feat(engine): add UpdateMesh renderer command

3 files changed, 99 insertions, 0 deletions

diff --git a/engine/src/renderer.rs b/engine/src/renderer.rs
index d7ce02e..bf1cb51 100644
--- a/engine/src/renderer.rs
+++ b/engine/src/renderer.rs
@@ -180,6 +180,12 @@ pub enum Command
 
         usage: MeshUsage,
     },
+    UpdateMesh
+    {
+        obj_id: ObjectId,
+        mesh: Mesh,
+        usage: MeshUsage,
+    },
     DrawMesh(ObjectId),
     SetPolygonModeConfig(PolygonModeConfig),
 }
diff --git a/engine/src/renderer/opengl.rs b/engine/src/renderer/opengl.rs
index 911a155..f1ca7a5 100644
--- a/engine/src/renderer/opengl.rs
+++ b/engine/src/renderer/opengl.rs
@@ -1026,6 +1026,57 @@ fn handle_commands(
 
                     *next_graphics_ctx_object_key += 1;
                 }
+                RendererCommand::UpdateMesh {
+                    obj_id: mesh_object_id,
+                    mesh,
+                    usage: mesh_usage,
+                } => {
+                    let Some(curr_gl_ctx) = &opt_curr_gl_ctx else {
+                        tracing::error!("No GL context is current");
+                        continue;
+                    };
+
+                    let Some(mesh_graphics_ctx_obj_key) = renderer_object_store
+                        .get_obj(&mesh_object_id)
+                        .map(|obj| obj.as_raw())
+                    else {
+                        tracing::error!(
+                            object_id=?mesh_object_id,
+                            "Object store does not contain a mesh object with this ID"
+                        );
+                        continue;
+                    };
+
+                    let Some(mesh_graphics_ctx_obj) =
+                        graphics_ctx_objects.get_mut(&mesh_graphics_ctx_obj_key)
+                    else {
+                        tracing::error!(
+                            object_id=?mesh_object_id,
+                            key=mesh_graphics_ctx_obj_key,
+                            "Graphics context does not contain a mesh object with this key"
+                        );
+                        continue;
+                    };
+
+                    #[allow(irrefutable_let_patterns)]
+                    let GraphicsContextObject::Mesh {
+                        mesh: graphics_mesh,
+                        compatible_shader_program_obj_id: _,
+                    } = mesh_graphics_ctx_obj
+                    else {
+                        tracing::error!(
+                            object_id=?mesh_object_id,
+                            key=mesh_graphics_ctx_obj_key,
+                            "Graphics context object with this key is not a mesh"
+                        );
+                        continue;
+                    };
+
+                    if let Err(err) = graphics_mesh.update(curr_gl_ctx, &mesh, mesh_usage)
+                    {
+                        tracing::error!("Failed to update mesh: {err}");
+                    }
+                }
                 RendererCommand::DrawMesh(mesh_object_id) => {
                     let Some(curr_gl_ctx) = &opt_curr_gl_ctx else {
                         tracing::error!("No GL context is current");
diff --git a/engine/src/renderer/opengl/graphics_mesh.rs b/engine/src/renderer/opengl/graphics_mesh.rs
index 3cf9181..c5ff0c6 100644
--- a/engine/src/renderer/opengl/graphics_mesh.rs
+++ b/engine/src/renderer/opengl/graphics_mesh.rs
@@ -143,6 +143,48 @@ impl GraphicsMesh
         })
     }
 
+    pub fn update(
+        &mut self,
+        current_context: &GlCurrentContextWithFns<'_>,
+        mesh: &Mesh,
+        mesh_usage: MeshUsage,
+    ) -> Result<(), Error>
+    {
+        let buffer_usage = mesh_usage_to_gl_buffer_usage(mesh_usage);
+
+        self.vertex_buffer
+            .store(current_context, mesh.vertex_buf().as_bytes(), buffer_usage)
+            .map_err(Error::StoreVerticesFailed)?;
+
+        if let Some(indices) = mesh.indices() {
+            let index_buffer = self
+                .index_buffer
+                .get_or_insert_with(|| GlBuffer::new(current_context));
+
+            index_buffer
+                .store(current_context, indices, buffer_usage)
+                .map_err(Error::StoreIndicesFailed)?;
+
+            self.vertex_arr
+                .bind_element_buffer(current_context, &index_buffer);
+
+            self.element_cnt = indices
+                .len()
+                .try_into()
+                .expect("Mesh index count does not fit into a 32-bit unsigned int");
+
+            return Ok(());
+        }
+
+        self.element_cnt = mesh
+            .vertex_buf()
+            .len()
+            .try_into()
+            .expect("Mesh vertex count does not fit into a 32-bit unsigned int");
+
+        Ok(())
+    }
+
     pub fn destroy(&mut self, curr_gl_ctx: &GlCurrentContextWithFns<'_>)
     {
         self.vertex_arr.delete(curr_gl_ctx);