1 files changed, 78 insertions, 2 deletions

diff --git a/make/gl-impl-CustomJavaCode.java b/make/gl-impl-CustomJavaCode.java
index 1669f07bc..949affbc7 100644
--- a/make/gl-impl-CustomJavaCode.java
+++ b/make/gl-impl-CustomJavaCode.java
@@ -64,7 +64,8 @@ public void setObjectTracker(GLObjectTracker tracker) {
     should catch most crashes. The logic in this routine is based on
     code in the SGI OpenGL sample implementation. */
 
-private int imageSizeInBytes(int format, int type, int w, int h, int d) {
+private int imageSizeInBytes(int format, int type, int w, int h, int d,
+                             int dimensions, boolean pack) {
   int elements = 0;
   int esize = 0;
   
@@ -146,7 +147,82 @@ private int imageSizeInBytes(int format, int type, int w, int h, int d) {
   default:
     return 0;
   }
-  return (elements * esize * w * h * d);
+  return imageSizeInBytes(elements * esize, w, h, d, dimensions, pack);
+}
+
+private int[] imageSizeTemp = new int[1];
+
+/** Helper for more precise computation of number of bytes that will
+    be touched by a pixel pack or unpack operation. */
+private int imageSizeInBytes(int bytesPerElement,
+                             int w, int h, int d,
+                             int dimensions,
+                             boolean pack) {
+    int rowLength = 0;
+    int skipRows = 0;
+    int skipPixels = 0;
+    int alignment = 1;
+    int imageHeight = 0;
+    int skipImages = 0;
+
+    if (pack) {
+        glGetIntegerv(GL_PACK_ROW_LENGTH, imageSizeTemp, 0);
+        rowLength = imageSizeTemp[0];
+        glGetIntegerv(GL_PACK_SKIP_ROWS, imageSizeTemp, 0);
+        skipRows = imageSizeTemp[0];
+        glGetIntegerv(GL_PACK_SKIP_PIXELS, imageSizeTemp, 0);
+        skipPixels = imageSizeTemp[0];
+        glGetIntegerv(GL_PACK_ALIGNMENT, imageSizeTemp, 0);
+        alignment = imageSizeTemp[0];
+        if (dimensions > 2) {
+            glGetIntegerv(GL_PACK_IMAGE_HEIGHT, imageSizeTemp, 0);
+            imageHeight = imageSizeTemp[0];
+            glGetIntegerv(GL_PACK_SKIP_IMAGES, imageSizeTemp, 0);
+            skipImages = imageSizeTemp[0];
+        }
+    } else {
+        glGetIntegerv(GL_UNPACK_ROW_LENGTH, imageSizeTemp, 0);
+        rowLength = imageSizeTemp[0];
+        glGetIntegerv(GL_UNPACK_SKIP_ROWS, imageSizeTemp, 0);
+        skipRows = imageSizeTemp[0];
+        glGetIntegerv(GL_UNPACK_SKIP_PIXELS, imageSizeTemp, 0);
+        skipPixels = imageSizeTemp[0];
+        glGetIntegerv(GL_UNPACK_ALIGNMENT, imageSizeTemp, 0);
+        alignment = imageSizeTemp[0];
+        if (dimensions > 2) {
+            glGetIntegerv(GL_UNPACK_IMAGE_HEIGHT, imageSizeTemp, 0);
+            imageHeight = imageSizeTemp[0];
+            glGetIntegerv(GL_UNPACK_SKIP_IMAGES, imageSizeTemp, 0);
+            skipImages = imageSizeTemp[0];
+        }
+    }
+    // Try to deal somewhat correctly with potentially invalid values
+    rowLength   = Math.max(0, rowLength);
+    skipRows    = Math.max(0, skipRows);
+    skipPixels  = Math.max(0, skipPixels);
+    alignment   = Math.max(1, alignment);
+    imageHeight = Math.max(0, imageHeight);
+    skipImages  = Math.max(0, skipImages);
+    rowLength   = Math.max(rowLength, w + skipPixels);
+    int rowLengthInBytes = rowLength * bytesPerElement;
+    if (alignment > 1) {
+        int modulus = rowLengthInBytes % alignment;
+        if (modulus > 0) {
+            rowLengthInBytes += alignment - modulus;
+        }
+    }
+
+    int size = 0;
+    if (dimensions == 1) {
+        return (w + skipPixels) * bytesPerElement;
+    } else {
+        int size2D = ((skipRows + h - 1) * rowLengthInBytes) + (w + skipPixels) * bytesPerElement;
+        if (dimensions == 2) {
+            return size2D;
+        }
+        int imageSizeInBytes = imageHeight * rowLength;
+        return ((skipImages + d - 1) * imageSizeInBytes) + size2D;
+    }
 }
 
 private boolean bufferObjectExtensionsInitialized = false;