Code is very slow

[malvislight]

The main problem is Texture.Apply(). Even on powerful Android devices (Samsung Galaxy S25 Ultra), FPS drops to 30 with just four 512×512 Lottie animations. You should change your native code to create the texture on the native side, and in Unity call Texture2D.CreateExternalTexture. I can help you with that.

[gindemit]

Hi @malvislight, I recently received similar issue from @LightSideMeowshop
Can you please review the current implementation. I do have the allocation for the native texture on the native side:

unity-rlottie/src/LottiePlugin.cpp

Line 120 in 708127f

EXPORT_API int32_t lottie_allocate_render_data(lottie_render_data** render_data) {

Here copy pasted code:

    EXPORT_API int32_t lottie_allocate_render_data(lottie_render_data** render_data) {
        *render_data = new lottie_render_data();
         if (*render_data == nullptr){

            fprintf(stderr, "Couldnt allocate lottie_render_data!");
            return -1;
        }
        return 0;
    }
    EXPORT_API int32_t lottie_dispose_render_data(lottie_render_data** render_data) {
        delete (*render_data);
        *render_data = nullptr;
        return 0;
    }

And I use the same Texture buffer between C# and C++ worlds:

unity-rlottie/unity/RLottieUnity/Assets/LottiePlugin/Runtime/src/LottieAnimation.cs

Line 135 in 708127f

_lottieRenderData.buffer = _pixelData.GetUnsafePtr();

Here copy pasted code:

private unsafe void CreateRenderDataTexture2DMarshalToNative(uint width, uint height)
        {
            _lottieRenderData = new LottieRenderData();
            _lottieRenderData.width = width;
            _lottieRenderData.height = height;
            _lottieRenderData.bytesPerLine = width * sizeof(uint);
            Texture = new Texture2D(
                (int)_lottieRenderData.width,
                (int)_lottieRenderData.height,
                TextureFormat.BGRA32,
                0,
                false);
            _pixelData = Texture.GetRawTextureData<byte>();
            _lottieRenderData.buffer = _pixelData.GetUnsafePtr();
            NativeBridge.LottieAllocateRenderData(ref _lottieRenderDataIntPtr);
            Marshal.StructureToPtr(_lottieRenderData, _lottieRenderDataIntPtr, false);
        }

Can you please elaborate what do you mean?

[malvislight]

The problem is that Texture.Apply() triggers a CPU→GPU upload of the pixel buffer, which is expensive to do every frame. On the native side you can create the texture yourself, then in Unity wrap it with Texture2D.CreateExternalTexture, and each frame only call Texture2D.UpdateExternalTexture. This way we avoid heavy CPU load from copying data between CPU and GPU memory—the texture stays resident on the GPU