TextureID=loadOpenGLTexture(I,TextureFormat,TextureInternalFormat,TextureInterpolation)

function TextureID=loadOpenGLTexture(I,TextureFormat,TextureInternalFormat,TextureInterpolation)
%  Load Matlab Image data 2D or 3D into a texture
%
%  TextureID=loadOpenGLTexture(I,TextureFormat,TextureInternalFormat,TextureInterpolation)
% 
%  inputs,
%   I : The matlab image data 2D or 3D (for example, m x n x 3 uint8)
%   TextureFormat : Gl.GL_RGB, Gl.GL_ALPHA or some other format. 
%   TextureInternalFormat: Gl.GL_RGB8, Gl.GL_ALPHA32F_ARB or some other format
%   TextureInterpolation : 'nearest' or 'linear'
%
%  outputs,
%   TextureID : The internal id of the texture, need to to bind the texture
%           like Gl.glEnable(Gl.GL_TEXTURE_2D); Gl.glBindTexture(Gl.GL_TEXTURE_2D, TextureID);
%
%
%  Example,
%   I=imread('texture.png');
%   TextureID=loadOpenGLTexture(I,Gl.GL_RGB,Gl.GL_RGB8,'linear');
%
% Function is written by D.Kroon University of Twente (April 2009)

% Allow to use GL functions without prefixing with Tao.Opengl.
import Tao.OpenGl.*

% Determine if 2D or 3D texture
Texture_is_2D=size(I,3)<5;

% In Matlab color is the last dimensions in a texture the first
if(Texture_is_2D)
    I=squeeze(permute(I,[3 2 1]));
    if(ndims(I)==2)
        TextureWidth=int32(size(I,1)); 
        TextureHeight=int32(size(I,2));
    else
        TextureWidth=int32(size(I,2)); 
        TextureHeight=int32(size(I,3));
    end
    
else
    I=squeeze(permute(I,[4 3 2 1]));
    if(ndims(I)==3)
        % Set texture size to size of image
        TextureWidth=int32(size(I,1)); 
        TextureHeight=int32(size(I,2));
        TextureDepth=int32(size(I,3));
    else
        % Set texture size to size of image
        TextureWidth=int32(size(I,2)); 
        TextureHeight=int32(size(I,3));
        TextureDepth=int32(size(I,4));        
    end
end


% Convert the data to .NET datatype
switch class(I),
    case 'uint8'
        TextureDataType=Gl.GL_UNSIGNED_BYTE;
        TextureData=NET.convertArray(I(:),'System.Byte',numel(I));
    case 'uint16'
        TextureDataType=Gl.GL_UNSIGNED_SHORT;
        TextureData=NET.convertArray(I(:),'System.UInt16',numel(I));
    case 'uint32'
        TextureDataType=Gl.GL_UNSIGNED_INT;
        TextureData=NET.convertArray(I(:),'System.UInt32',numel(I));
    case 'single'
        TextureDataType=Gl.GL_FLOAT;
        TextureData=NET.convertArray(I(:),'System.Single',numel(I));
    case 'double'
        TextureDataType=Gl.GL_DOUBLE;
        TextureData=NET.convertArray(I(:),'System.Double',numel(I));
    otherwise
    error('loadOpenGLTexture:inputs','Not yet supported');
end

switch (TextureInterpolation)
    case 'nearest'
         TextureInterpolation=Gl.GL_NEAREST;
    case 'linear'
        TextureInterpolation=Gl.GL_LINEAR;
end

% Display no border
TextureBorder=0;

% Check if power of 2
if(mod(TextureWidth,2)), error('loadOpenGLTexture:inputs','Texture Width must be 2*n+2'); end
if(mod(TextureHeight,2)), error('loadOpenGLTexture:inputs','Texture Height must be 2*n+2'); end

% First flush the openGL pipeline
Gl.glFlush();

if(Texture_is_2D)
    % Enable 2D texturing
    Gl.glEnable(Gl.GL_TEXTURE_2D);
    % Create Texture id
    TextureID=Gl.glGenTextures(1);                            
    % tell OpenGL we're going to be setting up the texture name it gave us	
    Gl.glBindTexture(Gl.GL_TEXTURE_2D, TextureID);
    % when this texture needs to be shrunk to fit on small polygons, use linear interpolation of the texels to determine the color
    Gl.glTexParameteri(Gl.GL_TEXTURE_2D, Gl.GL_TEXTURE_MIN_FILTER, TextureInterpolation);
    % when this texture needs to be magnified to fit on a big polygon, use linear interpolation of the texels to determine the color
    Gl.glTexParameteri(Gl.GL_TEXTURE_2D, Gl.GL_TEXTURE_MAG_FILTER, TextureInterpolation);
    % Check if texture fits in video memory
    Gl.glTexImage2D(Gl.GL_PROXY_TEXTURE_2D, 0, TextureInternalFormat, TextureWidth, TextureHeight, TextureBorder, TextureFormat, TextureDataType, []);
    EnoughMemory=Gl.glGetTexLevelParameterfv(Gl.GL_PROXY_TEXTURE_2D, 0, Gl.GL_TEXTURE_WIDTH); EnoughMemory=double(EnoughMemory)>0;
    % Read the data into the texture structure
    if(EnoughMemory)
        Gl.glTexImage2D(Gl.GL_TEXTURE_2D, 0, TextureInternalFormat, TextureWidth, TextureHeight, TextureBorder, TextureFormat, TextureDataType, TextureData);
    else
        warning('loadOpenGLTexture:Load','Texture dimensions are to large, or not enough memory');
    end
    
    % For now disable Texture 2D
    Gl.glDisable(Gl.GL_TEXTURE_2D);
else
    % Enable 3D texturing
    Gl.glEnable(Gl.GL_TEXTURE_3D);
    % Create Texture id
    TextureID=Gl.glGenTextures(1);  
    % tell OpenGL we're going to be setting up the texture name it gave us	
    Gl.glBindTexture(Gl.GL_TEXTURE_3D,  TextureID);
    % when this texture needs to be shrunk to fit on small polygons, use linear interpolation of the texels to determine the color
    Gl.glTexParameteri(Gl.GL_TEXTURE_3D, Gl.GL_TEXTURE_MIN_FILTER, TextureInterpolation);
    % when this texture needs to be magnified to fit on a big polygon, use linear interpolation of the texels to determine the color
    Gl.glTexParameteri(Gl.GL_TEXTURE_3D, Gl.GL_TEXTURE_MAG_FILTER, TextureInterpolation);
    % we want the texture to repeat over the S axis, so if we specify coordinates out of range we still get textured.
    Gl.glTexParameteri(Gl.GL_TEXTURE_3D, Gl.GL_TEXTURE_WRAP_S, Gl.GL_CLAMP);
    %  same as above for T axis
    Gl.glTexParameteri(Gl.GL_TEXTURE_3D, Gl.GL_TEXTURE_WRAP_T, Gl.GL_CLAMP);
    %  same as above for R axis
    Gl.glTexParameteri(Gl.GL_TEXTURE_3D, Gl.GL_TEXTURE_WRAP_R, Gl.GL_CLAMP);
    % Check if texture fits in video memory
    Gl.glTexImage3D(Gl.GL_PROXY_TEXTURE_3D, 0, TextureInternalFormat, TextureWidth, TextureHeight, TextureDepth, TextureBorder, TextureFormat, TextureDataType, []);
    EnoughMemory=Gl.glGetTexLevelParameterfv(Gl.GL_PROXY_TEXTURE_3D, 0, Gl.GL_TEXTURE_WIDTH); EnoughMemory=double(EnoughMemory)>0;
    % Read the data into the 3D texture structure
    if(EnoughMemory)
        Gl.glTexImage3D(Gl.GL_TEXTURE_3D, 0, TextureInternalFormat, TextureWidth, TextureHeight, TextureDepth, TextureBorder, TextureFormat, TextureDataType, TextureData);
    else
        warning('loadOpenGLTexture:Load','Texture dimensions are to large, or not enough memory');
    end
    % For now disable Texture 3D
    Gl.glDisable(Gl.GL_TEXTURE_3D);
end

erc=Gl.glGetError();
if(erc~=0)
    disp('Error loading texture, try dimensions of power of two like 32 or 128');
end