I found that the origin (0, 0, 0) lies at the center of the screen. Points on each of the x, y and z axis take fraction values between 0 and +/-1.

To test the “byte co-ordinates extension” of opengl es, the co-ordinates should be specified in byte format. I have understood this as, each of x, y and z should be of 1 byte size.

How to map the fraction co-ordinate values to byte format?

For E.g.:

GLfloat vertices[] = { //each element of the array is a fraction 0…+/-1

0.1, 0.1, -0.6,

-0.3, -0.1, 0.0,

-0.1, -0.3, 0.0,

0.1, -0.3, 0.0,

0.3, -0.1, 0.0,

-0.1, 0.3, 0.0,

};

glVertexPointer(3, GL_FLOAT, sizeof(GLfloat) * 3, vertices);

Should each of the fraction array elements mapped to coresponding byte value?

Thank you.