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SWORD25: Simplify & optimize PNG reading code

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The interlaced part is untested since I do not know any place
in the game where interlaced data is used.

svn-id: r53757
This commit is contained in:
Max Horn 2010-10-24 01:33:24 +00:00
parent 4d6fb4e768
commit 2a987c4a31
1 changed files with 14 additions and 36 deletions
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50
engines/sword25/gfx/image/pngloader.cpp
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@ -100,8 +100,6 @@ static bool doIsCorrectImageFormat(const byte *fileDataPtr, uint fileSize) {
bool PNGLoader::doDecodeImage(const byte *fileDataPtr, uint fileSize, byte *&uncompressedDataPtr, int &width, int &height, int &pitch) {
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
png_bytep rawDataBuffer = NULL;
png_bytep *pRowPtr = NULL;
int bitDepth;
int colorType;
@ -166,59 +164,39 @@ bool PNGLoader::doDecodeImage(const byte *fileDataPtr, uint fileSize, byte *&unc
png_read_update_info(png_ptr, info_ptr);
png_get_IHDR(png_ptr, info_ptr, (png_uint_32 *)&width, (png_uint_32 *)&height, &bitDepth, &colorType, NULL, NULL, NULL);
// PNGs ohne Interlacing werden Zeilenweise eingelesen
if (interlaceType == PNG_INTERLACE_NONE) {
// Speicher für eine Bildzeile reservieren
rawDataBuffer = new png_byte[png_get_rowbytes(png_ptr, info_ptr)];
if (!rawDataBuffer) {
error("Could not allocate memory for row buffer.");
}
// Bilddaten zeilenweise einlesen und in das gewünschte Zielformat konvertieren
// PNGs without interlacing can simply be read row by row.
for (i = 0; i < height; i++) {
// Zeile einlesen
png_read_row(png_ptr, rawDataBuffer, NULL);
// Zeile konvertieren
memcpy(&uncompressedDataPtr[i * pitch], rawDataBuffer, pitch);
png_read_row(png_ptr, uncompressedDataPtr + i * pitch, NULL);
}
} else {
// PNGs mit Interlacing werden an einem Stück eingelesen
// Speicher für das komplette Bild reservieren
rawDataBuffer = new png_byte[png_get_rowbytes(png_ptr, info_ptr) * height];
if (!rawDataBuffer) {
error("Could not allocate memory for raw image buffer.");
}
// PNGs with interlacing require us to allocate an auxillary
// buffer with pointers to all row starts.
// Speicher für die Rowpointer reservieren
pRowPtr = new png_bytep[height];
// Allocate row pointer buffer
png_bytep *pRowPtr = new png_bytep[height];
if (!pRowPtr) {
error("Could not allocate memory for row pointers.");
}
// Alle Rowpointer mit den richtigen Offsets initialisieren
// Initialize row pointers
for (i = 0; i < height; i++)
pRowPtr[i] = rawDataBuffer + i * png_get_rowbytes(png_ptr, info_ptr);
pRowPtr[i] = uncompressedDataPtr + i * pitch;
// Bild einlesen
// Read image data
png_read_image(png_ptr, pRowPtr);
// Bilddaten zeilenweise in das gewünschte Ausgabeformat konvertieren
for (i = 0; i < height; i++)
memcpy(&uncompressedDataPtr[i * pitch], &rawDataBuffer[i * png_get_rowbytes(png_ptr, info_ptr)], pitch);
// Free row pointer buffer
delete[] pRowPtr;
}
// Die zusätzlichen Daten am Ende des Bildes lesen
// Read additional data at the end.
png_read_end(png_ptr, NULL);
// Die Strukturen freigeben
// Destroy libpng structures
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
// Temporäre Buffer freigeben
delete[] pRowPtr;
delete[] rawDataBuffer;
// Der Funktionsaufruf war erfolgreich
// Signal success
return true;
}