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twn_textures.c: fix atlas packing, allow out of order population

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veclavtalica 2025-03-03 00:57:19 +03:00
parent ed8e826b94
commit a97515e948
1 changed files with 23 additions and 22 deletions
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41
src/twn_textures.c
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@ -255,17 +255,17 @@ static void upload_texture_from_surface(GPUTexture texture, SDL_Surface *surface
}
static void recreate_current_atlas_texture(TextureCache *cache) {
static void recreate_current_atlas_texture(TextureCache *cache, int atlas_index) {
profile_start("atlas recreation");
/* TODO: should surfaces be freed after they cannot be referenced in atlas builing? */
/* for example, if full page of 64x64 tiles was already filled, there's no real reason to process them further */
SDL_Surface *atlas_surface = cache->atlas_surfaces[cache->atlas_index];
SDL_Surface *atlas_surface = cache->atlas_surfaces[atlas_index];
/* blit the texture surfaces onto the atlas */
for (size_t i = 0; i < shlenu(cache->hash); ++i) {
/* skip all that aren't part of currently built one */
if (cache->hash[i].value.atlas_index != cache->atlas_index)
if (cache->hash[i].value.atlas_index != atlas_index)
continue;
/* skip loners */
@ -284,7 +284,7 @@ static void recreate_current_atlas_texture(TextureCache *cache) {
}
/* texturize it! */
upload_texture_from_surface(cache->atlas_textures[cache->atlas_index], atlas_surface);
upload_texture_from_surface(cache->atlas_textures[atlas_index], atlas_surface);
profile_end("atlas recreation");
}
@ -337,7 +337,7 @@ static stbrp_rect *filter_unpacked_rects(stbrp_rect *rects) {
/* updates the original rects array with the data from packed_rects */
/* returns true if all rects were packed successfully */
static bool update_rects(TextureCache *cache, stbrp_rect *rects, stbrp_rect *packed_rects) {
static bool update_rects(TextureCache *cache, stbrp_rect *rects, stbrp_rect *packed_rects, int atlas_index) {
/* !!! do not grow either of the arrays !!! */
/* the reallocation will try to reassign the array pointer, to no effect. */
/* see stb_ds.h */
@ -347,6 +347,8 @@ static bool update_rects(TextureCache *cache, stbrp_rect *rects, stbrp_rect *pac
/* we can check if any rects failed to be packed right here */
/* it's not ideal, but it avoids another iteration */
if (!packed_rects[i].was_packed) {
/* mark it as potentially filled in next atlas page */
cache->hash[packed_rects[i].id].value.atlas_index = atlas_index + 1;
packed_all = false;
continue;
}
@ -355,7 +357,7 @@ static bool update_rects(TextureCache *cache, stbrp_rect *rects, stbrp_rect *pac
/* while the order of the elements in the hash map is unknown to us, */
/* their equivalents in `rects` are in that same (unknown) order, which means */
/* we can use the index we had saved to find the original texture struct */
cache->hash[packed_rects[i].id].value.atlas_index = cache->atlas_index;
cache->hash[packed_rects[i].id].value.atlas_index = atlas_index;
}
return packed_all;
@ -566,9 +568,6 @@ void textures_update_atlas(TextureCache *cache) {
upload_texture_from_surface(response.loner_texture, response.data);
response.srcrect = (Rect) { .w = (float)response.data->w, .h = (float)response.data->h };
} else {
/* will be fully populated as the atlas updates */
response.atlas_index = cache->atlas_index;
}
cache->hash[texture_load_queue[i].index].value = response;
@ -576,6 +575,14 @@ void textures_update_atlas(TextureCache *cache) {
arrsetlen(texture_load_queue, 0);
stbrp_rect *rects = create_rects_from_cache(cache);
int current_atlas_index = 0;
/* we have to keep packing, and creating atlases if necessary, */
/* until all rects have been packed. */
/* ideally, this will not iterate more than once. */
bool textures_remaining = true;
while (textures_remaining) {
/* this function makes a lot more sense if you read stb_rect_pack.h */
stbrp_context pack_ctx; /* target info */
stbrp_init_target(&pack_ctx,
@ -584,32 +591,26 @@ void textures_update_atlas(TextureCache *cache) {
cache->node_buffer,
(int)ctx.texture_atlas_size);
stbrp_rect *rects = create_rects_from_cache(cache);
/* we have to keep packing, and creating atlases if necessary, */
/* until all rects have been packed. */
/* ideally, this will not iterate more than once. */
bool textures_remaining = true;
while (textures_remaining) {
stbrp_rect *rects_to_pack = filter_unpacked_rects(rects);
stbrp_pack_rects(&pack_ctx, rects_to_pack, (int)arrlen(rects_to_pack));
textures_remaining = !update_rects(cache, rects, rects_to_pack);
textures_remaining = !update_rects(cache, rects, rects_to_pack, current_atlas_index);
arrfree(rects_to_pack); /* got what we needed */
/* some textures couldn't be packed */
if (textures_remaining) {
update_texture_rects_in_atlas(cache, rects);
recreate_current_atlas_texture(cache);
recreate_current_atlas_texture(cache, current_atlas_index);
/* need a new atlas for next time */
add_new_atlas(cache);
++cache->atlas_index;
if (current_atlas_index >= cache->atlas_index) ++cache->atlas_index;
++current_atlas_index;
}
}
update_texture_rects_in_atlas(cache, rects);
recreate_current_atlas_texture(cache);
recreate_current_atlas_texture(cache, current_atlas_index);
cache->is_dirty = false;