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
|
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <dpmi.h>
#include <sys/nearptr.h>
#include <pc.h>
#include <dos.h>
#include "vga.h"
static uint8_t buffer[320 * 200];
static uint8_t *screen = NULL;
uint8_t open_framebuffer()
{
if (__djgpp_nearptr_enable() == 0)
return 0;
screen = (uint8_t *)(0xa0000 + __djgpp_conventional_base);
return 1;
}
void close_framebuffer()
{
__djgpp_nearptr_disable();
}
uint8_t set_mode(uint8_t mode)
{
__dpmi_regs regs = { 0 };
/* detect VGA card */
regs.x.ax = 0x1a00;
__dpmi_int(0x10, ®s);
if (regs.h.al != 0x1a)
return 0;
memset(®s, 0, sizeof(regs));
regs.x.ax = mode;
__dpmi_int(0x10, ®s);
if (mode == 0x13)
{
/* setup the VGA: 320x200 @ 60Hz */
/* from: https://gist.github.com/juj/34306e6da02a8a7043e393f01e013f24 */
disable();
/* XXX: probably not neeed */
wait_vsync();
outportw(0x3d4, 0x0011); /* Turn off write protect to CRTC registers */
outportw(0x3d4, 0x0b06); /* New vertical total=525 lines, bits 0-7 */
outportw(0x3d4, 0x3e07); /* New vertical total=525 lines, bits 8-9 */
outportw(0x3d4, 0xb910); /* Vsync start=scanline 185 */
outportw(0x3d4, 0x8f12); /* Vertical display end=scanline 399, bits 0-7 */
outportw(0x3d4, 0xb815); /* Vertical blanking start=scanline 440, bits 0-7 */
outportw(0x3d4, 0xe216); /* Adjust vblank end position */
outportw(0x3d4, 0x8511); /* Vsync length=2 lines + turn write protect back on */
/* XXX: probably not neeed */
wait_vsync();
outportw(0x3d4, 0x2813); /* 8 pixel chars */
outportw(0x3d4, 0x8e11); /* restore retrace */
enable();
}
return 1;
}
void wait_vsync()
{
while (inportb(0x3da) & 8);
while (!(inportb(0x3da) & 8));
}
void set_palette(const uint8_t *palette)
{
outportb(0x3c8, 0);
for (int i = 0; i < 768; i++)
outportb(0x3c9, palette[i] >> 2);
}
void blit(const uint8_t *sprite, const Rect *dst)
{
for (int32_t j = dst->y * 320; j < (dst->y + dst->h) * 320; j += 320)
for (int16_t i = dst->x; i < dst->x + dst->w; i++)
{
uint8_t b = *sprite++;
/* transparent */
if (b == TRANSPARENT)
continue;
/* clipping */
if (i < 0 || i >= 320 || j < 0 || j >= 200 * 320)
continue;
buffer[i + j] = b;
}
}
void blitrc(const uint8_t *sprite, const Rect *src, const Rect *dst)
{
for (int32_t j = dst->y * 320, sy = src->y * src->w; j < (dst->y + dst->h) * 320; j += 320, sy += src->w)
for (int16_t i = dst->x, sx = src->x; i < dst->x + dst->w; i++, sx++)
{
uint8_t b = sprite[sx + sy];
/* transparent */
if (b == TRANSPARENT)
continue;
/* clipping */
if (i < 0 || i >= 320 || j < 0 || j >= 200 * 320)
continue;
buffer[i + j] = b;
}
}
void blit_erase(uint8_t c)
{
memset(buffer, c, 320 * 200);
}
void blit_update()
{
memcpy(screen, buffer, 320 * 200);
}
|
