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1 /* |
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2 SDL - Simple DirectMedia Layer |
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3 Copyright (C) 1997-2006 Sam Lantinga |
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4 |
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5 This library is free software; you can redistribute it and/or |
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6 modify it under the terms of the GNU Lesser General Public |
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7 License as published by the Free Software Foundation; either |
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8 version 2.1 of the License, or (at your option) any later version. |
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9 |
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10 This library is distributed in the hope that it will be useful, |
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 Lesser General Public License for more details. |
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14 |
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15 You should have received a copy of the GNU Lesser General Public |
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16 License along with this library; if not, write to the Free Software |
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17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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18 |
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19 Sam Lantinga |
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20 slouken@libsdl.org |
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21 */ |
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22 #include "SDL_config.h" |
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23 |
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24 #ifdef SDL_JOYSTICK_RISCOS |
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25 |
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26 /* |
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27 RISC OS - Joystick support by Alan Buckley (alan_baa@hotmail.com) - 10 April 2003 |
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28 |
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29 Note: Currently assumes joystick is present if joystick module is loaded |
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30 and that there is one joystick with four buttons. |
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31 */ |
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32 |
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33 /* This is the system specific header for the SDL joystick API */ |
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34 |
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35 #include "SDL_events.h" |
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36 #include "SDL_joystick.h" |
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37 #include "../SDL_sysjoystick.h" |
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38 #include "../SDL_joystick_c.h" |
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39 |
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40 #include "kernel.h" |
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41 |
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42 #define JOYSTICK_READ 0x43F40 |
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43 |
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44 struct joystick_hwdata |
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45 { |
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46 int joystate; |
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47 }; |
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48 |
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49 |
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50 /* Function to scan the system for joysticks. |
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51 * This function should set SDL_numjoysticks to the number of available |
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52 * joysticks. Joystick 0 should be the system default joystick. |
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53 * It should return number of joysticks, or -1 on an unrecoverable fatal error. |
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54 */ |
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55 int SDL_SYS_JoystickInit(void) |
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56 { |
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57 _kernel_swi_regs regs; |
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58 |
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59 /* Try to read joystick 0 */ |
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60 regs.r[0] = 0; |
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61 if (_kernel_swi(JOYSTICK_READ, ®s, ®s) == NULL) |
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62 { |
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63 /* Switch works so assume we've got a joystick */ |
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64 return 1; |
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65 } |
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66 /* Switch fails so it looks like there's no joystick here */ |
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67 |
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68 return(0); |
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69 } |
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70 |
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71 /* Function to get the device-dependent name of a joystick */ |
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72 const char *SDL_SYS_JoystickName(int index) |
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73 { |
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74 if (index == 0) |
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75 { |
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76 return "RISC OS Joystick 0"; |
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77 } |
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78 |
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79 SDL_SetError("No joystick available with that index"); |
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80 return(NULL); |
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81 } |
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82 |
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83 /* Function to open a joystick for use. |
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84 The joystick to open is specified by the index field of the joystick. |
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85 This should fill the nbuttons and naxes fields of the joystick structure. |
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86 It returns 0, or -1 if there is an error. |
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87 */ |
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88 int SDL_SYS_JoystickOpen(SDL_Joystick *joystick) |
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89 { |
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90 _kernel_swi_regs regs; |
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91 |
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92 if(!(joystick->hwdata=SDL_malloc(sizeof(struct joystick_hwdata)))) |
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93 return -1; |
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94 |
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95 regs.r[0] = joystick->index; |
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96 |
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97 /* Don't know how to get exact count of buttons so assume max of 4 for now */ |
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98 joystick->nbuttons=4; |
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99 |
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100 joystick->nhats=0; |
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101 joystick->nballs=0; |
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102 joystick->naxes=2; |
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103 joystick->hwdata->joystate=0; |
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104 |
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105 return 0; |
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106 |
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107 } |
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108 |
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109 /* Function to update the state of a joystick - called as a device poll. |
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110 * This function shouldn't update the joystick structure directly, |
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111 * but instead should call SDL_PrivateJoystick*() to deliver events |
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112 * and update joystick device state. |
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113 */ |
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114 void SDL_SYS_JoystickUpdate(SDL_Joystick *joystick) |
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115 { |
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116 _kernel_swi_regs regs; |
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117 regs.r[0] = joystick->index; |
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118 |
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119 if (_kernel_swi(JOYSTICK_READ, ®s, ®s) == NULL) |
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120 { |
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121 int newstate = regs.r[0]; |
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122 int oldstate = joystick->hwdata->joystate; |
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123 if (newstate != oldstate) |
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124 { |
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125 if ((newstate & 0xFF) != (oldstate & 0xFF)) |
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126 { |
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127 int y = regs.r[0] & 0xFF; |
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128 /* Convert to signed values */ |
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129 if (y >= 128) y -= 256; |
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130 SDL_PrivateJoystickAxis(joystick,1,-y * 256); /* Up and down opposite to result in SDL */ |
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131 } |
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132 if ((newstate & 0xFF00) != (oldstate & 0xFF00)) |
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133 { |
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134 int x = (regs.r[0] & 0xFF00) >> 8; |
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135 if (x >= 128) x -= 256; |
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136 SDL_PrivateJoystickAxis(joystick,0,x * 256); |
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137 } |
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138 |
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139 if ((newstate & 0xFF0000) != (oldstate & 0xFF0000)) |
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140 { |
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141 int buttons = (regs.r[0] & 0xFF0000) >> 16; |
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142 int oldbuttons = (oldstate & 0xFF0000) >> 16; |
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143 int i; |
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144 for (i = 0; i < joystick->nbuttons; i++) |
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145 { |
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146 if ((buttons & (1<<i)) != (oldbuttons & (1<<i))) |
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147 { |
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148 if (buttons & (1<<i)) SDL_PrivateJoystickButton(joystick,i,SDL_PRESSED); |
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149 else SDL_PrivateJoystickButton(joystick,i,SDL_RELEASED); |
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150 } |
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151 } |
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152 } |
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153 joystick->hwdata->joystate = newstate; |
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154 } |
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155 } |
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156 |
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157 return; |
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158 } |
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159 |
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160 /* Function to close a joystick after use */ |
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161 void SDL_SYS_JoystickClose(SDL_Joystick *joystick) |
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162 { |
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163 if(joystick->hwdata) |
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164 SDL_free(joystick->hwdata); |
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165 return; |
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166 } |
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167 |
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168 /* Function to perform any system-specific joystick related cleanup */ |
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169 void SDL_SYS_JoystickQuit(void) |
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170 { |
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171 SDL_numjoysticks=0; |
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172 |
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173 return; |
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174 } |
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175 |
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176 #endif /* SDL_JOYSTICK_RISCOS */ |