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gterm: Speed up terminal by doing sub-character pixel comparisons and only printing differences

This commit is contained in:
mintsuki 2021-04-09 00:22:20 +02:00
parent 8bd7cf743c
commit bf9962e86f
1 changed files with 40 additions and 4 deletions
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44
stage23/lib/gterm.c
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@ -136,6 +136,23 @@ struct gterm_char {
int bg;
};
static void plot_char_mem(uint32_t *buf, struct gterm_char *c, int x, int y) {
uint8_t *glyph = &vga_font[(size_t)c->c * VGA_FONT_HEIGHT];
for (int i = 0; i < VGA_FONT_HEIGHT; i++) {
for (int j = 0; j < VGA_FONT_WIDTH; j++) {
if ((glyph[i] & (0x80 >> j))) {
buf[i * VGA_FONT_WIDTH + j] = ansi_colours[c->fg];
} else {
if (c->bg == 8)
buf[i * VGA_FONT_WIDTH + j] = bg_canvas[(y + i) * gterm_width + (x + j)];
else
buf[i * VGA_FONT_WIDTH + j] = ansi_colours[c->bg];
}
}
}
}
void gterm_plot_char(struct gterm_char *c, int x, int y) {
uint8_t *glyph = &vga_font[(size_t)c->c * VGA_FONT_HEIGHT];
@ -154,10 +171,25 @@ void gterm_plot_char(struct gterm_char *c, int x, int y) {
}
static void plot_char_grid(struct gterm_char *c, int x, int y) {
uint32_t old_char[VGA_FONT_WIDTH * VGA_FONT_HEIGHT];
uint32_t new_char[VGA_FONT_WIDTH * VGA_FONT_HEIGHT];
plot_char_mem(old_char, &grid[x + y * cols],
x * VGA_FONT_WIDTH + frame_width, y * VGA_FONT_HEIGHT + frame_height);
plot_char_mem(new_char, c,
x * VGA_FONT_WIDTH + frame_width, y * VGA_FONT_HEIGHT + frame_height);
if (!double_buffer_enabled) {
gterm_plot_char(c, x * VGA_FONT_WIDTH + frame_width,
y * VGA_FONT_HEIGHT + frame_height);
for (int i = 0; i < VGA_FONT_HEIGHT; i++) {
for (int j = 0; j < VGA_FONT_WIDTH; j++) {
if (old_char[i * VGA_FONT_WIDTH + j] != new_char[i * VGA_FONT_WIDTH + j])
gterm_plot_px(x * VGA_FONT_WIDTH + frame_width + j,
y * VGA_FONT_HEIGHT + frame_height + i,
new_char[i * VGA_FONT_WIDTH + j]);
}
}
}
grid[x + y * cols] = *c;
}
@ -177,11 +209,15 @@ static void draw_cursor(void) {
}
}
static inline bool compare_char(struct gterm_char *a, struct gterm_char *b) {
return !(a->c != b->c || a->bg != b->bg || a->fg != b->fg);
}
static void scroll(void) {
clear_cursor();
for (int i = cols; i < rows * cols; i++) {
if (memcmp(&grid[i], &grid[i - cols], sizeof(struct gterm_char) != 0))
if (!compare_char(&grid[i], &grid[i - cols]))
plot_char_grid(&grid[i], (i - cols) % cols, (i - cols) / cols);
}
@ -191,7 +227,7 @@ static void scroll(void) {
empty.fg = 9;
empty.bg = 8;
for (int i = rows * cols - cols; i < rows * cols; i++) {
if (memcmp(&grid[i], &empty, sizeof(struct gterm_char) != 0))
if (!compare_char(&grid[i], &empty))
plot_char_grid(&empty, i % cols, i / cols);
}