TEXTURE *material_map(const Vector3d& EPoint, const TEXTURE *Texture)
{
int reg_number = -1;
int Material_Number;
DBL xcoor = 0.0, ycoor = 0.0;
RGBFTColour colour;
/*
* Now we have transformed x, y, z we use image mapping routine to determine
* texture index.
*/
if(map_pos(EPoint, Texture->pattern.get(), &xcoor, &ycoor))
Material_Number = 0;
else
{
if (const ImagePatternImpl *pattern = dynamic_cast<ImagePatternImpl*>(Texture->pattern.get()))
image_colour_at(pattern->pImage, xcoor, ycoor, colour, ®_number); // TODO ALPHA - we should decide whether we prefer premultiplied or non-premultiplied alpha
else
POV_PATTERN_ASSERT(false);
if(reg_number == -1)
Material_Number = (int)(colour.red() * 255.0);
else
Material_Number = reg_number;
}
if(Material_Number > Texture->Materials.size())
Material_Number %= Texture->Materials.size();
return Texture->Materials[Material_Number % Texture->Materials.size()];
}
static void no_interpolation(const ImageData *image, DBL xcoor, DBL ycoor, RGBFTColour& colour, int *index, bool premul)
{
int iycoor, ixcoor;
if(image->Once_Flag)
{
// image is to be seen only once, so when taking samples for interpolation
// coordinates should not wrap around; instead, take the samples from the nearest
// pixel right at the edge of the image
if(xcoor < 0.0)
ixcoor = 0;
else if(xcoor >= (DBL)image->iwidth)
ixcoor = image->iwidth - 1;
else
ixcoor = (int)xcoor;
if(ycoor < 0.0)
iycoor = 0;
else if(ycoor >= (DBL)image->iheight)
iycoor = image->iheight - 1;
else
iycoor = (int)ycoor;
}
else
{
// image is to be repeated, so when taking samples for interpolation
// have coordinates wrap around
ixcoor = (int)wrap(xcoor, (DBL)image->iwidth);
iycoor = (int)wrap(ycoor, (DBL)image->iheight);
}
image->data->GetRGBFTValue(ixcoor, iycoor, colour, premul);
if(image->data->IsIndexed() == false)
{
*index = -1;
if (image->AllTransmitLegacyMode)
{
// Legacy versions applied "transmit/filter all" before interpolation,
// and with little respect to an image's inherent alpha information.
colour.transm() += image->AllTransmit;
colour.filter() += image->AllFilter;
}
}
else
*index = image->data->GetIndexedValue(ixcoor, iycoor);
}
DBL image_pattern(const Vector3d& EPoint, const BasicPattern* pPattern)
{
DBL xcoor = 0.0, ycoor = 0.0;
int index = -1;
RGBFTColour colour;
const ImageData *image = dynamic_cast<const ImagePatternImpl*>(pPattern)->pImage;
DBL Value;
colour.Clear();
// going to have to change this
// need to know if bump point is off of image for all 3 points
if(map_pos(EPoint, pPattern, &xcoor, &ycoor))
return 0.0;
else
image_colour_at(image, xcoor, ycoor, colour, &index); // TODO ALPHA - we should decide whether we prefer premultiplied or non-premultiplied alpha
if((index == -1) || image->Use)
{
if(image->Use == USE_ALPHA)
{
// use alpha channel or red channel
if(image->data->HasTransparency() == true)
Value = colour.transm();
else
Value = colour.red(); // otherwise, just use the red channel
}
else
// use grey-scaled version of the color
Value = colour.Greyscale();
}
else
Value = index / 255.0;
if(Value < 0)
Value = 0;
else if(Value > 1.0)
Value = 1.0;
return Value;
}
static void InterpolateBicubic(const ImageData *image, DBL xcoor, DBL ycoor, RGBFTColour& colour, int *index, bool premul)
{
int iycoor, ixcoor;
int cornerIndex;
RGBFTColour cornerColour;
DBL factor;
DBL factorsX[4];
DBL factorsY[4];
xcoor += 0.5;
ycoor += 0.5;
iycoor = (int)ycoor;
ixcoor = (int)xcoor;
cubic(factorsX, xcoor);
cubic(factorsY, ycoor);
// We're using double precision for the colors here to avoid higher-than-1.0 results due to rounding errors,
// which would otherwise lead to stray dot artifacts when clamped to [0..1] range for a color_map or similar.
// (Note that strictly speaking we don't avoid such rounding errors, but rather make them small enough that
// subsequent rounding to single precision will take care of them.)
// (Note that bicubic interpolation may still give values outside the range [0..1] at high-contrast edges;
// this is an inherent property of this interpolation method, and is therefore accepted here.)
PreciseRGBFTColour tempColour;
DBL tempIndex = 0;
for (int i = 0; i < 4; i ++)
{
for (int j = 0; j < 4; j ++)
{
cornerColour.Clear();
no_interpolation(image, (DBL)ixcoor + i-2, (DBL)iycoor + j-2, cornerColour, &cornerIndex, premul);
factor = factorsX[i] * factorsY[j];
tempColour += PreciseRGBFTColour(cornerColour) * factor;
tempIndex += cornerIndex * factor;
}
}
colour = RGBFTColour(tempColour);
*index = (int)tempIndex;
}
void AlphaUnPremultiply(RGBFTColour& colour)
{
AlphaUnPremultiply(colour.red(), colour.green(), colour.blue(), colour.FTtoA());
}
void image_colour_at(const ImageData *image, DBL xcoor, DBL ycoor, RGBFTColour& colour, int *index, bool premul)
{
*index = -1;
bool doProperTransmitAll = image->data->HasTransparency() &&
!image->AllTransmitLegacyMode &&
!image->data->IsIndexed() && ( (image->AllTransmit != 0.0) || (image->AllFilter != 0.0) );
// If either source or destination uses premultiplied alpha, make sure interpolation is done in premultiplied space
// as it makes the mathematical operations cleaner -- unless the alpha channel is modulated by "transmit all" or
// "filter all", in which case we prefer non-premultiplied space.
bool getPremul = doProperTransmitAll ? (premul && image->data->IsPremultiplied()) :
(premul || image->data->IsPremultiplied());
switch(image->Interpolation_Type)
{
case NO_INTERPOLATION:
no_interpolation(image, xcoor, ycoor, colour, index, getPremul);
break;
case BICUBIC:
InterpolateBicubic(image, xcoor, ycoor, colour, index, getPremul);
break;
default:
Interp(image, xcoor, ycoor, colour, index, getPremul);
break;
}
bool havePremul = getPremul;
if (!premul && havePremul)
{
// We fetched premultiplied data, but caller expects it non-premultiplied, so we need to fix that.
// As "transmit/filter all" handling also works best on non-premultiplied data, we're doing this now.
AlphaUnPremultiply(colour.rgb(), colour.FTtoA());
havePremul = false;
}
if (doProperTransmitAll)
{
COLC imageAlpha = colour.FTtoA();
if (imageAlpha != 0.0) // No need to apply "filter/transmit all" if the image is fully transparent here anyway.
{
colour.transm() += image->AllTransmit * imageAlpha;
colour.filter() += image->AllFilter * imageAlpha;
if (havePremul)
{
// We have premultiplied data here, and the caller expects it to stay that way (otherwise we'd already
// have converted to non-premultiplied by now), so we need to fix the premultiplication of the colour
// according to our modifications to the transparency components.
COLC alphaCorrection = colour.FTtoA() / imageAlpha;
AlphaPremultiply(colour.rgb(), alphaCorrection);
}
}
}
if (premul && !havePremul)
{
// We have non-premultiplied data here, but caller expects it premultiplied, so we need to fix that
// As "transmit/filter all" handling works best on non-premultiplied data, we haven't done this earlier.
AlphaPremultiply(colour.rgb(), colour.FTtoA());
}
}
