added Bitmap I/O support for the PPM file format

include/mitsuba/core/bitmap.h

@@ -223,6 +223,16 @@ public:
 		 */
 		EPFM,
 
+		/**
+		 * \brief PPM (Portable Pixel Map) image format
+		 *
+		 * The following is supported
+		 * <ul>
+		 *   <li>Loading and saving of \ref EUInt8 and \ref EUInt16 - based RGB bitmaps</li>
+		 * </ul>
+		 */
+		EPPM,
+
 		/**
 		 * \brief Joint Photographic Experts Group file format
 		 *
@@ -1115,6 +1125,12 @@ protected:
 	/// Write a file using the PFM file format
 	void writePFM(Stream *stream) const;
 
+	/// Read a file stored using the PPM file format
+	void readPPM(Stream *stream);
+
+	/// Write a file using the PPM file format
+	void writePPM(Stream *stream) const;
+
 	/// Read a file stored using the TGA file format
 	void readTGA(Stream *stream);
 

src/libcore/bitmap.cpp

@@ -305,6 +305,8 @@ Bitmap::Bitmap(EFileFormat format, Stream *stream, const std::string &prefix) :
 			format = ERGBE;
 		} else if (start[0] == 'P' && (start[1] == 'F' || start[1] == 'f')) {
 			format = EPFM;
+		} else if (start[0] == 'P' && start[1] == '6') {
+			format = EPPM;
 		#if defined(MTS_HAS_LIBJPEG)
 		} else if (start[0] == 0xFF && start[1] == 0xD8) {
 			format = EJPEG;
@@ -334,6 +336,7 @@ Bitmap::Bitmap(EFileFormat format, Stream *stream, const std::string &prefix) :
 		case EOpenEXR: readOpenEXR(stream, prefix); break;
 		case ERGBE: readRGBE(stream); break;
 		case EPFM: readPFM(stream); break;
+		case EPPM: readPPM(stream); break;
 		case ETGA: readTGA(stream); break;
 		case EPNG: readPNG(stream); break;
 		default:
@@ -356,6 +359,7 @@ void Bitmap::write(EFileFormat format, Stream *stream, int compression) const {
 		case EOpenEXR: writeOpenEXR(stream); break;
 		case ERGBE: writeRGBE(stream); break;
 		case EPFM: writePFM(stream); break;
+		case EPPM: writePPM(stream); break;
 		default:
 			Log(EError, "Bitmap::write(): Invalid file format!");
 	}
@@ -3402,6 +3406,54 @@ void Bitmap::writePFM(Stream *stream) const {
 	}
 }
 
+void Bitmap::readPPM(Stream *stream) {
+	int field = 0, nChars = 0;
+
+	std::string fields[4];
+
+	while (field < 4) {
+		char c = stream->readChar();
+		if (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
+			if (nChars != 0) {
+				nChars = 0;
+				++field;
+			}
+		} else {
+			fields[field] += c;
+			++nChars;
+		}
+	}
+	if (fields[0] != "P6")
+		Log(EError, "readPPM(): invalid format!");
+
+	int intValues[3];
+	for (int i=0; i<3; ++i) {
+		char *end_ptr = NULL;
+		intValues[i] = strtol(fields[i+1].c_str(), &end_ptr, 10);
+		if (*end_ptr != '\0')
+			SLog(EError, "readPPM(): unable to parse the file header!");
+	}
+
+	m_size.x = intValues[0];
+	m_size.y = intValues[1];
+	m_pixelFormat = ERGB;
+	m_channelCount = 3;
+	m_gamma = -1.0f;
+	m_ownsData = true;
+	m_componentFormat = intValues[2] <= 0xFF ? EUInt8 : EUInt16;
+	size_t size = getBufferSize();
+	m_data = static_cast<uint8_t *>(allocAligned(size));
+	stream->read(m_data, size);
+}
+
+void Bitmap::writePPM(Stream *stream) const {
+	if (m_pixelFormat != ERGB || (m_componentFormat != EUInt8 && m_componentFormat != EUInt16))
+		Log(EError, "writePPM(): Only 8 or 16-bit RGB images are supported");
+	stream->writeLine(formatString("P6\n%i\n%i\n%i\n", m_size.x, m_size.y,
+		m_componentFormat == EUInt8 ? 0xFF : 0xFFFF).c_str());
+	stream->write(m_data, getBufferSize());
+}
+
 void Bitmap::staticInitialization() {
 #if defined(MTS_HAS_OPENEXR)
 	/* Prevent races during the OpenEXR initialization */

src/libpython/core.cpp

@@ -1364,6 +1364,7 @@ void export_core() {
 		.value("EOpenEXR", Bitmap::EOpenEXR)
 		.value("ETGA", Bitmap::ETGA)
 		.value("EPFM", Bitmap::EPFM)
+		.value("EPPM", Bitmap::EPPM)
 		.value("ERGBE", Bitmap::ERGBE)
 		.value("EBMP", Bitmap::EBMP)
 		.value("EJPEG", Bitmap::EJPEG)

src/mtsgui/mainwindow.cpp

@@ -585,8 +585,8 @@ void MainWindow::on_actionOpen_triggered() {
 	QSettings settings;
 	QStringList fileNames = QFileDialog::getOpenFileNames(this, QString(),
 		settings.value("fileDir").toString(),
-		tr("All supported formats (*.xml *.exr *.rgbe *.hdr *.pfm *.png *.jpg *.jpeg);;"
+		tr("All supported formats (*.xml *.exr *.rgbe *.hdr *.pfm *.ppm *.png *.jpg *.jpeg);;"
-		   "Mitsuba scenes (*.xml);;High dynamic-range images (*.exr *.rgbe *.hdr *.pfm);;"
+		   "Mitsuba scenes (*.xml);;High dynamic-range images (*.exr *.rgbe *.hdr *.pfm *.ppm);;"
 		   "Low dynamic-range images (*.png *.jpg *.jpeg)"));
 
 	QStringList::ConstIterator it = fileNames.constBegin();
@@ -605,8 +605,8 @@ void MainWindow::onOpenDialogClose(int reason) { /* unused */ }
 
 void MainWindow::on_actionOpen_triggered() {
 	QFileDialog *dialog = new QFileDialog(this, Qt::Sheet);
-	dialog->setNameFilter(tr("All supported formats (*.xml *.exr *.rgbe *.hdr *.pfm *.png *.jpg *.jpeg);;"
+	dialog->setNameFilter(tr("All supported formats (*.xml *.exr *.rgbe *.hdr *.pfm *.ppm *.png *.jpg *.jpeg);;"
-			"Mitsuba scenes (*.xml);;High dynamic-range images (*.exr *.rgbe *.hdr *.pfm);;Low "
+			"Mitsuba scenes (*.xml);;High dynamic-range images (*.exr *.rgbe *.hdr *.pfm *.ppm);;Low "
 			"dynamic-range images (*.png *.jpg *.jpeg)"));
 	dialog->setAttribute(Qt::WA_DeleteOnClose);
 	dialog->setAcceptMode(QFileDialog::AcceptOpen);
@@ -1498,6 +1498,7 @@ void MainWindow::on_actionExportImage_triggered() {
 	        "High dynamic range OpenEXR image (*.exr);;"
 	        "High dynamic range Radiance RGBE image (*.rgbe *.hdr);;"
 	        "High dynamic range Portable Float Map image (*.pfm);;"
+	        "High dynamic range Portable Pixel Map image (*.ppm);;"
 	        "Tonemapped low dynamic range image (*.png *.jpg *.jpeg)"));
 	if (!fileName.isEmpty()) {
 		QSettings settings;
@@ -1516,6 +1517,7 @@ void MainWindow::on_actionExportImage_triggered() {
 	           "High dynamic range OpenEXR image (*.exr);;"
 	           "High dynamic range Radiance RGBE image (*.rgbe *.hdr);;"
 	           "High dynamic range Portable Float Map image (*.pfm);;"
+	        "High dynamic range Portable Pixel Map image (*.ppm);;"
 	           "Tonemapped low dynamic range image (*.png *.jpg *.jpeg)"));
 
 	QSettings settings;
@@ -1554,23 +1556,27 @@ void MainWindow::onExportDialogClose(int reason) {
 
 void MainWindow::exportImage(const QString &fileName) {
 	if (!fileName.isEmpty()) {
+		Bitmap::EComponentFormat compFormat = Bitmap::EInvalid;
 		Bitmap::EFileFormat format;
-		bool isHDR = true;
+
 		if (fileName.endsWith(".exr")) {
 			format = Bitmap::EOpenEXR;
 		} else if (fileName.endsWith(".png") || fileName == "__clipboard__") {
 			format = Bitmap::EPNG;
-			isHDR = false;
+			compFormat = Bitmap::EUInt8;
 		} else if (fileName.endsWith(".hdr") || fileName.endsWith(".rgbe")) {
 			format = Bitmap::ERGBE;
 		} else if (fileName.endsWith(".jpg") || fileName.endsWith(".jpeg")) {
 			format = Bitmap::EJPEG;
-			isHDR = false;
+			compFormat = Bitmap::EUInt8;
 		} else if (fileName.endsWith(".pfm")) {
 			format = Bitmap::EPFM;
+		} else if (fileName.endsWith(".ppm")) {
+			format = Bitmap::EPPM;
+			compFormat = Bitmap::EUInt16;
 		} else {
 			SLog(EError, "Unknown file type -- the filename must end in either"
-				" .exr, .rgbe, .hdr, .pfm, .png, .jpg, or .jpeg");
+				" .exr, .rgbe, .hdr, .pfm, .ppm, .png, .jpg, or .jpeg");
 			return;
 		}
 
@@ -1581,7 +1587,7 @@ void MainWindow::exportImage(const QString &fileName) {
 			ui->glView->downloadFramebuffer();
 
 		ref<Bitmap> bitmap = ctx->framebuffer;
-		if (!isHDR) {
+		if (compFormat == Bitmap::EUInt8 || compFormat == Bitmap::EUInt16) {
 			/* Tonemap the image */
 			if (ctx->toneMappingMethod == EReinhard) {
 				Float logAvgLuminance = 0, maxLuminance = 0; /* Unused */
@@ -1592,7 +1598,7 @@ void MainWindow::exportImage(const QString &fileName) {
 					ctx->reinhardKey, burn);
 			}
 
-			bitmap = bitmap->convert(Bitmap::ERGB, Bitmap::EUInt8,
+			bitmap = bitmap->convert(Bitmap::ERGB, compFormat,
 				ctx->srgb ? (Float) -1 : ctx->gamma,
 				ctx->toneMappingMethod == EReinhard
 				? (Float) 1.0f : std::pow((Float) 2, ctx->exposure));

src/mtsgui/sceneloader.cpp

@@ -67,7 +67,7 @@ void SceneLoader::run() {
 		m_result->diffuseReceivers = settings.value("preview_diffuseReceivers", false).toBool();
 
 		if (suffix == "exr" || suffix == "png"  || suffix == "jpg" || suffix == "jpeg" ||
-		    suffix == "hdr" || suffix == "rgbe" || suffix == "pfm") {
+		    suffix == "hdr" || suffix == "rgbe" || suffix == "pfm" || suffix == "ppm") {
 			/* This is an image, not a scene */
 			ref<FileStream> fs = new FileStream(toFsPath(m_filename), FileStream::EReadOnly);
 			ref<Bitmap> bitmap = new Bitmap(Bitmap::EAuto, fs);