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 (at) libsdl.org 21 */ 22 #include "SDL_config.h" 23 24 #ifdef SDL_JOYSTICK_RISCOS 25 26 /* 27 RISC OS - Joystick support by Alan Buckley (alan_baa (at) hotmail.com) - 10 April 2003 28 29 Note: Currently assumes joystick is present if joystick module is loaded 30 and that there is one joystick with four buttons. 31 */ 32 33 /* This is the system specific header for the SDL joystick API */ 34 35 #include "SDL_events.h" 36 #include "SDL_joystick.h" 37 #include "../SDL_sysjoystick.h" 38 #include "../SDL_joystick_c.h" 39 40 #include "kernel.h" 41 42 #define JOYSTICK_READ 0x43F40 43 44 struct joystick_hwdata 45 { 46 int joystate; 47 }; 48 49 50 /* Function to scan the system for joysticks. 51 * This function should set SDL_numjoysticks to the number of available 52 * joysticks. Joystick 0 should be the system default joystick. 53 * It should return number of joysticks, or -1 on an unrecoverable fatal error. 54 */ 55 int SDL_SYS_JoystickInit(void) 56 { 57 _kernel_swi_regs regs; 58 59 /* Try to read joystick 0 */ 60 regs.r[0] = 0; 61 if (_kernel_swi(JOYSTICK_READ, ®s, ®s) == NULL) 62 { 63 /* Switch works so assume we've got a joystick */ 64 return 1; 65 } 66 /* Switch fails so it looks like there's no joystick here */ 67 68 return(0); 69 } 70 71 /* Function to get the device-dependent name of a joystick */ 72 const char *SDL_SYS_JoystickName(int index) 73 { 74 if (index == 0) 75 { 76 return "RISC OS Joystick 0"; 77 } 78 79 SDL_SetError("No joystick available with that index"); 80 return(NULL); 81 } 82 83 /* Function to open a joystick for use. 84 The joystick to open is specified by the index field of the joystick. 85 This should fill the nbuttons and naxes fields of the joystick structure. 86 It returns 0, or -1 if there is an error. 87 */ 88 int SDL_SYS_JoystickOpen(SDL_Joystick *joystick) 89 { 90 _kernel_swi_regs regs; 91 92 if(!(joystick->hwdata=SDL_malloc(sizeof(struct joystick_hwdata)))) 93 return -1; 94 95 regs.r[0] = joystick->index; 96 97 /* Don't know how to get exact count of buttons so assume max of 4 for now */ 98 joystick->nbuttons=4; 99 100 joystick->nhats=0; 101 joystick->nballs=0; 102 joystick->naxes=2; 103 joystick->hwdata->joystate=0; 104 105 return 0; 106 107 } 108 109 /* Function to update the state of a joystick - called as a device poll. 110 * This function shouldn't update the joystick structure directly, 111 * but instead should call SDL_PrivateJoystick*() to deliver events 112 * and update joystick device state. 113 */ 114 void SDL_SYS_JoystickUpdate(SDL_Joystick *joystick) 115 { 116 _kernel_swi_regs regs; 117 regs.r[0] = joystick->index; 118 119 if (_kernel_swi(JOYSTICK_READ, ®s, ®s) == NULL) 120 { 121 int newstate = regs.r[0]; 122 int oldstate = joystick->hwdata->joystate; 123 if (newstate != oldstate) 124 { 125 if ((newstate & 0xFF) != (oldstate & 0xFF)) 126 { 127 int y = regs.r[0] & 0xFF; 128 /* Convert to signed values */ 129 if (y >= 128) y -= 256; 130 SDL_PrivateJoystickAxis(joystick,1,-y * 256); /* Up and down opposite to result in SDL */ 131 } 132 if ((newstate & 0xFF00) != (oldstate & 0xFF00)) 133 { 134 int x = (regs.r[0] & 0xFF00) >> 8; 135 if (x >= 128) x -= 256; 136 SDL_PrivateJoystickAxis(joystick,0,x * 256); 137 } 138 139 if ((newstate & 0xFF0000) != (oldstate & 0xFF0000)) 140 { 141 int buttons = (regs.r[0] & 0xFF0000) >> 16; 142 int oldbuttons = (oldstate & 0xFF0000) >> 16; 143 int i; 144 for (i = 0; i < joystick->nbuttons; i++) 145 { 146 if ((buttons & (1<<i)) != (oldbuttons & (1<<i))) 147 { 148 if (buttons & (1<<i)) SDL_PrivateJoystickButton(joystick,i,SDL_PRESSED); 149 else SDL_PrivateJoystickButton(joystick,i,SDL_RELEASED); 150 } 151 } 152 } 153 joystick->hwdata->joystate = newstate; 154 } 155 } 156 157 return; 158 } 159 160 /* Function to close a joystick after use */ 161 void SDL_SYS_JoystickClose(SDL_Joystick *joystick) 162 { 163 if(joystick->hwdata) 164 SDL_free(joystick->hwdata); 165 return; 166 } 167 168 /* Function to perform any system-specific joystick related cleanup */ 169 void SDL_SYS_JoystickQuit(void) 170 { 171 SDL_numjoysticks=0; 172 173 return; 174 } 175 176 #endif /* SDL_JOYSTICK_RISCOS */ 177
