64 lines
1.7 KiB
Mathematica
64 lines
1.7 KiB
Mathematica
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// VisionDisplayLink.m
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// VisionCamera
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//
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// Created by Marc Rousavy on 28.11.22.
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// Copyright © 2022 mrousavy. All rights reserved.
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//
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#import "VisionDisplayLink.h"
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#import <Foundation/Foundation.h>
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@implementation VisionDisplayLink
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- (void)start:(block_t)block {
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self.updateBlock = block;
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// check whether the loop is already running
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if (_displayLink == nil) {
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// specify update method
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_displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(update:)];
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// Start a new Queue/Thread that will run the runLoop
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dispatch_queue_attr_t qos = dispatch_queue_attr_make_with_qos_class(DISPATCH_QUEUE_SERIAL, QOS_CLASS_USER_INTERACTIVE, -1);
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dispatch_queue_t queue = dispatch_queue_create("mrousavy/VisionCamera.preview", qos);
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dispatch_async(queue, ^{
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// Add the display link to the current run loop (thread on which we're currently running on)
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NSRunLoop* loop = [NSRunLoop currentRunLoop];
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[self->_displayLink addToRunLoop:loop forMode:NSRunLoopCommonModes];
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// Run the runLoop (blocking)
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[loop run];
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NSLog(@"VisionCamera: DisplayLink runLoop ended.");
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});
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}
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}
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- (void)stop {
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// check whether the loop is already stopped
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if (_displayLink != nil) {
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// if the display link is present, it gets invalidated (loop stops)
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[_displayLink invalidate];
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_displayLink = nil;
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}
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}
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- (void)update:(CADisplayLink *)sender {
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double time = sender.timestamp;
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double diff = time - _previousFrameTimestamp;
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_currentFps = 1.0 / diff;
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_previousFrameTimestamp = time;
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_updateBlock(time);
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}
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- (double)targetFps {
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return 1.0 / _displayLink.duration;
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}
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- (double)currentFps {
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return _currentFps;
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}
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@end
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