From 9d94e1bd45835f87973fccdfcdbfa84fc1cadaa6 Mon Sep 17 00:00:00 2001
From: Simon Howard
Date: Mon, 29 May 2006 00:17:24 +0000
Subject: Change the mouse acceleration behavior to accelerate by multiplying
 by a linear amount when a threshold is exceeded.

Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 535
---
 src/i_video.c | 28 +++++++++++++++++++---------
 src/i_video.h |  3 ++-
 src/m_misc.c  |  5 +++--
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/src/i_video.c b/src/i_video.c
index acb8af1b..72e4d0f8 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -1,7 +1,7 @@
 // Emacs style mode select   -*- C++ -*- 
 //-----------------------------------------------------------------------------
 //
-// $Id: i_video.c 532 2006-05-26 15:37:09Z fraggle $
+// $Id: i_video.c 535 2006-05-29 00:17:24Z fraggle $
 //
 // Copyright(C) 1993-1996 Id Software, Inc.
 // Copyright(C) 2005 Simon Howard
@@ -175,7 +175,7 @@
 //-----------------------------------------------------------------------------
 
 static const char
-rcsid[] = "$Id: i_video.c 532 2006-05-26 15:37:09Z fraggle $";
+rcsid[] = "$Id: i_video.c 535 2006-05-29 00:17:24Z fraggle $";
 
 #include <SDL.h>
 #include <ctype.h>
@@ -269,14 +269,17 @@ static int disk_image_w, disk_image_h;
 static byte *saved_background;
 static boolean window_focused;
 
-// mouse acceleration
-// We accelerate the mouse by raising the mouse movement values to
-// the power of this value, to simulate the acceleration in DOS
-// mouse drivers
+// Mouse acceleration
 //
-// TODO: See what is a sensible default value for this
+// This emulates some of the behavior of DOS mouse drivers by increasing
+// the speed when the mouse is moved fast.
+//
+// The mouse input values are input directly to the game, but when
+// the values exceed the value of mouse_threshold, they are multiplied
+// by mouse_acceleration to increase the speed.
 
-float mouse_acceleration = 1.5;
+float mouse_acceleration = 2.0;
+int mouse_threshold = 10;
 
 static boolean MouseShouldBeGrabbed()
 {
@@ -485,7 +488,14 @@ static int AccelerateMouse(int val)
     if (val < 0)
         return -AccelerateMouse(-val);
 
-    return (int) pow(((float) val) / mouse_acceleration, mouse_acceleration);
+    if (val > mouse_threshold)
+    {
+        return (val - mouse_threshold) * mouse_acceleration + mouse_threshold;
+    }
+    else
+    {
+        return val;
+    }
 }
 
 void I_GetEvent(void)
diff --git a/src/i_video.h b/src/i_video.h
index 3b9b673f..ad48c3a4 100644
--- a/src/i_video.h
+++ b/src/i_video.h
@@ -1,7 +1,7 @@
 // Emacs style mode select   -*- C++ -*- 
 //-----------------------------------------------------------------------------
 //
-// $Id: i_video.h 532 2006-05-26 15:37:09Z fraggle $
+// $Id: i_video.h 535 2006-05-29 00:17:24Z fraggle $
 //
 // Copyright(C) 1993-1996 Id Software, Inc.
 // Copyright(C) 2005 Simon Howard
@@ -66,6 +66,7 @@ extern int screenmultiply;
 extern int fullscreen;
 extern boolean grabmouse;
 extern float mouse_acceleration;
+extern int mouse_threshold;
 extern int startup_delay;
 
 #endif
diff --git a/src/m_misc.c b/src/m_misc.c
index 57840604..899fad01 100644
--- a/src/m_misc.c
+++ b/src/m_misc.c
@@ -1,7 +1,7 @@
 // Emacs style mode select   -*- C++ -*- 
 //-----------------------------------------------------------------------------
 //
-// $Id: m_misc.c 532 2006-05-26 15:37:09Z fraggle $
+// $Id: m_misc.c 535 2006-05-29 00:17:24Z fraggle $
 //
 // Copyright(C) 1993-1996 Id Software, Inc.
 // Copyright(C) 2005 Simon Howard
@@ -106,7 +106,7 @@
 //-----------------------------------------------------------------------------
 
 static const char
-rcsid[] = "$Id: m_misc.c 532 2006-05-26 15:37:09Z fraggle $";
+rcsid[] = "$Id: m_misc.c 535 2006-05-29 00:17:24Z fraggle $";
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -402,6 +402,7 @@ static default_t extra_defaults_list[] =
     {"grabmouse",                   &grabmouse},
     {"novert",                      &novert},
     {"mouse_acceleration",          &mouse_acceleration,       DEFAULT_FLOAT},
+    {"mouse_threshold",             &mouse_threshold},
     {"show_endoom",                 &show_endoom},
     {"vanilla_savegame_limit",      &vanilla_savegame_limit},
 #ifdef FEATURE_MULTIPLAYER
-- 
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