Mac Platform Integration changes for Schnitzel Motor Engine:

- Extend build.sh to include Homebrew checks and GLFW, Freetype library paths on Mac.
- Remove old object files and build files during the build process.
- Add new quad shaders for OpenGL 4.1.
- Introduce separate README for Mac-specific instructions.
- Remove Linux-specific platform code in favor of a more unified approach.
- Refactor Mac platform integration, remove Objective-C dependency.
- Update README and .clang-format for better documentation and code style.
- Add .gitattributes for consistent Git configuration.
- Explicitly set C++ version requirement to c++14

renderer.cpp changes:
- Preprocessor Directives: Added #define USE_OPENGL410 to toggle between OpenGL 4.10 and earlier versions.
- Includes: Reordered includes for better organization.
- OpenGL Structs: Added #ifdef USE_OPENGL410 to include new IDs (vaoID, vboID) for OpenGL 4.10.
- Font Loading: Simplified assignments for glyph structures.
- Debug Callback: Wrapped the existing debug callback function with #ifndef __APPLE__.
- Shader Creation: Conditional compilation for shader source based on USE_OPENGL410.
- Link Errors: Added a function check_link_errors to check for shader program linking errors.
- Vertex Buffer Allocation: Added a new function create_vertex_array_buffer to create vertex array buffers.
- Initialize Vertex Array Buffers: Added a new function init_vertex_array_buffers to initialize vertex array and storage buffers conditionally based on USE_OPENGL410.
- OpenGL Initialization: Modified to use new functions for error checking and buffer initialization.
- Rendering: Modified to use VAO and VBO when USE_OPENGL410 is defined.

.clang-format

@@ -0,0 +1,35 @@
+---
+ColumnLimit: 90
+BreakBeforeBinaryOperators: false
+ReflowComments: true
+BasedOnStyle: LLVM
+IndentWidth: 2
+UseTab: false
+
+IndentCaseLabels: true
+BreakBeforeBraces: Custom
+BraceWrapping:
+  AfterClass: true
+  AfterControlStatement: Always
+  AfterEnum: true
+  AfterFunction: true
+  AfterNamespace: true
+  AfterStruct: true
+  AfterUnion: true
+  BeforeCatch: true
+  BeforeElse: true
+  IndentBraces: false
+  SplitEmptyFunction: true
+  SplitEmptyRecord: true
+  SplitEmptyNamespace: true
+AllowShortBlocksOnASingleLine: Never
+MaxEmptyLinesToKeep: 1
+
+PointerAlignment: Left
+AllowShortFunctionsOnASingleLine: None
+BinPackParameters: true
+BinPackArguments: true
+AlignAfterOpenBracket: Align
+BreakConstructorInitializers: BeforeColon
+
+---

.gitattributes

@@ -0,0 +1 @@
+* text=auto

.github/workflows/mac.yml

@@ -0,0 +1,19 @@
+name: mac
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: macos-latest
+    env:
+      CC: clang
+      CXX: clang++
+      flags: "-g -std=c++14"
+    steps:
+    - name: install dependencies
+      run: |
+        brew update
+        brew install glfw3 freetype
+    - name: checkout
+      uses: actions/checkout@v3
+    - name: build
+      run: ./build.sh

.gitignore

@@ -19,6 +19,7 @@ build
 .DS_Store
 *.swp
 *.dSYM/
+*.dylib
 *.so
 *.xcuserstate
 *.xcworkspace

MAC_README.md

@@ -0,0 +1,66 @@
+# Schnitzel Motor Engine: Mac Build Notes
+
+The goal in bring the Schnitzel Motor Engine to the Mac platform was to provide a seamless and consistent integration with the supported platforms, focusing on simplicity and foundational elements that make this engine a terrific choice for students learning to write games in C++ for the first time. This document details the technical considerations, challenges, and rationale we encountered and the solution we settled upon.
+
+## OpenGL Support on macOS
+
+The Schnitzel Motor Engine utilizes OpenGL 4.1, supported by Apple up to macOS 10.11 Mojave. Key factors influenced this choice:
+
+- **Ease of Adoption**: OpenGL 4.1 is native to macOS from version 10.11 Mojave onwards, eliminating additional software installations. Including necessary headers and libraries is straightforward.
+- **Portability**: Transitioning the OpenGL Schnitzel Motor Engine to macOS necessitates minimal code alterations, ensuring efficiency.
+- **Beginner-Friendly**: OpenGL is an intuitive graphics API, suitable for those new to game development.
+
+However, there are limitations:
+- **Deprecation**: OpenGL 4.1 is deprecated, risking removal in future macOS versions.
+- **Apple's Metal Recommendation**: Apple advocates Metal for graphics rendering on macOS and iOS, hinting at a potential phase-out of OpenGL support.
+
+## OpenGL Implementation Challenges on Mac
+
+Support for OpenGL 4.3 and above is absent on macOS, requiring reliance on OpenGL 4.1. This alignment allows progression with minimal codebase adjustments, albeit with certain missing features:
+
+- **Shader Storage Buffer Objects (SSBOs)**: Enable shaders to read from and write to buffer objects.
+- **Debug Output**: Furnishes debugging and performance information from the OpenGL driver.
+- **Texture Views**: Permit creating multiple views of a texture.
+- **Vertex Attribute Binding**: Manages binding between vertex attributes and buffer objects.
+
+These missing features necessitate alternative approaches or extensions for robust engine operation on OpenGL 4.1.
+
+## Shader Adaptation from OpenGL 4.3 to 4.1
+
+Transitioning the OpenGL 4.3 shader code to comply with OpenGL 4.1 standards posed challenges due to certain missing features. Various strategies ensured a successful transition with performance remaining close to the original version.
+
+### 1. **Buffer Management**:
+   - The `USE_OPENGL410` directive segregates buffer data handling for OpenGL 4.1 and 4.3.
+   - For OpenGL 4.1:
+      - A Vertex Buffer Object (VBO) stores vertex data, with `glBufferData` allocating buffer space, and `glVertexAttribPointer` setting up attribute pointers for interleaved data.
+   - For OpenGL 4.3:
+      - A Shader Storage Buffer Object (SSBO) manages transform data, a feature absent in OpenGL 4.1, requiring a different buffer management strategy.
+
+### **Key Differences**:
+   - **Buffer Management**: Use of VBOs in OpenGL 4.1 versus SSBOs in OpenGL 4.3 for handling buffer data.
+   - **Vertex Processing**: Explicit vertex data processing in OpenGL 4.1 compared to the more streamlined approach in OpenGL 4.3.
+   - **Shader Compilation**: Consistent shader compilation and error handling across both versions aids in debugging and ensures shader correctness.
+
+## Solution
+
+We opted for OpenGL as it aligns with the graphics API used on Windows and Linux, despite certain caveats on Mac due to its limitation to OpenGL 4.1 and the API's deprecation on this platform.
+
+### **Pros**:
+   - **Performance**: Employed strategies upheld performance despite OpenGL 4.1 restrictions.
+   - **Learning Opportunity**: Porting shader code across OpenGL versions enlightens on the API's evolution.
+
+Due to the absence of SSBOs in OpenGL 4.1, we opted for Vertex Buffer Objects (VBO) due to their speed, performance, simplicity, and alignment with our educational goals. VBOs, present since OpenGL 1.5, cater to our engine's needs efficiently. While the Schnitzel Motor Engine minimizes third-party library dependencies, we employed GLFW for its robust window management and streamlined OpenGL setup. GLFW simplifies build configurations, enabling a consistent build process across macOS, Windows, and Linux using the same "Single Compilation Unit" (SCU).
+
+## Summary
+
+The utilization of OpenGL 4.1 for the Schnitzel Motor Engine on macOS is driven by its ease of adoption, portability, and beginner-friendly nature, aligning with our educational goals. The deprecation of OpenGL 4.1 and the absence of certain features necessitate alternative strategies for robust engine operation. The use of GLFW enables a streamlined OpenGL setup on macOS, aligning with the engine's design principle of minimizing third-party dependencies.
+
+Looking ahead, the aging OpenGL 4.1 may necessitate exploring other graphics APIs or projects to ensure the engine's longevity and adaptability to modern graphics programming standards.
+
+### Resources
+- [OpenGL Official Website](https://www.opengl.org/)
+- [GLFW Official Website](https://www.glfw.org/)
+- [Vulkan Official Website](https://www.khronos.org/vulkan/)
+- [Metal - Apple Developer](https://developer.apple.com/metal/)
+- [MGL Project on GitHub](https://github.com/openglonmetal/MGL)
+- [Shader Storage Buffer Object - OpenGL Wiki](https://www.khronos.org/opengl/wiki/Shader_Storage_Buffer_Object)

README.md

@@ -1,9 +1,51 @@
 # SchnitzelMotor
-A crispy cross platform C/C++ engine. Supports Linux and Windows currently.
+A crispy cross platform C/C++ engine. Supports Linux, Windows, and macOS.
 
-# Building the engine (Windows)
-1. Download and install clang from here https://github.com/llvm/llvm-project/releases/download/llvmorg-16.0.6/LLVM-16.0.6-win64.exe
+# Building the Engine
+
+## Windows Instructions:
+1. Download and install clang from [here](https://github.com/llvm/llvm-project/releases/download/llvmorg-16.0.6/LLVM-16.0.6-win64.exe)
 2. ![image](https://github.com/Cakez77/SchnitzelMotor/assets/45374095/1ad4bdf5-f43c-4774-9f34-5fcdd2ed7f2c)
-3. Download and install git from here
+3. Download and install git from [here](https://git-scm.com/download/win)
 4. Add `sh.exe` to the path, you can find it here : `C:\Program Files\Git\bin`
-5. 
+
+## Mac Instructions:
+1. Ensure you have [Homebrew](https://brew.sh/) installed on your machine.
+   ```bash
+   /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+   ```
+2. Install dependencies using Homebrew:
+   ```bash
+   brew update
+   brew install llvm glfw freetype
+   ```
+3. Clone the repository:
+   ```bash
+   git clone https://github.com/Cakez77/SchnitzelMotor.git
+   cd SchnitzelMotor
+   ```
+4. Run the build script:
+   ```bash
+   ./build.sh
+   ```
+
+## GitHub Actions (macOS)
+For automated builds on macOS using GitHub Actions, the provided `mac.yml` workflow file can be utilized. This workflow installs necessary dependencies, checks out the code, and runs the build script:
+```yaml
+name: mac
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: macos-latest
+    steps:
+    - name: install dependencies
+      run: |
+        brew update
+        brew install glfw3 freetype
+    - name: checkout
+      uses: actions/checkout@v3
+    - name: build
+      run: ./build.sh
+```
+For more information on GitHub Actions, refer to the [official documentation](https://docs.github.com/en/actions).

assets/shaders/quad.vert

@@ -1,7 +1,6 @@
 
 // Input Uniforms
 uniform vec2 screenSize;
-uniform vec2 cameraPos;
 uniform mat4 orthoProjection;
 
 // Input Buffers
@@ -12,7 +11,7 @@ layout(std430, binding = 0) buffer TransformSBO
 
 // Output
 layout (location = 0) out vec2 textureCoordsOut;
-layout (location = 1) out int renderOptionsOut;
+layout (location = 1) out flat int renderOptionsOut;
 
 void main()
 {

assets/shaders/quad_41.frag

@@ -0,0 +1,35 @@
+// Input
+layout (location = 0) in vec2 textureCoords;  
+layout (location = 1) flat in int renderOptions;
+
+// Output
+layout (location = 0) out vec4 fragColor;
+
+// Uniforms (no binding)
+uniform sampler2D textureAtlas;
+uniform sampler2D fontAtlas;
+
+void main()
+{
+    vec4 textureColor;
+
+    if(bool(renderOptions & RENDERING_OPTION_FONT))  
+    {
+        textureColor = texelFetch(fontAtlas, ivec2(textureCoords), 0);  
+        if(textureColor.r == 0.0)
+        {
+            discard;
+        }
+        textureColor = vec4(1.0, 1.0, 1.0, 1.0); // Filling with white
+    }
+    else
+    {
+        textureColor = texelFetch(textureAtlas, ivec2(textureCoords), 0);  
+        if(textureColor.a == 0.0)
+        {
+            discard;
+        }
+    }
+
+    fragColor = textureColor;
+}

assets/shaders/quad_41.vert

@@ -0,0 +1,58 @@
+// Input Uniforms
+uniform vec2 screenSize;
+uniform mat4 orthoProjection;
+
+// Input Attributes from VBO
+layout (location = 0) in vec2 positionIn;
+layout (location = 1) in vec2 sizeIn;
+layout (location = 2) in vec2 atlasOffsetIn;
+layout (location = 3) in vec2 spriteSizeIn;
+layout (location = 4) in int  renderOptionsIn;
+layout (location = 5) in float layerIn;
+
+// Output
+layout (location = 0) out vec2 textureCoords;
+layout (location = 1) flat out int renderOptions;
+
+void main()
+{
+    // Creating Vertices on the GPU (2D Engine)
+    // OpenGL Device Coordinates
+    // -1 / 1                          1 / 1
+    // -1 /-1                          1 /-1
+    vec2 vertices[6];
+    vertices[0] = positionIn;
+    vertices[1] = positionIn + vec2(0.0, sizeIn.y);
+    vertices[2] = positionIn + vec2(sizeIn.x, 0.0);
+    vertices[3] = positionIn + vec2(sizeIn.x, 0.0);
+    vertices[4] = positionIn + vec2(0.0, sizeIn.y);
+    vertices[5] = positionIn + sizeIn;
+
+    // Initialize textureCoords
+    float left = atlasOffsetIn.x;
+    float top = atlasOffsetIn.y;
+    float right = atlasOffsetIn.x + spriteSizeIn.x;
+    float bottom = atlasOffsetIn.y + spriteSizeIn.y;
+
+    if (bool(renderOptionsIn & RENDERING_OPTION_FLIP_X))
+    {
+        float tmpLeft = left;
+        left = right;
+        right = tmpLeft;
+    }
+
+    vec2 localTextureCoords[6];
+    localTextureCoords[0] = vec2(left, top);
+    localTextureCoords[1] = vec2(left, bottom);
+    localTextureCoords[2] = vec2(right, top);
+    localTextureCoords[3] = vec2(right, top);
+    localTextureCoords[4] = vec2(left, bottom);
+    localTextureCoords[5] = vec2(right, bottom);
+
+    // Compute final positions and outputs
+    vec2 vertexPos = vertices[gl_VertexID];
+    gl_Position = orthoProjection * vec4(vertexPos, layerIn, 1.0);
+
+    textureCoords = localTextureCoords[gl_VertexID];
+    renderOptions = renderOptionsIn;
+}

build.sh

@@ -4,6 +4,7 @@ defines="-DENGINE"
 warnings="-Wno-writable-strings -Wno-format-security -Wno-c++11-extensions -Wno-deprecated-declarations"
 includes="-Ithird_party"
 timestamp=$(date +%s)
+flags="${flags:--g}"
 
 if [[ "$(uname)" == "Linux" ]]; then
     echo "Running on Linux"
@@ -13,35 +14,45 @@ if [[ "$(uname)" == "Linux" ]]; then
 
     # fPIC position independent code
     rm -f game_* # Remove old game_* files
-    clang++ -g "src/game.cpp" -shared -fPIC -o game_$timestamp.so $warnings $defines
+    clang++ $flags "src/game.cpp" -shared -fPIC -o game_$timestamp.so $warnings $defines
     mv game_$timestamp.so game.so
 
 elif [[ "$(uname)" == "Darwin" ]]; then
     echo "Running on Mac"
-    libs="-framework Cocoa"
-    sdkpath=$(xcode-select --print-path)/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
-    includes="-Ithird_party -isysroot ${sdkpath} -I${sdkpath}/System/Library/Frameworks/Cocoa.framework/Headers"
-    objc_dep="src/mac_platform.m"
+
+    # Check if Homebrew is installed
+    if ! command -v brew &> /dev/null; then
+        echo "Homebrew not found. Please install Homebrew and try again."
+        exit 1
+    fi
+
+    # Build Game Library
+    rm -f -R *.dylib *.dSYM  # Remove old build files
+    clang++ $flags -dynamiclib "src/game.cpp" -o game_$timestamp.dylib $warnings $defines
+    mv game_$timestamp.dylib game.dylib
+    mv game_$timestamp.dylib.dSYM game.dylib.dSYM
+
+    # Game Engine Compiler Settings on Mac
+    HOMEBREW_CELLAR=${HOMEBREW_CELLAR:-/usr/local/Cellar} # Homebrew defaults to /usr/local/Cellar 
+    libs="-framework Cocoa -framework OpenGL -L${HOMEBREW_CELLAR}/glfw/3.3.8/lib -lglfw -L${HOMEBREW_CELLAR}/freetype/2.13.2/lib -lfreetype"
+    includes="-Ithird_party -I${HOMEBREW_CELLAR}/glfw/3.3.8/include -I${HOMEBREW_CELLAR}/freetype/2.13.2/include/freetype2"
     outputFile=schnitzel
-    # clean up old object files
-    rm -f src/*.o
 else
     echo "Not running on Linux"
     libs="-luser32 -lgdi32 -lopengl32 -lole32 -Lthird_party/lib -lfreetype.lib"
     outputFile=schnitzel.exe
     queryProcesses=$(tasklist | grep $outputFile)
 
     rm -f game_* # Remove old game_* files
-    clang++ -g "src/game.cpp" -shared -o game_$timestamp.dll $warnings $defines
+    clang++ $flags "src/game.cpp" -shared -o game_$timestamp.dll $warnings $defines
     mv game_$timestamp.dll game.dll
 fi
 
 processRunning=$queryProcesses
 
 if [ -z "$processRunning" ]; then
     echo "Engine not running, building main..."
-    clang++ $includes -g "src/main.cpp" $objc_dep -o $outputFile $libs $warnings $defines
+    clang++ $includes $flags "src/main.cpp" -o $outputFile $libs $warnings $defines
 else
     echo "Engine running, not building!"
 fi
-