From 6e094221e8f89036e13e70bb68c24d19f02e3e74 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stephan=20A=C3=9Fmus?= <superstippi@gmx.de>
Date: Sun, 16 Nov 2008 22:21:34 +0000
Subject: [PATCH] * Fixed the mouse movement when speed or acceleration where
 below default   values. The implementation needs to sum up fractional
 movement, not   truncate to zero. Before this change, the mouse would be
 pretty much unusable   at lower speeds/acceleration. Now it is guaranteed to
 move. * No need to memset() before ioctl(), the driver does that anyways.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28669 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../devices/mouse/MouseInputDevice.cpp        | 56 ++++++++++++-------
 1 file changed, 35 insertions(+), 21 deletions(-)

diff --git a/src/add-ons/input_server/devices/mouse/MouseInputDevice.cpp b/src/add-ons/input_server/devices/mouse/MouseInputDevice.cpp
index d40fc7358f..724b153d49 100644
--- a/src/add-ons/input_server/devices/mouse/MouseInputDevice.cpp
+++ b/src/add-ons/input_server/devices/mouse/MouseInputDevice.cpp
@@ -86,8 +86,8 @@
 #	define TRACE(x...) do {} while (0)
 #	define MD_CALLED(x...) TRACE(x)
 #	define MID_CALLED(x...) TRACE(x)
-#	define LOG_ERR(text...) debug_printf(text)
-#	define LOG_EVENT(text...) TRACE(x)
+#	define LOG_ERR(x...) debug_printf(x)
+#	define LOG_EVENT(x...) TRACE(x)
 #endif
 
 
@@ -128,7 +128,9 @@ private:
 									int32 deltaX, int32 deltaY) const;
 			void				_ComputeAcceleration(
 									const mouse_movement& movements,
-									int32& deltaX, int32& deltaY) const;
+									int32& deltaX, int32& deltaY,
+									float& historyDeltaX,
+									float& historyDeltaY) const;
 			uint32				_RemapButtons(uint32 buttons) const;
 
 private:
@@ -368,11 +370,11 @@ MouseDevice::_ControlThread()
 	_UpdateSettings();
 
 	uint32 lastButtons = 0;
+	float historyDeltaX = 0.0;
+	float historyDeltaY = 0.0;
 
 	while (fActive) {
 		mouse_movement movements;
-		memset(&movements, 0, sizeof(movements));
-
 		if (ioctl(fDevice, MS_READ, &movements) != B_OK) {
 			_ControlThreadCleanup();
 			// TOAST!
@@ -399,12 +401,16 @@ MouseDevice::_ControlThread()
 
 		uint32 remappedButtons = _RemapButtons(movements.buttons);
 		int32 deltaX, deltaY;
-		_ComputeAcceleration(movements, deltaX, deltaY);
+		_ComputeAcceleration(movements, deltaX, deltaY, historyDeltaX,
+			historyDeltaY);
 
-		LOG_EVENT("%s: buttons: 0x%lx, x: %ld, y: %ld, clicks:%ld, wheel_x:%ld, wheel_y:%ld\n",
-			fDeviceRef.name, movements.buttons, movements.xdelta, movements.ydelta,
-			movements.clicks, movements.wheel_xdelta, movements.wheel_ydelta);
-		LOG_EVENT("%s: x: %ld, y: %ld\n", fDeviceRef.name, deltaX, deltaY);
+		LOG_EVENT("%s: buttons: 0x%lx, x: %ld, y: %ld, clicks:%ld, "
+			"wheel_x:%ld, wheel_y:%ld\n",
+			fDeviceRef.name, movements.buttons,
+			movements.xdelta, movements.ydelta, movements.clicks,
+			movements.wheel_xdelta, movements.wheel_ydelta);
+		LOG_EVENT("%s: x: %ld, y: %ld (%.4f, %.4f)\n", fDeviceRef.name,
+			deltaX, deltaY, historyDeltaX, historyDeltaY);
 
 		// Send single messages for each event
 
@@ -574,11 +580,14 @@ MouseDevice::_BuildMouseMessage(uint32 what, uint64 when, uint32 buttons,
 
 void
 MouseDevice::_ComputeAcceleration(const mouse_movement& movements,
-	int32& deltaX, int32& deltaY) const
+	int32& _deltaX, int32& _deltaY, float& historyDeltaX,
+	float& historyDeltaY) const
 {
 	// basic mouse speed
-	deltaX = movements.xdelta * fSettings.accel.speed >> 16;
-	deltaY = movements.ydelta * fSettings.accel.speed >> 16;
+	float deltaX = (float)movements.xdelta * fSettings.accel.speed / 65536.0
+		+ historyDeltaX;
+	float deltaY = (float)movements.ydelta * fSettings.accel.speed / 65536.0
+		+ historyDeltaY;
 
 	// acceleration
 	double acceleration = 1;
@@ -587,16 +596,21 @@ MouseDevice::_ComputeAcceleration(const mouse_movement& movements,
 			* fSettings.accel.accel_factor / 524288.0;
 	}
 
-	// make sure that we move at least one pixel (if there was a movement)
-	if (deltaX > 0)
-		deltaX = (int32)floor(deltaX * acceleration);
-	else
-		deltaX = (int32)ceil(deltaX * acceleration);
+	deltaX *= acceleration;
+	deltaY *= acceleration;
 
-	if (deltaY > 0)
-		deltaY = (int32)floor(deltaY * acceleration);
+	if (deltaX >= 0)
+		_deltaX = (int32)floorf(deltaX);
 	else
-		deltaY = (int32)ceil(deltaY * acceleration);
+		_deltaX = (int32)ceilf(deltaX);
+
+	if (deltaY >= 0)
+		_deltaY = (int32)floorf(deltaY);
+	else
+		_deltaY = (int32)ceilf(deltaY);
+
+	historyDeltaX = deltaX - _deltaX;
+	historyDeltaY = deltaY - _deltaY;
 }