Add renderer draw descriptor contract

src/renderer_api/renderer_api.cpp

@@ -337,6 +337,40 @@ pp::foundation::Status validate_mesh_desc(MeshDesc desc) noexcept
     return pp::foundation::Status::invalid_argument("mesh topology is not supported");
 }
 
+pp::foundation::Status validate_draw_desc(MeshDesc mesh, DrawDesc draw) noexcept
+{
+    const auto mesh_status = validate_mesh_desc(mesh);
+    if (!mesh_status.ok()) {
+        return mesh_status;
+    }
+
+    if (draw.instance_count == 0) {
+        return pp::foundation::Status::invalid_argument("draw instance count must be greater than zero");
+    }
+
+    if (draw.vertex_count == 0 && draw.index_count == 0) {
+        return pp::foundation::Status::invalid_argument("draw must include vertices or indices");
+    }
+
+    if (draw.index_count > 0) {
+        if (mesh.index_count == 0) {
+            return pp::foundation::Status::invalid_argument("indexed draw requires an indexed mesh");
+        }
+
+        if (draw.first_index > mesh.index_count || draw.index_count > mesh.index_count - draw.first_index) {
+            return pp::foundation::Status::out_of_range("draw index range exceeds the bound mesh");
+        }
+
+        return pp::foundation::Status::success();
+    }
+
+    if (draw.first_vertex > mesh.vertex_count || draw.vertex_count > mesh.vertex_count - draw.first_vertex) {
+        return pp::foundation::Status::out_of_range("draw vertex range exceeds the bound mesh");
+    }
+
+    return pp::foundation::Status::success();
+}
+
 pp::foundation::Status validate_texture_slot(std::uint32_t slot) noexcept
 {
     if (slot >= max_texture_slots) {