Mercurial > sdl-ios-xcode
view test/testjoystick.c @ 1287:15a89a0c52bf
Date: Tue, 15 Feb 2005 21:28:48 +0900 (JST)
From: "Michael Leonhard"
Subject: [SDL] resize bug on Win32 and patch
This is my first post to this mailing list. In this email I will detail a
bug in the behavior of resizable SDL windows on Win32. Then I will
explain the solution and provide a patch.
Symptoms:
Under Windows, an SDL display created with the SDL_RESIZABLE flag exhibits
quirky behavior when being maximized. The window is resized to the proper
size, but it is shifted upwards about half the height of the title bar.
Similarly, a window whose origin is above the top of the screen will
spontaneously move its upper-left origin upon being resized. After two
such resize-induced moves, the title bar will be entirely off the top edge
of the screen. Subsequently, when the mouse is clicked and released on
the window border, the window will shrink its height spontaneously. This
height shrinkage occurs even if the user did not resize the border.
To observe this curious situation, please invoke:
SDL-1.2.8/test/testwm.exe -resize
Cause:
A pair of integers, SDL_windowX and SDL_windowY, are defined in
video/wincommon/SDL_sysevents.c. They are used by the DirectX video
driver and the DIB video driver:
video/windx5/SDL_dx5video.c
video/windib/SDL_dibvideo.c
As I understand the source code, the primary use of these variables is to
create a rectangle that represents the surface area in CLIENT SPACE.
Client space refers to a coordinate system that originates at the upper
left corner of a Win32 Window's drawable area. This is just inside the
window border and title bar. This client space rectangle, called bounds,
is subsequently converted to screen space with a call to
AdjustWindowRectEx. The problem is found in SDL's handling of the
WM_WINDOWPOSCHANGED message. According to MSDN,
"The WM_WINDOWPOSCHANGED message is sent to a window whose
size, position, or place in the Z order has changed as a
result of a call to the SetWindowPos function or another
window-management function."
I have confirmed that this message is indeed being sent to the SDL window
when the mouse is clicked on the window border, even if the window border
is not dragged.
In video/wincommon/SDL_sysevents.c, on line 464, in response to the
WM_WINDOWPOSCHANGED message, the (potentially) new client rectangle is
obtained. This rectangle is translated into screen coordinates and THEN
assigned to the SDL_windowX and Y variables. Thus screen coordinates are
being assigned to client coordinate variables. Once this is understood,
the solution is apparent: assign SDL_windowX and Y before translating the
rectangle to screen coordinates. This is accomplished by the following
patch.
-Mike_L
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 29 Jan 2006 08:50:06 +0000 |
parents | 74212992fb08 |
children | 281d3f4870e5 |
line wrap: on
line source
/* Simple program to test the SDL joystick routines */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include "SDL.h" #define SCREEN_WIDTH 640 #define SCREEN_HEIGHT 480 void WatchJoystick(SDL_Joystick *joystick) { SDL_Surface *screen; const char *name; int i, done; SDL_Event event; int x, y, draw; SDL_Rect axis_area[2]; /* Set a video mode to display joystick axis position */ screen = SDL_SetVideoMode(SCREEN_WIDTH, SCREEN_HEIGHT, 16, 0); if ( screen == NULL ) { fprintf(stderr, "Couldn't set video mode: %s\n",SDL_GetError()); return; } /* Print info about the joystick we are watching */ name = SDL_JoystickName(SDL_JoystickIndex(joystick)); printf("Watching joystick %d: (%s)\n", SDL_JoystickIndex(joystick), name ? name : "Unknown Joystick"); printf("Joystick has %d axes, %d hats, %d balls, and %d buttons\n", SDL_JoystickNumAxes(joystick), SDL_JoystickNumHats(joystick), SDL_JoystickNumBalls(joystick),SDL_JoystickNumButtons(joystick)); /* Initialize drawing rectangles */ memset(axis_area, 0, (sizeof axis_area)); draw = 0; /* Loop, getting joystick events! */ done = 0; while ( ! done ) { while ( SDL_PollEvent(&event) ) { switch (event.type) { case SDL_JOYAXISMOTION: printf("Joystick %d axis %d value: %d\n", event.jaxis.which, event.jaxis.axis, event.jaxis.value); break; case SDL_JOYHATMOTION: printf("Joystick %d hat %d value:", event.jhat.which, event.jhat.hat); if ( event.jhat.value == SDL_HAT_CENTERED ) printf(" centered"); if ( event.jhat.value & SDL_HAT_UP ) printf(" up"); if ( event.jhat.value & SDL_HAT_RIGHT ) printf(" right"); if ( event.jhat.value & SDL_HAT_DOWN ) printf(" down"); if ( event.jhat.value & SDL_HAT_LEFT ) printf(" left"); printf("\n"); break; case SDL_JOYBALLMOTION: printf("Joystick %d ball %d delta: (%d,%d)\n", event.jball.which, event.jball.ball, event.jball.xrel, event.jball.yrel); break; case SDL_JOYBUTTONDOWN: printf("Joystick %d button %d down\n", event.jbutton.which, event.jbutton.button); break; case SDL_JOYBUTTONUP: printf("Joystick %d button %d up\n", event.jbutton.which, event.jbutton.button); break; case SDL_KEYDOWN: if ( event.key.keysym.sym != SDLK_ESCAPE ) { break; } /* Fall through to signal quit */ case SDL_QUIT: done = 1; break; default: break; } } /* Update visual joystick state */ for ( i=0; i<SDL_JoystickNumButtons(joystick); ++i ) { SDL_Rect area; area.x = i*34; area.y = SCREEN_HEIGHT-34; area.w = 32; area.h = 32; if (SDL_JoystickGetButton(joystick, i) == SDL_PRESSED) { SDL_FillRect(screen, &area, 0xFFFF); } else { SDL_FillRect(screen, &area, 0x0000); } SDL_UpdateRects(screen, 1, &area); } /* Erase previous axes */ SDL_FillRect(screen, &axis_area[draw], 0x0000); /* Draw the X/Y axis */ draw = !draw; x = (((int)SDL_JoystickGetAxis(joystick, 0))+32768); x *= SCREEN_WIDTH; x /= 65535; if ( x < 0 ) { x = 0; } else if ( x > (SCREEN_WIDTH-16) ) { x = SCREEN_WIDTH-16; } y = (((int)SDL_JoystickGetAxis(joystick, 1))+32768); y *= SCREEN_HEIGHT; y /= 65535; if ( y < 0 ) { y = 0; } else if ( y > (SCREEN_HEIGHT-16) ) { y = SCREEN_HEIGHT-16; } axis_area[draw].x = (Sint16)x; axis_area[draw].y = (Sint16)y; axis_area[draw].w = 16; axis_area[draw].h = 16; SDL_FillRect(screen, &axis_area[draw], 0xFFFF); SDL_UpdateRects(screen, 2, axis_area); } } int main(int argc, char *argv[]) { const char *name; int i; SDL_Joystick *joystick; /* Initialize SDL (Note: video is required to start event loop) */ if ( SDL_Init(SDL_INIT_VIDEO|SDL_INIT_JOYSTICK) < 0 ) { fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError()); exit(1); } /* Print information about the joysticks */ printf("There are %d joysticks attached\n", SDL_NumJoysticks()); for ( i=0; i<SDL_NumJoysticks(); ++i ) { name = SDL_JoystickName(i); printf("Joystick %d: %s\n",i,name ? name : "Unknown Joystick"); } if ( argv[1] ) { joystick = SDL_JoystickOpen(atoi(argv[1])); if ( joystick == NULL ) { printf("Couldn't open joystick %d: %s\n", atoi(argv[1]), SDL_GetError()); } else { WatchJoystick(joystick); SDL_JoystickClose(joystick); } } SDL_QuitSubSystem(SDL_INIT_VIDEO|SDL_INIT_JOYSTICK); return(0); }