feat: draw meshes with instanced multi-draw indirect

destrum/assets_src/shaders/instance_data.glsl

@@ -0,0 +1,21 @@
+#ifndef INSTANCE_DATA_GLSL
+#define INSTANCE_DATA_GLSL
+
+#extension GL_EXT_buffer_reference : require
+#extension GL_EXT_scalar_block_layout : require
+
+#include "vertex.glsl"
+
+// Must match GPUInstanceData in IndirectDrawList.h
+struct InstanceData {
+    mat4 transform;
+    VertexBuffer vertexBuffer;
+    uint materialID;
+    uint padding;
+};
+
+layout (buffer_reference, scalar) readonly buffer InstanceBuffer {
+    InstanceData instances[];
+};
+
+#endif // INSTANCE_DATA_GLSL