--- /dev/null
+//doomgeneric for a bare Linux VirtualTerminal
+// Copyright (C) 2025 Techflash
+// Based on doomgeneric_sdl.c
+
+#include "doomkeys.h"
+#include "m_argv.h"
+#include "doomgeneric.h"
+#include "i_system.h"
+
+// XXX: HACK
+// Linux's input-event-codes.h and doomkeys.h have many collisions.
+// Redefine some of doomkeys.h's names here to work around this.
+// I could try to redefine Linux's... but that sounds incredibly
+// fragile, and is very likely not a good idea.
+#undef KEY_TAB
+#undef KEY_ENTER
+#undef KEY_BACKSPACE
+#undef KEY_MINUS
+#undef KEY_F1
+#undef KEY_F2
+#undef KEY_F3
+#undef KEY_F4
+#undef KEY_F5
+#undef KEY_F6
+#undef KEY_F7
+#undef KEY_F8
+#undef KEY_F9
+#undef KEY_F10
+#undef KEY_F11
+#define DOOM_KEY_TAB 9
+#define DOOM_KEY_ENTER 13
+#define DOOM_KEY_MINUS 0x2d
+#define DOOM_KEY_BACKSPACE 0x7f
+#define DOOM_KEY_F1 (0x80+0x3b)
+#define DOOM_KEY_F2 (0x80+0x3c)
+#define DOOM_KEY_F3 (0x80+0x3d)
+#define DOOM_KEY_F4 (0x80+0x3e)
+#define DOOM_KEY_F5 (0x80+0x3f)
+#define DOOM_KEY_F6 (0x80+0x40)
+#define DOOM_KEY_F7 (0x80+0x41)
+#define DOOM_KEY_F8 (0x80+0x42)
+#define DOOM_KEY_F9 (0x80+0x43)
+#define DOOM_KEY_F10 (0x80+0x44)
+#define DOOM_KEY_F11 (0x80+0x57)
+#define DOOM_KEY_F12 (0x80+0x58)
+
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <dirent.h>
+#include <sys/mman.h>
+#include <sys/time.h>
+#include <sys/ioctl.h>
+#include <linux/input.h>
+#include <linux/input-event-codes.h>
+#include <linux/fb.h>
+
+#include <stdbool.h>
+
+#define KEYQUEUE_SIZE 16
+
+#define MAX_INPUT_DEVS 16
+#define INPUT_TYPE_KEYBOARD 0
+#define INPUT_TYPE_JOYSTICK 1
+#define INPUT_TYPE_MOUSE 2
+#define INPUT_TYPE_TOUCH 3
+
+// timing stuff
+static struct timeval startTime;
+
+// framebuffer stuff
+static uint8_t *fbPtr;
+static int fbFd;
+static unsigned int fbWidth, fbHeight, fbStride, fbBytesPerPixel, fbOffsetX, fbOffsetY;
+
+// input stuff
+static int numInputFds = 0;
+static int inputFds[MAX_INPUT_DEVS];
+static bool shiftPressed = false;
+static struct pollfd pollfds[MAX_INPUT_DEVS];
+
+static unsigned short s_KeyQueue[KEYQUEUE_SIZE];
+static unsigned int s_KeyQueueWriteIndex = 0;
+static unsigned int s_KeyQueueReadIndex = 0;
+
+// XXX: HACK
+// Linux's evdev system doesn't make it feasible to just use
+// tolower(key) like the existing conversions did, so we
+// use a few ranges of maps here to avoid an obscenely long switch/case
+static char evdevKeysToASCII1[10] = {
+ '1', '2', '3', '4', '5', '6', '7', '8', '9', '0'
+};
+static char evdevKeysToASCII2[12] = {
+ 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '[', ']'
+};
+static char evdevKeysToASCII3[12] = {
+ 'a', 's', 'd', 'f', 'g', 'h', 'i', 'j', 'k', 'l', ';', '\''
+};
+static char evdevKeysToASCII4[11] = {
+ '\\', 'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/'
+};
+
+
+static char evdevShiftKeysToASCII1[12] = {
+ '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '{', '}'
+};
+static char evdevShiftKeysToASCII2[12] = {
+ 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '{', '}'
+};
+static char evdevShiftKeysToASCII3[12] = {
+ 'a', 's', 'd', 'f', 'g', 'h', 'i', 'j', 'k', 'l', ':', '"'
+};
+static char evdevShiftKeysToASCII4[11] = {
+ '|', 'z', 'x', 'c', 'v', 'b', 'n', 'm', '<', '>', '?'
+};
+
+
+static unsigned char convertToDoomKey(unsigned int key){
+ switch (key) {
+ case KEY_ENTER:
+ key = DOOM_KEY_ENTER;
+ break;
+ case KEY_ESC:
+ key = KEY_ESCAPE;
+ break;
+ case KEY_LEFT:
+ key = KEY_LEFTARROW;
+ break;
+ case KEY_RIGHT:
+ key = KEY_RIGHTARROW;
+ break;
+ case KEY_UP:
+ key = KEY_UPARROW;
+ break;
+ case KEY_DOWN:
+ key = KEY_DOWNARROW;
+ break;
+ case KEY_LEFTCTRL:
+ case KEY_RIGHTCTRL:
+ key = KEY_FIRE;
+ break;
+ case KEY_SPACE:
+ key = KEY_USE;
+ break;
+ case KEY_LEFTSHIFT:
+ case KEY_RIGHTSHIFT:
+ key = KEY_RSHIFT;
+ break;
+ case KEY_LEFTALT:
+ case KEY_RIGHTALT:
+ key = KEY_LALT;
+ break;
+ case KEY_F2:
+ key = DOOM_KEY_F2;
+ break;
+ case KEY_F3:
+ key = DOOM_KEY_F3;
+ break;
+ case KEY_F4:
+ key = DOOM_KEY_F4;
+ break;
+ case KEY_F5:
+ key = DOOM_KEY_F5;
+ break;
+ case KEY_F6:
+ key = DOOM_KEY_F6;
+ break;
+ case KEY_F7:
+ key = DOOM_KEY_F7;
+ break;
+ case KEY_F8:
+ key = DOOM_KEY_F8;
+ break;
+ case KEY_F9:
+ key = DOOM_KEY_F9;
+ break;
+ case KEY_F10:
+ key = DOOM_KEY_F10;
+ break;
+ case KEY_F11:
+ key = DOOM_KEY_F11;
+ break;
+ case KEY_EQUAL:
+ key = KEY_EQUALS;
+ break;
+ case KEY_MINUS:
+ key = DOOM_KEY_MINUS;
+ break;
+ case KEY_BACKSPACE:
+ key = DOOM_KEY_BACKSPACE;
+ break;
+ case KEY_TAB:
+ key = DOOM_KEY_TAB;
+ break;
+
+ // sadly, yes, we need to handle every single alphanumeric
+ // key here, since evdev doesn't spit out keys in anything
+ // remotely resembling ASCII.....
+ // though, we can take many shortcuts
+ case KEY_1:
+ case KEY_2:
+ case KEY_3:
+ case KEY_4:
+ case KEY_5:
+ case KEY_6:
+ case KEY_7:
+ case KEY_8:
+ case KEY_9:
+ case KEY_0:
+ if (shiftPressed)
+ key = evdevShiftKeysToASCII1[key - KEY_1];
+ else
+ key = evdevKeysToASCII1[key - KEY_1];
+ break;
+ case KEY_Q:
+ case KEY_W:
+ case KEY_E:
+ case KEY_R:
+ case KEY_T:
+ case KEY_Y:
+ case KEY_U:
+ case KEY_I:
+ case KEY_O:
+ case KEY_P:
+ case KEY_LEFTBRACE:
+ case KEY_RIGHTBRACE:
+ if (shiftPressed)
+ key = evdevShiftKeysToASCII2[key - KEY_Q];
+ else
+ key = evdevKeysToASCII2[key - KEY_Q];
+ break;
+ case KEY_A:
+ case KEY_S:
+ case KEY_D:
+ case KEY_F:
+ case KEY_G:
+ case KEY_H:
+ case KEY_J:
+ case KEY_K:
+ case KEY_L:
+ case KEY_SEMICOLON:
+ case KEY_APOSTROPHE:
+ if (shiftPressed)
+ key = evdevShiftKeysToASCII3[key - KEY_A];
+ else
+ key = evdevKeysToASCII3[key - KEY_A];
+ break;
+ case KEY_BACKSLASH:
+ case KEY_Z:
+ case KEY_X:
+ case KEY_C:
+ case KEY_V:
+ case KEY_B:
+ case KEY_N:
+ case KEY_M:
+ case KEY_COMMA:
+ case KEY_DOT:
+ case KEY_SLASH:
+ if (shiftPressed)
+ key = evdevShiftKeysToASCII4[key - KEY_BACKSLASH];
+ else
+ key = evdevKeysToASCII4[key - KEY_BACKSLASH];
+ break;
+ default:
+ key = 0xFF;
+ break;
+ }
+
+ return key;
+}
+
+static void addKeyToQueue(int pressed, unsigned char keyCode) {
+ if ((keyCode == KEY_LEFTSHIFT || keyCode == KEY_RIGHTSHIFT) &&
+ (pressed == 1 || pressed == 0))
+ shiftPressed = pressed;
+
+
+ unsigned char key = convertToDoomKey(keyCode);
+ if (key == 0xFF) // unknown, don't process it
+ return;
+
+ if (pressed > 1 || pressed < 0) // bogus value
+ return;
+
+ unsigned short keyData = (pressed << 8) | key;
+
+ s_KeyQueue[s_KeyQueueWriteIndex] = keyData;
+ s_KeyQueueWriteIndex++;
+ s_KeyQueueWriteIndex %= KEYQUEUE_SIZE;
+}
+
+
+
+static void checkKeys() {
+ int ret, i;
+ bool keepGoing;
+ struct input_event ev;
+
+ keepGoing = true;
+ while (keepGoing) {
+ keepGoing = false; // exit if we haven't gotten anything
+ ret = poll(pollfds, numInputFds, 0); // don't wait at all, just give anything we've got
+
+ if (ret < 0) {
+ // borked
+ return;
+ }
+
+ for (i = 0; i < MAX_INPUT_DEVS; i++) {
+ if (pollfds[i].revents & POLLIN) {
+ read(inputFds[i], &ev, sizeof(ev));
+ keepGoing = true; // we read something, so keep trying
+ addKeyToQueue(ev.value, ev.code);
+ }
+ }
+ }
+
+ // we read the entire backlog, get back to doom
+ return;
+}
+
+
+#define TEST_KEY(k) (keybits[(k)/8] & (1 << ((k)%8)))
+static int isKeyboard(const char *devPath) {
+ unsigned long evbits;
+ unsigned char keybits[KEY_MAX/8 + 1];
+ int fd = open(devPath, O_RDONLY);
+ if (fd < 0) {
+ perror("Failed to open device");
+ return 0;
+ }
+
+ evbits = 0;
+ if (ioctl(fd, EVIOCGBIT(0, sizeof(evbits)), &evbits) < 0) {
+ close(fd);
+ return 0;
+ }
+
+ /* Must support EV_KEY */
+ if (!(evbits & (1 << EV_KEY))) {
+ close(fd);
+ return 0;
+ }
+
+
+ memset(keybits, 0, sizeof(keybits));
+ if (ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybits)), keybits) < 0) {
+ close(fd);
+ return 0;
+ }
+
+ if (TEST_KEY(KEY_A) && TEST_KEY(KEY_ENTER)) {
+ close(fd);
+ return 1; /* looks like a keyboard */
+ }
+
+ close(fd);
+ return 0;
+}
+
+static void checkInputDevs() {
+ struct dirent *dp;
+ DIR *dir;
+
+ /* check for devices */
+ dir = opendir("/dev/input");
+
+ while ((dp = readdir(dir)) != NULL) {
+ char fullpath[268]; /* d_name is 256 bytes */
+ int fd;
+
+ if (numInputFds >= MAX_INPUT_DEVS)
+ I_Error("Out of room in input devices array");
+
+ printf("checking %s\n", dp->d_name);
+ if (strncmp(dp->d_name, "event", 5) != 0)
+ continue;
+
+ sprintf(fullpath, "/dev/input/%s", dp->d_name);
+
+ printf("%s is a valid event device\n", fullpath);
+ if (!isKeyboard(fullpath)) {
+ printf("%s is not a keyboard, moving on\n", fullpath);
+ continue;
+ }
+
+ fd = open(fullpath, O_RDONLY | O_NONBLOCK);
+ if (fd < 0) {
+ // not necessarily fatal
+ perror("Failed to open device");
+ continue;
+ }
+
+ pollfds[numInputFds].fd = fd;
+ pollfds[numInputFds].events = POLLIN;
+ inputFds[numInputFds++] = fd;
+ printf("adding %s keyboard\n", fullpath);
+ ioctl(fd, EVIOCGRAB, 1); // grab exclusive access to the device
+ }
+ closedir(dir);
+}
+
+void DG_Init() {
+ int ret;
+ struct fb_var_screeninfo info;
+
+ //
+ // set up the framebuffer
+ //
+ fbFd = open("/dev/fb0", O_RDWR);
+ if (fbFd < 0)
+ I_Error("Failed to open /dev/fb0: %s", strerror(errno));
+
+ // get info
+ ret = ioctl(fbFd, FBIOGET_VSCREENINFO, &info);
+ if (ret != 0)
+ I_Error("Failed to get framebuffer info: %s", strerror(errno));
+
+ fbWidth = info.xres;
+ fbHeight = info.yres;
+ fbBytesPerPixel = info.bits_per_pixel / 8;
+ fbStride = fbWidth * fbBytesPerPixel;
+
+ // to center the image on screen
+ fbOffsetX = (fbWidth - DOOMGENERIC_RESX) / 2;
+ fbOffsetY = (fbHeight - DOOMGENERIC_RESY) / 2;
+
+ fbPtr = mmap(NULL, fbStride * fbHeight, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fbFd, 0);
+
+ if (!fbPtr)
+ I_Error("Failed to mmap /dev/fb0: %s", strerror(errno));
+
+ // clear the screen
+ memset(fbPtr, 0, fbStride * fbHeight);
+
+ //
+ // set up input
+ //
+ checkInputDevs();
+
+ if (numInputFds == 0)
+ I_Error("Failed to find any compatible input device, see the logs above for potential problems");
+
+ // get the start time
+ gettimeofday(&startTime, NULL);
+}
+
+void DG_DrawFrame() {
+ // we need to do it line-by-line like this to account for the
+ // fact that the system framebuffer resolution is very likely
+ // larger than the doomgeneric render resolution.
+ for (int line = 0; line < DOOMGENERIC_RESY; line++) {
+ memcpy(
+ (fbPtr + (fbStride * (line + fbOffsetY)) + (fbOffsetX * fbBytesPerPixel)),
+ fbBytesPerPixel == 4 ?
+ DG_ScreenBuffer + (DOOMGENERIC_RESX * line) :
+ DG_ScreenBuffer + (DOOMGENERIC_RESX * (line / 2)),
+ (fbBytesPerPixel * DOOMGENERIC_RESX)
+ );
+ }
+
+ checkKeys();
+}
+
+void DG_SleepMs(uint32_t ms) {
+ usleep(ms * 1000);
+}
+
+uint32_t DG_GetTicksMs() {
+ struct timeval curTime;
+ long seconds, usec;
+
+ gettimeofday(&curTime, NULL);
+ seconds = curTime.tv_sec - startTime.tv_sec;
+ usec = curTime.tv_usec - startTime.tv_usec;
+
+ return (seconds * 1000) + (usec / 1000);
+}
+
+int DG_GetKey(int* pressed, unsigned char* doomKey) {
+ checkKeys();
+
+ if (s_KeyQueueReadIndex == s_KeyQueueWriteIndex) {
+ //key queue is empty
+
+ return 0;
+ }
+ else {
+ unsigned short keyData = s_KeyQueue[s_KeyQueueReadIndex];
+ s_KeyQueueReadIndex++;
+ s_KeyQueueReadIndex %= KEYQUEUE_SIZE;
+
+ *pressed = keyData >> 8;
+ *doomKey = keyData & 0xFF;
+
+ return 1;
+ }
+
+}
+
+void DG_SetWindowTitle(const char * title) {
+ printf("Window Title: %s\n", title);
+}
+
+int main(int argc, char **argv) {
+ doomgeneric_Create(argc, argv);
+
+ while (1)
+ {
+ doomgeneric_Tick();
+ }
+
+
+ return 0;
+}
projects / doomgeneric-snom360 / commitdiff
