test/testjoystick.c
author Patrice Mandin <patmandin@gmail.com>
Thu, 19 Jan 2006 21:28:52 +0000
changeset 1257 448a9a64537b
parent 0 74212992fb08
child 1661 281d3f4870e5
permissions -rw-r--r--
[PATCH] SDL_GetVideoMode() does not find best mode, part 2

Following commit 1.51, I come accross a problem when SDL must choose between
several video modes that could suit the one asked.

If I ask 320x240 with this list:
768x480 768x240 640x400 640x200 384x480 384x240 320x400 320x200

The smallest selectables modes are 384x240 and 320x400. And SDL choose the later
in this list, but 384x240 is more suitable. So I added a check to compare
the pixel count (surface) of modes, and select the one which has the smallest
pixel count.

In my example, 384x240 has 92160 pixels, and 320x400 has 128000 pixels. So now
SDL will choose 384x240 for the asked 320x240 mode.
     1 
     2 /* Simple program to test the SDL joystick routines */
     3 
     4 #include <stdio.h>
     5 #include <stdlib.h>
     6 #include <string.h>
     7 
     8 #include "SDL.h"
     9 
    10 #define SCREEN_WIDTH	640
    11 #define SCREEN_HEIGHT	480
    12 
    13 void WatchJoystick(SDL_Joystick *joystick)
    14 {
    15 	SDL_Surface *screen;
    16 	const char *name;
    17 	int i, done;
    18 	SDL_Event event;
    19 	int x, y, draw;
    20 	SDL_Rect axis_area[2];
    21 
    22 	/* Set a video mode to display joystick axis position */
    23 	screen = SDL_SetVideoMode(SCREEN_WIDTH, SCREEN_HEIGHT, 16, 0);
    24 	if ( screen == NULL ) {
    25 		fprintf(stderr, "Couldn't set video mode: %s\n",SDL_GetError());
    26 		return;
    27 	}
    28 
    29 	/* Print info about the joystick we are watching */
    30 	name = SDL_JoystickName(SDL_JoystickIndex(joystick));
    31 	printf("Watching joystick %d: (%s)\n", SDL_JoystickIndex(joystick),
    32 	       name ? name : "Unknown Joystick");
    33 	printf("Joystick has %d axes, %d hats, %d balls, and %d buttons\n",
    34 	       SDL_JoystickNumAxes(joystick), SDL_JoystickNumHats(joystick),
    35 	       SDL_JoystickNumBalls(joystick),SDL_JoystickNumButtons(joystick));
    36 
    37 	/* Initialize drawing rectangles */
    38 	memset(axis_area, 0, (sizeof axis_area));
    39 	draw = 0;
    40 
    41 	/* Loop, getting joystick events! */
    42 	done = 0;
    43 	while ( ! done ) {
    44 		while ( SDL_PollEvent(&event) ) {
    45 			switch (event.type) {
    46 			    case SDL_JOYAXISMOTION:
    47 				printf("Joystick %d axis %d value: %d\n",
    48 				       event.jaxis.which,
    49 				       event.jaxis.axis,
    50 				       event.jaxis.value);
    51 				break;
    52 			    case SDL_JOYHATMOTION:
    53 				printf("Joystick %d hat %d value:",
    54 				       event.jhat.which,
    55 				       event.jhat.hat);
    56 				if ( event.jhat.value == SDL_HAT_CENTERED )
    57 					printf(" centered");
    58 				if ( event.jhat.value & SDL_HAT_UP )
    59 					printf(" up");
    60 				if ( event.jhat.value & SDL_HAT_RIGHT )
    61 					printf(" right");
    62 				if ( event.jhat.value & SDL_HAT_DOWN )
    63 					printf(" down");
    64 				if ( event.jhat.value & SDL_HAT_LEFT )
    65 					printf(" left");
    66 				printf("\n");
    67 				break;
    68 			    case SDL_JOYBALLMOTION:
    69 				printf("Joystick %d ball %d delta: (%d,%d)\n",
    70 				       event.jball.which,
    71 				       event.jball.ball,
    72 				       event.jball.xrel,
    73 				       event.jball.yrel);
    74 				break;
    75 			    case SDL_JOYBUTTONDOWN:
    76 				printf("Joystick %d button %d down\n",
    77 				       event.jbutton.which,
    78 				       event.jbutton.button);
    79 				break;
    80 			    case SDL_JOYBUTTONUP:
    81 				printf("Joystick %d button %d up\n",
    82 				       event.jbutton.which,
    83 				       event.jbutton.button);
    84 				break;
    85 			    case SDL_KEYDOWN:
    86 				if ( event.key.keysym.sym != SDLK_ESCAPE ) {
    87 					break;
    88 				}
    89 				/* Fall through to signal quit */
    90 			    case SDL_QUIT:
    91 				done = 1;
    92 				break;
    93 			    default:
    94 				break;
    95 			}
    96 		}
    97 		/* Update visual joystick state */
    98 		for ( i=0; i<SDL_JoystickNumButtons(joystick); ++i ) {
    99 			SDL_Rect area;
   100 
   101 			area.x = i*34;
   102 			area.y = SCREEN_HEIGHT-34;
   103 			area.w = 32;
   104 			area.h = 32;
   105 			if (SDL_JoystickGetButton(joystick, i) == SDL_PRESSED) {
   106 				SDL_FillRect(screen, &area, 0xFFFF);
   107 			} else {
   108 				SDL_FillRect(screen, &area, 0x0000);
   109 			}
   110 			SDL_UpdateRects(screen, 1, &area);
   111 		}
   112 
   113 		/* Erase previous axes */
   114 		SDL_FillRect(screen, &axis_area[draw], 0x0000);
   115 
   116 		/* Draw the X/Y axis */
   117 		draw = !draw;
   118 		x = (((int)SDL_JoystickGetAxis(joystick, 0))+32768);
   119 		x *= SCREEN_WIDTH;
   120 		x /= 65535;
   121 		if ( x < 0 ) {
   122 			x = 0;
   123 		} else
   124 		if ( x > (SCREEN_WIDTH-16) ) {
   125 			x = SCREEN_WIDTH-16;
   126 		}
   127 		y = (((int)SDL_JoystickGetAxis(joystick, 1))+32768);
   128 		y *= SCREEN_HEIGHT;
   129 		y /= 65535;
   130 		if ( y < 0 ) {
   131 			y = 0;
   132 		} else
   133 		if ( y > (SCREEN_HEIGHT-16) ) {
   134 			y = SCREEN_HEIGHT-16;
   135 		}
   136 		axis_area[draw].x = (Sint16)x;
   137 		axis_area[draw].y = (Sint16)y;
   138 		axis_area[draw].w = 16;
   139 		axis_area[draw].h = 16;
   140 		SDL_FillRect(screen, &axis_area[draw], 0xFFFF);
   141 
   142 		SDL_UpdateRects(screen, 2, axis_area);
   143 	}
   144 }
   145 
   146 int main(int argc, char *argv[])
   147 {
   148 	const char *name;
   149 	int i;
   150 	SDL_Joystick *joystick;
   151 
   152 	/* Initialize SDL (Note: video is required to start event loop) */
   153 	if ( SDL_Init(SDL_INIT_VIDEO|SDL_INIT_JOYSTICK) < 0 ) {
   154 		fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
   155 		exit(1);
   156 	}
   157 
   158 	/* Print information about the joysticks */
   159 	printf("There are %d joysticks attached\n", SDL_NumJoysticks());
   160 	for ( i=0; i<SDL_NumJoysticks(); ++i ) {
   161 		name = SDL_JoystickName(i);
   162 		printf("Joystick %d: %s\n",i,name ? name : "Unknown Joystick");
   163 	}
   164 
   165 	if ( argv[1] ) {
   166 		joystick = SDL_JoystickOpen(atoi(argv[1]));
   167 		if ( joystick == NULL ) {
   168 			printf("Couldn't open joystick %d: %s\n", atoi(argv[1]),
   169 			       SDL_GetError());
   170 		} else {
   171 			WatchJoystick(joystick);
   172 			SDL_JoystickClose(joystick);
   173 		}
   174 	}
   175 	SDL_QuitSubSystem(SDL_INIT_VIDEO|SDL_INIT_JOYSTICK);
   176 
   177 	return(0);
   178 }