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function retpixels = glReadnPixelsARB( x, y, width, height, format, type, bufSize )
% glReadnPixelsARB Interface to OpenGL function glReadnPixelsARB
%
% usage: data = glReadnPixelsARB( x, y, width, height, format, type, bufSize )
%
% C function: void glReadnPixelsARB(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLsizei bufSize, GLvoid* data)
% 30-Aug-2012 -- created (generated automatically from header files)
% ---allocate---
% ---protected---
global GL;
if nargin~=7,
error('invalid number of arguments');
end
% check format and type
if x < 0 || y < 0
error('Invalid (negative) (x,y) offset passed to glReadPixels.');
end
if width <= 0 || height<=0
error('Invalid (negative or zero) (width, height) passed to glReadPixels.');
end
switch(format)
case {GL.RED, GL.GREEN, GL.BLUE, GL.ALPHA, GL.LUMINANCE, GL.INTENSITY, GL.DEPTH_COMPONENT, GL.STENCIL_INDEX }
numperpixel = 1;
case {GL.LUMINANCE_ALPHA }
numperpixel = 2;
case {GL.RGB , GL.BGR }
numperpixel = 3;
case {GL.RGBA , GL.BGRA }
numperpixel = 4;
otherwise
error('Invalid format passed to glReadPixels.');
end
% Readback to host memory, aka Matlab- or Octave- matrix:
% Allocate memory:
pixels=zeros(numperpixel, width, height, 2);
% Tell OpenGL that we accept byte-aligned aka unaligned data.
glPixelStorei(GL.PACK_ALIGNMENT, 1);
% Perform proper type-cast:
switch(type)
case GL.UNSIGNED_BYTE
pixels = uint8(pixels);
pclass = 'uint8';
case GL.BYTE
pixels = int8(pixels);
pclass = 'int8';
case GL.UNSIGNED_SHORT
pixels = uint16(pixels);
pclass = 'uint16';
case GL.SHORT
pixels = int16(pixels);
pclass = 'int16';
case GL.UNSIGNED_INT
pixels = uint32(pixels);
pclass = 'uint32';
case GL.INT
pixels = int32(pixels);
pclass = 'int32';
case GL.FLOAT
pixels = moglsingle(pixels);
pclass = 'double';
otherwise
error('Invalid type argument passed to glReadPixels()!');
end;
% Execute actual call:
moglcore( 'glReadnPixelsARB', x, y, width, height, format, type, bufSize, pixels );
% Hack around Matlab R2015b+ bug: Needs > 1 component to be passed into
% moglcore as prhs argument for data return to work, so we extend pixels
% by a 4th dimension with one useless 2nd layer, which we strip away here
% again before returning data to usercode. The 2nd layer guarantees that
% prhs pixels has at least 2 components if width=height=numperpixel==1
pixels = pixels(:,:,:,1);
% Rearrange data in Matlab friendly format:
retpixels = zeros(size(pixels,2), size(pixels,3), size(pixels,1), pclass);
for i=1:numperpixel
retpixels(:,:,i) = pixels(i,:,:);
end
return
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