Files
jsix_import/src/drivers/fb/main.cpp
Justin C. Miller a97073848c [fb] Use double-buffering in fb driver
Allocate and use a back buffer, so that draws to the screen are always a
single memcpy()
2021-01-17 20:53:41 -08:00

106 lines
2.2 KiB
C++

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include "j6/init.h"
#include "j6/errors.h"
#include "j6/signals.h"
#include "j6/types.h"
#include <j6libc/syscalls.h>
#include "font.h"
#include "screen.h"
#include "scrollback.h"
extern "C" {
int main(int, const char **);
void _get_init(size_t *initc, struct j6_init_value **initv);
}
extern j6_handle_t __handle_sys;
struct entry
{
uint8_t bytes;
uint8_t area;
uint8_t severity;
uint8_t sequence;
char message[0];
};
int
main(int argc, const char **argv)
{
_syscall_system_log("fb driver starting");
size_t initc = 0;
j6_init_value *initv = nullptr;
_get_init(&initc, &initv);
j6_init_framebuffer *fb = nullptr;
for (unsigned i = 0; i < initc; ++i) {
if (initv[i].type == j6_init_desc_framebuffer) {
fb = reinterpret_cast<j6_init_framebuffer*>(initv[i].value);
break;
}
}
if (!fb || fb->addr == nullptr) {
_syscall_system_log("fb driver didn't find a framebuffer, exiting");
return 1;
}
const screen::pixel_order order = (fb->flags & 1) ?
screen::pixel_order::bgr8 : screen::pixel_order::rgb8;
screen scr(fb->addr, fb->horizontal, fb->vertical, order);
font fnt;
screen::pixel_t fg = scr.color(0xb0, 0xb0, 0xb0);
screen::pixel_t bg = scr.color(49, 79, 128);
scr.fill(bg);
scr.update();
constexpr int margin = 2;
const unsigned xstride = (margin + fnt.width());
const unsigned ystride = (margin + fnt.height());
const unsigned rows = (scr.height() - margin) / ystride;
const unsigned cols = (scr.width() - margin) / xstride;
scrollback scroll(rows, cols);
int pending = 0;
constexpr int pending_threshold = 10;
char message_buffer[256];
while (true) {
size_t size = sizeof(message_buffer);
_syscall_system_get_log(__handle_sys, message_buffer, &size);
if (size != 0) {
entry *e = reinterpret_cast<entry*>(&message_buffer);
size_t eom = e->bytes - sizeof(entry);
e->message[eom] = 0;
scroll.add_line(e->message, eom);
if (++pending > pending_threshold) {
scroll.render(scr, fnt);
scr.update();
pending = 0;
}
} else {
if (pending) {
scroll.render(scr, fnt);
scr.update();
pending = 0;
}
}
}
_syscall_system_log("fb driver done, exiting");
return 0;
}