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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 width, int height, int depth,
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
height = Math.max(0, height);
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(Math.max(0, rowLength), width); // > 0 && >= width
int rowLengthInBytes = rowLength * bytesPerElement;
if (alignment > 1) {
int modulus = rowLengthInBytes % alignment;
if (modulus > 0) {
rowLengthInBytes += alignment - modulus;
}
}
/**
* skipPixels and skipRows is a static one time offset
*
* rowlenght is the actual repeating offset
* from line-start to the next line-start.
*/
int size = height * rowLengthInBytes; // height == 1 for 1D
if(dimensions==3) {
size *= (skipImages + depth);
}
int skipOffset = skipPixels * bytesPerElement +
skipRows * rowLengthInBytes;
return size + skipOffset;
}
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