39 lines
1.2 KiB
Go
39 lines
1.2 KiB
Go
//go:build !arm64
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package rdpgfx
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import "unsafe"
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// ictToBGRA converts n pixels from YCbCr (ICT) to BGRA and writes them into
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// dst (which must hold ≥ 4*n bytes). Processing n pixels in [8]int32 arrays
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// with a scalar inner loop.
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func ictToBGRA(yRow, cbRow, crRow []int16, dst []byte, n int) {
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const batch = 8
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full := (n / batch) * batch
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for base := 0; base < full; base += batch {
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var yv, cb, cr [batch]int32
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for k := range batch {
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yv[k] = int32(yRow[base+k])
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cb[k] = int32(cbRow[base+k])
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cr[k] = int32(crRow[base+k])
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}
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for k := range batch {
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ys := (yv[k] + 4096) << 16
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bv := uint32(max(0, min((cb[k]*115992+ys)>>21, 255)))
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gv := uint32(max(0, min((ys-cb[k]*22527-cr[k]*46819)>>21, 255)))
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rv := uint32(max(0, min((cr[k]*91916+ys)>>21, 255)))
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*(*uint32)(unsafe.Pointer(&dst[(base+k)*4])) = bv | gv<<8 | rv<<16 | 0xFF000000
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}
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}
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for col := full; col < n; col++ {
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yv := int32(yRow[col])
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cb := int32(cbRow[col])
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cr := int32(crRow[col])
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ys := (yv + 4096) << 16
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bv := uint32(max(0, min((cb*115992+ys)>>21, 255)))
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gv := uint32(max(0, min((ys-cb*22527-cr*46819)>>21, 255)))
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rv := uint32(max(0, min((cr*91916+ys)>>21, 255)))
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*(*uint32)(unsafe.Pointer(&dst[col*4])) = bv | gv<<8 | rv<<16 | 0xFF000000
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}
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}
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