1 files changed, 36 insertions, 0 deletions
diff --git a/src/classes/com/sun/opengl/util/texture/spi/DDSImage.java b/src/classes/com/sun/opengl/util/texture/spi/DDSImage.java
index 52dbc25b1..835025b5c 100755
--- a/src/classes/com/sun/opengl/util/texture/spi/DDSImage.java
+++ b/src/classes/com/sun/opengl/util/texture/spi/DDSImage.java
@@ -43,6 +43,9 @@ import java.io.*;
 import java.nio.*;
 import java.nio.channels.*;
 
+import javax.media.opengl.*;
+import com.sun.opengl.util.*;
+
 /** A reader and writer for DirectDraw Surface (.dds) files, which are
     used to describe textures. These files can contain multiple mipmap
     levels in one file. This class is currently minimal and does not
@@ -469,6 +472,39 @@ public class DDSImage {
     return buf.toString();
   }
 
+  /** Allocates a temporary, empty ByteBuffer suitable for use in a
+      call to glCompressedTexImage2D. This is used by the Texture
+      class to expand non-power-of-two DDS compressed textures to
+      power-of-two sizes on hardware not supporting OpenGL 2.0 and the
+      NPOT texture extension. The specified OpenGL internal format
+      must be one of GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+      GL_COMPRESSED_RGBA_S3TC_DXT1_EXT,
+      GL_COMPRESSED_RGBA_S3TC_DXT3_EXT, or
+      GL_COMPRESSED_RGBA_S3TC_DXT5_EXT.
+  */
+  public static ByteBuffer allocateBlankBuffer(int width,
+                                               int height,
+                                               int openGLInternalFormat) {
+    int size = width * height;
+    switch (openGLInternalFormat) {
+      case GL.GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+      case GL.GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
+        size /= 2;
+        break;
+
+      case GL.GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+      case GL.GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+        break;
+
+      default:
+        throw new IllegalArgumentException("Illegal OpenGL texture internal format " +
+                                           openGLInternalFormat);
+    }
+    if (size == 0)
+      size = 1;
+    return BufferUtil.newByteBuffer(size);
+  }
+
   public void debugPrint() {
     PrintStream tty = System.err;
     tty.println("Compressed texture: " + isCompressed());