Commit 82ca58da authored by amarcu5's avatar amarcu5 Committed by Camilla Löwy
Browse files

NSGL: Implement swap interval with CVDisplayLink

This fixes OpenGL swap interval (vsync) on macOS 10.14 Mojave by using
CVDisplayLink to synchronise to the monitor refresh rate rather than
setting NSOpenGLContextParameterSwapInterval.

Solution based on advice provided by @rcgordon.

Closes #1417.
parent 4e3204d8
......@@ -27,13 +27,21 @@
#define _GLFW_PLATFORM_CONTEXT_STATE _GLFWcontextNSGL nsgl
#define _GLFW_PLATFORM_LIBRARY_CONTEXT_STATE _GLFWlibraryNSGL nsgl
#import <CoreVideo/CoreVideo.h>
#include <stdatomic.h>
// NSGL-specific per-context data
//
typedef struct _GLFWcontextNSGL
{
id pixelFormat;
id object;
id pixelFormat;
id object;
CVDisplayLinkRef displayLink;
atomic_int swapInterval;
int swapIntervalsPassed;
id swapIntervalCond;
} _GLFWcontextNSGL;
......
......@@ -31,6 +31,27 @@
#define NSOpenGLContextParameterSurfaceOpacity NSOpenGLCPSurfaceOpacity
#endif
static CVReturn displayLinkCallback(CVDisplayLinkRef displayLink,
const CVTimeStamp* now,
const CVTimeStamp* outputTime,
CVOptionFlags flagsIn,
CVOptionFlags* flagsOut,
void* userInfo)
{
_GLFWwindow* window = (_GLFWwindow *) userInfo;
const int setting = atomic_load(&window->context.nsgl.swapInterval);
if (setting > 0)
{
[window->context.nsgl.swapIntervalCond lock];
window->context.nsgl.swapIntervalsPassed++;
[window->context.nsgl.swapIntervalCond signal];
[window->context.nsgl.swapIntervalCond unlock];
}
return kCVReturnSuccess;
}
static void makeContextCurrentNSGL(_GLFWwindow* window)
{
@autoreleasepool {
......@@ -48,21 +69,33 @@ static void makeContextCurrentNSGL(_GLFWwindow* window)
static void swapBuffersNSGL(_GLFWwindow* window)
{
@autoreleasepool {
const int setting = atomic_load(&window->context.nsgl.swapInterval);
if (setting > 0)
{
[window->context.nsgl.swapIntervalCond lock];
do
{
[window->context.nsgl.swapIntervalCond wait];
} while (window->context.nsgl.swapIntervalsPassed % setting != 0);
window->context.nsgl.swapIntervalsPassed = 0;
[window->context.nsgl.swapIntervalCond unlock];
}
// ARP appears to be unnecessary, but this is future-proof
[window->context.nsgl.object flushBuffer];
} // autoreleasepool
}
static void swapIntervalNSGL(int interval)
{
@autoreleasepool {
_GLFWwindow* window = _glfwPlatformGetTls(&_glfw.contextSlot);
GLint sync = interval;
[window->context.nsgl.object setValues:&sync
forParameter:NSOpenGLContextParameterSwapInterval];
atomic_store(&window->context.nsgl.swapInterval, interval);
[window->context.nsgl.swapIntervalCond lock];
window->context.nsgl.swapIntervalsPassed = 0;
[window->context.nsgl.swapIntervalCond unlock];
} // autoreleasepool
}
......@@ -330,6 +363,17 @@ GLFWbool _glfwCreateContextNSGL(_GLFWwindow* window,
window->context.getProcAddress = getProcAddressNSGL;
window->context.destroy = destroyContextNSGL;
CVDisplayLinkCreateWithActiveCGDisplays(&window->context.nsgl.displayLink);
CVDisplayLinkSetOutputCallback(window->context.nsgl.displayLink,
&displayLinkCallback,
window);
CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(window->context.nsgl.displayLink,
(CGLContextObj) window->context.nsgl.object,
(CGLPixelFormatObj) window->context.nsgl.pixelFormat);
CVDisplayLinkStart(window->context.nsgl.displayLink);
window->context.nsgl.swapIntervalCond = [NSCondition new];
return GLFW_TRUE;
}
......
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