C_COMPILER=${{ matrix.c_compiler }}
+        # -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
+        -S ${{ github.workspace }}
+
+    - name: Build
+      # Build your program with the given configuration. Note that --config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
+      run: cmake --build ${{ steps.strings.outputs.build-output-dir }}
+
+    # - name: Test
+    #   working-directory: ${{ steps.strings.outputs.build-output-dir }}
+    #   # Execute tests defined by the CMake configuration. Note that --build-config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
+    #   # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
+    #   run: ctest --build-config ${{ matrix.build_type }}
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 3d7875c..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,24 +0,0 @@
-os:
-  - linux
-  - osx
-
-language: c
-
-compiler:
-  - gcc
-
-addons:
-  homebrew:
-    packages:
-    - sdl2
-    - boost
-    update: true
-  apt:
-    packages:
-    - libsdl2-dev
-    - libboost-all-dev
-
-
-script:
-  - cmake .
-  - cmake --build .
diff --git a/README.md b/README.md
index 31ffa04..cc18269 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # gbc_cpp
 GameBoy (eventually Color) Emulator in C(++)
 
-[![Build Status](https://travis-ci.com/finagle29/gbc_cpp.svg?branch=master)](https://travis-ci.com/finagle29/gbc_cpp)
+[![Build (ubuntu, macos)](https://github.com/finagle29/gbc_cpp/actions/workflows/build.yml/badge.svg)](https://github.com/finagle29/gbc_cpp/actions/workflows/build.yml)
 
 Use cmake to build.
 
diff --git a/gpu.c b/gpu.c
index dc1578d..08de24d 100644
--- a/gpu.c
+++ b/gpu.c
@@ -5,6 +5,10 @@
 
 gpu_type gpu;
 
+SDL_Window *window, *vram_w, *bg_w;
+SDL_Renderer *renderer, *vram_r, *bg_r;
+SDL_Texture *framebuffer, *framebuffer_tileset, *framebuffer_bgmap;
+
 #define RGBA(r, g, b) (((((r << 8) | g) << 8) | b) << 8) | 0xFF
 
 bool show_tileset, show_bgmap;
diff --git a/gpu.h b/gpu.h
index e45183f..ab25f56 100644
--- a/gpu.h
+++ b/gpu.h
@@ -40,10 +40,8 @@ typedef struct
 } gpu_type;
 
 extern gpu_type gpu;
-
-SDL_Window *window, *vram_w, *bg_w;
-SDL_Renderer *renderer, *vram_r, *bg_r;
-SDL_Texture *framebuffer, *framebuffer_tileset, *framebuffer_bgmap;
+extern SDL_Window *window, *vram_w, *bg_w;
+extern bool show_tileset, show_bgmap;
 
 void setup(bool, bool);
 void cleanup(void);
diff --git a/main.c b/main.c
index 1321649..234adb1 100644
--- a/main.c
+++ b/main.c
@@ -12,8 +12,8 @@
 #include "keys.h"
 #include "mmu.h"
 
-extern bool show_tileset, show_bgmap;
-extern SDL_Window *window, *vram_w, *bg_w;
+// extern bool show_tileset, show_bgmap;
+// extern SDL_Window *window, *vram_w, *bg_w;
 
 bool frame(void);