FramebufferReadPixelsT Method

public void ReadPixels<T>(
	int left,
	int bottom,
	int width,
	int height,
	T[] data,
	glPixelFormat format = glPixelFormat.Rgba,
	glPixelDataType dataType = glPixelDataType.UnsignedByte
)
where T : struct, new()

Public Sub ReadPixels(Of T As {Structure, New}) ( 
	left As Integer,
	bottom As Integer,
	width As Integer,
	height As Integer,
	data As T(),
	Optional format As glPixelFormat = glPixelFormat.Rgba,
	Optional dataType As glPixelDataType = glPixelDataType.UnsignedByte
)

public:
generic<typename T>
where T : value class, gcnew()
void ReadPixels(
	int left, 
	int bottom, 
	int width, 
	int height, 
	array<T>^ data, 
	glPixelFormat format = glPixelFormat::Rgba, 
	glPixelDataType dataType = glPixelDataType::UnsignedByte
)

member ReadPixels : 
        left : int * 
        bottom : int * 
        width : int * 
        height : int * 
        data : 'T[] * 
        ?format : glPixelFormat * 
        ?dataType : glPixelDataType 
(* Defaults:
        let _format = defaultArg format glPixelFormat.Rgba
        let _dataType = defaultArg dataType glPixelDataType.UnsignedByte
*)
-> unit  when 'T : struct, new()

Parameters

left

Type: SystemInt32
left window coordinate of the first pixel that is read from the framebuffer.

bottom

Type: SystemInt32
bottom window coordinate of the first pixel that is read from the framebuffer.

width

Type: SystemInt32
width of the rectangle in pixels.

height

Type: SystemInt32
height of the rectangle in pixels.

data

Type: T
the pixel data to be filled.

format (Optional)

Type: OooglesglPixelFormat
(optional) format of the pixels to return. Only Alpha, RGB and RGBA are supported. Defaults to RGBA.

dataType (Optional)

Type: OooglesglPixelDataType
(optional) data type of the pixels to return. Defaults to UnsignedByte.

Type Parameters

T

the type of the elements in the data array.

Pixels are returned in row order from the lowest to the highest row, left to right in each row.

format specifies the format for the returned pixel values. RGBA color components are read from the color buffer. Each color component is converted to floating point such that zero intensity maps to 0.0 and full intensity maps to 1.0.

Unneeded data is then discarded. For example, Alpha discards the red, green, and blue components, while Rgb discards only the alpha component. The final values are clamped to the range 0..1.

Finally, the components are converted to the proper format, as specified by dataType. When type is UnsignedByte (the default), each component is multiplied by 255. When dataType is UnsignedShort565, UnsignedShort4444 or UnsignedShort5551, each component is multiplied accordingly.

Note: if the currently bound framebuffer is not the default framebuffer object, color components are read from the color image attached to the Color attachment point.

Note: only two format/dataType parameter pairs are accepted. Rgba/UnsignedByte is always accepted, and the other acceptable pair can be discovered by calling ColorReadFormat and ColorReadType.

Note: values for pixels that lie outside the window connected to the current GL context are undefined.

Note: if an error is generated, no change is made to the contents of data.

Note: in DEBUG mode with assertions enabled, an error will be logged to the debug console if this framebuffer is not bound.

OpenGL API: glReadPixels

Reference