How to release memory in Unity? - unity3d

Question

I see that when I create mesh and textures in Unity on each frame (30fps) feels like Unity doesn't release these data from memory after the usage.
There is my code
private bool UpdateFrame(int frameIdx)
{
bool result = true;
int readyBuffSize = DecoderAPI.stream_get_ready_buffer_size(m_stream);
if (m_currMeshFrameIndex != frameIdx
&& readyBuffSize > 0)
{
m_currMeshFrameIndex = frameIdx;
IntPtr frame = DecoderAPI.stream_get_next_frame_obj(m_stream);
if (frame == IntPtr.Zero)
{
result = false;
}
else
{
long sequentialFrameIdx = DecoderAPI.get_sequential_number(frame);
DebugMethod("UNITY UpdateFrame", $"readyBuffSize :: {readyBuffSize}");
DebugMethod("UNITY UpdateFrame", $"sequentialFrameIdx :: {sequentialFrameIdx}");
Mesh releaseFormer = m_meshFilter.mesh;
m_meshFilter.mesh = CrteateMesh(frame);
Texture2D texture = CreateTexture(frame);
m_meshRenderer.material.SetTexture("_MainTex", texture);
DecoderAPI.stream_release_frame_obj(m_stream, frame);
Destroy(releaseFormer); // does not seem to help: even when there are no more allocations in C++ the process grows endlessly
}
}
return result;
}
private Mesh CrteateMesh(IntPtr frame)
{
Mesh mesh = new Mesh();
//Vertices***
int vertexCount = DecoderAPI.frame_get_vertex_count(frame);
byte[] xyzBytes = new byte[vertexCount * 3 * 4];
IntPtr xyz = DecoderAPI.frame_get_vertex_xyz(frame);
Vector3[] vertices = new Vector3[vertexCount];
GCHandle handle = GCHandle.Alloc(vertices, GCHandleType.Pinned);
IntPtr pointer = handle.AddrOfPinnedObject();
Marshal.Copy(xyz, xyzBytes, 0, xyzBytes.Length);
Marshal.Copy(xyzBytes, 0, pointer, xyzBytes.Length);
handle.Free();
mesh.vertices = vertices;
//***
//Faces***
int faceCount = DecoderAPI.frame_face_count(frame);
int trisArrSize = faceCount * 3;
int[] tris = new int[trisArrSize];
IntPtr indices = DecoderAPI.frame_face_indices(frame);
Marshal.Copy(indices, tris, 0, trisArrSize);
mesh.triangles = tris;
//***
mesh.RecalculateNormals();
//UV***
int uvCount = DecoderAPI.frame_get_uv_count(frame);
IntPtr uvData = DecoderAPI.frame_get_uv_data(frame);
int uvArrSize = uvCount * 2;
float[] uvArr = new float[uvArrSize];
Vector2[] uv = new Vector2[uvCount];
Marshal.Copy(uvData, uvArr, 0, uvArrSize);
for (int i = 0; i < uvCount; i++)
{
Vector2 result = new Vector2(uvArr[i * 2], uvArr[i * 2 + 1]) * new Vector2(1, -1);
uv[i] = result;
}
mesh.uv = uv;
//***
if (vertexCount != uvCount)
{
long frameId = DecoderAPI.get_sequential_number(frame);
DebugMethod("UNITY CrteateMesh", $"HERE : in frame id :: {frameId}, vertexCount : {vertexCount}, uvCount : {uvCount}");
}
return mesh;
}
private Texture2D CreateTexture(IntPtr frame)
{
IntPtr textureObj = DecoderAPI.frame_get_texture_obj(frame);
DecoderAPI.TextureInfo textureInfo = DecoderAPI.texture_get_info(textureObj);
int width = textureInfo.width;
int height = textureInfo.height;
int channels = textureInfo.channels;
int stride = textureInfo.stride;
//DecoderAPI.ColorType colorType = textureInfo.color_type;
IntPtr pixels = textureInfo.pixels;
Texture2D texture = new Texture2D(width, height, TextureFormat.RGB24, false);
//Texture2D texture = new Texture2D(width, height, TextureFormat.DXT5, false);
texture.LoadRawTextureData(pixels, width * channels * height);
texture.Apply();
return texture;
}
So, what I do is - I create a mesh and texture for each frame use it and then I expect that Unity should release them from memory after the usage, but no. Ok, I found like this method Destroy(releaseFormer) should help, but anyway it is the same I see in TaskManager that memory grows endlessly...
For test I have tried -> I start my c++ code generate (let's say 100 frames) then I stop it (so my c++ doesn't allocate nothing) and I still see that memory grows up to the end. What I expect is - ok even if Unity doesn't release data that I don't need more, I loaded 100 frames that is it, why memory continues to grow?
Question is - how to release from memory all that frames that I don't need?
EDIT
I have changed this method, added Destroy in proper order
private bool UpdateFrame(int frameIdx)
{
bool result = true;
int readyBuffSize = -1;
if (m_stream != IntPtr.Zero)
{
readyBuffSize = DecoderAPI.stream_get_ready_buffer_size(m_stream);
}
if (m_currMeshFrameIndex != frameIdx
&& readyBuffSize > 0)
{
m_currMeshFrameIndex = frameIdx;
IntPtr frame = DecoderAPI.stream_get_next_frame_obj(m_stream);
if (frame == IntPtr.Zero)
{
result = false;
}
else
{
long sequentialFrameIdx = DecoderAPI.frame_get_sequential_number(frame);
DebugMethod("UNITY UpdateFrame", $"readyBuffSize :: {readyBuffSize}");
DebugMethod("UNITY UpdateFrame", $"sequentialFrameIdx :: {sequentialFrameIdx}");
if (m_meshFilter.mesh != null)
{
Destroy(m_meshFilter.mesh);
}
m_meshFilter.mesh = CrteateMesh(frame);
if (m_texture != null)
{
Destroy(m_texture);
}
m_texture = CreateTexture(frame);
m_meshRenderer.material.SetTexture("_MainTex", m_texture);
if (m_stream != IntPtr.Zero)
{
DecoderAPI.stream_release_frame_obj(m_stream, frame);
}
}
}
return result;
}

Answer 1

releaseFormer is the mesh right? Did you try calling Destroy on the texture object itself?
Another thread suggested Resources.UnloadUnusedAssets()
Personally I'd be trying to do this with a RenderTexture especially if the texture size doesn't change too often, though might not be possible for your use case