This location is the lower left corner of a rectangular block of pixels. Width , Height Specify the dimensions of the pixel rectangle. Format Specifies the format of the pixel data. Type Specifies the data type for Pixels . Pixels Returns the pixel data.
Several parameters control the processing of the pixel data before it is placed into client memory.
The effects on glReadPixels of most, but not all, of the parameters specified by these three subroutines are described here. This pixel is said to be the i th pixel in the j th row. Pixels are returned in row order from the lowest to the highest row, left to right in each row. The Format parameter specifies the format for the returned pixel values. Color indexes are read from the color buffer selected by the glReadBuffer subroutine.