summaryrefslogtreecommitdiff
path: root/textscreen/txt_main.c
blob: 049549e314352eced6cd6917bdcb6ba0923f2a21 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id: txt_main.c 183 2005-10-09 20:19:21Z fraggle $
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005 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.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA.
//
// $Log$
// Revision 1.3  2005/10/09 20:19:21  fraggle
// Handle blinking text in ENDOOM lumps properly.
//
// Revision 1.2  2005/10/09 16:42:46  fraggle
// Cannot do arithmetic on void pointers in standard C
//
// Revision 1.1  2005/10/02 03:16:03  fraggle
// Text mode emulation code
//
//
//-----------------------------------------------------------------------------
//
// Text mode emulation in SDL
//
//-----------------------------------------------------------------------------

#include <SDL.h>
#include <stdlib.h>
#include <string.h>

#include "txt_main.h"
#include "txt_font.h"

#define SCREEN_W 80
#define SCREEN_H 25
#define CHAR_W 8
#define CHAR_H 16

static SDL_Surface *screen;
static unsigned char *screendata;

static SDL_Color ega_colors[] = 
{
    {0x00, 0x00, 0x00},          // 0: Black
    {0x00, 0x00, 0xa8},          // 1: Blue
    {0x00, 0xa8, 0x00},          // 2: Green
    {0x00, 0xa8, 0xa8},          // 3: Cyan
    {0xa8, 0x00, 0x00},          // 4: Red
    {0xa8, 0x00, 0xa8},          // 5: Magenta
    {0xa8, 0x54, 0x00},          // 6: Brown
    {0xa8, 0xa8, 0xa8},          // 7: Grey
    {0x54, 0x54, 0x54},          // 8: Dark grey
    {0x54, 0x54, 0xfe},          // 9: Bright blue
    {0x54, 0xfe, 0x54},          // 10: Bright green
    {0x54, 0xfe, 0xfe},          // 11: Bright cyan
    {0xfe, 0x54, 0x54},          // 12: Bright red
    {0xfe, 0x54, 0xfe},          // 13: Bright magenta
    {0xfe, 0xfe, 0x54},          // 14: Yellow
    {0xfe, 0xfe, 0xfe},          // 15: Bright white
};

//
// Initialise text mode screen
//
// Returns 1 if successful, 0 if an error occurred
//

int TXT_Init(void)
{
    SDL_InitSubSystem(SDL_INIT_VIDEO);
    
    screen = SDL_SetVideoMode(SCREEN_W * CHAR_W, SCREEN_H * CHAR_H, 8, 0);

    if (screen == NULL)
        return 0;

    SDL_SetColors(screen, ega_colors, 0, 16);

    screendata = malloc(SCREEN_W * SCREEN_H * 2);
    memset(screendata, 0, SCREEN_W * SCREEN_H * 2);

    return 1;
}

void TXT_Shutdown(void)
{
    free(screendata);
    SDL_QuitSubSystem(SDL_INIT_VIDEO);
}

unsigned char *TXT_GetScreenData(void)
{
    return screendata;
}

static inline void UpdateCharacter(int x, int y)
{
    unsigned char character;
    unsigned char *p;
    unsigned char *s, *s1;
    int bg, fg;
    int x1, y1;

    p = &screendata[(y * 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() % 500 < 250)
            fg = bg;
    }

    p = &int10_font_16[character * CHAR_H];

    s = ((unsigned char *) screen->pixels) 
          + (y * CHAR_H * screen->pitch) + (x * CHAR_W);

    for (y1=0; y1<CHAR_H; ++y1)
    {
        s1 = s;

        for (x1=0; x1<CHAR_W; ++x1)
        {
            if (*p & (1 << (7-x1)))
            {
                *s1++ = fg;
            }
            else
            {
                *s1++ = bg;
            }
        }

        ++p;
        s += screen->pitch;
    }
}

void TXT_UpdateScreenArea(int x, int y, int w, int h)
{
    int x1, y1;

    for (y1=y; y1<y+h; ++y1)
    {
        for (x1=x; x1<x+w; ++x1)
        {
            UpdateCharacter(x1, y1);
        }
    }

    SDL_UpdateRect(screen, x * CHAR_W, y * CHAR_H, w * CHAR_W, h * CHAR_H);
}

void TXT_UpdateScreen(void)
{
    TXT_UpdateScreenArea(0, 0, SCREEN_W, SCREEN_H);
}