diff --git a/IGLU/simple_renderer/ShaderUniforms.cpp b/IGLU/simple_renderer/ShaderUniforms.cpp
index 46f076192a..27530caecd 100644
--- a/IGLU/simple_renderer/ShaderUniforms.cpp
+++ b/IGLU/simple_renderer/ShaderUniforms.cpp
@@ -516,7 +516,26 @@ void ShaderUniforms::setFloat3x3Array(const igl::NameHandle& uniformName,
                                       const iglu::simdtypes::float3x3* value,
                                       size_t count,
                                       size_t arrayIndex) {
-  setUniformBytes(uniformName, value, sizeof(iglu::simdtypes::float3x3), count, arrayIndex);
+  if (device_.getBackendType() == igl::BackendType::Metal ||
+      device_.getBackendType() == igl::BackendType::Vulkan) {
+    setUniformBytes(uniformName, value, sizeof(iglu::simdtypes::float3x3), count, arrayIndex);
+  } else {
+    // simdtypes::float3x3 has an extra float per float-vector.
+    // Remove it so we can send the packed version to OpenGL
+    auto paddedMatrixPtr = reinterpret_cast<const float*>(value);
+    auto packedMatrix = new float[9 * count];
+    auto packedMatrixPtr = packedMatrix;
+    for (int n = 0; n < count; n++) {
+      for (int i = 0; i < 3; i++) {
+        for (int j = 0; j < 3; j++) {
+          *packedMatrixPtr++ = *paddedMatrixPtr++;
+        }
+        paddedMatrixPtr++; // skip over padded float
+      }
+    }
+    setUniformBytes(uniformName, packedMatrix, sizeof(float) * 9, count, arrayIndex);
+    delete[] packedMatrix;
+  }
 }
 
 void ShaderUniforms::setFloat4x4(const igl::NameHandle& uniformName,