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Merged
bettio merged 3 commits into from
Oct 3, 2026
+24 −182
Merged

sdl: Fix plugin build and remove broken damage tracking #23

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79fcc8e
sdl: Fix register_font for ufontlib API
bettio Sep 28, 2026
1f1500f
sdl: Fix subscribe_input option index
bettio Sep 28, 2026
8a100c6
sdl: Remove the broken damage tracking
bettio Oct 2, 2026
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206 changes: 24 additions & 182 deletions sdl_display/display.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
#include <SDL.h>
#include <pthread.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <context.h>
Expand Down Expand Up @@ -64,15 +65,6 @@ struct MouseEvent
int y;
};

struct Rectangle
{
int x;
int y;
int width;
int height;
bool valid;
};

static term keyboard_pid;
static struct timespec ts0;
Context *the_ctx;
Expand All @@ -96,135 +88,13 @@ UFontManager *ufont_manager;
static NativeHandlerResult consume_display_mailbox(Context *ctx);
static void *display_loop();

Message *prev_message = NULL;
BaseDisplayItem *prev_items = NULL;
int prev_items_len = 0;

static void destroy_message(Message *m, GlobalContext *global)
{
BEGIN_WITH_STACK_HEAP(1, temp_heap);
mailbox_message_dispose(&m->base, &temp_heap);
END_WITH_STACK_HEAP(temp_heap, global);
}

static inline int int_min(int a, int b)
{
return (a > b) ? b : a;
}

static inline int int_max(int a, int b)
{
return (a > b) ? a : b;
}

static bool cmp_display_item(BaseDisplayItem *a, BaseDisplayItem *b)
{
if (a->primitive != b->primitive || a->x != b->x || a->y != b->y ||
a->width != b->width || a->height != b->height || a->brcolor != b->brcolor) {
return false;
}

switch (a->primitive) {
case PrimitiveImage:
return a->data.image_data.pix == b->data.image_data.pix;

case PrimitiveRect:
return true;

case PrimitiveText:
return (a->data.text_data.fgcolor == b->data.text_data.fgcolor) &&
!strcmp(a->data.text_data.text, b->data.text_data.text);

case PrimitiveScaledCroppedImage:
return (a->data.image_data.pix == b->data.image_data.pix) &&
(a->x_scale == b->x_scale) && (a->y_scale == b->y_scale) &&
(a->source_x == b->source_x) && (a->source_y == b->source_y);

default: {
return true;
}
}
}

static void update_damaged_area(struct Rectangle *area, const struct Rectangle *damage)
{
if (area->valid) {
area->x = int_min(area->x, damage->x);
area->y = int_min(area->y, damage->y);
area->width = int_max(area->x + area->width, damage->x + damage->width) - area->x;
area->height = int_max(area->y + area->height, damage->y + damage->height) - area->y;
} else {
area->x = damage->x;
area->y = damage->y;
area->width = damage->width;
area->height = damage->height;
area->valid = true;
}
}

static void clip_rectangle(struct Rectangle *rectangle, const struct Rectangle *clip_region)
{
rectangle->x = int_max(rectangle->x, clip_region->x);
rectangle->y = int_max(rectangle->y, clip_region->y);
rectangle->width = int_min(rectangle->x + rectangle->width, clip_region->x + clip_region->width) - rectangle->x;
rectangle->height = int_min(rectangle->y + rectangle->height, clip_region->y + clip_region->height) - rectangle->y;
}

static void dumb_diff(BaseDisplayItem *orig, int orig_len, BaseDisplayItem *new, int new_len, struct Rectangle *damaged)
{
if (orig_len == 0) {
for (int i = 0; i < new_len; i++) {
struct Rectangle irect = {
.x = new[i].x,
.y = new[i].y,
.width = new[i].width,
.height = new[i].height,
.valid = true
};
update_damaged_area(damaged, &irect);
}
return;
}

int j = 0;

for (int i = 0; i < new_len; i++) {
if (cmp_display_item(&new[i], &orig[j])) {
j++;
} else {
bool found = false;
for (int k = j + 1; k < orig_len; k++) {
if (cmp_display_item(&new[i], &orig[k])) {
for (int l = k - j; l < k; l++) {
struct Rectangle irect = {
.x = orig[l].x,
.y = orig[l].y,
.width = orig[l].width,
.height = orig[l].height,
.valid = true
};
update_damaged_area(damaged, &irect);
}

j = k + 1;
found = true;
break;
}
}
if (!found) {
struct Rectangle irect = {
.x = new[i].x,
.y = new[i].y,
.width = new[i].width,
.height = new[i].height,
.valid = true
};
update_damaged_area(damaged, &irect);
}
}
}
}

static inline Uint32 uint32_color_to_surface(struct Screen *screen, uint32_t color)
{
return SDL_MapRGB(screen->format, (color >> 24) & 0xFF, (color >> 16) & 0xFF, (color >> 8) & 0xFF);
Expand Down Expand Up @@ -455,55 +325,22 @@ static int draw_x(int xpos, int ypos, BaseDisplayItem items[], size_t items_len)
return 1;
}

static bool do_update(Context *ctx, term display_list)
static void do_update(Context *ctx, term display_list)
{
BaseDisplayItem *items;
size_t len;
if (UNLIKELY(display_items_new_list(display_list, &items, &len, ctx) != DisplayItemsOk)) {
return false;
}

struct Rectangle damaged;
damaged.valid = false;
dumb_diff(prev_items, prev_items_len, items, len, &damaged);
if (prev_message) {
display_items_delete(prev_items, prev_items_len);
destroy_message(prev_message, ctx->global);
}
prev_items = items;
prev_items_len = len;

if (!damaged.valid) {
// skip update
return true;
return;
}

struct Rectangle screen_rect = {
.x = 0,
.y = 0,
.width = screen->w,
.height = screen->h,
.valid = true
};
clip_rectangle(&damaged, &screen_rect);

// BUG: damage area is not correct
// WORKAROUND: always damage the whole screen to force full redraw
damaged.x = 0;
damaged.y = 0;
damaged.height = screen->h;
damaged.width = screen->w;
// END OF WORKAROUND

for (int ypos = damaged.y; ypos < damaged.y + damaged.height; ypos++) {
int xpos = damaged.x;
while (xpos < damaged.x + damaged.width) {
int drawn_pixels = draw_x(xpos, ypos, items, len);
xpos += drawn_pixels;
for (int ypos = 0; ypos < screen->h; ypos++) {
int xpos = 0;
while (xpos < screen->w) {
xpos += draw_x(xpos, ypos, items, len);
}
}

return true;
display_items_delete(items, len);
}

static void process_message(Context *ctx)
Expand Down Expand Up @@ -532,9 +369,7 @@ static void process_message(Context *ctx)
if (cmd == globalcontext_make_atom(ctx->global, "\x6"
"update")) {
term display_list = term_get_tuple_element(req, 1);
if (do_update(ctx, display_list)) {
prev_message = message;
}
do_update(ctx, display_list);

// Copy and scale up
int scale = screen->scale;
Expand All @@ -551,7 +386,7 @@ static void process_message(Context *ctx)
if (term_get_tuple_arity(req) != 2) {
goto invalid_message;
}
term sources = term_get_tuple_element(req, 2);
term sources = term_get_tuple_element(req, 1);
if (term_is_pid(keyboard_pid) || sources != globalcontext_make_atom(ctx->global, "\x3" "all")) {
fprintf(stderr, "Warning: only one subscriber to all sources is supported now\n");
}
Expand All @@ -566,13 +401,22 @@ static void process_message(Context *ctx)

} else if (cmd == globalcontext_make_atom(ctx->global, "\xD" "register_font")) {
term font_bin = term_get_tuple_element(req, 2);
EpdFont *loaded_font = ufont_parse(term_binary_data(font_bin), term_binary_size(font_bin));
size_t font_size = term_binary_size(font_bin);
void *owned_buf = malloc(font_size);
EpdFont *loaded_font = NULL;
if (owned_buf != NULL) {
memcpy(owned_buf, term_binary_data(font_bin), font_size);
loaded_font = ufont_parse(owned_buf, font_size);
if (loaded_font == NULL) {
free(owned_buf);
}
}

char *handle = interop_atom_to_string(ctx, term_get_tuple_element(req, 1));
if (handle != NULL) {
ufont_manager_register(ufont_manager, handle, loaded_font);
free(handle);
if (loaded_font != NULL && handle != NULL) {
ufont_manager_register(ufont_manager, handle, loaded_font, owned_buf);
}
free(handle);

} else {
fprintf(stderr, "unexpected command: ");
Expand Down Expand Up @@ -605,9 +449,7 @@ static void process_message(Context *ctx)
fprintf(stderr, "Expected gen_server call.\n");

free_msg_and_exit:
if (prev_message != message) {
destroy_message(message, ctx->global);
}
destroy_message(message, ctx->global);
return;
}

Expand Down
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