Reading Pixels from the Offscreen Framebuffer

We can now go to the offscreen buffer and read the color from the appropriate coordinates:

WebGL allows us to read back from a framebuffer using the readPixels function. As usual, having gl as the WebGL context variable within our context:

Function

Description

gl.readPixels(x, y, width, height, format, type, pixels)

x and y: Starting coordinates. width and height: The extent of pixels to read from the framebuffer. In our example, we are just reading one pixel (where the user clicks), so this will be 1, 1. format: Supports the gl.RGBA format. type:: Supports the gl.UNSIGNED_BYTE type. pixels: A typed array that will contain the results of querying the framebuffer. It needs to have sufficient space to store the results depending on the extent of the query (x, y, width, height). It supports the Uint8Array type.

Remember that...