OpenGL support

Overview

// global functions

void
cv::imshow(
    const String& winname,
    const ogl::Texture2D& tex
    );

void
cv::setOpenGlContext(const String& winname);

void
cv::setOpenGlDrawCallback(
    const String& winname,
    OpenGlDrawCallback onOpenGlDraw,
    void* userdata = 0
    );

void
cv::updateWindow(const String& winname);

Detailed Documentation

Global Functions

void
cv::imshow(
    const String& winname,
    const ogl::Texture2D& tex
    )

Displays OpenGL 2D texture in the specified window.

Parameters:

winname	Name of the window.
tex	OpenGL 2D texture data.

void
cv::setOpenGlContext(const String& winname)

Sets the specified window as current OpenGL context.

Parameters:

winname

Name of the window.

void
cv::setOpenGlDrawCallback(
    const String& winname,
    OpenGlDrawCallback onOpenGlDraw,
    void* userdata = 0
    )

Sets a callback function to be called to draw on top of displayed image.

The function setOpenGlDrawCallback can be used to draw 3D data on the window. See the example of callback function below:

void on_opengl(void* param)
{
    glLoadIdentity();

    glTranslated(0.0, 0.0, -1.0);

    glRotatef( 55, 1, 0, 0 );
    glRotatef( 45, 0, 1, 0 );
    glRotatef( 0, 0, 0, 1 );

    static const int coords[6][4][3] = {
        { { +1, -1, -1 }, { -1, -1, -1 }, { -1, +1, -1 }, { +1, +1, -1 } },
        { { +1, +1, -1 }, { -1, +1, -1 }, { -1, +1, +1 }, { +1, +1, +1 } },
        { { +1, -1, +1 }, { +1, -1, -1 }, { +1, +1, -1 }, { +1, +1, +1 } },
        { { -1, -1, -1 }, { -1, -1, +1 }, { -1, +1, +1 }, { -1, +1, -1 } },
        { { +1, -1, +1 }, { -1, -1, +1 }, { -1, -1, -1 }, { +1, -1, -1 } },
        { { -1, -1, +1 }, { +1, -1, +1 }, { +1, +1, +1 }, { -1, +1, +1 } }
    };

    for (int i = 0; i < 6; ++i) {
                glColor3ub( i*20, 100+i*10, i*42 );
                glBegin(GL_QUADS);
                for (int j = 0; j < 4; ++j) {
                        glVertex3d(0.2 * coords[i][j][0], 0.2 * coords[i][j][1], 0.2 * coords[i][j][2]);
                }
                glEnd();
    }
}

Parameters:

winname	Name of the window.
onOpenGlDraw	Pointer to the function to be called every frame. This function should be prototyped as void Foo(void*) .
userdata	Pointer passed to the callback function.(Optional)

void
cv::updateWindow(const String& winname)

Force window to redraw its context and call draw callback ( See cv::setOpenGlDrawCallback).

Parameters:

winname

Name of the window.