ref: b695b71233b831c49fa3155c36ace08bcffcf5c6
dir: /textscreen/txt_sdl.c/
//
// Copyright(C) 2005-2014 Simon Howard
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
//
// Text mode emulation in SDL
//
#include "SDL.h"
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "doomkeys.h"
#include "txt_main.h"
#include "txt_sdl.h"
#include "txt_utf8.h"
#if defined(_MSC_VER) && !defined(__cplusplus)
#define inline __inline
#endif
typedef struct
{
const char *name;
const uint8_t *data;
unsigned int w;
unsigned int h;
} txt_font_t;
// Fonts:
#include "fonts/small.h"
#include "fonts/normal.h"
#include "fonts/large.h"
#include "fonts/codepage.h"
// Time between character blinks in ms
#define BLINK_PERIOD 250
SDL_Window *TXT_SDLWindow;
static SDL_Surface *screenbuffer;
static unsigned char *screendata;
static SDL_Renderer *renderer;
// Current input mode.
static txt_input_mode_t input_mode = TXT_INPUT_NORMAL;
// Dimensions of the screen image in screen coordinates (not pixels); this
// is the value that was passed to SDL_CreateWindow().
static int screen_image_w, screen_image_h;
static TxtSDLEventCallbackFunc event_callback;
static void *event_callback_data;
// Font we are using:
static const txt_font_t *font;
// Dummy "font" that means to try highdpi rendering, or fallback to
// normal_font otherwise.
static const txt_font_t highdpi_font = { "normal-highdpi", NULL, 8, 16 };
// Mapping from SDL keyboard scancode to internal key code.
static const int scancode_translate_table[] = SCANCODE_TO_KEYS_ARRAY;
// String names of keys. This is a fallback; we usually use the SDL API.
static const struct {
int key;
const char *name;
} key_names[] = KEY_NAMES_ARRAY;
// Unicode key mapping; see codepage.h.
static const short code_page_to_unicode[] = CODE_PAGE_TO_UNICODE;
static SDL_Color ega_colors[] =
{
{0x00, 0x00, 0x00, 0xff}, // 0: Black
{0x00, 0x00, 0xa8, 0xff}, // 1: Blue
{0x00, 0xa8, 0x00, 0xff}, // 2: Green
{0x00, 0xa8, 0xa8, 0xff}, // 3: Cyan
{0xa8, 0x00, 0x00, 0xff}, // 4: Red
{0xa8, 0x00, 0xa8, 0xff}, // 5: Magenta
{0xa8, 0x54, 0x00, 0xff}, // 6: Brown
{0xa8, 0xa8, 0xa8, 0xff}, // 7: Grey
{0x54, 0x54, 0x54, 0xff}, // 8: Dark grey
{0x54, 0x54, 0xfe, 0xff}, // 9: Bright blue
{0x54, 0xfe, 0x54, 0xff}, // 10: Bright green
{0x54, 0xfe, 0xfe, 0xff}, // 11: Bright cyan
{0xfe, 0x54, 0x54, 0xff}, // 12: Bright red
{0xfe, 0x54, 0xfe, 0xff}, // 13: Bright magenta
{0xfe, 0xfe, 0x54, 0xff}, // 14: Yellow
{0xfe, 0xfe, 0xfe, 0xff}, // 15: Bright white
};
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
// Examine system DPI settings to determine whether to use the large font.
static int Win32_UseLargeFont(void)
{
HDC hdc = GetDC(NULL);
int dpix;
if (!hdc)
{
return 0;
}
dpix = GetDeviceCaps(hdc, LOGPIXELSX);
ReleaseDC(NULL, hdc);
// 144 is the DPI when using "150%" scaling. If the user has this set
// then consider this an appropriate threshold for using the large font.
return dpix >= 144;
}
#endif
static const txt_font_t *FontForName(const char *name)
{
int i;
const txt_font_t *fonts[] =
{
&small_font,
&normal_font,
&large_font,
&highdpi_font,
NULL,
};
for (i = 0; fonts[i]->name != NULL; ++i)
{
if (!strcmp(fonts[i]->name, name))
{
return fonts[i];
}
}
return NULL;
}
//
// Select the font to use, based on screen resolution
//
// If the highest screen resolution available is less than
// 640x480, use the small font.
//
static void ChooseFont(void)
{
SDL_DisplayMode desktop_info;
char *env;
// Allow normal selection to be overridden from an environment variable:
env = getenv("TEXTSCREEN_FONT");
if (env != NULL)
{
font = FontForName(env);
if (font != NULL)
{
return;
}
}
// Get desktop resolution.
// If in doubt and we can't get a list, always prefer to
// fall back to the normal font:
if (SDL_GetCurrentDisplayMode(0, &desktop_info))
{
font = &highdpi_font;
return;
}
// On tiny low-res screens (eg. palmtops) use the small font.
// If the screen resolution is at least 1920x1080, this is
// a modern high-resolution display, and we can use the
// large font.
if (desktop_info.w < 640 || desktop_info.h < 480)
{
font = &small_font;
}
#ifdef _WIN32
// On Windows we can use the system DPI settings to make a
// more educated guess about whether to use the large font.
else if (Win32_UseLargeFont())
{
font = &large_font;
}
#endif
// TODO: Detect high DPI on Linux by inquiring about Gtk+ scale
// settings. This looks like it should just be a case of shelling
// out to invoke the 'gsettings' command, eg.
// gsettings get org.gnome.desktop.interface text-scaling-factor
// and using large_font if the result is >= 2.
else
{
// highdpi_font usually means normal_font (the normal resolution
// version), but actually means "set the HIGHDPI flag and try
// to use large_font if we initialize successfully".
font = &highdpi_font;
}
}
//
// Initialize text mode screen
//
// Returns 1 if successful, 0 if an error occurred
//
int TXT_Init(void)
{
int flags = 0;
if (SDL_Init(SDL_INIT_VIDEO) < 0)
{
return 0;
}
ChooseFont();
screen_image_w = TXT_SCREEN_W * font->w;
screen_image_h = TXT_SCREEN_H * font->h;
// If highdpi_font is selected, try to initialize high dpi rendering.
if (font == &highdpi_font)
{
flags |= SDL_WINDOW_ALLOW_HIGHDPI;
}
TXT_SDLWindow =
SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
screen_image_w, screen_image_h, flags);
if (TXT_SDLWindow == NULL)
return 0;
renderer = SDL_CreateRenderer(TXT_SDLWindow, -1, 0);
// Special handling for OS X retina display. If we successfully set the
// highdpi flag, check the output size for the screen renderer. If we get
// the 2x doubled size we expect from a retina display, use the large font
// for drawing the screen.
if ((SDL_GetWindowFlags(TXT_SDLWindow) & SDL_WINDOW_ALLOW_HIGHDPI) != 0)
{
int render_w, render_h;
if (SDL_GetRendererOutputSize(renderer, &render_w, &render_h) == 0
&& render_w >= TXT_SCREEN_W * large_font.w
&& render_h >= TXT_SCREEN_H * large_font.h)
{
font = &large_font;
// Note that we deliberately do not update screen_image_{w,h}
// since these are the dimensions of textscreen image in screen
// coordinates, not pixels.
}
}
// Failed to initialize for high dpi (retina display) rendering? If so
// then use the normal resolution font instead.
if (font == &highdpi_font)
{
font = &normal_font;
}
// Instead, we draw everything into an intermediate 8-bit surface
// the same dimensions as the screen. SDL then takes care of all the
// 8->32 bit (or whatever depth) color conversions for us.
screenbuffer = SDL_CreateRGBSurface(0,
TXT_SCREEN_W * font->w,
TXT_SCREEN_H * font->h,
8, 0, 0, 0, 0);
SDL_LockSurface(screenbuffer);
SDL_SetPaletteColors(screenbuffer->format->palette, ega_colors, 0, 16);
SDL_UnlockSurface(screenbuffer);
screendata = malloc(TXT_SCREEN_W * TXT_SCREEN_H * 2);
memset(screendata, 0, TXT_SCREEN_W * TXT_SCREEN_H * 2);
return 1;
}
void TXT_Shutdown(void)
{
free(screendata);
screendata = NULL;
SDL_FreeSurface(screenbuffer);
screenbuffer = NULL;
SDL_QuitSubSystem(SDL_INIT_VIDEO);
}
unsigned char *TXT_GetScreenData(void)
{
return screendata;
}
static inline void UpdateCharacter(int x, int y)
{
unsigned char character;
const uint8_t *p;
unsigned char *s, *s1;
unsigned int bit;
int bg, fg;
unsigned int x1, y1;
p = &screendata[(y * TXT_SCREEN_W + x) * 2];
character = p[0];
fg = p[1] & 0xf;
bg = (p[1] >> 4) & 0xf;
if (bg & 0x8)
{
// blinking
bg &= ~0x8;
if (((SDL_GetTicks() / BLINK_PERIOD) % 2) == 0)
{
fg = bg;
}
}
// How many bytes per line?
p = &font->data[(character * font->w * font->h) / 8];
bit = 0;
s = ((unsigned char *) screenbuffer->pixels)
+ (y * font->h * screenbuffer->pitch)
+ (x * font->w);
for (y1=0; y1<font->h; ++y1)
{
s1 = s;
for (x1=0; x1<font->w; ++x1)
{
if (*p & (1 << bit))
{
*s1++ = fg;
}
else
{
*s1++ = bg;
}
++bit;
if (bit == 8)
{
++p;
bit = 0;
}
}
s += screenbuffer->pitch;
}
}
static int LimitToRange(int val, int min, int max)
{
if (val < min)
{
return min;
}
else if (val > max)
{
return max;
}
else
{
return val;
}
}
static void GetDestRect(SDL_Rect *rect)
{
int w, h;
SDL_GetRendererOutputSize(renderer, &w, &h);
rect->x = (w - screenbuffer->w) / 2;
rect->y = (h - screenbuffer->h) / 2;
rect->w = screenbuffer->w;
rect->h = screenbuffer->h;
}
void TXT_UpdateScreenArea(int x, int y, int w, int h)
{
SDL_Texture *screentx;
SDL_Rect rect;
int x1, y1;
int x_end;
int y_end;
SDL_LockSurface(screenbuffer);
x_end = LimitToRange(x + w, 0, TXT_SCREEN_W);
y_end = LimitToRange(y + h, 0, TXT_SCREEN_H);
x = LimitToRange(x, 0, TXT_SCREEN_W);
y = LimitToRange(y, 0, TXT_SCREEN_H);
for (y1=y; y1<y_end; ++y1)
{
for (x1=x; x1<x_end; ++x1)
{
UpdateCharacter(x1, y1);
}
}
SDL_UnlockSurface(screenbuffer);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
// TODO: This is currently creating a new texture every time we render
// the screen; find a more efficient way to do it.
screentx = SDL_CreateTextureFromSurface(renderer, screenbuffer);
SDL_RenderClear(renderer);
GetDestRect(&rect);
SDL_RenderCopy(renderer, screentx, NULL, &rect);
SDL_RenderPresent(renderer);
SDL_DestroyTexture(screentx);
}
void TXT_UpdateScreen(void)
{
TXT_UpdateScreenArea(0, 0, TXT_SCREEN_W, TXT_SCREEN_H);
}
void TXT_GetMousePosition(int *x, int *y)
{
int window_w, window_h;
int origin_x, origin_y;
SDL_GetMouseState(x, y);
// Translate mouse position from 'pixel' position into character position.
// We are working here in screen coordinates and not pixels, since this is
// what SDL_GetWindowSize() returns; we must calculate and subtract the
// origin position since we center the image within the window.
SDL_GetWindowSize(TXT_SDLWindow, &window_w, &window_h);
origin_x = (window_w - screen_image_w) / 2;
origin_y = (window_h - screen_image_h) / 2;
*x = ((*x - origin_x) * TXT_SCREEN_W) / screen_image_w;
*y = ((*y - origin_y) * TXT_SCREEN_H) / screen_image_h;
if (*x < 0)
{
*x = 0;
}
else if (*x >= TXT_SCREEN_W)
{
*x = TXT_SCREEN_W - 1;
}
if (*y < 0)
{
*y = 0;
}
else if (*y >= TXT_SCREEN_H)
{
*y = TXT_SCREEN_H - 1;
}
}
//
// Translates the SDL key
//
// XXX: duplicate from doomtype.h
#define arrlen(array) (sizeof(array) / sizeof(*array))
static int TranslateScancode(SDL_Scancode scancode)
{
switch (scancode)
{
case SDL_SCANCODE_LCTRL:
case SDL_SCANCODE_RCTRL:
return KEY_RCTRL;
case SDL_SCANCODE_LSHIFT:
case SDL_SCANCODE_RSHIFT:
return KEY_RSHIFT;
case SDL_SCANCODE_LALT:
return KEY_LALT;
case SDL_SCANCODE_RALT:
return KEY_RALT;
default:
if (scancode < arrlen(scancode_translate_table))
{
return scancode_translate_table[scancode];
}
else
{
return 0;
}
}
}
static int TranslateKeysym(const SDL_Keysym *sym)
{
int translated;
// We cheat here and make use of TranslateScancode. The range of keys
// associated with printable characters is pretty contiguous, so if it's
// inside that range we want the localized version of the key instead.
translated = TranslateScancode(sym->scancode);
if (translated >= 0x20 && translated < 0x7f)
{
return sym->sym;
}
else
{
return translated;
}
}
// Convert an SDL button index to textscreen button index.
//
// Note special cases because 2 == mid in SDL, 3 == mid in textscreen/setup
static int SDLButtonToTXTButton(int button)
{
switch (button)
{
case SDL_BUTTON_LEFT:
return TXT_MOUSE_LEFT;
case SDL_BUTTON_RIGHT:
return TXT_MOUSE_RIGHT;
case SDL_BUTTON_MIDDLE:
return TXT_MOUSE_MIDDLE;
default:
return TXT_MOUSE_BASE + button - 1;
}
}
// Convert an SDL wheel motion to a textscreen button index.
static int SDLWheelToTXTButton(const SDL_MouseWheelEvent *wheel)
{
if (wheel->y <= 0)
{
return TXT_MOUSE_SCROLLDOWN;
}
else
{
return TXT_MOUSE_SCROLLUP;
}
}
static int MouseHasMoved(void)
{
static int last_x = 0, last_y = 0;
int x, y;
TXT_GetMousePosition(&x, &y);
if (x != last_x || y != last_y)
{
last_x = x; last_y = y;
return 1;
}
else
{
return 0;
}
}
signed int TXT_GetChar(void)
{
SDL_Event ev;
while (SDL_PollEvent(&ev))
{
// If there is an event callback, allow it to intercept this
// event.
if (event_callback != NULL)
{
if (event_callback(&ev, event_callback_data))
{
continue;
}
}
// Process the event.
switch (ev.type)
{
case SDL_MOUSEBUTTONDOWN:
if (ev.button.button < TXT_MAX_MOUSE_BUTTONS)
{
return SDLButtonToTXTButton(ev.button.button);
}
break;
case SDL_MOUSEWHEEL:
return SDLWheelToTXTButton(&ev.wheel);
case SDL_KEYDOWN:
switch (input_mode)
{
case TXT_INPUT_RAW:
return TranslateScancode(ev.key.keysym.scancode);
case TXT_INPUT_NORMAL:
return TranslateKeysym(&ev.key.keysym);
case TXT_INPUT_TEXT:
// We ignore key inputs in this mode, except for a
// few special cases needed during text input:
if (ev.key.keysym.sym == SDLK_ESCAPE
|| ev.key.keysym.sym == SDLK_BACKSPACE
|| ev.key.keysym.sym == SDLK_RETURN)
{
return TranslateKeysym(&ev.key.keysym);
}
break;
}
break;
case SDL_TEXTINPUT:
if (input_mode == TXT_INPUT_TEXT)
{
// TODO: Support input of more than just the first char?
const char *p = ev.text.text;
int result = TXT_DecodeUTF8(&p);
// 0-127 is ASCII, but we map non-ASCII Unicode chars into
// a higher range to avoid conflicts with special keys.
return TXT_UNICODE_TO_KEY(result);
}
break;
case SDL_QUIT:
// Quit = escape
return 27;
case SDL_MOUSEMOTION:
if (MouseHasMoved())
{
return 0;
}
default:
break;
}
}
return -1;
}
int TXT_GetModifierState(txt_modifier_t mod)
{
SDL_Keymod state;
state = SDL_GetModState();
switch (mod)
{
case TXT_MOD_SHIFT:
return (state & KMOD_SHIFT) != 0;
case TXT_MOD_CTRL:
return (state & KMOD_CTRL) != 0;
case TXT_MOD_ALT:
return (state & KMOD_ALT) != 0;
default:
return 0;
}
}
int TXT_UnicodeCharacter(unsigned int c)
{
unsigned int i;
// Check the code page mapping to see if this character maps
// to anything.
for (i = 0; i < arrlen(code_page_to_unicode); ++i)
{
if (code_page_to_unicode[i] == c)
{
return i;
}
}
return -1;
}
// Returns true if the given UTF8 key name is printable to the screen.
static int PrintableName(const char *s)
{
const char *p;
unsigned int c;
p = s;
while (*p != '\0')
{
c = TXT_DecodeUTF8(&p);
if (TXT_UnicodeCharacter(c) < 0)
{
return 0;
}
}
return 1;
}
static const char *NameForKey(int key)
{
const char *result;
int i;
// Overrides purely for aesthetical reasons, so that default
// window accelerator keys match those of setup.exe.
switch (key)
{
case KEY_ESCAPE: return "ESC";
case KEY_ENTER: return "ENTER";
default:
break;
}
// This key presumably maps to a scan code that is listed in the
// translation table. Find which mapping and once we have a scancode,
// we can convert it into a virtual key, then a string via SDL.
for (i = 0; i < arrlen(scancode_translate_table); ++i)
{
if (scancode_translate_table[i] == key)
{
result = SDL_GetKeyName(SDL_GetKeyFromScancode(i));
if (TXT_UTF8_Strlen(result) > 6 || !PrintableName(result))
{
break;
}
return result;
}
}
// Use US English fallback names, if the localized name is too long,
// not found in the scancode table, or contains unprintable chars
// (non-extended ASCII character set):
for (i = 0; i < arrlen(key_names); ++i)
{
if (key_names[i].key == key)
{
return key_names[i].name;
}
}
return NULL;
}
void TXT_GetKeyDescription(int key, char *buf, size_t buf_len)
{
const char *keyname;
int i;
keyname = NameForKey(key);
if (keyname != NULL)
{
TXT_StringCopy(buf, keyname, buf_len);
// Key description should be all-uppercase to match setup.exe.
for (i = 0; buf[i] != '\0'; ++i)
{
buf[i] = toupper(buf[i]);
}
}
else
{
TXT_snprintf(buf, buf_len, "??%i", key);
}
}
// Searches the desktop screen buffer to determine whether there are any
// blinking characters.
int TXT_ScreenHasBlinkingChars(void)
{
int x, y;
unsigned char *p;
// Check all characters in screen buffer
for (y=0; y<TXT_SCREEN_H; ++y)
{
for (x=0; x<TXT_SCREEN_W; ++x)
{
p = &screendata[(y * TXT_SCREEN_W + x) * 2];
if (p[1] & 0x80)
{
// This character is blinking
return 1;
}
}
}
// None found
return 0;
}
// Sleeps until an event is received, the screen needs to be redrawn,
// or until timeout expires (if timeout != 0)
void TXT_Sleep(int timeout)
{
unsigned int start_time;
if (TXT_ScreenHasBlinkingChars())
{
int time_to_next_blink;
time_to_next_blink = BLINK_PERIOD - (SDL_GetTicks() % BLINK_PERIOD);
// There are blinking characters on the screen, so we
// must time out after a while
if (timeout == 0 || timeout > time_to_next_blink)
{
// Add one so it is always positive
timeout = time_to_next_blink + 1;
}
}
if (timeout == 0)
{
// We can just wait forever until an event occurs
SDL_WaitEvent(NULL);
}
else
{
// Sit in a busy loop until the timeout expires or we have to
// redraw the blinking screen
start_time = SDL_GetTicks();
while (SDL_GetTicks() < start_time + timeout)
{
if (SDL_PollEvent(NULL) != 0)
{
// Received an event, so stop waiting
break;
}
// Don't hog the CPU
SDL_Delay(1);
}
}
}
void TXT_SetInputMode(txt_input_mode_t mode)
{
if (mode == TXT_INPUT_TEXT && !SDL_IsTextInputActive())
{
SDL_StartTextInput();
}
else if (SDL_IsTextInputActive() && mode != TXT_INPUT_TEXT)
{
SDL_StopTextInput();
}
input_mode = mode;
}
void TXT_SetWindowTitle(const char *title)
{
SDL_SetWindowTitle(TXT_SDLWindow, title);
}
void TXT_SDL_SetEventCallback(TxtSDLEventCallbackFunc callback, void *user_data)
{
event_callback = callback;
event_callback_data = user_data;
}
// Safe string functions.
void TXT_StringCopy(char *dest, const char *src, size_t dest_len)
{
if (dest_len < 1)
{
return;
}
dest[dest_len - 1] = '\0';
strncpy(dest, src, dest_len - 1);
}
void TXT_StringConcat(char *dest, const char *src, size_t dest_len)
{
size_t offset;
offset = strlen(dest);
if (offset > dest_len)
{
offset = dest_len;
}
TXT_StringCopy(dest + offset, src, dest_len - offset);
}
// On Windows, vsnprintf() is _vsnprintf().
#ifdef _WIN32
#if _MSC_VER < 1400 /* not needed for Visual Studio 2008 */
#define vsnprintf _vsnprintf
#endif
#endif
// Safe, portable vsnprintf().
int TXT_vsnprintf(char *buf, size_t buf_len, const char *s, va_list args)
{
int result;
if (buf_len < 1)
{
return 0;
}
// Windows (and other OSes?) has a vsnprintf() that doesn't always
// append a trailing \0. So we must do it, and write into a buffer
// that is one byte shorter; otherwise this function is unsafe.
result = vsnprintf(buf, buf_len, s, args);
// If truncated, change the final char in the buffer to a \0.
// A negative result indicates a truncated buffer on Windows.
if (result < 0 || result >= buf_len)
{
buf[buf_len - 1] = '\0';
result = buf_len - 1;
}
return result;
}
// Safe, portable snprintf().
int TXT_snprintf(char *buf, size_t buf_len, const char *s, ...)
{
va_list args;
int result;
va_start(args, s);
result = TXT_vsnprintf(buf, buf_len, s, args);
va_end(args);
return result;
}