Merge pull request #632 from coderocket/linux-joystick

joystick/gamepad support for Linux

platforms/unix/plugins/JoystickTabletPlugin/sqUnixJoystickTablet.c

@@ -26,19 +26,313 @@
  */
 
 /* Author: [email protected]
+/* Author: [email protected]
  */
 
-#include "sq.h"
+#include <assert.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <errno.h>
+#include <poll.h>
+#include <linux/input-event-codes.h>
+#include <linux/input.h>
 #include "JoystickTabletPlugin.h"
 
-/* we don't have any joysticks */
+#define DEVICE_DIR 	"/dev/input/by-id/"
+#define JOYSTICK_TOKEN 	"-event-joystick"
+#define MAX_JOYSTICK 	2
+#define BITS_IN_WORD 	32
 
-void *joySticks= 0;
+#define EVENT_BUF_SIZE	10
 
-int joystickRead(int index)	{ return 0; }
-int joystickInit(void)		{ return 0; }
+typedef struct _input_event {
+	    struct timeval time;
+	    unsigned short type;
+	    unsigned short code;
+	    unsigned int value;
+} input_event;
 
-/* we don't have any tablets either */
+typedef struct {
+	int fd;
+	int button_index[4]; // key code for each button
+	int button_state[4];
+	struct input_absinfo abs_x;
+	struct input_absinfo abs_y;	
+} joystick_state_t ;
+
+joystick_state_t joystick_state[MAX_JOYSTICK]; 
+int joystick_count;
+
+int 
+testBit(int i, uint32_t* x) {
+	return x[i / BITS_IN_WORD] & (1 << (i % BITS_IN_WORD));
+}
+
+int 
+enumerateJoysticks() 
+{
+
+	char dev_path[PATH_MAX];
+	struct dirent* current_entry;
+	DIR* device_dir;
+	int result;
+
+	result = 1;
+	errno = 0;
+	device_dir = opendir(DEVICE_DIR);
+
+	if (device_dir == NULL) {
+		perror("opendir");
+		return 0;
+	}
+
+	current_entry = readdir(device_dir);	
+
+	if (current_entry == NULL) {
+		perror("readdir");
+		result = 0;
+	}
+
+	while (current_entry != NULL) {
+
+		if (current_entry->d_type == DT_LNK &&
+			strstr(current_entry->d_name, JOYSTICK_TOKEN) != NULL &&
+			strlen(current_entry->d_name) + strlen(DEVICE_DIR) < PATH_MAX + 1 &&
+			joystick_count < MAX_JOYSTICK) {
+
+			dev_path[0] = '\0';
+			strcat(dev_path, DEVICE_DIR);
+			strcat(dev_path, current_entry->d_name);
+
+			joystick_state[joystick_count].fd = open(dev_path, O_RDONLY);
+
+			if (joystick_state[joystick_count].fd != -1) {
+				++joystick_count;
+			}
+
+		}
+		current_entry = readdir(device_dir);
+	}
+
+	closedir(device_dir);
+
+	return result; 
+}
+
+int 
+detectButtons(joystick_state_t* pj) 
+{
+
+	int fd;
+
+	uint32_t supported_keys[KEY_CNT / BITS_IN_WORD + 1] = { 0 };
+
+	fd = pj->fd;
+
+	if (ioctl(fd, EVIOCGBIT(EV_KEY, KEY_MAX), &supported_keys) == -1) {
+		perror("ioctl");
+		return -1;
+	}
+
+	if (testBit(BTN_JOYSTICK, supported_keys) == 0 && testBit(BTN_GAMEPAD, supported_keys) == 0) { 
+
+		// we did not find any buttons, something is wrong with this device.
+		return -1;
+	}
+
+	if (testBit(BTN_JOYSTICK, supported_keys) == 1) {
+
+		// it's an old style joystick device
+
+		pj->button_index[0] = BTN_JOYSTICK;
+		pj->button_index[1] = BTN_THUMB;
+		pj->button_index[2] = BTN_THUMB2;
+		pj->button_index[3] = BTN_TOP;
+
+	}
+	else {
+		// it's a modern gamepad device
+
+		pj->button_index[0] = BTN_NORTH;
+		pj->button_index[1] = BTN_EAST;
+		pj->button_index[2] = BTN_SOUTH;
+		pj->button_index[3] = BTN_WEST;
+	}
+
+	return 1;
+}
+
+int 
+detectAxes(joystick_state_t* pj) 
+{
+
+	int fd;
+
+	uint32_t supported_axes[ABS_CNT / BITS_IN_WORD + 1] = { 0 };
+
+	fd = pj->fd;
+
+	if (ioctl(fd, EVIOCGBIT(EV_ABS, ABS_MAX), &supported_axes) == -1) {
+		perror("ioctl");
+	    return -1;
+	}
+
+	if (testBit(ABS_X, supported_axes) == 0 || testBit(ABS_Y, supported_axes) == 0) {
+		// something is wrong, we could not find both required axes
+		return -1;
+	}
+
+	return 1;
+}
+
+int 
+readJoystickState(joystick_state_t* pj) 
+{
+
+	if (ioctl(pj->fd, EVIOCGABS(ABS_X), &pj->abs_x) == -1)
+		return -1;
+
+	if (ioctl(pj->fd, EVIOCGABS(ABS_Y), &pj->abs_y) == -1)
+		return -1;
+
+	return 1;
+}
+
+int 
+initializeJoystickState(joystick_state_t* pj) 
+{
+	if (detectButtons(pj) == -1) {
+		return 0;
+	}
+
+	if (detectAxes(pj) == -1) {
+		return 0;
+	}
+
+	if (readJoystickState(pj) == -1) {
+		return 0;
+	}
+
+	return 1;
+}
+
+int 
+joystickInit(void) 
+{
+
+	if (enumerateJoysticks() == 0) {
+		return 0;
+	}
+
+	for(int i = 0; i < joystick_count; ++i) {
+		if(initializeJoystickState(&joystick_state[i]) == 0) 
+			return 0;
+	}
+
+	return 1;
+}
+
+double 
+map(double x, double from_begin,double from_end, double to_begin, double 
+to_end) 
+{
+	return to_begin + (to_end-to_begin)*(x-from_begin)/(from_end-from_begin);
+}
+
+int 
+readNewEvents(joystick_state_t* pj) 
+{
+	input_event event[EVENT_BUF_SIZE];
+	int count;
+	int i, j;
+
+	count = read(pj->fd, &event, sizeof(input_event)*EVENT_BUF_SIZE);
+
+	for(i = 0 ; i < count / sizeof(input_event) ; ++i) {
+
+		if (event[i].type == EV_KEY) {
+			for(j = 0 ; j < 4 ; ++j) {
+				if (pj->button_index[j] == event[i].code) {
+					pj->button_state[j] = event[i].value;
+				}
+			}
+		}
+
+		if (event[i].type == EV_ABS) {
+			if (event[i].code == ABS_X) {
+				pj->abs_x.value = event[i].value; 
+			}
+
+			if (event[i].code == ABS_Y) {
+				pj->abs_y.value = event[i].value; 
+			}
+		}
+	}
+	return 1;
+}
+
+int 
+joystickRead(int index) 
+{ 
+	uint32_t result;
+	joystick_state_t* pj; 
+	struct pollfd poll_fds;
+	int ret;
+	int x, y;
+
+	result = 0;
+	--index;
+
+	if (index < 0 || index >= joystick_count)
+		return 0;
+
+	pj = &joystick_state[index];
+
+	poll_fds.fd = pj->fd;
+	poll_fds.events = POLLIN;
+
+	ret = poll(&poll_fds, 1, 0);
+
+	if (ret == -1)
+		return 0;
+
+	if (ret > 0) {
+
+		ret = readNewEvents(pj);
+
+		if (ret == -1)
+			return 0;
+	}
+
+	x = (int)map(pj->abs_x.value, pj->abs_x.minimum, pj->abs_x.maximum, 0, 0x7FF);
+	y = (int)map(pj->abs_y.value, pj->abs_y.minimum, pj->abs_y.maximum, 0, 0x7FF); 
+
+	return (1 << 27) | (pj->button_state[0] << 22) | (pj->button_state[1] << 23) | (pj->button_state[2] << 24) | (pj->button_state[3] << 25) | (y << 11) | x;
+
+}
+
+int 
+joystickShutdown(void) 
+{
+	int i;
+
+	for(i = 0; i < joystick_count; ++i) {
+		close(joystick_state[i].fd);
+	}
+
+	joystick_count = 0;
+}
+
+
+/* we don't have any tablets */
 
 int tabletInit(void)
 {
@@ -60,7 +354,3 @@ int tabletResultSize(void)
   return 0;
 }
 
-int joystickShutdown(void)
-{
-  return 0;
-}