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Thread: Context difference between QGLwidget and QOpenGLWidget

  1. #1
    Join Date
    May 2017
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    Qt products
    Qt5
    Platforms
    Windows

    Default Context difference between QGLwidget and QOpenGLWidget

    So, i know there is lots of post concerning the difference between these two widgets. Like here : https://blog.qt.io/blog/2014/09/10/q...qopenglwidget/
    But i don't get why some code are working on QGLWidget and not on QOpenGLWidget. I'm using an extension of OpenGL to capture the video stream from a camera and put it in a texture. This is working with a QGLWidget but return a GL_FAILURE_NV when i change the widget in a QOpenGLWidget. I try to create a widget i could call in a QApplication without creating a new Window. That's why i try to create a qOpenGLWidget.

    The openGL context doesn't seem to be a problem because when the OpenGL extension need it to retrieve the video stream configuration, it succeed. It only fail when it tries to capture it. And i really don't get it.

    Here is the widget code:
    Qt Code:
    1. #include "widget.h"
    2. #include "ui_widget.h"
    3.  
    4. Widget::Widget(QOpenGLWidget *parent) :
    5. QOpenGLWidget(parent),
    6. ui(new Ui::Widget)
    7. {
    8. ui->setupUi(this);
    9. }
    10.  
    11. Widget::~Widget()
    12. {
    13. wglMakeCurrent(wglGetCurrentDC(), this->contextGL);
    14. nvGl.cleanupVideo(wglGetCurrentDC());
    15. delete ui;
    16. }
    17.  
    18. void Widget::initializeGL(){
    19. initializeOpenGLFunctions();
    20. glewInit();
    21. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    22. nvC = NVConfig();
    23. nvC.GlobalInit();
    24. this->contextGL = wglGetCurrentContext();
    25. nvGl = NVGL(nvC.l_vioConfig,wglGetCurrentDC());
    26. QTimer::singleShot(16,this,SLOT(Tick()));
    27. }
    28.  
    29. void Widget::resizeGL(int w, int h){
    30. if(h==0)
    31. h =1;
    32. glViewport(0,0,w,h);
    33. glMatrixMode(GL_PROJECTION);
    34. glLoadIdentity();
    35. perspectiveGL(45.0f,w/h,0.1f,100.0f);
    36. glMatrixMode(GL_MODELVIEW);
    37. glLoadIdentity();
    38.  
    39. }
    40. void Widget::Tick(){
    41. nvC.DetectIStatus();
    42. nvC.setCaptureDevice();
    43. Capture();
    44. paintGL();
    45. QTimer::singleShot(16,this,SLOT(Tick()));
    46. }
    47.  
    48. void Widget::Capture(){
    49. nvGl.StartCapture();
    50. }
    51.  
    52.  
    53. void Widget::paintGL(){
    54. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    55. glLoadIdentity();
    56. glTranslatef(-0.5f,-.5f,-1.1f);
    57. glBegin(GL_QUADS);
    58. glTexCoord2f(0,0);
    59. glVertex3f(0,0,0);
    60. glTexCoord2f(0,1.0f);
    61. glVertex3f(0,1.0f,0);
    62. glTexCoord2f(1.0f,1.0f);
    63. glVertex3f(1.0f,1.0f,0);
    64. glTexCoord2f(1.0f,0);
    65. glVertex3f(1.0f,0,0);
    66. glEnd();
    67. }
    68.  
    69. void Widget::perspectiveGL(GLdouble fovY, GLdouble aspect, GLdouble zNear, GLdouble zFar){
    70. const GLdouble pi = 3.1415926535897932384626433832795;
    71. GLdouble fW, fH;
    72. fH = tan( fovY / 360 * pi) * zNear;
    73. fW = fH * aspect;
    74. glFrustum( -fW,fW,-fH,fH,zNear,zFar);
    75. }
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    And here is the code of the class capturing the stream:
    Qt Code:
    1. #include "nvgl.h"
    2. #include <stdio.h>
    3. #include <assert.h>
    4.  
    5.  
    6. NVGL::NVGL()
    7. {
    8.  
    9. }
    10.  
    11. NVGL::NVGL(NVVIOCONFIG_V2 &_l_vioConfig,HDC widget)
    12. {
    13. l_vioConfig=_l_vioConfig;
    14. LockDevice(widget);
    15. InitStream();
    16. InitBuffer();
    17. }
    18. void NVGL::LockDevice(HDC widget){
    19. UINT numDevices = wglEnumerateVideoCaptureDevicesNV(widget, NULL);
    20. if (numDevices <= 0) {
    21. printf("No devices found");
    22. }
    23. HVIDEOINPUTDEVICENV* m_videoDevices = (HVIDEOINPUTDEVICENV*)malloc(numDevices *
    24. sizeof(m_videoDevices[0]));
    25. if (!m_videoDevices) {
    26. fprintf(stderr, "malloc failed. OOM?");
    27. }
    28. if (numDevices != wglEnumerateVideoCaptureDevicesNV(widget,m_videoDevices)) {
    29. free(m_videoDevices);
    30. }
    31. // Find an available device we can lock
    32. for (UINT i=0; i< numDevices; ++i) {
    33. BOOL bLocked;
    34. bLocked = wglLockVideoCaptureDeviceNV(widget, m_videoDevices[i]);
    35. if (bLocked) {
    36. m_device = m_videoDevices[i];
    37. break;
    38. }
    39. }
    40. free(m_videoDevices);
    41. if (m_device == NULL) {
    42. printf("no lockable decives found");
    43. }
    44. // wglBindVideoCaptureDeviceNV needs a context current
    45. bool bRet = wglBindVideoCaptureDeviceNV(1, m_device);
    46. assert(bRet && "Failed trying to bind the video capture device!");
    47. }
    48.  
    49. void NVGL::StartCapture(){
    50. GLuint sequenceNum=0;
    51. GLuint64EXT timestamp=0;
    52.  
    53. glBeginVideoCaptureNV(1);
    54. GLenum eval = glVideoCaptureNV(1, &sequenceNum, &timestamp);
    55. switch(eval) {
    56. case GL_SUCCESS_NV:
    57. qDebug("\n************************************************");
    58. break;
    59. case GL_PARTIAL_SUCCESS_NV:
    60. qDebug("\n2ooooooooooooooooooooooooooooooooooooooooooooooooo");
    61.  
    62. break;
    63. case GL_FAILURE_NV:
    64. qDebug("\n3##################################################");
    65.  
    66. break;
    67. default:
    68. qDebug("\nkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk");
    69.  
    70. break;
    71. }
    72. glEndVideoCaptureNV(1);
    73. GLenum test= glGetError();
    74. }
    75.  
    76. void NVGL::InitStream(){
    77. // Setup CSC for each stream.
    78. GLfloat mat[4][4];
    79. float scale = 1.0f;
    80. GLfloat max[] = {5000, 5000, 5000, 5000};;
    81. GLfloat min[] = {0, 0, 0, 0};
    82. UINT m_videoSlot= 1;
    83. // Initialize matrix to the identity.
    84. mat[0][0] = scale; mat[0][1] = 0; mat[0][2] = 0; mat[0][3] = 0;
    85. mat[1][0] = 0; mat[1][1] = scale; mat[1][2] = 0; mat[1][3] = 0;
    86. mat[2][0] = 0; mat[2][1] = 0; mat[2][2] = scale; mat[2][3] = 0;
    87. mat[3][0] = 0; mat[3][1] = 0; mat[3][2] = 0; mat[3][3] = scale;
    88. GLfloat offset[] = {0, 0, 0, 0};
    89. mat[0][0] = 1.164f *scale;
    90. mat[0][1] = 1.164f *scale;
    91. mat[0][2] = 1.164f *scale;
    92. mat[0][3] = 0;
    93. mat[1][0] = 0;
    94. mat[1][1] = -0.392f *scale;
    95. mat[1][2] = 2.017f *scale;
    96. mat[1][3] = 0;
    97. mat[2][0] = 1.596f *scale;
    98. mat[2][1] = -0.813f *scale;
    99. mat[2][2] = 0.f;
    100. mat[2][3] = 0;
    101. mat[3][0] = 0;
    102. mat[3][1] = 0;
    103. mat[3][2] = 0;
    104. mat[3][3] = 1;
    105. offset[0] =-0.87f;
    106. offset[1] = 0.53026f;
    107. offset[2] = -1.08f;
    108. offset[3] = 0;
    109. for (int i=0; i < l_vioConfig.vioConfig.inConfig.numStreams; i++) {
    110. glVideoCaptureStreamParameterfvNV(m_videoSlot, i,GL_VIDEO_COLOR_CONVERSION_MATRIX_NV,&mat[0][0]);
    111. glVideoCaptureStreamParameterfvNV(m_videoSlot, i,GL_VIDEO_COLOR_CONVERSION_MAX_NV,&max[0]);
    112. glVideoCaptureStreamParameterfvNV(m_videoSlot, i,GL_VIDEO_COLOR_CONVERSION_MIN_NV,&min[0]);
    113. glVideoCaptureStreamParameterfvNV(m_videoSlot, i,GL_VIDEO_COLOR_CONVERSION_OFFSET_NV,&offset[0]);
    114. }
    115. }
    116.  
    117. void NVGL::InitBuffer(){
    118. UINT m_videoSlot= 1;
    119. GLint bufferPitch;
    120.  
    121. /*GLint videoBufferFormat = GL_YCBYCR8_422_NV;
    122.   // Create video buffer objects
    123.   glGenBuffersARB(l_vioConfig.vioConfig.inConfig.numStreams,&m_videoBuffer);
    124.   // Allocate space in the buffer objects.
    125.   for (NvU32 i = 0; i < l_vioConfig.vioConfig.inConfig.numStreams; i++) {
    126.   // Set the buffer object capture data format for each stream.
    127.   glVideoCaptureStreamParameterivNV(m_videoSlot, i,GL_VIDEO_BUFFER_INTERNAL_FORMAT_NV,&videoBufferFormat);
    128.   // Bind the buffer.
    129.   glBindBufferARB(GL_VIDEO_BUFFER_NV, m_videoBuffer);
    130.   // Get the video buffer pitch
    131.   glGetVideoCaptureStreamivNV(m_videoSlot, i,GL_VIDEO_BUFFER_PITCH_NV,&bufferPitch);
    132.   // Allocate space in the buffer object
    133.   glBufferDataARB(GL_VIDEO_BUFFER_NV, bufferPitch * 720, NULL,GL_STREAM_READ_ARB);
    134.   // Bind the buffer object to the video capture stream.
    135.   glBindVideoCaptureStreamBufferNV(m_videoSlot, i, GL_FRAME_NV, m_videoBuffer);
    136.   }*/
    137.  
    138. // Create and initialize video texture objects.
    139. glEnable(GL_TEXTURE_2D);
    140. glGenTextures(l_vioConfig.vioConfig.inConfig.numStreams, &m_videoTexture);
    141. for (UINT i = 0; i < l_vioConfig.vioConfig.inConfig.numStreams; i++) {
    142. glBindTexture(GL_TEXTURE_2D, m_videoTexture);
    143. // Set texture parameters
    144. glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    145. if(l_vioConfig.vioConfig.inConfig.signalFormat==NVVIOSIGNALFORMAT_720P_50_00_SMPTE296){
    146. // Set texture format and size.
    147. glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1280, 720, 0,GL_RGBA, GL_UNSIGNED_BYTE, NULL);
    148. }else{
    149. glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1920, 1080, 0,GL_RGBA, GL_UNSIGNED_BYTE, NULL);
    150.  
    151. }
    152. // Bind the outputs for the stream
    153. glBindVideoCaptureStreamTextureNV(m_videoSlot, i, GL_FRAME_NV,GL_TEXTURE_RECTANGLE_NV,m_videoTexture);
    154. }
    155. }
    156.  
    157. HRESULT NVGL::cleanupVideo(HDC m_hDC)
    158. {
    159. BOOL bRet;
    160. // Unbind and release the capture device.
    161. bRet = wglBindVideoCaptureDeviceNV(1, NULL);
    162. assert(bRet && "Failed trying to unbind the video capture device!");
    163. // wglReleaseVideoCaptureDeviceNV should work even without a context current
    164. wglMakeCurrent(m_hDC, NULL);
    165. bRet = wglReleaseVideoCaptureDeviceNV(m_hDC, m_device);
    166. assert(bRet && "Failed trying to release the video capture device!");
    167. return S_OK;
    168. }
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    If you have any idea, thanks.

  2. #2
    Join Date
    May 2017
    Posts
    8
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    Qt products
    Qt5
    Platforms
    Windows

    Default Re: Context difference between QGLwidget and QOpenGLWidget

    hi, i was using badly the QGLWidget, i just promote a QWidget to my custom QGLWidget and i get the correct result.

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