Added the base for an opengl backend example

Author: nullcatalyst

examples/hello_macgl/AppDelegate.h

@@ -0,0 +1,5 @@
+#import <Cocoa/Cocoa.h>
+
+@interface AppDelegate : NSObject <NSApplicationDelegate, NSWindowDelegate>
+
+@end

examples/hello_macgl/AppDelegate.mm

@@ -0,0 +1,55 @@
+#import "./AppDelegate.h"
+#import "./GLView.h"
+
+@implementation AppDelegate {
+    NSString *  _appName;
+    NSWindow *  _window;
+}
+
+- (nonnull instancetype) init {
+    if ((self = [super init])) {
+        _appName = [[NSProcessInfo processInfo] processName];
+
+        NSApplication * application = [NSApplication sharedApplication];
+        [application setMainMenu:[self createMenu]];
+        _window = [self createWindow];
+    }
+
+    return self;
+}
+
+- (void) applicationWillFinishLaunching:(NSNotification *)notification {
+    [_window setTitle:_appName];
+    [_window cascadeTopLeftFromPoint:NSMakePoint(20, 20)];
+    [_window makeKeyAndOrderFront:self];
+}
+
+- (BOOL) applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)sender {
+    return TRUE;
+}
+
+- (NSMenu *) createMenu {
+    NSMenuItem * quit   = [[NSMenuItem alloc] initWithTitle:[@"Quit " stringByAppendingString:_appName] action:@selector(terminate:) keyEquivalent:@"q"];
+    NSMenuItem * item   = [[NSMenuItem alloc] init];
+    item.submenu        = [[NSMenu alloc] init];
+    [item.submenu addItem:quit];
+
+    NSMenu * mainMenu   = [[NSMenu alloc] init];
+    [mainMenu addItem:item];
+
+    return mainMenu;
+}
+
+- (NSWindow *) createWindow {
+    NSWindow * window = [[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 640, 480)
+                                                    styleMask:NSWindowStyleMaskTitled | NSWindowStyleMaskClosable
+                                                      backing:NSBackingStoreBuffered
+                                                        defer:NO];
+
+    GLView * glView = [[GLView alloc] initWithFrame:window.contentView.frame];
+    [window.contentView addSubview:glView];
+
+    return window;
+}
+
+@end

examples/hello_macgl/CMakeLists.txt

@@ -0,0 +1,28 @@
+cmake_minimum_required(VERSION 3.10)
+
+if(NOT APPLE)
+    message(
+    WARNING
+        "Cannot create `hello_macgl` example"
+    )
+else()
+    project(hello_macgl)
+    set(CMAKE_CXX_STANDARD 17)
+
+    add_executable(hello_macgl)
+
+    target_sources(hello_macgl
+    PRIVATE
+        main.mm
+        AppDelegate.mm
+        GLView.mm
+    )
+
+    target_link_libraries(hello_macgl
+    PRIVATE
+        graphics
+        "-framework Cocoa"
+        "-framework CoreVideo"
+        "-framework OpenGL"
+    )
+endif()

examples/hello_macgl/GLView.h

@@ -0,0 +1,8 @@
+#define GL_SILENCE_DEPRECATION 1
+#import <Cocoa/Cocoa.h>
+
+@interface GLView : NSOpenGLView
+
+- (void) drawFrame;
+
+@end

examples/hello_macgl/GLView.mm

@@ -0,0 +1,104 @@
+#import "./GLView.h"
+
+#import <CoreVideo/CoreVideo.h> // CVDisplayLinkRef
+#include <graphics/graphics.hpp>
+
+#define SIZEOF_ARRAY(array) (sizeof(array) / sizeof(*array))
+
+// Declare the graphics data used for initialization
+// #include "../shared/decl.inc"
+
+namespace {
+    CVReturn displayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp * now, const CVTimeStamp * outputTime, CVOptionFlags flagsIn, CVOptionFlags * flagsOut, void * displayLinkContext) {
+        @autoreleasepool {
+            // go back to Obj-C for easy access to instance variables
+            [((__bridge GLView *) displayLinkContext) drawFrame];
+            return kCVReturnSuccess;
+        }
+    }
+}
+
+@implementation GLView {
+    CVDisplayLinkRef    _displayLink;
+    graphics::Context * _context;
+}
+
+- (nonnull instancetype) initWithFrame:(NSRect)frameRect {
+    NSOpenGLPixelFormatAttribute pixelFormatAttribs[] = {
+        NSOpenGLPFAAccelerated,
+        NSOpenGLPFADoubleBuffer,
+        NSOpenGLPFAColorSize, 32,
+        NSOpenGLPFADepthSize, 32,
+        NSOpenGLPFAOpenGLProfile, NSOpenGLProfileVersion3_2Core,
+        0,
+    };
+
+    NSOpenGLPixelFormat * pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:pixelFormatAttribs];
+    if (pixelFormat == nil) {
+        fprintf(stderr, "Unable to create windowed pixel format.\n");
+        abort();
+    }
+
+    if ((self = [super initWithFrame:frameRect pixelFormat:pixelFormat])) {
+        NSOpenGLContext * currentContext = self.openGLContext;
+        [currentContext makeCurrentContext];
+
+        // Remember to lock the context before we touch it since display link is threaded
+        CGLContextObj cglContext = currentContext.CGLContextObj;
+        CGLLockContext(cglContext);
+
+        // Enable vsync to eliminate tearing
+        GLint vsync = 1;
+        [[self openGLContext] setValues:&vsync forParameter:NSOpenGLContextParameterSwapInterval];
+
+        // Create the graphics context
+        // _context = new graphics::Context();
+
+        // Initialize the graphics objects
+        // #include "../shared/init.inc"
+
+        CGLUnlockContext(cglContext);
+
+        // Set up the display link
+        CVDisplayLinkCreateWithActiveCGDisplays(&_displayLink);
+        CVDisplayLinkSetOutputCallback(_displayLink, displayLinkCallback, (__bridge void *) self);
+        CGLPixelFormatObj cglPixelFormat = (CGLPixelFormatObj) [[self pixelFormat] CGLPixelFormatObj];
+        CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(_displayLink, cglContext, cglPixelFormat);
+
+        CVDisplayLinkStart(_displayLink);
+    }
+
+    return self;
+}
+
+- (void) dealloc {
+    CVDisplayLinkStop(_displayLink);
+
+    [super dealloc];
+}
+
+- (void) drawFrame {
+    NSOpenGLContext * currentContext = self.openGLContext;
+    [currentContext makeCurrentContext];
+
+    // Must lock GL context because display link is threaded
+    CGLLockContext(currentContext.CGLContextObj);
+
+    // Render the frame
+    // #include "../shared/update.inc"
+
+    // Render the frame
+    // #include "../shared/render.inc"
+
+    glClearColor(0.0, 0.5, 0.75, 1.0);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    [currentContext flushBuffer];
+    CGLUnlockContext(currentContext.CGLContextObj);
+}
+
+- (void) drawRect:(NSRect)rect {
+    [self drawFrame];
+}
+
+@end

examples/hello_macgl/main.mm

@@ -0,0 +1,17 @@
+#import <Cocoa/Cocoa.h>
+
+#import "./AppDelegate.h"
+
+int main() {
+    @autoreleasepool {
+        NSApplication * application = [NSApplication sharedApplication];
+        [application setActivationPolicy:NSApplicationActivationPolicyRegular];
+
+        AppDelegate * appDelegate = [[AppDelegate alloc] init];
+        [application setDelegate:appDelegate];
+        [application activateIgnoringOtherApps:YES];
+        [application run];
+    }
+
+    return EXIT_SUCCESS;
+}

include/graphics/graphics.hpp

@@ -20,7 +20,7 @@
 #endif
 
 #if GRAPHICS_USE_OPENGL
-    #include "graphics/opengl/graphics.hpp"
+    #include "graphics/opengl/context.hpp"
     namespace graphics {
         using namespace opengl;
     }