gems: simple oscilloscope for audio input

repos/gems/recipes/pkg/osci/README

@@ -0,0 +1,2 @@
+
+             Virtual print button for a touch-screen device

repos/gems/recipes/pkg/osci/archives

@@ -0,0 +1 @@
+_/src/osci

repos/gems/recipes/pkg/osci/hash

@@ -0,0 +1 @@
+2023-01-31 0d3ec33511f8d3c157580a734dfed41504dc34c6

repos/gems/recipes/pkg/osci/runtime

@@ -0,0 +1,10 @@
+<runtime ram="4M" caps="100" binary="osci">
+
+	<requires> <gui/> <audio_in/> </requires>
+
+	<content>
+		<rom label="ld.lib.so"/>
+		<rom label="osci"/>
+	</content>
+
+</runtime>

repos/gems/recipes/src/osci/content.mk

@@ -0,0 +1,2 @@
+SRC_DIR = src/app/osci
+include $(GENODE_DIR)/repos/base/recipes/src/content.inc

repos/gems/recipes/src/osci/hash

@@ -0,0 +1 @@
+2023-01-31 4b14ae81ac3638c5db44bf52ba6853620c820072

repos/gems/recipes/src/osci/used_apis

@@ -0,0 +1,10 @@
+base
+os
+blit
+gems
+framebuffer_session
+input_session
+gui_session
+timer_session
+audio_in_session
+polygon_gfx

repos/gems/src/app/osci/main.cc

@@ -0,0 +1,197 @@
+/*
+ * \brief  Oscilloscope showing audio input
+ * \author Norman Feske
+ * \date   2023-01-29
+ */
+
+/*
+ * Copyright (C) 2023 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#include <base/env.h>
+#include <base/component.h>
+#include <base/attached_rom_dataspace.h>
+#include <gui_session/connection.h>
+#include <audio_in_session/connection.h>
+#include <timer_session/connection.h>
+#include <input/event.h>
+#include <os/pixel_rgb888.h>
+#include <polygon_gfx/line_painter.h>
+#include <gems/gui_buffer.h>
+
+namespace Osci {
+	using namespace Genode;
+	struct Main;
+}
+
+
+struct Osci::Main
+{
+	Env &_env;
+
+	using Point = Gui_buffer::Point;
+	using Area  = Gui_buffer::Area;
+	using Rect  = Gui_buffer::Rect;
+
+	Area  _size       { };
+	Color _background { };
+	Color _color      { };
+	int   _v_scale    { };
+
+	Gui::Connection _gui { _env };
+
+	Timer::Connection _timer { _env };
+
+	Audio_in::Connection _audio_in { _env, "left" };
+
+	Constructible<Gui_buffer> _gui_buffer { };
+
+	struct View
+	{
+		Gui::Connection &_gui;
+
+		Gui::Session::View_handle _handle { _gui.create_view() };
+
+		View(Gui::Connection &gui, Point position, Area size) : _gui(gui)
+		{
+			using Command = Gui::Session::Command;
+			_gui.enqueue<Command::Geometry>(_handle, Rect(position, size));
+			_gui.enqueue<Command::To_front>(_handle, Gui::Session::View_handle());
+			_gui.execute();
+		}
+
+		~View() { _gui.destroy_view(_handle); }
+	};
+
+	Constructible<View> _view { };
+
+	Signal_handler<Main> _timer_handler { _env.ep(), *this, &Main::_handle_timer };
+
+	Attached_rom_dataspace _config { _env, "config" };
+
+	Signal_handler<Main> _config_handler { _env.ep(), *this, &Main::_handle_config };
+
+	struct Captured_audio
+	{
+		enum { SIZE_LOG2 = 10, SIZE = 1 << SIZE_LOG2, MASK = SIZE - 1 };
+
+		float _samples[SIZE] { };
+
+		unsigned _pos = 0;
+
+		void _insert(float value)
+		{
+			_pos = (_pos + 1) & MASK;
+			_samples[_pos] = value;
+		}
+
+		float past_value(unsigned past) const
+		{
+			return _samples[(_pos - past) & MASK];
+		}
+
+		void capture_from_audio_in(Audio_in::Session &audio_in)
+		{
+			Audio_in::Stream &stream = *audio_in.stream();
+
+			while (!stream.empty()) {
+
+				Audio_in::Packet &p = *stream.get(stream.pos());
+
+				if (p.valid()) {
+					float *data_ptr = p.content();
+
+					for (unsigned i = 0; i < Audio_in::PERIOD; i++)
+						_insert(*data_ptr++);
+
+					p.invalidate();
+					p.mark_as_recorded();
+				}
+
+				stream.increment_position();
+			}
+		}
+	} _captured_audio { };
+
+	void _handle_config()
+	{
+		_config.update();
+
+		Xml_node const config = _config.xml();
+
+		_size       = Area::from_xml(config);
+		_background = config.attribute_value("background", Color { 0, 0, 0 });
+		_color      = config.attribute_value("color",      Color { 255, 255, 255 });
+		_v_scale    = config.attribute_value("v_scale",    3000);
+
+		_gui_buffer.construct(_gui, _size, _env.ram(), _env.rm(),
+		                      Gui_buffer::Alpha::OPAQUE, _background);
+
+		_view.construct(_gui, Point::from_xml(config), _size);
+
+		_timer.trigger_periodic(1000*config.attribute_value("period_ms",  20));
+	}
+
+	Line_painter const _line_painter { };
+
+	void _render(Gui_buffer::Pixel_surface &pixel, Gui_buffer::Alpha_surface &)
+	{
+		/*
+		 * Draw captured audio from right to left.
+		 */
+
+		Point const centered { 0, int(pixel.size().h()/2) };
+
+		Point previous_p { };
+
+		bool first_iteration = true;
+
+		unsigned const w = pixel.size().w();
+
+		for (unsigned i = 0; i < w; i++) {
+
+			Point p { int(w - i),
+			          int(float(_v_scale)*_captured_audio.past_value(i)) };
+
+			p = p + centered;
+
+			if (!first_iteration)
+				_line_painter.paint(pixel, p, previous_p, _color);
+
+			previous_p = p;
+			first_iteration = false;
+		}
+	}
+
+	void _handle_timer()
+	{
+		_captured_audio.capture_from_audio_in(_audio_in);
+
+		_gui_buffer->reset_surface();
+		_gui_buffer->apply_to_surface([&] (auto &pixel, auto &alpha) {
+			_render(pixel, alpha); });
+
+		_gui_buffer->flush_surface();
+
+		_gui.framebuffer()->refresh(0, 0, _size.w(), _size.h());
+	}
+
+	Main(Env &env) : _env(env)
+	{
+		_config.sigh(_config_handler);
+		_handle_config();
+
+		_timer.sigh(_timer_handler);
+
+		_audio_in.start();
+	}
+};
+
+
+void Component::construct(Genode::Env &env)
+{
+	static Osci::Main main(env);
+}

repos/gems/src/app/osci/target.mk

@@ -0,0 +1,3 @@
+TARGET = osci
+SRC_CC = main.cc
+LIBS   = base blit