src/events/SDL_mouse.c
author Sam Lantinga
Mon, 06 Feb 2006 08:28:51 +0000
changeset 1330 450721ad5436
parent 1312 c9b51268668f
child 1336 3692456e7b0f
permissions -rw-r--r--
It's now possible to build SDL without any C runtime at all on Windows,
using Visual C++ 2005
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2006 Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Lesser General Public
     7     License as published by the Free Software Foundation; either
     8     version 2.1 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Lesser General Public License for more details.
    14 
    15     You should have received a copy of the GNU Lesser General Public
    16     License along with this library; if not, write to the Free Software
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 /* General mouse handling code for SDL */
    24 
    25 #include "SDL_events.h"
    26 #include "SDL_string.h"
    27 #include "SDL_events_c.h"
    28 #include "SDL_cursor_c.h"
    29 #include "SDL_sysvideo.h"
    30 
    31 
    32 /* These are static for our mouse handling code */
    33 static Sint16 SDL_MouseX = -1;
    34 static Sint16 SDL_MouseY = -1;
    35 static Sint16 SDL_DeltaX = 0;
    36 static Sint16 SDL_DeltaY = 0;
    37 static Uint8  SDL_ButtonState = 0;
    38 
    39 
    40 /* Public functions */
    41 int SDL_MouseInit(void)
    42 {
    43 	/* The mouse is at (0,0) */
    44 	SDL_MouseX = -1;
    45 	SDL_MouseY = -1;
    46 	SDL_DeltaX = 0;
    47 	SDL_DeltaY = 0;
    48 	SDL_ButtonState = 0;
    49 
    50 	/* That's it! */
    51 	return(0);
    52 }
    53 void SDL_MouseQuit(void)
    54 {
    55 }
    56 
    57 /* We lost the mouse, so post button up messages for all pressed buttons */
    58 void SDL_ResetMouse(void)
    59 {
    60 	Uint8 i;
    61 	for ( i = 0; i < sizeof(SDL_ButtonState)*8; ++i ) {
    62 		if ( SDL_ButtonState & SDL_BUTTON(i) ) {
    63 			SDL_PrivateMouseButton(SDL_RELEASED, i, 0, 0);
    64 		}
    65 	}
    66 }
    67 
    68 Uint8 SDL_GetMouseState (int *x, int *y)
    69 {
    70 	if ( x ) {
    71 		if ( SDL_MouseX < 0 ) {
    72 			*x = 0;
    73 		} else {
    74 			*x = SDL_MouseX;
    75 		}
    76 	}
    77 	if ( y ) {
    78 		if ( SDL_MouseY < 0 ) {
    79 			*y = 0;
    80 		} else {
    81 			*y = SDL_MouseY;
    82 		}
    83 	}
    84 	return(SDL_ButtonState);
    85 }
    86 
    87 Uint8 SDL_GetRelativeMouseState (int *x, int *y)
    88 {
    89 	if ( x )
    90 		*x = SDL_DeltaX;
    91 	if ( y )
    92 		*y = SDL_DeltaY;
    93 	SDL_DeltaX = 0;
    94 	SDL_DeltaY = 0;
    95 	return(SDL_ButtonState);
    96 }
    97 
    98 static void ClipOffset(Sint16 *x, Sint16 *y)
    99 {
   100 	/* This clips absolute mouse coordinates when the apparent
   101 	   display surface is smaller than the real display surface.
   102 	 */
   103 	if ( SDL_VideoSurface->offset ) {
   104 		*y -= SDL_VideoSurface->offset/SDL_VideoSurface->pitch;
   105 		*x -= (SDL_VideoSurface->offset%SDL_VideoSurface->pitch)/
   106 				SDL_VideoSurface->format->BytesPerPixel;
   107 	}
   108 }
   109 
   110 /* These are global for SDL_eventloop.c */
   111 int SDL_PrivateMouseMotion(Uint8 buttonstate, int relative, Sint16 x, Sint16 y)
   112 {
   113 	int posted;
   114 	Uint16 X, Y;
   115 	Sint16 Xrel;
   116 	Sint16 Yrel;
   117 
   118 	/* Don't handle mouse motion if there's no cursor surface */
   119 	if ( SDL_VideoSurface == NULL ) {
   120 		return(0);
   121 	}
   122 
   123 	/* Default buttonstate is the current one */
   124 	if ( ! buttonstate ) {
   125 		buttonstate = SDL_ButtonState;
   126 	}
   127 
   128 	Xrel = x;
   129 	Yrel = y;
   130 	if ( relative ) {
   131 		/* Push the cursor around */
   132 		x = (SDL_MouseX+x);
   133 		y = (SDL_MouseY+y);
   134 	} else {
   135 		/* Do we need to clip {x,y} ? */
   136 		ClipOffset(&x, &y);
   137 	}
   138 
   139 	/* Mouse coordinates range from 0 - width-1 and 0 - height-1 */
   140 	if ( x < 0 )
   141 		X = 0;
   142 	else
   143 	if ( x >= SDL_VideoSurface->w )
   144 		X = SDL_VideoSurface->w-1;
   145 	else
   146 		X = (Uint16)x;
   147 
   148 	if ( y < 0 )
   149 		Y = 0;
   150 	else
   151 	if ( y >= SDL_VideoSurface->h )
   152 		Y = SDL_VideoSurface->h-1;
   153 	else
   154 		Y = (Uint16)y;
   155 
   156 	/* If not relative mode, generate relative motion from clamped X/Y.
   157 	   This prevents lots of extraneous large delta relative motion when
   158 	   the screen is windowed mode and the mouse is outside the window.
   159 	*/
   160 	if ( ! relative && SDL_MouseX >= 0 && SDL_MouseY >= 0 ) {
   161 		Xrel = X-SDL_MouseX;
   162 		Yrel = Y-SDL_MouseY;
   163 	}
   164 
   165 	/* Drop events that don't change state */
   166 	if ( ! Xrel && ! Yrel ) {
   167 #if 0
   168 printf("Mouse event didn't change state - dropped!\n");
   169 #endif
   170 		return(0);
   171 	}
   172 
   173 	/* Update internal mouse state */
   174 	SDL_ButtonState = buttonstate;
   175 	SDL_MouseX = X;
   176 	SDL_MouseY = Y;
   177 	SDL_DeltaX += Xrel;
   178 	SDL_DeltaY += Yrel;
   179 	SDL_MoveCursor(SDL_MouseX, SDL_MouseY);
   180 
   181 	/* Post the event, if desired */
   182 	posted = 0;
   183 	if ( SDL_ProcessEvents[SDL_MOUSEMOTION] == SDL_ENABLE ) {
   184 		SDL_Event event;
   185 		memset(&event, 0, sizeof(event));
   186 		event.type = SDL_MOUSEMOTION;
   187 		event.motion.state = buttonstate;
   188 		event.motion.x = X;
   189 		event.motion.y = Y;
   190 		event.motion.xrel = Xrel;
   191 		event.motion.yrel = Yrel;
   192 		if ( (SDL_EventOK == NULL) || (*SDL_EventOK)(&event) ) {
   193 			posted = 1;
   194 			SDL_PushEvent(&event);
   195 		}
   196 	}
   197 	return(posted);
   198 }
   199 
   200 int SDL_PrivateMouseButton(Uint8 state, Uint8 button, Sint16 x, Sint16 y)
   201 {
   202 	SDL_Event event;
   203 	int posted;
   204 	int move_mouse;
   205 	Uint8 buttonstate;
   206 
   207 	memset(&event, 0, sizeof(event));
   208 
   209 	/* Check parameters */
   210 	if ( x || y ) {
   211 		ClipOffset(&x, &y);
   212 		move_mouse = 1;
   213 		/* Mouse coordinates range from 0 - width-1 and 0 - height-1 */
   214 		if ( x < 0 )
   215 			x = 0;
   216 		else
   217 		if ( x >= SDL_VideoSurface->w )
   218 			x = SDL_VideoSurface->w-1;
   219 
   220 		if ( y < 0 )
   221 			y = 0;
   222 		else
   223 		if ( y >= SDL_VideoSurface->h )
   224 			y = SDL_VideoSurface->h-1;
   225 	} else {
   226 		move_mouse = 0;
   227 	}
   228 	if ( ! x )
   229 		x = SDL_MouseX;
   230 	if ( ! y )
   231 		y = SDL_MouseY;
   232 
   233 	/* Figure out which event to perform */
   234 	buttonstate = SDL_ButtonState;
   235 	switch ( state ) {
   236 		case SDL_PRESSED:
   237 			event.type = SDL_MOUSEBUTTONDOWN;
   238 			buttonstate |= SDL_BUTTON(button);
   239 			break;
   240 		case SDL_RELEASED:
   241 			event.type = SDL_MOUSEBUTTONUP;
   242 			buttonstate &= ~SDL_BUTTON(button);
   243 			break;
   244 		default:
   245 			/* Invalid state -- bail */
   246 			return(0);
   247 	}
   248 
   249 	/* Update internal mouse state */
   250 	SDL_ButtonState = buttonstate;
   251 	if ( move_mouse ) {
   252 		SDL_MouseX = x;
   253 		SDL_MouseY = y;
   254 		SDL_MoveCursor(SDL_MouseX, SDL_MouseY);
   255 	}
   256 
   257 	/* Post the event, if desired */
   258 	posted = 0;
   259 	if ( SDL_ProcessEvents[event.type] == SDL_ENABLE ) {
   260 		event.button.state = state;
   261 		event.button.button = button;
   262 		event.button.x = x;
   263 		event.button.y = y;
   264 		if ( (SDL_EventOK == NULL) || (*SDL_EventOK)(&event) ) {
   265 			posted = 1;
   266 			SDL_PushEvent(&event);
   267 		}
   268 	}
   269 	return(posted);
   270 }
   271