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Move bayer to RGB to a separate function
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Signed-off-by: Hector Martin <[email protected]>
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@marcan
marcan committed Nov 28, 2010
1 parent bac69ea commit b1aa98b
Showing 1 changed file with 163 additions and 161 deletions.
324 changes: 163 additions & 161 deletions src/cameras.c
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Original file line number Diff line number Diff line change
Expand Up @@ -253,188 +253,190 @@ static void depth_process(freenect_device *dev, uint8_t *pkt, int len)
dev->depth_cb(dev, dev->depth.proc_buf, dev->depth.timestamp);
}

static void rgb_process(freenect_device *dev, uint8_t *pkt, int len)
static void convert_bayer_to_rgb(uint8_t *raw_buf, uint8_t *proc_buf)
{
freenect_context *ctx = dev->parent;
int x,y;

if (len == 0)
return;

if (!dev->rgb.running)
return;

int got_frame = stream_process(ctx, &dev->rgb, pkt, len);

if (!got_frame)
return;

FN_SPEW("Got RGB frame %d/%d packets arrived, TS %08x\n", dev->rgb.valid_pkts,
dev->rgb.pkts_per_frame, dev->rgb.timestamp);

if (dev->rgb_format == FREENECT_FORMAT_RGB) {
uint8_t *raw_buf = dev->rgb.raw_buf;
uint8_t *proc_buf = dev->rgb.proc_buf;
/* Pixel arrangement:
* G R G R G R G R
* B G B G B G B G
* G R G R G R G R
* B G B G B G B G
* G R G R G R G R
* B G B G B G B G
*
* To convert a Bayer-pattern into RGB you have to handle four pattern
* configurations:
* 1) 2) 3) 4)
* B1 B1 G1 B2 R1 G1 R2 R1 <- previous line
* R1 G1 R2 G2 R1 G3 G2 B1 G3 B1 G1 B2 <- current line
* B2 B3 G4 B4 R3 G4 R4 R2 <- next line
* ^ ^ ^
* | | next pixel
* | current pixel
* previous pixel
*
* The RGB values (r,g,b) for each configuration are calculated as
* follows:
*
* 1) r = (R1 + R2) / 2
* g = G1
* b = (B1 + B2) / 2
*
* 2) r = R1
* g = (G1 + G2 + G3 + G4) / 4
* b = (B1 + B2 + B3 + B4) / 4
*
* 3) r = (R1 + R2 + R3 + R4) / 4
* g = (G1 + G2 + G3 + G4) / 4
* b = B1
*
* 4) r = (R1 + R2) / 2
* g = G1
* b = (B1 + B2) / 2
*
* To efficiently calculate these values, two 32bit integers are used
* as "shift-buffers". One integer to store the 3 horizontal bayer pixel
* values (previous, current, next) of the current line. The other
* integer to store the vertical average value of the bayer pixels
* (previous, current, next) of the previous and next line.
*
* The boundary conditions for the first and last line and the first
* and last column are solved via mirroring the second and second last
* line and the second and second last column.
*
* To reduce slow memory access, the values of a rgb pixel are packet
* into a 32bit variable and transfered together.
*/

uint8_t *dst = proc_buf; // pointer to destination

uint8_t *prevLine; // pointer to previous, current and next line
uint8_t *curLine; // of the source bayer pattern
uint8_t *nextLine;

// storing horizontal values in hVals:
// previous << 16, current << 8, next
uint32_t hVals;
// storing vertical averages in vSums:
// previous << 16, current << 8, next
uint32_t vSums;

// init curLine and nextLine pointers
curLine = raw_buf;
nextLine = curLine + 640;
for (y = 0; y < 480; ++y) {

if ((y > 0) && (y < 479))
prevLine = curLine - 640; // normal case
else if (y == 0)
prevLine = nextLine; // top boundary case
else
nextLine = prevLine; // bottom boundary case

// init horizontal shift-buffer with current value
hVals = (*(curLine++) << 8);
// handle left column boundary case
hVals |= (*curLine << 16);
// init vertical average shift-buffer with current values average
vSums = ((*(prevLine++) + *(nextLine++)) << 7) & 0xFF00;
// handle left column boundary case
vSums |= ((*prevLine + *nextLine) << 15) & 0xFF0000;

// store if line is odd or not
uint8_t yOdd = y & 1;
// the right column boundary case is not handled inside this loop
// thus the "639"
for (x = 0; x < 639; ++x) {
// place next value in shift buffers
hVals |= *(curLine++);
vSums |= (*(prevLine++) + *(nextLine++)) >> 1;

// calculate the horizontal sum as this sum is needed in
// any configuration
uint8_t hSum = ((uint8_t)(hVals >> 16) + (uint8_t)(hVals)) >> 1;

if (yOdd == 0) {
if ((x & 1) == 0) {
// Configuration 1
*(dst++) = hSum; // r
*(dst++) = hVals >> 8; // g
*(dst++) = vSums >> 8; // b
} else {
// Configuration 2
*(dst++) = hVals >> 8;
*(dst++) = (hSum + (uint8_t)(vSums >> 8)) >> 1;
*(dst++) = ((uint8_t)(vSums >> 16) + (uint8_t)(vSums)) >> 1;
}
} else {
if ((x & 1) == 0) {
// Configuration 3
*(dst++) = ((uint8_t)(vSums >> 16) + (uint8_t)(vSums)) >> 1;
*(dst++) = (hSum + (uint8_t)(vSums >> 8)) >> 1;
*(dst++) = hVals >> 8;
} else {
// Configuration 4
*(dst++) = vSums >> 8;
*(dst++) = hVals >> 8;
*(dst++) = hSum;
}
}

// shift the shift-buffers
hVals <<= 8;
vSums <<= 8;
} // end of for x loop
// right column boundary case, mirroring second last column
hVals |= (uint8_t)(hVals >> 16);
vSums |= (uint8_t)(vSums >> 16);

// the horizontal sum simplifies to the second last column value
uint8_t hSum = (uint8_t)(hVals);
/* Pixel arrangement:
* G R G R G R G R
* B G B G B G B G
* G R G R G R G R
* B G B G B G B G
* G R G R G R G R
* B G B G B G B G
*
* To convert a Bayer-pattern into RGB you have to handle four pattern
* configurations:
* 1) 2) 3) 4)
* B1 B1 G1 B2 R1 G1 R2 R1 <- previous line
* R1 G1 R2 G2 R1 G3 G2 B1 G3 B1 G1 B2 <- current line
* B2 B3 G4 B4 R3 G4 R4 R2 <- next line
* ^ ^ ^
* | | next pixel
* | current pixel
* previous pixel
*
* The RGB values (r,g,b) for each configuration are calculated as
* follows:
*
* 1) r = (R1 + R2) / 2
* g = G1
* b = (B1 + B2) / 2
*
* 2) r = R1
* g = (G1 + G2 + G3 + G4) / 4
* b = (B1 + B2 + B3 + B4) / 4
*
* 3) r = (R1 + R2 + R3 + R4) / 4
* g = (G1 + G2 + G3 + G4) / 4
* b = B1
*
* 4) r = (R1 + R2) / 2
* g = G1
* b = (B1 + B2) / 2
*
* To efficiently calculate these values, two 32bit integers are used
* as "shift-buffers". One integer to store the 3 horizontal bayer pixel
* values (previous, current, next) of the current line. The other
* integer to store the vertical average value of the bayer pixels
* (previous, current, next) of the previous and next line.
*
* The boundary conditions for the first and last line and the first
* and last column are solved via mirroring the second and second last
* line and the second and second last column.
*
* To reduce slow memory access, the values of a rgb pixel are packet
* into a 32bit variable and transfered together.
*/

uint8_t *dst = proc_buf; // pointer to destination

uint8_t *prevLine; // pointer to previous, current and next line
uint8_t *curLine; // of the source bayer pattern
uint8_t *nextLine;

// storing horizontal values in hVals:
// previous << 16, current << 8, next
uint32_t hVals;
// storing vertical averages in vSums:
// previous << 16, current << 8, next
uint32_t vSums;

// init curLine and nextLine pointers
curLine = raw_buf;
nextLine = curLine + 640;
for (y = 0; y < 480; ++y) {

if ((y > 0) && (y < 479))
prevLine = curLine - 640; // normal case
else if (y == 0)
prevLine = nextLine; // top boundary case
else
nextLine = prevLine; // bottom boundary case

// init horizontal shift-buffer with current value
hVals = (*(curLine++) << 8);
// handle left column boundary case
hVals |= (*curLine << 16);
// init vertical average shift-buffer with current values average
vSums = ((*(prevLine++) + *(nextLine++)) << 7) & 0xFF00;
// handle left column boundary case
vSums |= ((*prevLine + *nextLine) << 15) & 0xFF0000;

// store if line is odd or not
uint8_t yOdd = y & 1;
// the right column boundary case is not handled inside this loop
// thus the "639"
for (x = 0; x < 639; ++x) {
// place next value in shift buffers
hVals |= *(curLine++);
vSums |= (*(prevLine++) + *(nextLine++)) >> 1;

// calculate the horizontal sum as this sum is needed in
// any configuration
uint8_t hSum = ((uint8_t)(hVals >> 16) + (uint8_t)(hVals)) >> 1;

if (yOdd == 0) {
if ((x & 1) == 0) {
*(dst++) = hSum;
*(dst++) = hVals >> 8;
*(dst++) = vSums >> 8;
// Configuration 1
*(dst++) = hSum; // r
*(dst++) = hVals >> 8; // g
*(dst++) = vSums >> 8; // b
} else {
// Configuration 2
*(dst++) = hVals >> 8;
*(dst++) = (hSum + (uint8_t)(vSums >> 8)) >> 1;
*(dst++) = vSums;
*(dst++) = ((uint8_t)(vSums >> 16) + (uint8_t)(vSums)) >> 1;
}
} else {
if ((x & 1) == 0) {
*(dst++) = vSums;
// Configuration 3
*(dst++) = ((uint8_t)(vSums >> 16) + (uint8_t)(vSums)) >> 1;
*(dst++) = (hSum + (uint8_t)(vSums >> 8)) >> 1;
*(dst++) = hVals >> 8;
} else {
// Configuration 4
*(dst++) = vSums >> 8;
*(dst++) = hVals >> 8;
*(dst++) = hSum;
}
}

} // end of for y loop
// shift the shift-buffers
hVals <<= 8;
vSums <<= 8;
} // end of for x loop
// right column boundary case, mirroring second last column
hVals |= (uint8_t)(hVals >> 16);
vSums |= (uint8_t)(vSums >> 16);

// the horizontal sum simplifies to the second last column value
uint8_t hSum = (uint8_t)(hVals);

if (yOdd == 0) {
if ((x & 1) == 0) {
*(dst++) = hSum;
*(dst++) = hVals >> 8;
*(dst++) = vSums >> 8;
} else {
*(dst++) = hVals >> 8;
*(dst++) = (hSum + (uint8_t)(vSums >> 8)) >> 1;
*(dst++) = vSums;
}
} else {
if ((x & 1) == 0) {
*(dst++) = vSums;
*(dst++) = (hSum + (uint8_t)(vSums >> 8)) >> 1;
*(dst++) = hVals >> 8;
} else {
*(dst++) = vSums >> 8;
*(dst++) = hVals >> 8;
*(dst++) = hSum;
}
}

} // end of for y loop
}

static void rgb_process(freenect_device *dev, uint8_t *pkt, int len)
{
freenect_context *ctx = dev->parent;

if (len == 0)
return;

if (!dev->rgb.running)
return;

int got_frame = stream_process(ctx, &dev->rgb, pkt, len);

if (!got_frame)
return;

FN_SPEW("Got RGB frame %d/%d packets arrived, TS %08x\n", dev->rgb.valid_pkts,
dev->rgb.pkts_per_frame, dev->rgb.timestamp);

if (dev->rgb_format == FREENECT_FORMAT_RGB) {
convert_bayer_to_rgb(dev->rgb.raw_buf, dev->rgb.proc_buf);
}

if (dev->rgb_cb)
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