4 files changed, 107 insertions, 21 deletions
diff --git a/src/vk/graphics_pipeline_2d_solid.cpp b/src/vk/graphics_pipeline_2d_solid.cpp
index 5d210be..380bb65 100644
--- a/src/vk/graphics_pipeline_2d_solid.cpp
+++ b/src/vk/graphics_pipeline_2d_solid.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 Frederico de Oliveira Linhares
+ * Copyright 2022-2023 Frederico de Oliveira Linhares
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -299,33 +299,37 @@ GraphicsPipeline2DSolid::draw(
     vkCmdSetScissor(draw_command_buffer, 0, 1, &vk_scissor);
   }
 
+  vkCmdBindPipeline(
+    draw_command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS,
+    this->graphic_pipeline);
+
+  // FIXME: I know sorting is expensive, but I need to figure out better what
+  // to do here.
+  std::sort(view->sprites_to_draw[current_frame].rbegin(),
+            view->sprites_to_draw[current_frame].rend());
+
   // Draw sprites
-  for(auto& [sprite, positions]: view->sprites_to_draw[current_frame])
+  for(auto& sprite_to_draw: view->sprites_to_draw[current_frame])
   {
     std::array<VkDescriptorSet, 2> vk_descriptor_sets{
       view->descriptor_sets_2d[image_index],
-      sprite->descriptor_sets[image_index]};
+      sprite_to_draw.sprite->descriptor_sets[image_index]};
     VkDeviceSize offsets[]{0};
 
     vkCmdBindDescriptorSets(
       draw_command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS,
       cg_core.vk_graphics_pipeline_2d_solid_layout->pipeline, 0,
       vk_descriptor_sets.size(), vk_descriptor_sets.data(), 0, nullptr);
-    vkCmdBindPipeline(
-      draw_command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS,
-      this->graphic_pipeline);
     vkCmdBindVertexBuffers(
-      draw_command_buffer, 0, 1, &sprite->vertex_buffer->buffer, offsets);
-
-    for(auto i{0}; i < positions.size(); i++)
-    {
-      ODOVector4D position{positions[i]};
-      vkCmdPushConstants(
-        draw_command_buffer,
-        cg_core.vk_graphics_pipeline_2d_solid_layout->pipeline,
-        VK_SHADER_STAGE_VERTEX_BIT, 0, sizeof(ODOVector4D), &position);
-      vkCmdDraw(draw_command_buffer, Sprite::vertex_count, 1, 0, 0);
-    }
+      draw_command_buffer, 0, 1, &sprite_to_draw.sprite->vertex_buffer->buffer,
+      offsets);
+
+    ODOVector4D position{sprite_to_draw.position};
+    vkCmdPushConstants(
+      draw_command_buffer,
+      cg_core.vk_graphics_pipeline_2d_solid_layout->pipeline,
+      VK_SHADER_STAGE_VERTEX_BIT, 0, sizeof(ODOVector4D), &position);
+    vkCmdDraw(draw_command_buffer, Sprite::vertex_count, 1, 0, 0);
   }
 
   // Prepare for the next frame.
diff --git a/src/vk/sprite_to_draw.cpp b/src/vk/sprite_to_draw.cpp
new file mode 100644
index 0000000..76ee847
--- /dev/null
+++ b/src/vk/sprite_to_draw.cpp
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022-2023 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "sprite_to_draw.hpp"
+
+namespace VK
+{
+  SpriteToDraw::SpriteToDraw(
+    std::shared_ptr<Sprite> sprite, const glm::vec4 &position, float z_index):
+    sprite{sprite},
+    position{position},
+    z_index{z_index}
+  {
+  }
+
+  bool
+  operator<(const SpriteToDraw& a, const SpriteToDraw& b)
+  {
+    return a.z_index < b.z_index;
+  }
+
+  bool
+  operator>(const SpriteToDraw& a, const SpriteToDraw& b)
+  {
+    return a.z_index > b.z_index;
+  }
+}
diff --git a/src/vk/sprite_to_draw.hpp b/src/vk/sprite_to_draw.hpp
new file mode 100644
index 0000000..3bd6af3
--- /dev/null
+++ b/src/vk/sprite_to_draw.hpp
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2022-2023 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_VK_SPRITES_TO_DRAW_2D_H
+#define CANDY_GEAR_VK_SPRITES_TO_DRAW_2D_H 1
+
+#include <memory>
+
+#include "core.hpp"
+#include "sprite.hpp"
+
+namespace VK
+{
+  struct SpriteToDraw
+  {
+    std::shared_ptr<Sprite> sprite;
+    glm::vec4 position;
+    float z_index;
+
+    SpriteToDraw(std::shared_ptr<Sprite> sprite, const glm::vec4 &position,
+                 float z_index);
+  };
+
+  bool
+  operator<(const SpriteToDraw &a, const SpriteToDraw &b);
+
+  bool
+  operator<(const SpriteToDraw &a, const SpriteToDraw &b);
+}
+
+#endif /* CANDY_GEAR_VK_SPRITES_TO_DRAW_2D_H */
diff --git a/src/vk/view_2d.hpp b/src/vk/view_2d.hpp
index caa3d0f..ead21e2 100644
--- a/src/vk/view_2d.hpp
+++ b/src/vk/view_2d.hpp
@@ -22,7 +22,7 @@
 #include <vector>
 
 #include "core.hpp"
-#include "sprite.hpp"
+#include "sprite_to_draw.hpp"
 #include "rectangle.hpp"
 
 namespace VK
@@ -40,9 +40,7 @@ struct View2D
   std::vector<VkDescriptorSet> descriptor_sets_2d;
 
   std::vector<std::vector<Rectangle>> rectangles_to_draw;
-  std::vector<
-    std::unordered_map<std::shared_ptr<Sprite>, std::vector<glm::vec4>>>
-  sprites_to_draw;
+  std::vector<std::vector<SpriteToDraw>> sprites_to_draw;
 
   View2D(glm::vec4 region, float projection_width, float projection_height);
   virtual ~View2D();