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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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45
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"); profile_start("atlas recreation");
/* TODO: should surfaces be freed after they cannot be referenced in atlas builing? */ /* 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 */ /* 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 */ /* blit the texture surfaces onto the atlas */
for (size_t i = 0; i < shlenu(cache->hash); ++i) { for (size_t i = 0; i < shlenu(cache->hash); ++i) {
/* skip all that aren't part of currently built one */ /* 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; continue;
/* skip loners */ /* skip loners */
@ -284,7 +284,7 @@ static void recreate_current_atlas_texture(TextureCache *cache) {
} }
/* texturize it! */ /* 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"); profile_end("atlas recreation");
} }
@ -337,16 +337,18 @@ static stbrp_rect *filter_unpacked_rects(stbrp_rect *rects) {
/* updates the original rects array with the data from packed_rects */ /* updates the original rects array with the data from packed_rects */
/* returns true if all rects were packed successfully */ /* 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 !!! */ /* !!! do not grow either of the arrays !!! */
/* the reallocation will try to reassign the array pointer, to no effect. */ /* the reallocation will try to reassign the array pointer, to no effect. */
/* see stb_ds.h */ /* see stb_ds.h */
bool packed_all = true; bool packed_all = true;
for (size_t i = 0; i < arrlenu(packed_rects); ++i) { for (size_t i = 0; i < arrlenu(packed_rects); ++i) {
/* we can check if any rects failed to be packed right here */ /* we can check if any rects failed to be packed right here */
/* it's not ideal, but it avoids another iteration */ /* it's not ideal, but it avoids another iteration */
if (!packed_rects[i].was_packed) { 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; packed_all = false;
continue; 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, */ /* 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 */ /* 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 */ /* 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; return packed_all;
@ -566,9 +568,6 @@ void textures_update_atlas(TextureCache *cache) {
upload_texture_from_surface(response.loner_texture, response.data); upload_texture_from_surface(response.loner_texture, response.data);
response.srcrect = (Rect) { .w = (float)response.data->w, .h = (float)response.data->h }; 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; cache->hash[texture_load_queue[i].index].value = response;
@ -576,40 +575,42 @@ void textures_update_atlas(TextureCache *cache) {
arrsetlen(texture_load_queue, 0); arrsetlen(texture_load_queue, 0);
/* 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,
(int)ctx.texture_atlas_size,
(int)ctx.texture_atlas_size,
cache->node_buffer,
(int)ctx.texture_atlas_size);
stbrp_rect *rects = create_rects_from_cache(cache); stbrp_rect *rects = create_rects_from_cache(cache);
int current_atlas_index = 0;
/* we have to keep packing, and creating atlases if necessary, */ /* we have to keep packing, and creating atlases if necessary, */
/* until all rects have been packed. */ /* until all rects have been packed. */
/* ideally, this will not iterate more than once. */ /* ideally, this will not iterate more than once. */
bool textures_remaining = true; bool textures_remaining = true;
while (textures_remaining) { 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,
(int)ctx.texture_atlas_size,
(int)ctx.texture_atlas_size,
cache->node_buffer,
(int)ctx.texture_atlas_size);
stbrp_rect *rects_to_pack = filter_unpacked_rects(rects); stbrp_rect *rects_to_pack = filter_unpacked_rects(rects);
stbrp_pack_rects(&pack_ctx, rects_to_pack, (int)arrlen(rects_to_pack)); 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 */ arrfree(rects_to_pack); /* got what we needed */
/* some textures couldn't be packed */ /* some textures couldn't be packed */
if (textures_remaining) { if (textures_remaining) {
update_texture_rects_in_atlas(cache, rects); 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 */ /* need a new atlas for next time */
add_new_atlas(cache); 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); update_texture_rects_in_atlas(cache, rects);
recreate_current_atlas_texture(cache); recreate_current_atlas_texture(cache, current_atlas_index);
cache->is_dirty = false; cache->is_dirty = false;