add pvr export support

Author: esterTion

UnityAsset.php

@@ -781,6 +781,11 @@ function __construct($preloadData, $readSwitch) {
           $this->transcodeFormat = 'bmp';
           $this->bitDepth = 16;
           break;
+        case TextureFormat::PVRTC_RGB4:
+          $this->outputMethod = 'pvr';
+          $this->transcodeFormat = 'bmp';
+          // use PVRTexToolCLI
+          break;
         default:
         throw new Exception('not implemented: '.$this->textureFormat.' '.$this->textureFormatStr);
       }
@@ -837,8 +842,34 @@ function exportTo($saveTo, $format = 'png', $extraEncodeParam = '') {
       file_put_contents('output.bmp', $bmp->readData($bmp->size));
       unset($bmp);
       $transcodeFile = 'output.bmp';
+    } else if ($this->outputMethod == 'pvr') {
+      /*fclose(fopen('output.pvr','wb'));
+      $pvr = new FileStream('output.pvr');
+      $pvr->write(hex2bin('5056520300000000'));
+      $pvr->write(pack('P', [
+        TextureFormat::PVRTC_RGB2 => 0,
+        TextureFormat::PVRTC_RGB4 => 2,
+        TextureFormat::PVRTC_RGBA2 => 1,
+        TextureFormat::PVRTC_RGBA4 => 3,
+      ][$this->textureFormat]));
+      $pvr->write(hex2bin('0000000000000000'));
+      $pvr->write(pack('V', $this->height));
+      $pvr->write(pack('V', $this->width));
+      $pvr->write(hex2bin('0100000001000000010000000100000000000000'));
+      $pvr->write($this->imageData);
+      unset($pvr);*/
+      file_put_contents('output.pvr', $this->imageData);
+      exec('pvr-decompress output.pvr output.bmp '.implode(' ', [$this->width, $this->height, [
+        TextureFormat::PVRTC_RGB2 => 1,
+        TextureFormat::PVRTC_RGB4 => 0,
+        TextureFormat::PVRTC_RGBA2 => 1,
+        TextureFormat::PVRTC_RGBA4 => 0,
+      ][$this->textureFormat]]));
+      unlink('output.pvr');
+      $transcodeFile = 'output.bmp';
+      //throw new Exception('wip');
     } else {
-      throw new Excpetion('not supported');
+      throw new Exception('not supported');
     }
 
     if ($this->transcodeFormat != $format) {