hyperion.ng/libsrc/dispmanx-grabber/DispmanxFrameGrabber.cpp
2013-10-02 07:46:12 +00:00

90 lines
2.7 KiB
C++

#include "DispmanxFrameGrabber.h"
// Because the shapshot function is incompatible between versions (use of different enum as
// third argument) and no proper version number is available as preprocessor define we cast the
// function to the same function with the third argument as 'int'.
// This way we can call the function in both versions of the VideoCore library without
// switching.
static int my_vc_dispmanx_snapshot(DISPMANX_DISPLAY_HANDLE_T display, DISPMANX_RESOURCE_HANDLE_T snapshot_resource, int transform)
{
typedef int (*SnapshotFunctionPtr)(DISPMANX_DISPLAY_HANDLE_T, DISPMANX_RESOURCE_HANDLE_T, int);
SnapshotFunctionPtr snapshot = (SnapshotFunctionPtr) &vc_dispmanx_snapshot;
return (*snapshot)(display, snapshot_resource, transform);
}
DispmanxFrameGrabber::DispmanxFrameGrabber(const unsigned width, const unsigned height) :
_vc_display(0),
_vc_resource(0),
_vc_flags(0),
_width(width),
_height(height)
{
// Initiase BCM
bcm_host_init();
{
// Check if the display can be opened and display the current resolution
// Open the connection to the display
_vc_display = vc_dispmanx_display_open(0);
assert(_vc_display > 0);
// Obtain the display information
DISPMANX_MODEINFO_T vc_info;
int result = vc_dispmanx_display_get_info(_vc_display, &vc_info);
// Keep compiler happy in 'release' mode
(void)result;
assert(result == 0);
std::cout << "Display opened with resolution: " << vc_info.width << "x" << vc_info.height << std::endl;
// Close the displaye
vc_dispmanx_display_close(_vc_display);
}
// Create the resources for capturing image
uint32_t vc_nativeImageHandle;
_vc_resource = vc_dispmanx_resource_create(
VC_IMAGE_RGB888,
width,
height,
&vc_nativeImageHandle);
assert(_vc_resource);
// Define the capture rectangle with the same size
vc_dispmanx_rect_set(&_rectangle, 0, 0, width, height);
}
DispmanxFrameGrabber::~DispmanxFrameGrabber()
{
// Clean up resources
vc_dispmanx_resource_delete(_vc_resource);
// De-init BCM
bcm_host_deinit();
}
void DispmanxFrameGrabber::setFlags(const int vc_flags)
{
_vc_flags = vc_flags;
}
void DispmanxFrameGrabber::grabFrame(RgbImage& image)
{
// Sanity check of the given image size
assert(image.width() == _width && image.height() == _height);
// Open the connection to the display
_vc_display = vc_dispmanx_display_open(0);
// Create the snapshot (incl down-scaling)
my_vc_dispmanx_snapshot(_vc_display, _vc_resource, _vc_flags);
// Read the snapshot into the memory
void* image_ptr = image.memptr();
const unsigned destPitch = _width * 3;
vc_dispmanx_resource_read_data(_vc_resource, &_rectangle, image_ptr, destPitch);
// Close the displaye
vc_dispmanx_display_close(_vc_display);
}