Move the slow part of alpha testing into korlib

korman/exporter/material.py

@@ -577,13 +577,7 @@ class MaterialConverter:
         else:
             # Using bpy.types.Image.pixels is VERY VERY VERY slow...
             with korlib.GLTexture(image) as glimage:
-                data = glimage.get_level_data(quiet=True)
+                result = glimage.has_alpha
-                for i in range(3, len(data), 4):
-                    if data[i] != 255:
-                        result = True
-                        break
-                else:
-                    result = False
 
         self._alphatest[image] = result
         return result

korman/korlib/texture.py

@@ -95,3 +95,11 @@ class GLTexture:
         else:
             bgl.glGetTexLevelParameteriv(bgl.GL_TEXTURE_2D, level, param, buf)
         return int(buf[0])
+
+    @property
+    def has_alpha(self):
+        data = self.get_level_data(quiet=True)
+        for i in range(3, len(data), 4):
+            if data[i] != 255:
+                return True
+        return False