OpenGL Draw Points with indeces - opengl

Question

I was trying to draw a single point at 0,0 but my screen turns white and stops responding.
Can someone look into the code and see where I am making a mistake?
float *vertices;
GLubyte *pindices;
int width, height;
GLuint vboHandlePoints[1];
GLuint indexVBOPoints;
int numberOfPoints;
GLuint buf;
void initVboPoints(){
GLenum err = glewInit();
if (err != GLEW_OK)
{
fprintf(stderr, "Error: %s\n", glewGetErrorString(err));
}
glGenBuffers(1, &vboHandlePoints[0]); // create a VBO handle
glBindBuffer(GL_ARRAY_BUFFER, vboHandlePoints[0]); // bind the handle to the current VBO
glBufferData(GL_ARRAY_BUFFER, 1 * 2 * 4, vertices, GL_STATIC_DRAW); // allocate space and copy the data over
glBindBuffer(GL_ARRAY_BUFFER, 0); // clean up
glGenBuffers(1, &indexVBOPoints);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexVBOPoints);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLubyte)*1 * 2, pindices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0); //clean up
}
void display(){
glClearColor(0, 1, 0, 1);
glClear(GL_COLOR_BUFFER_BIT);
glColor4f(0, 0, 0, 1);
glPointSize(5);
glEnableClientState(GL_VERTEX_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER, vboHandlePoints[0]);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexVBOPoints);
glVertexPointer(2, GL_FLOAT, 0, 0);// 2-dimension
glDrawElements(GL_POINTS, 1, GL_UNSIGNED_BYTE, (char*)NULL + 0);
}
void initializeGlut(int argc, char** argv){
glutInit(&argc, argv);
width = 400;
height = 400;
glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
glutInitWindowSize(width, height);
glutCreateWindow("Bhavya's Program");
glutDisplayFunc(display);
}
void initNormal(){
vertices = new float[2];
pindices = new GLubyte[1];
vertices[0] = 0;
vertices[1] = 0;
pindices[0] = 0;
}
int main(int argc, char** argv){
initNormal();
initializeGlut(argc, argv);
initVboPoints();
glutMainLoop();
return 0;
}

Answer 1

You have no GL_ARRAY_BUFFER bound at the time of the glVertexPointer call. All of the gl*Pointer functions reference the currently bound GL_ARRAY_BUFFER, the buffer name becomes part of the pointer. That way, you can source each attribute from a different VBO. The GL_ARRAY_BUFFER binding is totally irrelevant for the glDraw* family of functions.
Since you use deprecated legacy GL, binding VBO 0 is still valid, and your pointer references the client memory. So your application is likely to just crash because you told the GL to read the data at memory address 0...

Answer 2

The problem is that glFlush(); is required