Merge pull request #1 from trapexit/packed_transparent

Fix packing of transparent pixels
trapexit · Aug 6, 2022 · 841d08c · 841d08c
2 parents 1279d71 + c60849e
commit 841d08c
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Showing 4 changed files with 69 additions and 28 deletions.
diff --git a/examples/alpha.png b/examples/alpha.png
diff --git a/src/cel_packer.cpp b/src/cel_packer.cpp
@@ -96,20 +96,50 @@ pass0(const Bitmap        &b_,
 
 static
 void
-pass1_pack_packed(AbstractPackedImage &pi_)
+pass1_replace_alpha(AbstractPackedImage &pi_,
+                    RGB8888              transparent_)
+{
+  for(auto &pdp_list : pi_)
+    {
+      for(auto &pdp : pdp_list)
+        {
+          if(pdp.pixels[0].a == 0x00)
+            pdp.pixels[0] = transparent_;
+        }
+    }
+}
+
+static
+bool
+can_pack(PackedDataPacket &curpdp_,
+         PackedDataPacket &newpdp_)
+{
+  if(!(curpdp_.pixels[0] == newpdp_.pixels[0]))
+    return false;
+  if(newpdp_.pixels.size() < 64)
+    return true;
+  return false;
+}
+
+static
+void
+pass2_pack_packed(AbstractPackedImage &pi_)
 {
   for(auto &pdp_list : pi_)
     {
       std::vector<PackedDataPacket> newpdp_list;
 
       newpdp_list.emplace_back(pdp_list[0]);
+
       for(size_t i = 1; i < pdp_list.size(); i++)
         {
-          if((pdp_list[i].pixels[0] == newpdp_list.back().pixels[0]) &&
-             (newpdp_list.back().pixels.size() < 64))
+          PackedDataPacket &curpdp = pdp_list[i];
+          PackedDataPacket &newpdp = newpdp_list.back();
+
+          if(::can_pack(curpdp,newpdp))
             {
-              newpdp_list.back().type = PACK_PACKED;
-              newpdp_list.back().pixels.emplace_back(pdp_list[0].pixels[0]);
+              newpdp.type = PACK_PACKED;
+              newpdp.pixels.emplace_back(curpdp.pixels[0]);
             }
           else
             {
@@ -123,7 +153,27 @@ pass1_pack_packed(AbstractPackedImage &pi_)
 
 static
 void
-pass2_pack_literal(AbstractPackedImage &pi_)
+pass3_make_transparent(AbstractPackedImage &pi_,
+                       RGB8888              transparent_)
+{
+  for(auto &pdp_list : pi_)
+    {
+      for(auto &pdp : pdp_list)
+        {
+          if(!(pdp.pixels[0] == transparent_))
+            continue;
+
+          if(pdp.type == PACK_PACKED)
+            pdp.type = PACK_TRANSPARENT;
+          else if(pdp.type == PACK_LITERAL)
+            pdp.type = PACK_TRANSPARENT;
+        }
+    }
+}
+
+static
+void
+pass4_pack_literal(AbstractPackedImage &pi_)
 {
   for(auto &pdp_list : pi_)
     {
@@ -132,7 +182,7 @@ pass2_pack_literal(AbstractPackedImage &pi_)
       for(size_t i = 0; i < pdp_list.size();)
         {
           newpdp_list.emplace_back(pdp_list[i]);
-          if(pdp_list[i].type == PACK_PACKED)
+          if(pdp_list[i].type != PACK_LITERAL)
             {
               i++;
               continue;
@@ -152,23 +202,6 @@ pass2_pack_literal(AbstractPackedImage &pi_)
     }
 }
 
-static
-void
-pass3_pack_transparent(AbstractPackedImage &pi_,
-                       RGB8888              transparent_)
-{
-  for(auto &pdp_list : pi_)
-    {
-      for(auto &pdp : pdp_list)
-        {
-          if(pdp.pixels[0] == transparent_)
-            pdp.type = PACK_TRANSPARENT;
-          else if(pdp.pixels[0].a == 0xFF)
-            pdp.type = PACK_TRANSPARENT;
-        }
-    }
-}
-
 static
 void
 api_to_bytevec(const Bitmap              &b_,
@@ -239,9 +272,10 @@ CelPacker::pack(const Bitmap            &b_,
 
 
   pass0(b_,api);
-  pass1_pack_packed(api);
-  pass2_pack_literal(api);
-  pass3_pack_transparent(api,transparent_color_);
+  pass1_replace_alpha(api,transparent_color_);
+  pass2_pack_packed(api);
+  pass3_make_transparent(api,transparent_color_);
+  pass4_pack_literal(api);
 
   api_to_bytevec(b_,api,pc_,pdat_);
 };
diff --git a/src/convert.cpp b/src/convert.cpp
@@ -793,7 +793,7 @@ unpack_row(BitStreamReader &bs_,
         case PACK_TRANSPARENT:
           {
             count = bs_.read(6) + 1;
-            pw_.write(0,count);
+            pw_.write_transparent(count);
           }
           break;
         case PACK_PACKED:

diff --git a/src/pixel_writer.hpp b/src/pixel_writer.hpp
@@ -160,6 +160,13 @@ class PixelWriter
     _data[_idx++] = a_;
   }
 
+  void
+  write_transparent(const uint32_t n_)
+  {
+    for(uint32_t i = 0; i < n_; i++)
+      write_rgba(0,0,0,0);
+  }
+
   void
   write_0555(const uint16_t rgb_)
   {