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* Accelerated sRGB <=> linear conversion using lookup table, this can speed up
  loading of images in the compositor and simple renders quite a bit.
* Dithering now uses the Floyd-Steinberg algorithm. Previously it would simply
  randomize each pixel slightly, adding noise, now that should be reduced.

Patch #29309 by David M.
This commit is contained in:
Brecht Van Lommel
2012-01-08 13:55:53 +00:00
parent 3dead22c73
commit 4487103e61
5 changed files with 289 additions and 45 deletions
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170
source/blender/imbuf/intern/divers.c
View File

@@ -46,9 +46,9 @@
/**************************** Interlace/Deinterlace **************************/
void IMB_de_interlace(struct ImBuf *ibuf)
void IMB_de_interlace(ImBuf *ibuf)
{
struct ImBuf * tbuf1, * tbuf2;
ImBuf * tbuf1, * tbuf2;
if (ibuf == NULL) return;
if (ibuf->flags & IB_fields) return;
@@ -73,9 +73,9 @@ void IMB_de_interlace(struct ImBuf *ibuf)
ibuf->y /= 2;
}
void IMB_interlace(struct ImBuf *ibuf)
void IMB_interlace(ImBuf *ibuf)
{
struct ImBuf * tbuf1, * tbuf2;
ImBuf * tbuf1, * tbuf2;
if (ibuf == NULL) return;
ibuf->flags &= ~IB_fields;
@@ -100,14 +100,76 @@ void IMB_interlace(struct ImBuf *ibuf)
}
}
/************************* Floyd-Steinberg dithering *************************/
typedef struct DitherContext {
int *error_buf, *e;
int v[4], v0[4], v1[4];
float f;
} DitherContext;
DitherContext *create_dither_context(int w, float factor)
{
DitherContext *di;
int i;
di= MEM_callocN(sizeof(DitherContext), "dithering context");
di->f= factor / 16.0f;
di->error_buf= MEM_callocN(4*(w+1)*sizeof(int), "dithering error");
di->e= di->error_buf;
for(i=0; i<4; ++i)
di->v[i]= di->v0[i]= di->v1[i]= 1024.0f*(BLI_frand()-0.5f);
return di;
}
static void clear_dither_context(DitherContext *di)
{
MEM_freeN(di->error_buf);
MEM_freeN(di);
}
static void dither_finish_row(DitherContext *di)
{
int i;
for(i=0; i<4; i++)
di->v[i]= di->v0[i]= di->v1[i] = 0;
di->e= di->error_buf;
}
MINLINE unsigned char dither_value(unsigned short v_in, DitherContext *di, int i)
{
int dv, d2;
unsigned char v_out;
di->v[i] = v_in + (2*di->v[i] + di->e[4]) * di->f;
CLAMP(di->v[i], 0, 0xFF00);
v_out = USHORTTOUCHAR(di->v[i]);
di->v[i] -= v_out<<8;
dv = di->v[i];
d2 = di->v[i]<<1;
di->v[i] += d2;
*(di->e++) = di->v[i] + di->v0[i];
di->v[i] += d2;
di->v0[i] = di->v[i] + di->v1[i];
di->v1[i] = dv;
di->v[i] += d2;
return v_out;
}
/************************* Generic Buffer Conversion *************************/
MINLINE void byte_to_float_v4(float f[4], const uchar b[4])
{
f[0] = b[0] * (1.0f/255.0f);
f[1] = b[1] * (1.0f/255.0f);
f[2] = b[2] * (1.0f/255.0f);
f[3] = b[3] * (1.0f/255.0f);
f[0]= b[0] * (1.0f/255.0f);
f[1]= b[1] * (1.0f/255.0f);
f[2]= b[2] * (1.0f/255.0f);
f[3]= b[3] * (1.0f/255.0f);
}
MINLINE void float_to_byte_v4(uchar b[4], const float f[4])
@@ -115,10 +177,26 @@ MINLINE void float_to_byte_v4(uchar b[4], const float f[4])
F4TOCHAR4(f, b);
}
MINLINE void float_to_byte_dither_v4(uchar b[4], const float f[4], float dither)
MINLINE void ushort_to_byte_v4(uchar b[4], const unsigned short us[4])
{
float tmp[4] = {f[0]+dither, f[1]+dither, f[2]+dither, f[3]+dither};
float_to_byte_v4(b, tmp);
b[0]= USHORTTOUCHAR(us[0]);
b[1]= USHORTTOUCHAR(us[1]);
b[2]= USHORTTOUCHAR(us[2]);
b[3]= USHORTTOUCHAR(us[3]);
}
MINLINE void ushort_to_byte_dither_v4(uchar b[4], const unsigned short us[4], DitherContext *di)
{
b[0]= dither_value(us[0], di, 0);
b[1]= dither_value(us[0], di, 1);
b[2]= dither_value(us[0], di, 2);
b[3]= dither_value(us[0], di, 3);
}
MINLINE void float_to_byte_dither_v4(uchar b[4], const float f[4], DitherContext *di)
{
unsigned short us[4] = {FTOUSHORT(f[0]), FTOUSHORT(f[1]), FTOUSHORT(f[2]), FTOUSHORT(f[3])};
ushort_to_byte_dither_v4(b, us, di);
}
/* float to byte pixels, output 4-channel RGBA */
@@ -127,26 +205,28 @@ void IMB_buffer_byte_from_float(uchar *rect_to, const float *rect_from,
int width, int height, int stride_to, int stride_from)
{
float tmp[4];
float dither_fac = dither/255.0f;
int x, y;
DitherContext *di;
/* we need valid profiles */
BLI_assert(profile_to != IB_PROFILE_NONE);
BLI_assert(profile_from != IB_PROFILE_NONE);
if(channels_from==1) {
BLI_init_srgb_conversion();
if(dither)
di= create_dither_context(width, dither);
for(y = 0; y < height; y++) {
if(channels_from == 1) {
/* single channel input */
for(y = 0; y < height; y++) {
const float *from = rect_from + stride_from*y;
uchar *to = rect_to + stride_to*y*4;
for(x = 0; x < width; x++, from++, to+=4)
to[0] = to[1] = to[2] = to[3] = FTOCHAR(from[0]);
}
}
else if(channels_from == 3) {
else if(channels_from == 3) {
/* RGB input */
for(y = 0; y < height; y++) {
const float *from = rect_from + stride_from*y*3;
uchar *to = rect_to + stride_to*y*4;
@@ -174,10 +254,8 @@ void IMB_buffer_byte_from_float(uchar *rect_to, const float *rect_from,
}
}
}
}
else if(channels_from == 4) {
else if(channels_from == 4) {
/* RGBA input */
for(y = 0; y < height; y++) {
const float *from = rect_from + stride_from*y*4;
uchar *to = rect_to + stride_to*y*4;
@@ -185,7 +263,7 @@ void IMB_buffer_byte_from_float(uchar *rect_to, const float *rect_from,
/* no color space conversion */
if(dither) {
for(x = 0; x < width; x++, from+=4, to+=4)
float_to_byte_dither_v4(to, from, (BLI_frand()-0.5f)*dither_fac);
float_to_byte_dither_v4(to, from, di);
}
else {
for(x = 0; x < width; x++, from+=4, to+=4)
@@ -194,28 +272,30 @@ void IMB_buffer_byte_from_float(uchar *rect_to, const float *rect_from,
}
else if(profile_to == IB_PROFILE_SRGB) {
/* convert from linear to sRGB */
unsigned short us[4];
if(dither && predivide) {
for(x = 0; x < width; x++, from+=4, to+=4) {
linearrgb_to_srgb_predivide_v4(tmp, from);
float_to_byte_dither_v4(to, tmp, (BLI_frand()-0.5f)*dither_fac);
linearrgb_to_srgb_ushort4_predivide(us, from);
ushort_to_byte_dither_v4(to, us, di);
}
}
else if(dither) {
for(x = 0; x < width; x++, from+=4, to+=4) {
linearrgb_to_srgb_v4(tmp, from);
float_to_byte_dither_v4(to, tmp, (BLI_frand()-0.5f)*dither_fac);
linearrgb_to_srgb_ushort4(us, from);
ushort_to_byte_dither_v4(to, us, di);
}
}
else if(predivide) {
for(x = 0; x < width; x++, from+=4, to+=4) {
linearrgb_to_srgb_predivide_v4(tmp, from);
float_to_byte_v4(to, tmp);
linearrgb_to_srgb_ushort4_predivide(us, from);
ushort_to_byte_v4(to, us);
}
}
else {
for(x = 0; x < width; x++, from+=4, to+=4) {
linearrgb_to_srgb_v4(tmp, from);
float_to_byte_v4(to, tmp);
linearrgb_to_srgb_ushort4(us, from);
ushort_to_byte_v4(to, us);
}
}
}
@@ -224,13 +304,13 @@ void IMB_buffer_byte_from_float(uchar *rect_to, const float *rect_from,
if(dither && predivide) {
for(x = 0; x < width; x++, from+=4, to+=4) {
srgb_to_linearrgb_predivide_v4(tmp, from);
float_to_byte_dither_v4(to, tmp, (BLI_frand()-0.5f)*dither_fac);
float_to_byte_dither_v4(to, tmp, di);
}
}
else if(dither) {
for(x = 0; x < width; x++, from+=4, to+=4) {
srgb_to_linearrgb_v4(tmp, from);
float_to_byte_dither_v4(to, tmp, (BLI_frand()-0.5f)*dither_fac);
float_to_byte_dither_v4(to, tmp, di);
}
}
else if(predivide) {
@@ -247,7 +327,13 @@ void IMB_buffer_byte_from_float(uchar *rect_to, const float *rect_from,
}
}
}
if(dither)
dither_finish_row(di);
}
if(dither)
clear_dither_context(di);
}
/* byte to float pixels, input and output 4-channel RGBA */
@@ -262,6 +348,8 @@ void IMB_buffer_float_from_byte(float *rect_to, const uchar *rect_from,
BLI_assert(profile_to != IB_PROFILE_NONE);
BLI_assert(profile_from != IB_PROFILE_NONE);
BLI_init_srgb_conversion();
/* RGBA input */
for(y = 0; y < height; y++) {
const uchar *from = rect_from + stride_from*y*4;
@@ -276,14 +364,12 @@ void IMB_buffer_float_from_byte(float *rect_to, const uchar *rect_from,
/* convert sRGB to linear */
if(predivide) {
for(x = 0; x < width; x++, from+=4, to+=4) {
byte_to_float_v4(tmp, from);
srgb_to_linearrgb_predivide_v4(to, tmp);
srgb_to_linearrgb_uchar4_predivide(to, from);
}
}
else {
for(x = 0; x < width; x++, from+=4, to+=4) {
byte_to_float_v4(tmp, from);
srgb_to_linearrgb_v4(to, tmp);
srgb_to_linearrgb_uchar4(to, from);
}
}
}
@@ -451,7 +537,7 @@ void IMB_buffer_byte_from_byte(uchar *rect_to, const uchar *rect_from,
/****************************** ImBuf Conversion *****************************/
void IMB_rect_from_float(struct ImBuf *ibuf)
void IMB_rect_from_float(ImBuf *ibuf)
{
int predivide= (ibuf->flags & IB_cm_predivide);
int profile_from;
@@ -482,7 +568,7 @@ void IMB_rect_from_float(struct ImBuf *ibuf)
}
/* converts from linear float to sRGB byte for part of the texture, buffer will hold the changed part */
void IMB_partial_rect_from_float(struct ImBuf *ibuf, float *buffer, int x, int y, int w, int h)
void IMB_partial_rect_from_float(ImBuf *ibuf, float *buffer, int x, int y, int w, int h)
{
float *rect_float;
uchar *rect_byte;
@@ -521,7 +607,7 @@ void IMB_partial_rect_from_float(struct ImBuf *ibuf, float *buffer, int x, int y
ibuf->userflags &= ~IB_RECT_INVALID;
}
void IMB_float_from_rect(struct ImBuf *ibuf)
void IMB_float_from_rect(ImBuf *ibuf)
{
int predivide= (ibuf->flags & IB_cm_predivide);
int profile_from;
@@ -547,7 +633,7 @@ void IMB_float_from_rect(struct ImBuf *ibuf)
}
/* no profile conversion */
void IMB_float_from_rect_simple(struct ImBuf *ibuf)
void IMB_float_from_rect_simple(ImBuf *ibuf)
{
int predivide= (ibuf->flags & IB_cm_predivide);
@@ -559,7 +645,7 @@ void IMB_float_from_rect_simple(struct ImBuf *ibuf)
ibuf->x, ibuf->y, ibuf->x, ibuf->x);
}
void IMB_convert_profile(struct ImBuf *ibuf, int profile)
void IMB_convert_profile(ImBuf *ibuf, int profile)
{
int predivide= (ibuf->flags & IB_cm_predivide);
int profile_from, profile_to;
@@ -601,7 +687,7 @@ void IMB_convert_profile(struct ImBuf *ibuf, int profile)
/* use when you need to get a buffer with a certain profile
* if the return */
float *IMB_float_profile_ensure(struct ImBuf *ibuf, int profile, int *alloc)
float *IMB_float_profile_ensure(ImBuf *ibuf, int profile, int *alloc)
{
int predivide= (ibuf->flags & IB_cm_predivide);
int profile_from, profile_to;
@@ -649,7 +735,7 @@ float *IMB_float_profile_ensure(struct ImBuf *ibuf, int profile, int *alloc)
/**************************** Color to Grayscale *****************************/
/* no profile conversion */
void IMB_color_to_bw(struct ImBuf *ibuf)
void IMB_color_to_bw(ImBuf *ibuf)
{
float *rctf= ibuf->rect_float;
uchar *rct= (uchar*)ibuf->rect;