Re: [Vala] How to bitwise math and implement a jagged array in Vala?

[Thomas F Steinhauer <tom_steinhauer hotmail com>]

for some reason after doing this with your code the quads show up but 
the texture does not. if I use a 1D array I can get a stripe to show up 
but that is not what I what. I guess I must being doing something wrong.

this code will produce a red stripe with green next to it but still 
cannot produce a checker board effect that I am after.

void makeCheckImage()
{
    int j = 0;

    for (j = 0; j < checkImageWidth; j++) {
        checkImage[4*j] = (GLubyte)((j<=4) ? 255 : 0);
        checkImage[4*j+1] = (GLubyte) ((j>4) ? 255 : 0);
          checkImage[4*j+2] = (GLubyte) 0;
          checkImage[4*j+3] = (GLubyte) 255;
    }
}

must be something that I am still missing.

Thanks
 Tom


On 07/02/2013 07:02 PM, Evan Nemerson wrote:
> On Tue, 2013-07-02 at 18:49 -0500, Thomas F Steinhauer wrote:
> > I tried your code as you suggested however that did not work. I guess
> > the real question that I am asking here is has anyone successfully
> > generated a Checker board type texture with OpenGL and Vala and
> > displayed it on a cube or square. That is the code that I really need.
> > It seems that because Vala does not supported "jagged" arrays that this
> > is not possible or did I miss something in the reading somewhere?
> Yes.  For one thing, there is no reason this needs to be a jagged array.
> The C example isn't.  The part of the tutorial I linked to explains the
> difference.
>
> Here is everything together.  I've changed GL.ubyte to uint8 because it
> was more convenient (I don't get an opengl vapi), but s/uint8/GL.ubyte/
> and it should be exactly what you're after.
>
>
> private static uint8[,,]
> make_check_image (int width = 64, int height = 64) {
>    uint8[,,] check_image = new uint8[height,width,4];
>
>    for ( var i = 0 ; i < height ; i++ ) {
>      for ( var j = 0 ; j < width ; j++ ) {
>        uint8 c = (((uint8)((i&0x8)==0))^((uint8)((j&0x8)==0)))*255;
>        check_image[i,j,0] = c;
>        check_image[i,j,1] = c;
>        check_image[i,j,2] = c;
>        check_image[i,j,3] = 255;
>      }
>    }
>
>    return check_image;
> }
>
>
> -Evan