a2gameio: Add support for the Softape Bright Pen (#12721)

* a2gameio: Add Softape Bright Pen support for the Apple ][/][+

scripts/src/bus.lua

@@ -3141,6 +3141,8 @@ end
 
 if (BUSES["A2GAMEIO"]~=null) then
 	files {
+		MAME_DIR .. "src/devices/bus/a2gameio/brightpen.cpp",
+		MAME_DIR .. "src/devices/bus/a2gameio/brightpen.h",
 		MAME_DIR .. "src/devices/bus/a2gameio/computereyes.cpp",
 		MAME_DIR .. "src/devices/bus/a2gameio/computereyes.h",
 		MAME_DIR .. "src/devices/bus/a2gameio/gameio.cpp",

src/devices/bus/a2gameio/brightpen.cpp

@@ -0,0 +1,140 @@
+// license:BSD-3-Clause
+// copyright-holders:kmg
+/*********************************************************************
+
+    Apple II Softape Bright Pen interface for the Apple ][/][+
+
+*********************************************************************/
+
+#include "emu.h"
+#include "bus/a2gameio/brightpen.h"
+#include "screen.h"
+
+
+namespace {
+
+#define BRIGHTPEN_POINT "BRIGHTPEN_POINT"
+#define BRIGHTPEN_X     "BRIGHTPEN_X"
+#define BRIGHTPEN_Y     "BRIGHTPEN_Y"
+
+// ======================> apple2_brightpen_device
+
+class apple2_brightpen_device : public device_t, public device_a2gameio_interface
+{
+public:
+	// construction/destruction
+	apple2_brightpen_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+		: device_t(mconfig, APPLE2_BRIGHTPEN, tag, owner, clock)
+		, device_a2gameio_interface(mconfig, *this)
+		, m_brightpen_point(*this, BRIGHTPEN_POINT)
+		, m_brightpen_x(*this, BRIGHTPEN_X)
+		, m_brightpen_y(*this, BRIGHTPEN_Y)
+	{
+	}
+
+protected:
+	// device_t implementation
+	virtual ioport_constructor device_input_ports() const override;
+	virtual void device_start() override;
+
+	// device_a2gameio_interface implementation
+	virtual int sw0_r() override;
+
+private:
+	// input ports
+	required_ioport m_brightpen_point;
+	required_ioport m_brightpen_x;
+	required_ioport m_brightpen_y;
+
+	// radius of circle picked up by the bright pen
+	static constexpr int PEN_X_RADIUS = 2;
+	static constexpr int PEN_Y_RADIUS = 1;
+	// brightness threshold
+	static constexpr int BRIGHTNESS_THRESHOLD = 0x20;
+	// # of CRT scanlines that sustain brightness
+	static constexpr int SUSTAIN = 22;
+};
+
+//**************************************************************************
+//  INPUT PORTS
+//**************************************************************************
+
+static INPUT_PORTS_START( apple2_brightpen )
+	PORT_START(BRIGHTPEN_X)
+	PORT_BIT( 0x3ff, 0x80, IPT_LIGHTGUN_X ) PORT_CROSSHAIR(X, 1.0, 0.0, 0) PORT_SENSITIVITY(45) PORT_KEYDELTA(15) PORT_MINMAX(0, 559) PORT_NAME("Bright Pen X")
+	PORT_START(BRIGHTPEN_Y)
+	PORT_BIT( 0x3ff, 0x80, IPT_LIGHTGUN_Y ) PORT_CROSSHAIR(Y, 1.0, 0.0, 0) PORT_SENSITIVITY(45) PORT_KEYDELTA(15) PORT_MINMAX(0, 191) PORT_NAME("Bright Pen Y")
+	PORT_START(BRIGHTPEN_POINT)
+	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON1 ) PORT_NAME("Bright Pen pointed at screen")
+	PORT_BIT( 0xfe, IP_ACTIVE_LOW, IPT_UNUSED )
+INPUT_PORTS_END
+
+ioport_constructor apple2_brightpen_device::device_input_ports() const
+{
+	return INPUT_PORTS_NAME(apple2_brightpen);
+}
+
+void apple2_brightpen_device::device_start()
+{
+}
+
+// light detection logic based on zapper_sensor.cpp nes_zapper_sensor_device::detect_light
+
+int apple2_brightpen_device::sw0_r()
+{
+	if (!BIT(m_brightpen_point->read(), 0)) return 0;
+
+	int pen_x_pos = m_brightpen_x->read();
+	int pen_y_pos = m_brightpen_y->read();
+	int beam_vpos = m_screen->vpos();
+	int beam_hpos = m_screen->hpos();
+
+	// update the screen if the beam position is within the radius of the pen
+	if (!machine().side_effects_disabled())
+	{
+		if (!m_screen->vblank())
+		{
+			if (beam_vpos > pen_y_pos - PEN_Y_RADIUS || (beam_vpos == pen_y_pos - PEN_Y_RADIUS && beam_hpos >= pen_x_pos - PEN_X_RADIUS))
+			{
+				m_screen->update_now();
+			}
+		}
+	}
+
+	int brightness_sum = 0;
+	int pixels_scanned = 0;
+
+	// sum brightness of pixels nearby the pen position
+	for (int i = pen_x_pos - PEN_X_RADIUS; i <= pen_x_pos + PEN_X_RADIUS; i++)
+	{
+		for (int j = pen_y_pos - PEN_Y_RADIUS; j <= pen_y_pos + PEN_Y_RADIUS; j++)
+		{
+			// look at pixels within circular sensor
+			if ((pen_x_pos - i) * (pen_x_pos - i) + (pen_y_pos - j) * (pen_y_pos - j) <= PEN_X_RADIUS * PEN_Y_RADIUS)
+			{
+				rgb_t pix = m_screen->pixel(i, j);
+
+				// only detect light if pen position is near, and behind,
+				// where the video generator is drawing on the CRT,
+				if (j <= beam_vpos && j > beam_vpos - SUSTAIN && (j != beam_vpos || i <= beam_hpos))
+				{
+					brightness_sum += pix.r() + pix.g() + pix.b();
+				}
+				pixels_scanned++;
+			}
+		}
+	}
+
+	// light detected if average brightness is above threshold
+	return (brightness_sum >= BRIGHTNESS_THRESHOLD * pixels_scanned);
+}
+
+} // anonymous namespace
+
+
+//**************************************************************************
+//  GLOBAL VARIABLES
+//**************************************************************************
+
+// device type definition
+DEFINE_DEVICE_TYPE_PRIVATE(APPLE2_BRIGHTPEN, device_a2gameio_interface, apple2_brightpen_device, "a2brightpen", "Softape Bright Pen")

src/devices/bus/a2gameio/brightpen.h

@@ -0,0 +1,18 @@
+// license:BSD-3-Clause
+/*********************************************************************
+
+    Apple II Softape Bright Pen interface for a lightpen
+
+*********************************************************************/
+
+#ifndef MAME_BUS_A2GAMEIO_BRIGHTPEN_H
+#define MAME_BUS_A2GAMEIO_BRIGHTPEN_H
+
+#pragma once
+
+#include "bus/a2gameio/gameio.h"
+
+// device type declaration
+DECLARE_DEVICE_TYPE(APPLE2_BRIGHTPEN, device_a2gameio_interface)
+
+#endif // MAME_BUS_A2GAMEIO_BRIGHTPEN_H

src/devices/bus/a2gameio/gameio.cpp

@@ -50,6 +50,7 @@
 
 #include "emu.h"
 #include "bus/a2gameio/gameio.h"
+#include "bus/a2gameio/brightpen.h"
 #include "bus/a2gameio/joystick.h"
 #include "bus/a2gameio/joyport.h"
 #include "bus/a2gameio/joyport_paddles.h"
@@ -68,6 +69,7 @@ DEFINE_DEVICE_TYPE(APPLE2_GAMEIO, apple2_gameio_device, "a2gameio", "Apple II Ga
 apple2_gameio_device::apple2_gameio_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
 	: device_t(mconfig, APPLE2_GAMEIO, tag, owner, clock)
 	, device_single_card_slot_interface<device_a2gameio_interface>(mconfig, *this)
+	, m_screen(*this, finder_base::DUMMY_TAG)
 	, m_intf(nullptr)
 	, m_sw_pullups(false)
 {
@@ -82,6 +84,7 @@ void apple2_gameio_device::iiandplus_options(device_slot_interface &slot)
 	slot.option_add("gizmo", APPLE2_GIZMO);
 	slot.option_add("compeyes", APPLE2_COMPUTEREYES);
 	slot.option_add("wicojoy", APPLE2_WICO_JOYSTICK);
+	slot.option_add("brightpen", APPLE2_BRIGHTPEN);
 }
 
 void apple2_gameio_device::default_options(device_slot_interface &slot)
@@ -105,8 +108,10 @@ void apple2_gameio_device::device_config_complete()
 
 void apple2_gameio_device::device_resolve_objects()
 {
-	if (m_intf)
+	if (m_intf) {
 		m_intf->m_connector = this;
+		m_intf->set_screen(m_screen);
+	}
 }
 
 void apple2_gameio_device::device_start()

src/devices/bus/a2gameio/gameio.h

@@ -11,6 +11,7 @@
 
 #pragma once
 
+#include "screen.h"
 
 //**************************************************************************
 //  TYPE DEFINITIONS
@@ -37,6 +38,13 @@ public:
 		set_fixed(false);
 	}
 
+	template <typename T, typename U>
+	apple2_gameio_device(const machine_config &mconfig, const char *tag, device_t *owner, T &&screen_tag, U &&opts, const char *dflt)
+		: apple2_gameio_device(mconfig, tag, owner, opts, dflt)
+	{
+		m_screen.set_tag(std::forward<T>(screen_tag));
+	}
+
 	// configuration
 	void set_sw_pullups(bool enabled) { m_sw_pullups = enabled; }
 	bool has_sw_pullups() const { return m_sw_pullups; }
@@ -77,6 +85,8 @@ protected:
 	virtual void device_resolve_objects() override;
 	virtual void device_start() override;
 
+	optional_device<screen_device> m_screen;
+
 private:
 	// selected device
 	device_a2gameio_interface *m_intf;
@@ -115,6 +125,8 @@ protected:
 	virtual void an4_w(int state) { }
 	virtual void strobe_w(int state) { }
 
+	void set_screen(screen_device *screen) { m_screen = screen; }
+	screen_device *m_screen;
 private:
 	apple2_gameio_device *m_connector;
 };

src/mame/apple/apple2.cpp

@@ -1155,7 +1155,7 @@ void apple2_state::apple2_common(machine_config &config)
 	m_softlatch->q_out_cb<6>().append(m_video, FUNC(a2_video_device::an2_w));
 	m_softlatch->q_out_cb<7>().set(m_gameio, FUNC(apple2_gameio_device::an3_w));
 
-	APPLE2_GAMEIO(config, m_gameio, apple2_gameio_device::iiandplus_options, nullptr);
+	APPLE2_GAMEIO(config, m_gameio, m_screen, apple2_gameio_device::iiandplus_options, nullptr);
 
 	/* keyboard controller */
 	AY3600(config, m_ay3600, 0);