Draw the RGB data from kinect C++ via opengl

In order to improve my English writing skills,I am going to write the blogs in English form now!

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Today,we will learn how to initialize the kinect and get RGB data form it,then convert the data to a texture,which will be drawn to the windows.

We have two real pieces of kinect-specific code. I will go over these in some detail, and give a fairly hight level overview of the display code

include the header files:

#include <Windows.h>
#include <Ole2.h>

#include <gl/GL.h>
#include <gl/GLU.h>
#include <gl/glut.h>

#include <NuiApi.h>
#include <NuiImageCamera.h>
#include <NuiSensor.h>

Constants and global variables:

#define width 640
#define height 480

// OpenGL Variables
GLuint textureId;              // ID of the texture to contain Kinect RGB Data
GLubyte data[width*height*4];  // BGRA array containing the texture data

// Kinect variables
HANDLE rgbStream;              // The identifier of the Kinect's RGB Camera
INuiSensor* sensor;            // The kinect sensor

Kinect Initialization:

bool initKinect() {
// Get a working kinect sensor
int numSensors;
if (NuiGetSensorCount(&numSensors) < 0 || numSensors < 1) return false;
if (NuiCreateSensorByIndex(0, &sensor) < 0) return false;

// Initialize sensor
sensor->NuiInitialize(NUI_INITIALIZE_FLAG_USES_DEPTH | NUI_INITIALIZE_FLAG_USES_COLOR);
sensor->NuiImageStreamOpen(
NUI_IMAGE_TYPE_COLOR,            // Depth camera or rgb camera?
NUI_IMAGE_RESOLUTION_640x480,    // Image resolution
0,      // Image stream flags, e.g. near mode
2,      // Number of frames to buffer
NULL,   // Event handle
&rgbStream);
return sensor;
}

get an RGB frame from the Kinect:

void getKinectData(GLubyte* dest) {
NUI_IMAGE_FRAME imageFrame;
NUI_LOCKED_RECT LockedRect;
if (sensor->NuiImageStreamGetNextFrame(rgbStream, 0, &imageFrame) < 0) return;
INuiFrameTexture* texture = imageFrame.pFrameTexture;
texture->LockRect(0, &LockedRect, NULL, 0);

if (LockedRect.Pitch != 0)
{
const BYTE* curr = (const BYTE*) LockedRect.pBits;
const BYTE* dataEnd = curr + (width*height)*4;

while (curr < dataEnd) {
*dest++ = *curr++;
}
}

texture->UnlockRect(0);
sensor->NuiImageStreamReleaseFrame(rgbStream, &imageFrame);
}

Something about the window:

void draw() {
drawKinectData();
glutSwapBuffers();
}

void execute() {
glutMainLoop();
}

bool init(int argc, char* argv[]) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowSize(width,height);
glutCreateWindow("Kinect SDK Tutorial");
glutDisplayFunc(draw);
glutIdleFunc(draw);
return true;
}

Display via OpenGL:

// Initialize textures
glGenTextures(1, &textureId);
glBindTexture(GL_TEXTURE_2D, textureId);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height,
0, GL_BGRA, GL_UNSIGNED_BYTE, (GLvoid*) data);
glBindTexture(GL_TEXTURE_2D, 0);

// OpenGL setup
glClearColor(0,0,0,0);
glClearDepth(1.0f);
glEnable(GL_TEXTURE_2D);

// Camera setup
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, width, height, 0, 1, -1);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

int main(int argc, char* argv[]) {
if (!init(argc, argv)) return 1;
if (!initKinect()) return 1;

/* ...OpenGL texture and camera initialization... */

// Main loop
execute();
return 0;
}

Draw a frame to the screen:

void drawKinectData() {
glBindTexture(GL_TEXTURE_2D, textureId);
getKinectData(data);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_BGRA, GL_UNSIGNED_BYTE, (GLvoid*)data);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(0, 0, 0);
glTexCoord2f(1.0f, 0.0f);
glVertex3f(width, 0, 0);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(width, height, 0.0f);
glTexCoord2f(0.0f, 1.0f);
glVertex3f(0, height, 0.0f);
glEnd();
}

The End! Build and run,making sure that your Kinect is plugged in.You should see a window containing a viseo stream of what your Kinect sees.