30b56153db
Before, Frame Processors ran on a separate Thread.
After, Frame Processors run fully synchronous and always at the same FPS as the Camera.
Two new functions have been introduced:
* `runAtTargetFps(fps: number, func: () => void)`: Runs the given code as often as the given `fps`, effectively throttling it's calls.
* `runAsync(frame: Frame, func: () => void)`: Runs the given function on a separate Thread for Frame Processing. A strong reference to the Frame is held as long as the function takes to execute.
You can use `runAtTargetFps` to throttle calls to a specific API (e.g. if your Camera is running at 60 FPS, but you only want to run face detection at ~25 FPS, use `runAtTargetFps(25, ...)`.)
You can use `runAsync` to run a heavy algorithm asynchronous, so that the Camera is not blocked while your algorithm runs. This is useful if your main sync processor draws something, and your async processor is doing some image analysis on the side.
You can also combine both functions.
Examples:
```js
const frameProcessor = useFrameProcessor((frame) => {
'worklet'
console.log("I'm running at 60 FPS!")
}, [])
```
```js
const frameProcessor = useFrameProcessor((frame) => {
'worklet'
console.log("I'm running at 60 FPS!")
runAtTargetFps(10, () => {
'worklet'
console.log("I'm running at 10 FPS!")
})
}, [])
```
```js
const frameProcessor = useFrameProcessor((frame) => {
'worklet'
console.log("I'm running at 60 FPS!")
runAsync(frame, () => {
'worklet'
console.log("I'm running on another Thread, I can block for longer!")
})
}, [])
```
```js
const frameProcessor = useFrameProcessor((frame) => {
'worklet'
console.log("I'm running at 60 FPS!")
runAtTargetFps(10, () => {
'worklet'
runAsync(frame, () => {
'worklet'
console.log("I'm running on another Thread at 10 FPS, I can block for longer!")
})
})
}, [])
```
99 lines
4.0 KiB
Plaintext
99 lines
4.0 KiB
Plaintext
//
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// FrameHostObject.m
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// VisionCamera
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//
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// Created by Marc Rousavy on 22.03.21.
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// Copyright © 2021 mrousavy. All rights reserved.
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//
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#import "FrameHostObject.h"
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#import <Foundation/Foundation.h>
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#import <jsi/jsi.h>
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#import "JsiHostObject.h"
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#import "JsiSharedValue.h"
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std::vector<jsi::PropNameID> FrameHostObject::getPropertyNames(jsi::Runtime& rt) {
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std::vector<jsi::PropNameID> result;
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result.push_back(jsi::PropNameID::forUtf8(rt, std::string("width")));
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result.push_back(jsi::PropNameID::forUtf8(rt, std::string("height")));
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result.push_back(jsi::PropNameID::forUtf8(rt, std::string("bytesPerRow")));
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result.push_back(jsi::PropNameID::forUtf8(rt, std::string("planesCount")));
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// Debugging
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result.push_back(jsi::PropNameID::forUtf8(rt, std::string("toString")));
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// Ref Management
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result.push_back(jsi::PropNameID::forUtf8(rt, std::string("isValid")));
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result.push_back(jsi::PropNameID::forUtf8(rt, std::string("incrementRefCount")));
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result.push_back(jsi::PropNameID::forUtf8(rt, std::string("decrementRefCount")));
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return result;
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}
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jsi::Value FrameHostObject::get(jsi::Runtime& runtime, const jsi::PropNameID& propName) {
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auto name = propName.utf8(runtime);
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if (name == "toString") {
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auto toString = JSI_HOST_FUNCTION_LAMBDA {
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if (this->frame == nil) {
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return jsi::String::createFromUtf8(runtime, "[closed frame]");
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}
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auto imageBuffer = CMSampleBufferGetImageBuffer(frame.buffer);
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auto width = CVPixelBufferGetWidth(imageBuffer);
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auto height = CVPixelBufferGetHeight(imageBuffer);
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NSMutableString* string = [NSMutableString stringWithFormat:@"%lu x %lu Frame", width, height];
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return jsi::String::createFromUtf8(runtime, string.UTF8String);
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};
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return jsi::Function::createFromHostFunction(runtime, jsi::PropNameID::forUtf8(runtime, "toString"), 0, toString);
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}
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if (name == "incrementRefCount") {
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auto incrementRefCount = JSI_HOST_FUNCTION_LAMBDA {
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// Increment retain count by one so ARC doesn't destroy the Frame Buffer.
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CFRetain(frame.buffer);
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return jsi::Value::undefined();
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};
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return jsi::Function::createFromHostFunction(runtime,
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jsi::PropNameID::forUtf8(runtime, "incrementRefCount"),
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0,
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incrementRefCount);
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}
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if (name == "decrementRefCount") {
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auto decrementRefCount = JSI_HOST_FUNCTION_LAMBDA {
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// Decrement retain count by one. If the retain count is zero, ARC will destroy the Frame Buffer.
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CFRelease(frame.buffer);
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return jsi::Value::undefined();
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};
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return jsi::Function::createFromHostFunction(runtime,
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jsi::PropNameID::forUtf8(runtime, "decrementRefCount"),
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0,
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decrementRefCount);
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}
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if (name == "isValid") {
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auto isValid = frame != nil && frame.buffer != nil && CFGetRetainCount(frame.buffer) > 0 && CMSampleBufferIsValid(frame.buffer);
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return jsi::Value(isValid);
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}
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if (name == "width") {
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auto imageBuffer = CMSampleBufferGetImageBuffer(frame.buffer);
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auto width = CVPixelBufferGetWidth(imageBuffer);
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return jsi::Value((double) width);
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}
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if (name == "height") {
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auto imageBuffer = CMSampleBufferGetImageBuffer(frame.buffer);
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auto height = CVPixelBufferGetHeight(imageBuffer);
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return jsi::Value((double) height);
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}
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if (name == "bytesPerRow") {
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auto imageBuffer = CMSampleBufferGetImageBuffer(frame.buffer);
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auto bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
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return jsi::Value((double) bytesPerRow);
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}
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if (name == "planesCount") {
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auto imageBuffer = CMSampleBufferGetImageBuffer(frame.buffer);
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auto planesCount = CVPixelBufferGetPlaneCount(imageBuffer);
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return jsi::Value((double) planesCount);
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}
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// fallback to base implementation
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return HostObject::get(runtime, propName);
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}
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