feat(engine): add offset options to renderer::Command::DrawMesh

1 files changed, 11 insertions, 7 deletions

diff --git a/engine/src/renderer/opengl.rs b/engine/src/renderer/opengl.rs
index b434cd8..81cbdc2 100644
--- a/engine/src/renderer/opengl.rs
+++ b/engine/src/renderer/opengl.rs
@@ -93,6 +93,7 @@ use crate::renderer::{
     Command as RendererCommand,
     CommandQueue as RendererCommandQueue,
     CtxUsedByWindow as RendererCtxUsedByWindow,
+    DrawMeshOptions,
     DrawPropertiesUpdateFlags,
     GraphicsProperties,
     PRE_RENDER_PHASE,
@@ -1089,7 +1090,7 @@ fn handle_commands(
                         tracing::error!("Failed to update mesh: {err}");
                     }
                 }
-                RendererCommand::DrawMesh(mesh_object_id) => {
+                RendererCommand::DrawMesh(mesh_object_id, draw_mesh_opts) => {
                     let Some(curr_gl_ctx) = &opt_curr_gl_ctx else {
                         tracing::error!("No GL context is current");
                         continue;
@@ -1145,7 +1146,9 @@ fn handle_commands(
                         continue;
                     }
 
-                    if let Err(err) = draw_mesh(&curr_gl_ctx, graphics_mesh) {
+                    if let Err(err) =
+                        draw_mesh(&curr_gl_ctx, graphics_mesh, &draw_mesh_opts)
+                    {
                         tracing::error!("Failed to draw mesh: {err}");
                     };
                 }
@@ -1330,6 +1333,7 @@ fn set_viewport(
 fn draw_mesh(
     current_context: &CurrentContextWithFns<'_>,
     graphics_mesh: &GraphicsMesh,
+    opts: &DrawMeshOptions,
 ) -> Result<(), GlDrawError>
 {
     graphics_mesh.vertex_arr.bind(current_context);
@@ -1339,17 +1343,17 @@ fn draw_mesh(
             current_context,
             opengl_bindings::vertex_array::DrawElementsOptions {
                 primitive_kind: PrimitiveKind::Triangles,
-                element_offset: 0,
-                element_cnt: graphics_mesh.element_cnt,
-                vertex_offset: 0,
+                element_offset: opts.element_offset,
+                element_cnt: opts.element_cnt.unwrap_or(graphics_mesh.element_cnt),
+                vertex_offset: opts.vertex_offset,
             },
         )?;
     } else {
         VertexArray::draw_arrays(
             current_context,
             PrimitiveKind::Triangles,
-            0,
-            graphics_mesh.element_cnt,
+            opts.vertex_offset,
+            opts.element_cnt.unwrap_or(graphics_mesh.element_cnt),
         )?;
     }