From 684438cd678dac0840a162a36e6c7bd120178205 Mon Sep 17 00:00:00 2001
From: caiowakamatsu <caiodcw@gmail.com>
Date: Mon, 30 Mar 2026 00:07:21 -0300
Subject: [PATCH] add indirect command buffer to registered meshes

---
 source/render/renderer.cpp | 24 ++++++++++++++++++++----
 source/render/renderer.hpp |  1 +
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/source/render/renderer.cpp b/source/render/renderer.cpp
index 990560c..6bd84cc 100644
--- a/source/render/renderer.cpp
+++ b/source/render/renderer.cpp
@@ -103,18 +103,34 @@ std::uint32_t renderer::register_mesh(const game::mesh_node &mesh) {
       context.superframe_allocator, vuk::MemoryUsage::eCPUtoGPU,
       vuk::DomainFlagBits::eTransferOperation, std::span(mesh.indices));
 
+  const auto indirect_draw = std::array<std::uint32_t, 5>({
+      static_cast<std::uint32_t>(mesh.indices.size()), // index count
+      1,                                               // instance count
+      0,                                               // first index
+      0, // vertex offset (int32 technically)
+      0, // first instance
+  });
+
+  auto [indirect_buffer, indirect_future] = vuk::create_buffer(
+      context.superframe_allocator, vuk::MemoryUsage::eCPUtoGPU,
+      vuk::DomainFlagBits::eTransferOperation,
+      std::span<const std::uint32_t>(indirect_draw));
+
   auto futures = std::vector<vuk::UntypedValue>();
   futures.push_back(std::move(vertex_future));
   futures.push_back(std::move(index_future));
+  futures.push_back(std::move(indirect_future));
 
   // TODO: Make async?
   vuk::wait_for_values_explicit(context.superframe_allocator, context.compiler,
                                 std::span(futures));
 
-  registered_meshes.insert({id, loaded_mesh{
-                                    .vertices = std::move(vertex_buffer),
-                                    .indices = std::move(index_buffer),
-                                }});
+  registered_meshes.insert(
+      {id, loaded_mesh{
+               .vertices = std::move(vertex_buffer),
+               .indices = std::move(index_buffer),
+               .indirect_command = std::move(indirect_buffer),
+           }});
 
   return id;
 }
diff --git a/source/render/renderer.hpp b/source/render/renderer.hpp
index f2cd2b6..53f093a 100644
--- a/source/render/renderer.hpp
+++ b/source/render/renderer.hpp
@@ -26,6 +26,7 @@ private:
   struct loaded_mesh {
     vuk::Unique<vuk::Buffer> vertices;
     vuk::Unique<vuk::Buffer> indices;
+    vuk::Unique<vuk::Buffer> indirect_command;
   };
   std::unordered_map<std::uint32_t, loaded_mesh> registered_meshes;