From 203cc2a6715dbee3f81c20f7306d3d5f0b78cedc Mon Sep 17 00:00:00 2001
From: Serkyo <serkyo-dev@proton.me>
Date: Sat, 16 May 2026 19:04:20 +0200
Subject: [PATCH] feat(renderer): add dynamic mesh updates via buffer
 reallocation

---
 crates/renderer/src/lib.rs      |  5 +++-
 crates/renderer/src/mesh.rs     |  5 ++++
 crates/renderer/src/renderer.rs | 53 +++++++++++++++++++++++++++++----
 3 files changed, 57 insertions(+), 6 deletions(-)

diff --git a/crates/renderer/src/lib.rs b/crates/renderer/src/lib.rs
index b6b90e6..5d03e2a 100644
--- a/crates/renderer/src/lib.rs
+++ b/crates/renderer/src/lib.rs
@@ -8,7 +8,7 @@
 mod device;
 pub mod error;
 mod instance;
-mod mesh;
+pub mod mesh;
 mod pipeline;
 mod renderer;
 mod surface;
@@ -119,6 +119,8 @@ impl Renderer {
         let (vertex_buffer, vertex_allocation, index_buffer, index_allocation) =
             create_geometry(&device, &mut allocator)?;
 
+        let index_count = 36;
+
         let (depth_image, depth_allocation, depth_image_view) =
             create_depth_resources(&device, &mut allocator, swapchain_extent)?;
 
@@ -144,6 +146,7 @@ impl Renderer {
             allocator,
             index_buffer,
             index_allocation,
+            index_count,
             depth_image,
             depth_allocation,
             depth_image_view,
diff --git a/crates/renderer/src/mesh.rs b/crates/renderer/src/mesh.rs
index 51bd690..6c4c8ec 100644
--- a/crates/renderer/src/mesh.rs
+++ b/crates/renderer/src/mesh.rs
@@ -10,7 +10,9 @@ use bytemuck::{Pod, Zeroable};
 #[derive(Copy, Clone, Debug, Pod, Zeroable)]
 pub struct Vertex {
     /// 3D position of the vertex (X, Y, Z).
+    /// The position coordinates of the vertex [x, y, z].
     pub position: [f32; 3],
+    /// The RGB color of the vertex [r, g, b].
     pub color: [f32; 3],
 }
 
@@ -19,6 +21,9 @@ impl Vertex {
     ///
     /// This defines the 'stride' (distance between vertices) and specifies that
     /// data is read per-vertex rather than per-instance.
+    ///
+    /// # Panics
+    /// Panics if the size of the vertex structure exceeds the maximum value of a 32-bit unsigned integer.
     #[allow(clippy::expect_used)]
     pub fn get_binding_description() -> ash::vk::VertexInputBindingDescription {
         ash::vk::VertexInputBindingDescription::default()
diff --git a/crates/renderer/src/renderer.rs b/crates/renderer/src/renderer.rs
index 79dfb5c..184196a 100644
--- a/crates/renderer/src/renderer.rs
+++ b/crates/renderer/src/renderer.rs
@@ -1,4 +1,5 @@
-use crate::error::RendererError;
+use crate::create_gpu_buffer;
+use crate::{error::RendererError, mesh::Vertex};
 use crate::sync::SyncPrimitives;
 use ash::{Device, Instance, khr, vk};
 use gpu_allocator::vulkan::{Allocation, Allocator};
@@ -58,6 +59,7 @@ pub struct Renderer {
     pub(crate) index_buffer: vk::Buffer,
     /// Memory allocation for the index buffer.
     pub(crate) index_allocation: Allocation,
+    pub(crate) index_count: u32,
     /// The depth image used for depth testing.
     pub(crate) depth_image: vk::Image,
     /// Image view for the depth buffer.
@@ -276,12 +278,12 @@ impl Renderer {
                 f64::from(self.swapchain_extent.width) / f64::from(self.swapchain_extent.height);
             #[allow(clippy::cast_possible_truncation)]
             let mut projection =
-                glam::Mat4::perspective_rh(45.0_f32.to_radians(), aspect as f32, 0.1, 100.0);
+                glam::Mat4::perspective_rh(45.0_f32.to_radians(), aspect as f32, 0.1, 500.0);
             projection.col_mut(1).y *= -1.0;
 
             let view = glam::Mat4::look_at_rh(
-                glam::vec3(2.0, 2.0, 2.0),
-                glam::vec3(0.0, 0.0, 0.0),
+                glam::vec3(16.0, 40.0, 60.0),
+                glam::vec3(16.0, 16.0, 16.0),
                 glam::vec3(0.0, 1.0, 0.0),
             );
 
@@ -297,7 +299,7 @@ impl Renderer {
                 mvp_bytes,
             );
 
-            self.device.cmd_draw_indexed(cmd, 36, 1, 0, 0, 0);
+            self.device.cmd_draw_indexed(cmd, self.index_count, 1, 0, 0, 0);
         }
     }
 
@@ -335,6 +337,47 @@ impl Renderer {
 
         Ok(())
     }
+
+    /// Replaces the currently rendering mesh with a new set of vertices and indices.
+    /// 
+    /// # Errors
+    /// Returns a `RendererError` if new Vulkan buffers cannot be allocated or created.
+    #[allow(clippy::cast_possible_truncation)]
+    pub fn update_mesh(&mut self, vertices: &[Vertex], indices: &[u32]) -> Result<(), RendererError> {
+        unsafe {
+            let _ = self.device.device_wait_idle();
+
+            let _ = self.allocator.free(std::ptr::read(&raw const self.vertex_allocation));
+            self.device.destroy_buffer(self.vertex_buffer, None);
+
+            let _ = self.allocator.free(std::ptr::read(&raw const self.index_allocation));
+            self.device.destroy_buffer(self.index_buffer, None);
+        }
+
+        let (v_buf, v_alloc) = create_gpu_buffer(
+            &self.device, 
+            &mut self.allocator, 
+            bytemuck::cast_slice(vertices), 
+            vk::BufferUsageFlags::VERTEX_BUFFER, 
+            "Chunk Vertex Buffer",
+        )?;
+
+        let (i_buf, i_alloc) = crate::create_gpu_buffer(
+            &self.device,
+            &mut self.allocator,
+            bytemuck::cast_slice(indices),
+            vk::BufferUsageFlags::INDEX_BUFFER,
+            "Chunk Index Buffer",
+        )?;
+
+        self.vertex_buffer = v_buf;
+        self.vertex_allocation = v_alloc;
+        self.index_buffer = i_buf;
+        self.index_allocation = i_alloc;
+        self.index_count = indices.len() as u32;
+
+        Ok(())
+    }
 }
 
 impl Drop for Renderer {