Abstracted some complexity related to WebcamStream.

Sming/Libraries/WebCam/src/Camera/CameraInterface.h

@@ -45,7 +45,7 @@ class CameraInterface
 	}
 
 	/**
-	 * Prepare for the next picture
+	 * @brief Prepare for the next picture
 	 */
 	virtual void next()
 	{
@@ -64,6 +64,11 @@ class CameraInterface
 	 */
 	virtual size_t getSize() = 0;
 
+	/**
+	 * @brief Gets the frames per second the camera can capture
+	 */
+	virtual uint8_t getFramesPerSecond() = 0;
+
 	/**
 	 * @brief Read picture data from the camera.
 	 * @param buffer the allocated data buffer to store the data

Sming/Libraries/WebCam/src/Camera/FakeCamera.h

@@ -15,16 +15,19 @@
 #include "CameraInterface.h"
 #include <Data/Stream/FileStream.h>
 
-class FakeCamera: public CameraInterface
+class FakeCamera : public CameraInterface
 {
 public:
-
 	/**
-	 * Sets the list of all images that should be used to roll over.
+	 * @brief Sets the list of all images that should be used to roll over.
 	 */
-	FakeCamera(const Vector<String>& files)
+	FakeCamera()
 	{
-		this->files = files;
+	}
+
+	void addImage(const String& filename)
+	{
+		files.add(filename);
 	}
 
 	const String getMimeType() const override
@@ -43,8 +46,6 @@ class FakeCamera: public CameraInterface
 			return true;
 		}
 
-		state = eWCS_INITIALISING;
-		spiffs_mount(); // Mount file system, in order to work with files
 		state = eWCS_READY;
 		index = 0;
 		return true;
@@ -59,6 +60,11 @@ class FakeCamera: public CameraInterface
 			return false;
 		}
 
+		if(files.count() == 0) {
+			debug_w("No images added to the fake camera");
+			return false;
+		}
+
 		// go to the next picture.
 		auto& filename = files[index++];
 		if(index == files.count()) {
@@ -73,13 +79,18 @@ class FakeCamera: public CameraInterface
 	}
 
 	/**
-	 * Gets the size of the current picture
+	 * @brief Gets the size of the current picture
 	 */
 	size_t getSize() override
 	{
 		return file.getSize();
 	}
 
+	uint8_t getFramesPerSecond() override
+	{
+		return 10; // fake camera supports 10 fps
+	}
+
 	/**
 	 * @brief Read picture data from the camera.
 	 * @param buffer the allocated data buffer to store the data

Sming/Libraries/WebCam/src/WebcamPictureStream.h

@@ -0,0 +1,67 @@
+/****
+ * Sming Framework Project - Open Source framework for high efficiency native ESP8266 development.
+ * Created 2015 by Skurydin Alexey
+ * http://github.com/SmingHub/Sming
+ * All files of the Sming Core are provided under the LGPL v3 license.
+ *
+ * WebcamPictureStream.h
+ *
+ * @author: 2019 - Slavey Karadzhov <slav@attachix.com>
+ *
+ ****/
+
+#pragma once
+
+#include <Data/Stream/DataSourceStream.h>
+#include "Camera/CameraInterface.h"
+
+class WebcamPictureStream : public IDataSourceStream
+{
+public:
+	/**
+	 * @param camera reference to the camera object.
+	 */
+	WebcamPictureStream(CameraInterface& camera, size_t blockSize = 512) : camera(camera), blockSize(blockSize)
+	{
+	}
+
+	uint16_t readMemoryBlock(char* data, int bufSize)
+	{
+		if(camera.getState() == eWCS_HAS_PICTURE) {
+			if(!size) {
+				size = camera.getSize();
+				offset = 0;
+			}
+
+			return camera.read(data, bufSize, offset);
+		}
+
+		return 0;
+	}
+
+	int available()
+	{
+		return size;
+	}
+
+	bool seek(int len)
+	{
+		offset += len; // TODO: check for invalid offsets
+		return true;
+	}
+
+	bool isFinished()
+	{
+		bool finished = (size && offset >= size);
+		if(finished) {
+			camera.next();
+		}
+		return finished;
+	}
+
+private:
+	CameraInterface& camera;
+	size_t blockSize;
+	size_t size = 0;
+	size_t offset = 0;
+};

Sming/Libraries/WebCam/src/WebcamStream.h

@@ -12,68 +12,54 @@
 
 #pragma once
 
-#include <Data/Stream/DataSourceStream.h>
+#include <Data/Stream/MultipartStream.h>
 #include "Camera/CameraInterface.h"
+#include "WebcamPictureStream.h"
 
-class WebcamStream: public IDataSourceStream
+/**
+ * @brief Webcam stream producer for multipart streaming
+ */
+class WebcamStream : public MultipartStream
 {
 public:
-	/**
-	 * @param camera pointer to the camera object.
-	 */
-	WebcamStream(CameraInterface* camera, size_t blockSize = 512): camera(camera), blockSize(blockSize)
+	WebcamStream(CameraInterface& camera) : MultipartStream(std::bind(&WebcamStream::produce, this)), camera(camera)
 	{
-		assert(camera != nullptr);
 	}
 
-	uint16_t readMemoryBlock(char* data, int bufSize)
+	uint16_t readMemoryBlock(char* data, int bufSize) override
 	{
-		if(camera->getState() == eWCS_HAS_PICTURE) {
-			if(!size) {
-				size = camera->getSize();
-				offset = 0;
+		if(camera.getState() == eWCS_READY) {
+			uint8_t fps = camera.getFramesPerSecond();
+			if(fps > 0 && lastFrameTime) {
+				uint16_t frameTimeMs = 1000 / fps;
+				uint32_t now = millis();
+				if(now < lastFrameTime + frameTimeMs) {
+					debug_d("Skipping frame to maintain fps");
+					return 0;
+				}
 			}
 
-			return camera->read(data, bufSize, offset);
+			camera.capture();
+			lastFrameTime = millis();
 		}
 
-		if(camera->getState() != eWCS_WORKING) {
-			if(camera->capture()) {
-				size = 0;
-				offset = 0;
-			}
-		}
-
-		return 0;
+		return MultipartStream::readMemoryBlock(data, bufSize);
 	}
 
-	int available()
+	MultipartStream::BodyPart produce()
 	{
-		return size;
-	}
+		MultipartStream::BodyPart result;
 
-	bool seek(int len)
-	{
-		offset += len; // TODO: check for invalid offsets
-		return true;
-	}
+		WebcamPictureStream* webcamStream = new WebcamPictureStream(camera);
+		result.stream = webcamStream;
 
-	bool isFinished()
-	{
-		bool finished = (size && offset >= size);
-		if(finished) {
-			camera->next();
-		}
-		return finished;
-	}
+		result.headers = new HttpHeaders();
+		(*result.headers)[HTTP_HEADER_CONTENT_TYPE] = camera.getMimeType();
 
-	~WebcamStream()
-	{
-		camera = nullptr;
+		return result;
 	}
+
 private:
-	CameraInterface* camera = nullptr;
-	size_t blockSize;
-	size_t size = 0;
-	size_t offset = 0;
+	CameraInterface& camera;
+	unsigned long lastFrameTime = 0;
 };

samples/WebcamServer/app/application.cpp

@@ -1,6 +1,5 @@
 #include <SmingCore.h>
 
-#include <Data/Stream/MultipartStream.h>
 #include <WebcamStream.h>
 #include <Camera/FakeCamera.h>
 
@@ -13,7 +12,7 @@
 namespace
 {
 HttpServer server;
-FakeCamera* camera;
+FakeCamera camera;
 
 /*
  * default http handler to check if server is up and running
@@ -36,24 +35,11 @@ void onFile(HttpRequest& request, HttpResponse& response)
 	}
 }
 
-MultipartStream::BodyPart snapshotProducer()
-{
-	MultipartStream::BodyPart result;
-
-	WebcamStream* webcamStream = new WebcamStream(camera);
-	result.stream = webcamStream;
-
-	result.headers = new HttpHeaders();
-	(*result.headers)[HTTP_HEADER_CONTENT_TYPE] = camera->getMimeType();
-
-	return result;
-}
-
 void onStream(HttpRequest& request, HttpResponse& response)
 {
 	Serial.println(_F("perform onCapture()"));
 
-	MultipartStream* stream = new MultipartStream(snapshotProducer);
+	WebcamStream* stream = new WebcamStream(camera);
 	response.sendDataStream(stream, F("multipart/x-mixed-replace; boundary=") + stream->getBoundary());
 }
 
@@ -66,15 +52,15 @@ void onFavicon(HttpRequest& request, HttpResponse& response)
 void startWebServer()
 {
 	// Initialize the camera
-	Vector<String> images;
 	for(unsigned int i = 1; i < 6; i++) {
 		String s = "img";
 		s.concat(i, DEC, 2);
 		s += ".jpeg";
-		images.add(s);
+		camera.addImage(s);
 	}
-	camera = new FakeCamera(images);
-	camera->init();
+
+	spiffs_mount(); // Mount file system, in order to work with files
+	camera.init();
 
 	// .. and run the HTTP server
 	server.listen(80);