PHP Isometric cube with GD

Question

I need to create something like this with PHP and GD:

The three visible faces will be three parts of the same image, of which I know the coordinates.

I suppose that this can be done with image transformations and some maths.

The rotation of the cube will be always the same.

I don't need "stroke" edges and face lighting like in that picture, I just need a "shadeless" cube.

Finally, the result should be an alpha-transparent PNG.

P.S. I only have GD on my host, I don't have access to ImageMagick.

Answer 1

Starting from kraysak's answer, do the following:

In order to use images instead of colors, please replace these lines:

$blue = imagecolorallocate($im, 0, 0, 255);
$white = imagecolorallocate($im, 255, 255, 255);
$red = imagecolorallocate($im, 255, 0, 0);

and

imagefilledpolygon($im, $first_poligon, 4, $blue);
imagefilledpolygon($im, $second_poligon, 4, $white);
imagefilledpolygon($im, $third_poligon, 4, $red);

With something like this (this example is only for one of the three faces):

1. For PNG:

   function LoadPNG($imgname)
   {
   /* Attempt to open */
   $im = @imagecreatefrompng($imgname);
   
   /* See if it failed */
   if(!$im)
   {
       /* Create a blank image */
       $im  = imagecreatetruecolor(150, 30);
       $bgc = imagecolorallocate($im, 255, 255, 255);
       $tc  = imagecolorallocate($im, 0, 0, 0);
   
       imagefilledrectangle($im, 0, 0, 150, 30, $bgc);
   
       /* Output an error message */
       imagestring($im, 1, 5, 5, 'Error loading ' . $imgname, $tc);
   }
   
   return $im;
   }
   
   header('Content-Type: image/png');
   
   $img = LoadPNG('bogus.image');
   

2. Instead of:

    $blue = imagecolorallocate($im, 0, 0, 255)
   

   You will use:

    $cube_face_1 = imagepng($img);
   

3. And instead of:

   imagefilledpolygon($im, $first_poligon, 4, $blue);
   

   You will use:

   imagefilledpolygon($im, $first_poligon, 4, $cube_face_1);
   

Source: http://php.net/manual/en/book.image.php

On the above link, you can find details regarding gif/jpeg images. My demonstration is for png images.

Answer 2

you are searching for something like this?

<?php
$size=100;

$first_poligon = array(
            0,  $size/4,  // Point 1 (x, y) ---->  0,20
            $size/2,  $size/2, // Point 2 (x, y) ---->  50,50
            $size/2,  $size,    // Point 3 (x, y) ---->  50,100
            0, ($size/4)*3,  // Point 4 (x, y) ---->  0,60
            );
$second_poligon = array(
            0,  $size/4,  // Point 1 (x, y) ---->  0,33
            $size/2,  0, // Point 2 (x, y) ---->  50,0
            $size,  $size/4,    // Point 3 (x, y) ---->  100,20
            $size/2,  $size/2,  // Point 4 (x, y) ---->  50,50
            );          
$third_poligon = array(
            $size,  $size/4,  // Point 1 (x, y) ---->  100,20
            $size/2,  $size/2, // Point 2 (x, y) ---->  50,50
            $size/2,  $size,    // Point 3 (x, y) ---->  50,100
            $size, ($size/4)*3,  // Point 4 (x, y) ---->  100,60
            );          

$im = imagecreatetruecolor($size, $size);

$fondo   = imagecolorallocate($im, 51, 0, 0);
imagefilledrectangle($im, 0, 0, $size, $size, $fondo);

$blue = imagecolorallocate($im, 0, 0, 255);
$white = imagecolorallocate($im, 255, 255, 255);
$red = imagecolorallocate($im, 255, 0, 0);

imagefilledpolygon($im, $first_poligon, 4, $blue);
imagefilledpolygon($im, $second_poligon, 4, $white);
imagefilledpolygon($im, $third_poligon, 4, $red);

imagepng($im, './image.png');

imagedestroy($im);
?>
 <img src="image.png" > 

image result:

Answer 3

i can´t let that this problem defeat me... (also i want to help you, but not that much :P) so, i made this litle code that resolve almost 70% of your problem:

  <?php
  $size=200;

    $im= imagecreatetruecolor($size,$size);
    $orige = imagecreatefrompng("test2.png");
    $orige2 = imagecreatefrompng("tesst3.png");

    $limit=0;
    $newlimit=0;
        for($y=$size/4;$y<=$size;$y++){
            for($x=0;$x<=$size/2;$x++){

                    if($y>($size/4)*3){
                            if( $x>=$newlimit){
                            copy_pixel($im,$orige,$x,$y,NULL);  //copy left image
                            copy_pixel($im,$orige2,$x,$y,$size-$x); //copy rightimage
                            }
                    }
                    else{
                            copy_pixel($im,$orige,$x,$y,NULL);  //copy left image
                            copy_pixel($im,$orige2,$x,$y,$size-$x); //copy rightimage           
                    }

            if($x==$limit and $limit<= $size/2){ $limit=$limit+2; break;}                           
            }
            if($y>=($size/4)*3)$newlimit=$newlimit+2;
        }                               
    imagepng($im, "n.png");

    function copy_pixel($im,&$orige,$x,$y,$newx){
                if($newx==NULL) $newx=$x;
                    $rgb = imagecolorat($orige, $x, $y);
                    $color = imagecolorsforindex($orige, $rgb);

                    $red=preg_replace("/[^0-9]/","",$color["red"]);
                    $green=preg_replace("/[^0-9]/","",$color["green"]);
                    $blue=preg_replace("/[^0-9]/","",$color["blue"]);

                    $color_to_paste = imagecolorallocate($im, $red, $green, $blue); 
                    imagesetpixel($im,$newx, $y, $color_to_paste);  
    }
    ?>
    <img src="n.png" > 

and, the result: at right is the image made by previous code.