Feature: Joystick support for up to 4 Devices.

examples/joysticks.lua

@@ -0,0 +1,67 @@
+--
+-- simple demo of joystick input
+-- by torpor (seclorum@me.com)
+--
+-- the joystick[] table is global, and contains .x/.y/.name fields
+-- describing the joystick.  the JOYSTICK global contains the
+-- number of physical joysticks detected by LOAD81 at startup.
+--
+-- the maximum number of joysticks available is 4.
+--
+
+-- each joystick will have its own color, and since there 
+-- a maximum of 4 joysticks available then we have 4
+-- unique colors to use
+colors = {}
+colors = {
+{r=255,g=0,b=255,a=1},
+{r=0,g=0,b=255,a=1}, 
+{r=255,g=0,b=0,a=1}, 
+{r=0,g=255,b=0,a=1} 
+}
+
+function setup()
+    background(0,0,0,0)
+    -- divide the screen in 4, one quad for each joystick device
+    joy_quad = HEIGHT / 4;
+end
+
+-- simple map function
+function map(x, in_min, in_max, out_min, out_max)
+  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
+end
+
+function draw_joystick_info(joynum)
+    -- each joystick gets its own color
+    fill(colors[joynum].r,colors[joynum].g,colors[joynum].b,colors[joynum].a);
+
+    -- text explaining joystick name and x/y values goes in a 'quarter' of the screen
+    text(10, joynum * joy_quad, string.format("# %d %s x:%d/y:%d",
+        joynum, joystick[joynum].name,
+        joystick[joynum].x, joystick[joynum].y));
+
+    -- each joystick returns x/y axes values from -32767 to 32767, so we map to 
+    -- the screen size
+    dot_x, dot_y = 0;
+    dot_x = map(joystick[joynum].x, 32767, -32767, WIDTH, 0);
+    dot_y = map(joystick[joynum].y, 32767, -32767, 0, HEIGHT);
+
+    -- draw the joystick dot
+    ellipse(dot_x, dot_y, 10, 10);
+end
+
+
+function draw()
+    -- clear the screen
+    background(0,0,0,0);
+
+    if JOYSTICKS == 0 then
+        fill (255,0,0,1);
+        text(10, joy_quad, string.format("No joysticks detected .. plug one in and try again!"));
+    end
+
+    -- draw the info for each joystick
+    for jn = 1, JOYSTICKS, 1 do
+        draw_joystick_info(jn);
+    end 
+end

framebuffer.c

@@ -8,7 +8,7 @@ SDL_Surface *sdlInit(int width, int height, int bpp, int fullscreen) {
     SDL_Surface *screen;
 
     if (fullscreen) flags |= SDL_FULLSCREEN;
-    if (SDL_Init(SDL_INIT_VIDEO) == -1) {
+    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_JOYSTICK) == -1) {
         fprintf(stderr, "SDL Init error: %s\n", SDL_GetError());
         return NULL;
     }
@@ -22,6 +22,7 @@ SDL_Surface *sdlInit(int width, int height, int bpp, int fullscreen) {
      * keys are translated into characters with automatic support for modifiers
      * (for instance shift modifier to print capital letters and symbols). */
     SDL_EnableUNICODE(SDL_ENABLE);
+
     return screen;
 }
 
@@ -34,6 +35,7 @@ frameBuffer *createFrameBuffer(int width, int height, int bpp, int fullscreen) {
     SDL_initFramerate(&fb->fps_mgr);
     /* Load the bitmap font */
     bfLoadFont((char**)BitmapFont);
+
     return fb;
 }
 

framebuffer.h

@@ -9,11 +9,14 @@
 #define FONT_HEIGHT 16
 #define FONT_KERNING 10
 
+#define MAX_JOYSTICKS 4
+
 typedef struct frameBuffer {
     int width;
     int height;
-    SDL_Surface *screen;
     FPSmanager fps_mgr;
+    SDL_Surface *screen;
+    SDL_Joystick *joysticks[MAX_JOYSTICKS];
 } frameBuffer;
 
 frameBuffer *createFrameBuffer(int width, int height, int bpp, int fullscreen);

load81.c

@@ -276,6 +276,68 @@ void draw(void) {
     }
 }
 
+/*  update the joystick[] table, by given field
+    e.g. joystick[1].x = 100
+    stack:
+        joystick                global
+            [1]                 joynum
+                .x              field
+                    = 100       value
+*/
+void updateJoystickState(int joynum, char *field, int value)
+{
+    lua_getglobal(l81.L, "joystick");
+
+    if (lua_isnil(l81.L,-1)) {
+        lua_pop(l81.L,1);
+        lua_newtable(l81.L);
+        lua_setglobal(l81.L,"joystick");
+        lua_getglobal(l81.L,"joystick");
+    }
+
+    if (lua_istable(l81.L, -1)) {
+        lua_pushnumber(l81.L, joynum);
+        lua_gettable(l81.L, -2);
+        lua_pushstring(l81.L, field);
+        lua_pushnumber(l81.L, value);
+        lua_settable(l81.L, -3);
+    }
+
+    lua_pop(l81.L, 2);
+}
+
+/* 
+    update the joystick[] table, .name field
+    e.g. joystick[1].name = "nub0"
+    stack:
+        joystick                global
+            [1]                 joynum
+                .name           field
+                    = "nub0"    value
+*/
+void updateJoystickName(int joynum, const char *name)
+{
+    lua_getglobal(l81.L, "joystick");
+
+    if (lua_isnil(l81.L,-1)) {
+        lua_pop(l81.L,1);
+        lua_newtable(l81.L);
+        lua_setglobal(l81.L,"joystick");
+        lua_getglobal(l81.L,"joystick");
+    }
+
+    if (lua_istable(l81.L, -1)) {
+        lua_pushnumber(l81.L, joynum);
+        lua_gettable(l81.L, -2);
+        lua_pushstring(l81.L, "name");
+        lua_pushstring(l81.L, name);
+        lua_settable(l81.L, -3);
+    }
+
+    lua_pop(l81.L, 2);
+}
+
+
 /* Update the keyboard.pressed and mouse.pressed Lua table. */
 void updatePressedState(char *object, char *keyname, int pressed) {
     lua_getglobal(l81.L,object);         /* $keyboard */
@@ -306,6 +368,18 @@ void mouseMovedEvent(int x, int y, int xrel, int yrel) {
     setTableFieldNumber("mouse","yrel",-yrel);
 }
 
+void joystickXMovedEvent(int joy_num, Sint16 x) { 
+    if (joy_num < MAX_JOYSTICKS) {
+        updateJoystickState(joy_num, "x", x);
+    }
+}
+
+void joystickYMovedEvent(int joy_num, Sint16 y) { 
+    if (joy_num < MAX_JOYSTICKS) {
+        updateJoystickState(joy_num, "y", y);
+    }
+}
+
 void mouseButtonEvent(int button, int pressed) {
     char buttonname[32];
 
@@ -357,6 +431,16 @@ int processSdlEvents(void) {
         case SDL_MOUSEBUTTONUP:
             mouseButtonEvent(event.button.button,0);
             break;
+        case SDL_JOYAXISMOTION:  /* Handle Joystick Motion */
+            //printf("joystick %d moved on %d axis\n", event.jaxis.which, event.jaxis.axis);
+            if( event.jaxis.axis == 0) { /* x-axis */
+                joystickXMovedEvent(event.jaxis.which + 1, event.jaxis.value);  /* C vs. Lua offsets */
+            }
+            if( event.jaxis.axis == 1) { /* y-axis */
+                joystickYMovedEvent(event.jaxis.which + 1, event.jaxis.value);  /* C vs. Lua offsets */
+            }
+        break;
+
         case SDL_QUIT:
             exit(0);
             break;
@@ -422,16 +506,59 @@ int loadProgram(void) {
     editorClearError();
     return 0;
 }
+
+void initJoysticks(frameBuffer *fb) { 
+    int cur_joy;
+    /* Initialize Joysticks */
+    SDL_JoystickEventState(SDL_ENABLE);
+
+    for(cur_joy=0; cur_joy < SDL_NumJoysticks(); cur_joy++ ) {
+        fb->joysticks[cur_joy] = SDL_JoystickOpen(cur_joy);
+
+        updateJoystickName(cur_joy + 1, SDL_JoystickName(cur_joy));
+#if 0
+        {
+            printf("joy %d init: %p\n", cur_joy, fb->joysticks[cur_joy]);
+            printf("Joystick name: %s\n ", SDL_JoystickName(cur_joy));
+            printf("Axis: %d\nt", SDL_JoystickNumAxes(fb->joysticks[cur_joy]));
+            printf("Trackballs:%d\n", SDL_JoystickNumBalls(fb->joysticks[cur_joy]));
+            printf("Hats: %d\n", SDL_JoystickNumHats(fb->joysticks[cur_joy]));
+            printf("Buttons: %d\n", SDL_JoystickNumButtons(fb->joysticks[cur_joy]));
+        }
+#endif
+
+   }
+}
 
+/*
+ Close joysticks.
+*/
+void closeJoysticks(frameBuffer *fb) {
+    int cur_joy;
+    for(cur_joy=0; cur_joy < SDL_NumJoysticks(); cur_joy++) {
+        if (fb->joysticks[cur_joy]) {
+            SDL_JoystickClose( fb->joysticks[cur_joy]);
+            updateJoystickName(cur_joy + 1, "none");
+        }
+    }
+    setNumber("JOYSTICKS", 0);
+}
+
 void initScreen(void) {
     l81.fb = createFrameBuffer(l81.width,l81.height,
                                l81.bpp,l81.opt_full_screen);
 }
 
 void resetProgram(void) {
     char *initscript =
-        "keyboard={}; keyboard['pressed']={};"
-        "mouse={}; mouse['pressed']={};";
+        "keyboard={}; keyboard['pressed']={};" \
+        "mouse={}; mouse['pressed']={};" \
+        "joystick={};" \
+        "joystick[1]={x=0;y=0;name='none'};" \
+        "joystick[2]={x=0;y=0;name='none'};" \
+        "joystick[3]={x=0;y=0;name='none'};" \
+        "joystick[4]={x=0;y=0;name='none'};";
+        /* !J! should set joystick[] from MAX_JOYSTICKS */
 
     l81.epoch = 0;
     if (l81.L) lua_close(l81.L);
@@ -443,6 +570,7 @@ void resetProgram(void) {
     luaopen_debug(l81.L);
     setNumber("WIDTH",l81.width);
     setNumber("HEIGHT",l81.height);
+    setNumber("JOYSTICKS", SDL_NumJoysticks());
     luaL_loadbuffer(l81.L,initscript,strlen(initscript),"initscript");
     lua_pcall(l81.L,0,0,0);
 
@@ -453,6 +581,8 @@ void resetProgram(void) {
     setTableFieldNumber("mouse","xrel",0);
     setTableFieldNumber("mouse","yrel",0);
 
+    initJoysticks(l81.fb);
+
     /* Register API */
     lua_pushcfunction(l81.L,fillBinding);
     lua_setglobal(l81.L,"fill");
@@ -552,5 +682,6 @@ int main(int argc, char **argv) {
         }
         editorRun();
     }
+    closeJoysticks(l81.fb);
     return 0;
 }