# Qt+OpenCV use cv::ogl::texture2D::copyFrom( cv::cuda::GpuMat) to get texture directly **URL:** \ **Category:** C++\ **Tags:** gpu, cuda\ **Created:** [July 5, 2022, 9:01am UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400 "2022-07-05T09:01:00Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Touch](https://avatars.discourse-cdn.com/v4/letter/t/51bf81/32.png) [@Touch](https://forum.opencv.org/u/Touch)\ **Post date:** [July 5, 2022, 9:01am UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/1 "2022-07-05T09:01:00Z")
I am writing a module which gets `cv::cuda::GpuMat` data on gpu and draw it on `QOpenGLWidget`. To accelarate the speed, I want to avoid downloading data from device to host. This is the main code ```auto void MyPainter::drawImage(QMatrix4x4 transform_matrix, const cv::Mat &img) { if(parent->context() == 0){ parent->makeCurrent(); } shader_program->bind(); cv::cuda::GpuMat gpumat_img; qDebug() << "upload img...."; gpumat_img.upload(img); // for test, because other modules are unfished qDebug() << gpumat_img.empty() << gpumat_img.type() << "Finish upload"; qDebug() << gpumat_img.size().width << gpumat_img.size().height; cv::ogl::Texture2D test_texture; qDebug() << "copy to texture memory...."; test_texture.copyFrom(gpumat_img); // here raise an error. qDebug() << "Finish copy"; test_texture.bind(); vbo.bind(); qDebug() << test_texture.size().width << test_texture.size().height; shader_program->setUniformValue("matrix", transform_matrix); shader_program->enableAttributeArray(MYSHADER_VERTEX_ATTRIBUTE); shader_program->enableAttributeArray(MYSHADER_TEXCOORD_ATTRIBUTE); shader_program->setAttributeBuffer(MYSHADER_VERTEX_ATTRIBUTE, GL_FLOAT, 0, 2); shader_program->setAttributeBuffer(MYSHADER_TEXCOORD_ATTRIBUTE, GL_FLOAT, 0, 2); QOpenGLFunctions *gl_function_ptr = QOpenGLContext::currentContext()->functions(); gl_function_ptr->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); shader_program->release(); test_texture.release(); vbo.release(); } ``` The error tells **“OpenCV(4.6.0) Error: Gpu API call (OS call failed or operation not supported on this OS) in `anonymous-namespace’::CudaResource::registerBuffer, file D:\lib\opencv\_my\source\opencv-4.6.0\modules\core\src\opengl.cpp, line 176”** But if I use the `cv::ogl::texture2D::copyFrom(cv::Mat)` instead of `cv::ogl::texture2D::copyFrom(cv::cuda::GpuMat)`, it can work well. I read some source code of opencv and find the error is appear at here: ```auto void CudaResource::registerBuffer(GLuint buffer) { CV_DbgAssert( buffer != 0 ); if (buffer_ == buffer) return; cudaGraphicsResource_t resource; cudaSafeCall( cudaGraphicsGLRegisterBuffer(&resource, buffer, cudaGraphicsMapFlagsNone) ); // here raise the error release(); resource_ = resource; buffer_ = buffer; } ``` But i can’t find `cudaGraphicsGLRegisterBuffer()`. My environment ```auto Qt 7.0.0 OpenCV 4.6.0 CUDA 11.6 ``` Apologize for my poor English. ---
**Author:** ![cudawarped](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@cudawarped](https://forum.opencv.org/u/cudawarped)\ **Post date:** [July 5, 2022, 4:53pm UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/2 "2022-07-05T16:53:50Z")
This is something I’ve wanted to try for ages, so please let me know how you get on. Regarding the error, have you checked the [test cases](https://github.com/opencv/opencv_contrib/blob/9d0a451bee4cdaf9d3f76912e5abac6000865f1a/modules/cudaarithm/test/test_opengl.cpp#L311)? I had a quick look and didn’t get any errors from ```auto cv::namedWindow("test", cv::WINDOW_OPENGL); const Size sz(128, 128); cv::cuda::GpuMat tmp(sz, CV_8UC1); cv::ogl::Texture2D tex(sz, cv::ogl::Texture2D::DEPTH_COMPONENT, true); tex.copyFrom(tmp, true); ``` ---
**Author:** ![Touch](https://avatars.discourse-cdn.com/v4/letter/t/51bf81/32.png) [@Touch](https://forum.opencv.org/u/Touch)\ **Post date:** [July 6, 2022, 9:02am UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/3 "2022-07-06T09:02:30Z")
Thanks! And I tried the code you given. But it shows the same error ```auto OpenCV: terminate handler is called! The last OpenCV error is: OpenCV(4.6.0) Error: Gpu API call (OS call failed or operation not supported on this OS) in `anonymous-namespace'::CudaResource::registerBuffer, file D:\lib\opencv_my\source\opencv-4.6.0\modules\core\src\opengl.cpp, line 176 ``` I guess it is because of the cuda environment, but I can’t find more information about the error. !!! I use the same code in my vs+cuda+opencv project. And it can work without error and show an image. ```auto cv::Mat mat_img; mat_img = cv::imread("C:/Users/Touch/Desktop/0.jpg"); cv::namedWindow("test", cv::WINDOW_OPENGL); cv::cuda::GpuMat tmp; tmp.upload(mat_img); cv::ogl::Texture2D tex; tex.copyFrom(tmp, true); cv::imshow("test", tex); cv::waitKey(0); ``` ---
**Author:** ![cudawarped](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@cudawarped](https://forum.opencv.org/u/cudawarped)\ **Post date:** [July 6, 2022, 9:18am UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/4 "2022-07-06T09:18:57Z")
Can you run `bin\opencv_test_cudaarithm.exe --gtest_filter=OpenGL/Texture2D.Constructor1/0` without errors? e.g. > [RUN] OpenGL/Texture2D.Constructor1/0, where GetParam() = (128x128, 8UC1) > [OK] OpenGL/Texture2D.Constructor1/0 (2926 ms) > [----------] 1 test from OpenGL/Texture2D (2927 ms total) > > [----------] Global test environment tear-down > [==========] 1 test from 1 test case ran. (3090 ms total) > [PASSED] 1 test. Do any of the tests from opencv\_test\_cudaarithm.exe report that they have `PASSED` ---
**Author:** ![Touch](https://avatars.discourse-cdn.com/v4/letter/t/51bf81/32.png) [@Touch](https://forum.opencv.org/u/Touch)\ **Post date:** [July 6, 2022, 9:30am UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/5 "2022-07-06T09:30:03Z")
Yes i can pass the test. ```auto OpenCV version: 4.6.0 OpenCV VCS version: unknown Build type: Debug Release WARNING: build value differs from runtime: Release Compiler: C:/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.32.31326/bin/Hostx64/x64/cl.exe (ver 19.32.31329.0) Parallel framework: ms-concurrency (nthreads=16) CPU features: SSE? SSE2? SSE3? Intel(R) IPP version: disabled OpenCL is disabled TEST: Skip tests with tags: 'mem_6gb', 'verylong' Note: Google Test filter = OpenGL/Texture2D.Constructor1/0 [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from OpenGL/Texture2D [RUN] OpenGL/Texture2D.Constructor1/0, where GetParam() = (128x128, 8UC1) [OK] OpenGL/Texture2D.Constructor1/0 (3 ms) [----------] 1 test from OpenGL/Texture2D (3 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (172 ms total) [PASSED] 1 test. ``` I guess the problem is on my qt project environment. Because my visual studio project with opencv+cuda doesn’t have the error. ---
**Author:** ![cudawarped](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@cudawarped](https://forum.opencv.org/u/cudawarped)\ **Post date:** [July 6, 2022, 9:31am UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/6 "2022-07-06T09:31:50Z")
Let me know if you solve the problem, I will try later in a QT project to see if I get the same issue. ---
**Author:** ![Touch](https://avatars.discourse-cdn.com/v4/letter/t/51bf81/32.png) [@Touch](https://forum.opencv.org/u/Touch)\ **Post date:** [July 6, 2022, 11:17am UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/7 "2022-07-06T11:17:50Z")
OK but i haven’t found any solution yet. 😂 ---
**Author:** ![cudawarped](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@cudawarped](https://forum.opencv.org/u/cudawarped)\ **Post date:** [July 6, 2022, 1:34pm UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/8 "2022-07-06T13:34:16Z")
I don’t get any errors in QT running the test code in a class derived from QLabel. ---
**Author:** ![Touch](https://avatars.discourse-cdn.com/v4/letter/t/51bf81/32.png) [@Touch](https://forum.opencv.org/u/Touch)\ **Post date:** [July 7, 2022, 2:29am UTC](https://forum.opencv.org/t/qt-opencv-use-cv-copyfrom-cv-gpumat-to-get-texture-directly/9400/9 "2022-07-07T02:29:59Z")
wow. I create a clickbutton on mainWidget and connect the signal and the test code as slot funtion. I think this doesn’t matter. Could you please show me you `.pro` file? And this is my `.prg` file. ```auto QT += core gui greaterThan(QT_MAJOR_VERSION, 4): QT += widgets CONFIG += c++17 # You can make your code fail to compile if it uses deprecated APIs. # In order to do so, uncomment the following line. #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0 # Default rules for deployment. qnx: target.path = /tmp/$${TARGET}/bin else: unix:!android: target.path = /opt/$${TARGET}/bin !isEmpty(target.path): INSTALLS += target # ===========opengl============== QT += opengl QT += core gui openglwidgets QT += widgets # =============================== # ============opencv============= INCLUDEPATH += D:\lib\opencv_my\build\install\include #LIBS += D:\lib\opencv_my\build\install\x64\vc17\lib LIBS += D:\lib\opencv_my\build\install\x64\vc17\lib\opencv_world460.lib # =============================== # ============eigen============ INCLUDEPATH += D:\lib\eigen-3.4.0 # ============================= # ============cuda============= CUDA_DIR = $$(CUDA_PATH) #message($${CUDA_DIR}) INCLUDEPATH += $${CUDA_DIR}/include # ============================= # ============vtk============== #LIBS += D:\lib\VTK-8.2.0\build\install_prefix\lib # ============================= DISTFILES += \ draw_image.frag \ draw_image.vert ```