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#include "IOStream.h"
#include "GL2Encoder.h"
#include <GLES3/gl31.h>
#include <vector>
void IOStream::readbackPixels(void* context, int width, int height, unsigned int format, unsigned int type, void* pixels) {
GL2Encoder *ctx = (GL2Encoder *)context;
assert (ctx->state() != NULL);
int startOffset = 0;
int pixelRowSize = 0;
int totalRowSize = 0;
int skipRows = 0;
ctx->state()->getPackingOffsets2D(width, height, format, type,
&startOffset,
&pixelRowSize,
&totalRowSize,
&skipRows);
size_t pixelDataSize =
ctx->state()->pixelDataSize(
width, height, 1, format, type, 1 /* is pack */);
if (startOffset == 0 &&
pixelRowSize == totalRowSize) {
// fast path
readback(pixels, pixelDataSize);
} else if (pixelRowSize == totalRowSize) {
// fast path but with skip in the beginning
std::vector<char> paddingToDiscard(startOffset, 0);
readback(&paddingToDiscard[0], startOffset);
readback((char*)pixels + startOffset, pixelDataSize - startOffset);
} else {
int totalReadback = 0;
if (startOffset > 0) {
std::vector<char> paddingToDiscard(startOffset, 0);
readback(&paddingToDiscard[0], startOffset);
totalReadback += startOffset;
}
// need to read back row by row
size_t paddingSize = totalRowSize - pixelRowSize;
std::vector<char> paddingToDiscard(paddingSize, 0);
char* start = (char*)pixels + startOffset;
for (int i = 0; i < height; i++) {
readback(start, pixelRowSize);
totalReadback += pixelRowSize;
readback(&paddingToDiscard[0], paddingSize);
totalReadback += paddingSize;
start += totalRowSize;
}
}
}
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