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Improve input handling of special keys
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@olafkryus @veikkos
olafkryus authored and veikkos committed Nov 8, 2020
1 parent 3feb1a0 commit cd189ca
Showing 1 changed file with 165 additions and 11 deletions.
176 changes: 165 additions & 11 deletions SDLPORT.PAS
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Original file line number Diff line number Diff line change
Expand Up @@ -238,9 +238,23 @@ begin

if event.type_= SDL_KEYDOWN then
begin
pressed:=true;
SDL_PushEvent(@event);
break;
// Ignore modifier and status keys, since they did not trigger a keypress in DOS version.
// F11, F12 and probably others were ignored too, but that would probably be counterintuitive.
case event.key.keysym.sym of
SDLK_LCTRL, SDLK_RCTRL,
SDLK_LSHIFT, SDLK_RSHIFT,
SDLK_LALT, SDLK_RALT,
SDLK_LGUI, SDLK_RGUI,
SDLK_CAPSLOCK, SDLK_SCROLLLOCK, SDLK_NUMLOCKCLEAR,
SDLK_PRINTSCREEN, SDLK_SYSREQ, SDLK_PAUSE:
; // Keypress ignored
else
begin
pressed:=true;
SDL_PushEvent(@event);
break;
end;
end;
end;
end;
KeyPressed:=pressed
Expand All @@ -259,21 +273,30 @@ end;

procedure WaitForKeyPress(var ch1, ch2:char);
var event : TSDL_Event;
keyPressed: TSDL_ScanCode;
scancode: TSDL_ScanCode;
keyPressed: TSDL_KeyCode;
keyMod: UInt16;
begin
ch1:=#0;
ch2:=#0;
// Setting ch2 to a correct scancode value for the key pressed can be largely ignored.
// It is only checked by the game for special keys, where ch1 is checked or assumed to be 0.
// This also means that the game cannot differentiate between different keys producing the same character.

while (true) do
begin
while SDL_PollEvent(@event) = 1 do
begin
if event.type_= SDL_KEYDOWN then
begin
scancode := event.key.keysym.scancode;
keyPressed := event.key.keysym.sym;
keyMod := event.key.keysym._mod;

if ((event.key.keysym._mod and KMOD_LALT) > 0) then
// SDL version specific shortcuts
if ((keyMod and KMOD_LALT) > 0) then
begin
Case event.key.keysym.scancode of
Case scancode of
SDL_SCANCODE_RETURN :
begin
toggleFullscreen;
Expand Down Expand Up @@ -302,16 +325,147 @@ begin
end;
end;

// Some nordic characters
// Special cases for key combinations used throughout the game.
// Check for Right Alt/AltGr first, since pressing it can make Left Ctrl look as pressed too.
if ((keyMod and KMOD_MODE) > 0) then exit;
if ((keyMod and KMOD_RALT) > 0) then exit;
if ((keyMod and KMOD_LALT) > 0) then
begin
Case keyPressed of
SDLK_x: begin ch1:=#0; ch2:=#45; exit end; {ALT-X}
else
exit
end;
end;
if ((keyMod and KMOD_CTRL) > 0) then
begin
Case keyPressed of
SDLK_c: begin ch1:=#3; exit end; {CTRL-C}
else
exit
end;
end;
if ((keyMod and KMOD_GUI) > 0) then exit;

// Handle conversion of letters to uppercase.
// Convert only if Caps Lock is off and Shift is pressed or vice versa.
if (
((keyMod and KMOD_SHIFT) > 0) xor ((keyMod and KMOD_CAPS) > 0)
) then
begin
Case keypressed of
97..122, 224..246, 248..254: keyPressed:=TSDL_KeyCode(keyPressed - 32);
end;
end;

// If modifier is Shift, convert the key pressed accordingly.
// For special keys, standard US QWERTY layout is assumed.
if ((keyMod and KMOD_SHIFT) > 0) then
begin
Case keyPressed of
65..90, 97..122, 190..214, 216..222, 224..246, 248..254: ; // Already handled above
SDLK_1 : keyPressed:=SDLK_EXCLAIM;
SDLK_2 : keyPressed:=SDLK_AT;
SDLK_3 : keyPressed:=SDLK_HASH;
SDLK_4 : keyPressed:=SDLK_DOLLAR;
SDLK_5 : keyPressed:=SDLK_PERCENT;
SDLK_6 : keyPressed:=SDLK_CARET;
SDLK_7 : keyPressed:=SDLK_AMPERSAND;
SDLK_8 : keyPressed:=SDLK_ASTERISK;
SDLK_9 : keyPressed:=SDLK_LEFTPAREN;
SDLK_0 : keyPressed:=SDLK_RIGHTPAREN;
SDLK_MINUS : keyPressed:=SDLK_UNDERSCORE;
SDLK_EQUALS : keyPressed:=SDLK_PLUS;
SDLK_LEFTBRACKET : keyPressed:=TSDL_KeyCode('{');
SDLK_RIGHTBRACKET : keyPressed:=TSDL_KeyCode('}');
SDLK_SEMICOLON : keyPressed:=SDLK_COLON;
{SDLK_QUOTE} TSDL_KeyCode('''') : keyPressed:=SDLK_QUOTEDBL; // bug in ev1313/Pascal-SDL-2-Headers - wrong value of SDLK_QUOTE
SDLK_BACKQUOTE : keyPressed:=TSDL_KeyCode('~');
SDLK_BACKSLASH : keyPressed:=TSDL_KeyCode('|');
SDLK_COMMA : keyPressed:=SDLK_LESS;
SDLK_PERIOD : keyPressed:=SDLK_GREATER;
SDLK_SLASH : keyPressed:=SDLK_QUESTION;
else
exit
end;
end;

// If NumLock modifier is not set, convert the charaters accordingly
if ((keyMod and KMOD_NUM) = 0) then
begin
Case keyPressed of
SDLK_KP_1 : keyPressed:=SDLK_END;
SDLK_KP_2 : keyPressed:=SDLK_DOWN;
SDLK_KP_3 : keyPressed:=SDLK_PAGEDOWN;
SDLK_KP_4 : keyPressed:=SDLK_LEFT;
SDLK_KP_5 : begin ch1:=#0; ch2:=#76; exit end;
SDLK_KP_6 : keyPressed:=SDLK_RIGHT;
SDLK_KP_7 : keyPressed:=SDLK_HOME;
SDLK_KP_8 : keyPressed:=SDLK_UP;
SDLK_KP_9 : keyPressed:=SDLK_PAGEUP;
SDLK_KP_0 : keyPressed:=SDLK_INSERT;
SDLK_KP_PERIOD : keyPressed:=SDLK_DELETE;
end;
end;

// Merge keypad characters with their regular counterparts.
// It is not needed to differentiate between them, since the scancode isn't checked for normal characters.
// Checks for Shift and Num Lock were already done, so they won't interfere with the merge.
Case keyPressed of
228 : begin ch1:=#132; ch2:=#36; exit end; // a with diaeresis
246 : begin ch1:=#148; ch2:=#39; exit end; // a with ring above
229 : begin ch1:=#134; ch2:=#26; exit end; // o with diaeresis
SDLK_KP_DIVIDE : keyPressed:=SDLK_SLASH;
SDLK_KP_MULTIPLY : keyPressed:=SDLK_ASTERISK;
SDLK_KP_MINUS : keyPressed:=SDLK_MINUS;
SDLK_KP_PLUS : keyPressed:=SDLK_PLUS;
SDLK_KP_ENTER : keyPressed:=SDLK_RETURN;
SDLK_KP_1 : keyPressed:=SDLK_1;
SDLK_KP_2 : keyPressed:=SDLK_2;
SDLK_KP_3 : keyPressed:=SDLK_3;
SDLK_KP_4 : keyPressed:=SDLK_4;
SDLK_KP_5 : keyPressed:=SDLK_5;
SDLK_KP_6 : keyPressed:=SDLK_6;
SDLK_KP_7 : keyPressed:=SDLK_7;
SDLK_KP_8 : keyPressed:=SDLK_8;
SDLK_KP_9 : keyPressed:=SDLK_9;
SDLK_KP_0 : keyPressed:=SDLK_0;
SDLK_KP_PERIOD : keyPressed:=SDLK_PERIOD;
SDLK_KP_EQUALS : keyPressed:=SDLK_EQUALS;
end;

if (keyPressed < SDLK_CAPSLOCK) then ch1:=char(keyPressed);
Case keyPressed of
SDLK_RETURN : ch1:=#13;
SDLK_ESCAPE : ch1:=#27;
SDLK_BACKSPACE : ch1:=#8;
SDLK_TAB : ch1:=#9;

32..126 : ch1:=chr(keyPressed);

// Special characters supported by the game, OEM 865 nordic encoding is used for ch1 values
196 : begin ch1:=#142; exit end; // A with diaeresis
197 : begin ch1:=#143; exit end; // A with ring above
198 : begin ch1:=#146; exit end; // AE
214 : begin ch1:=#153; exit end; // O with diaeresis
216 : begin ch1:=#157; exit end; // O with stroke
220 : begin ch1:=#154; exit end; // U with diaeresis
223 : begin ch1:=#225; exit end; // sharp s

228 : begin ch1:=#132; ch2:=#36; exit end; // a with diaeresis
229 : begin ch1:=#134; ch2:=#26; exit end; // a with ring above
230 : begin ch1:=#145; exit end; // ae
246 : begin ch1:=#148; ch2:=#39; exit end; // o with diaeresis
248 : begin ch1:=#158; exit end; // o with stroke
252 : begin ch1:=#129; exit end; // u with diaeresis
end;

Case keyPressed of
SDLK_F1 : ch2:=#59;
SDLK_F2 : ch2:=#60;
SDLK_F3 : ch2:=#61;
SDLK_F4 : ch2:=#62;
SDLK_F5 : ch2:=#63;
SDLK_F6 : ch2:=#64;
SDLK_F7 : ch2:=#65;
SDLK_F8 : ch2:=#66;
SDLK_F9 : ch2:=#67;
SDLK_F10 : ch2:=#68;

SDLK_LEFT : ch2:=#75;
Expand Down

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