[Scummvm-cvs-logs] SF.net SVN: scummvm:[35530] scummvm/trunk
drmccoy at users.sourceforge.net
drmccoy at users.sourceforge.net
Wed Dec 24 17:59:37 CET 2008
Revision: 35530
http://scummvm.svn.sourceforge.net/scummvm/?rev=35530&view=rev
Author: drmccoy
Date: 2008-12-24 16:59:37 +0000 (Wed, 24 Dec 2008)
Log Message:
-----------
Documenting the dither code a bit more and removing SierraLight's not needed height argument
Modified Paths:
--------------
scummvm/trunk/engines/gob/coktelvideo.cpp
scummvm/trunk/engines/gob/indeo3.cpp
scummvm/trunk/engines/gob/video_v6.cpp
scummvm/trunk/graphics/dither.cpp
scummvm/trunk/graphics/dither.h
Modified: scummvm/trunk/engines/gob/coktelvideo.cpp
===================================================================
--- scummvm/trunk/engines/gob/coktelvideo.cpp 2008-12-24 16:44:14 UTC (rev 35529)
+++ scummvm/trunk/engines/gob/coktelvideo.cpp 2008-12-24 16:59:37 UTC (rev 35530)
@@ -1542,7 +1542,7 @@
assert(_palLUT);
Graphics::SierraLight *dither =
- new Graphics::SierraLight(width, height, _palLUT);
+ new Graphics::SierraLight(width, _palLUT);
for (int i = 0; i < height; i++) {
byte *d = dest;
Modified: scummvm/trunk/engines/gob/indeo3.cpp
===================================================================
--- scummvm/trunk/engines/gob/indeo3.cpp 2008-12-24 16:44:14 UTC (rev 35529)
+++ scummvm/trunk/engines/gob/indeo3.cpp 2008-12-24 16:59:37 UTC (rev 35530)
@@ -95,7 +95,7 @@
switch(dither) {
case kDitherSierraLight:
- _ditherSL = new Graphics::SierraLight(_width, _height, _palLUT);
+ _ditherSL = new Graphics::SierraLight(_width, _palLUT);
break;
default:
Modified: scummvm/trunk/engines/gob/video_v6.cpp
===================================================================
--- scummvm/trunk/engines/gob/video_v6.cpp 2008-12-24 16:44:14 UTC (rev 35529)
+++ scummvm/trunk/engines/gob/video_v6.cpp 2008-12-24 16:59:37 UTC (rev 35530)
@@ -177,7 +177,7 @@
_palLUT->getEntry(color, sY, sU, sV);
Graphics::SierraLight *dither =
- new Graphics::SierraLight(width, height, _palLUT);
+ new Graphics::SierraLight(width, _palLUT);
for (int i = 0; i < height; i++) {
byte *d = vidMem;
@@ -256,7 +256,7 @@
height = destDesc->getHeight() - y;
Graphics::SierraLight *dither =
- new Graphics::SierraLight(width, height, _palLUT);
+ new Graphics::SierraLight(width, _palLUT);
for (int i = 0; i < height; i++) {
byte *dest = vidMem;
Modified: scummvm/trunk/graphics/dither.cpp
===================================================================
--- scummvm/trunk/graphics/dither.cpp 2008-12-24 16:44:14 UTC (rev 35529)
+++ scummvm/trunk/graphics/dither.cpp 2008-12-24 16:59:37 UTC (rev 35530)
@@ -204,11 +204,10 @@
return true;
}
-SierraLight::SierraLight(int16 width, int16 height, PaletteLUT *palLUT) {
- assert((width > 0) && (height > 0));
+SierraLight::SierraLight(int16 width, PaletteLUT *palLUT) {
+ assert(width > 0);
_width = width;
- _height = height;
_palLUT = palLUT;
// Big buffer for the errors of the current and next line
@@ -239,6 +238,7 @@
byte SierraLight::dither(byte c1, byte c2, byte c3, uint32 x) {
assert(_palLUT);
+ assert(x < _width);
int32 eC1, eC2, eC3;
Modified: scummvm/trunk/graphics/dither.h
===================================================================
--- scummvm/trunk/graphics/dither.h 2008-12-24 16:44:14 UTC (rev 35529)
+++ scummvm/trunk/graphics/dither.h 2008-12-24 16:59:37 UTC (rev 35530)
@@ -30,77 +30,157 @@
namespace Graphics {
+/** A palette lookup table to find the nearest matching entry of a fixed palette to a true color.
+ *
+ * The table can be build up in slices, one slice consisting of all entries for
+ * one value of the first color component.
+ */
class PaletteLUT {
public:
+ /** Palette format. */
enum PaletteFormat {
- kPaletteRGB,
- kPaletteYUV
+ kPaletteRGB, //!< Palette in RGB colorspace
+ kPaletteYUV //!< Palette in YUV colorspace
};
+ /** Converting a color from YUV to RGB colorspace. */
inline static void YUV2RGB(byte y, byte u, byte v, byte &r, byte &g, byte &b) {
r = CLIP<int>(y + ((1357 * (v - 128)) >> 10), 0, 255);
g = CLIP<int>(y - (( 691 * (v - 128)) >> 10) - ((333 * (u - 128)) >> 10), 0, 255);
b = CLIP<int>(y + ((1715 * (u - 128)) >> 10), 0, 255);
}
+ /** Converting a color from RGB to YUV colorspace. */
inline static void RGB2YUV(byte r, byte g, byte b, byte &y, byte &u, byte &v) {
y = CLIP<int>( ((r * 306) >> 10) + ((g * 601) >> 10) + ((b * 117) >> 10) , 0, 255);
u = CLIP<int>(-((r * 172) >> 10) - ((g * 340) >> 10) + ((b * 512) >> 10) + 128, 0, 255);
v = CLIP<int>( ((r * 512) >> 10) - ((g * 429) >> 10) - ((b * 83) >> 10) + 128, 0, 255);
}
+ /** Create a lookup table of a given depth and palette format.
+ *
+ * @param depth How many bits of each color component to consider.
+ * @param format The format the palette should be in.
+ */
PaletteLUT(byte depth, PaletteFormat format);
~PaletteLUT();
+ /** Setting a palette.
+ *
+ * Any already built slices will be purged.
+ *
+ * @param palette The palette, plain 256 * 3 color components.
+ * @param format The format the palette is in.
+ * @param depth The number of significant bits in each color component.
+ */
void setPalette(const byte *palette, PaletteFormat format, byte depth);
+ /** Build the next slice.
+ *
+ * This will build the next slice, if any.
+ */
void buildNext();
+ /** Querying the color components to a given palette entry index. */
void getEntry(byte index, byte &c1, byte &c2, byte &c3) const;
+ /** Finding the nearest matching entry.
+ *
+ * @param c1 The first component of the wanted color.
+ * @param c2 The second component of the wanted color.
+ * @param c3 The third component of the wanted color.
+ * @return The palette entry matching the wanted color best.
+ */
byte findNearest(byte c1, byte c2, byte c3);
+ /** Finding the nearest matching entry, together with its color components.
+ *
+ * @param c1 The first component of the wanted color.
+ * @param c2 The second component of the wanted color.
+ * @param c3 The third component of the wanted color.
+ * @paran nC1 The first component of the found color.
+ * @paran nC2 The second component of the found color.
+ * @paran nC3 The third component of the found color.
+ * @return The palette entry matching the wanted color best.
+ */
byte findNearest(byte c1, byte c2, byte c3, byte &nC1, byte &nC2, byte &nC3);
+ /** Save the table to a stream.
+ *
+ * This will build the whole table first.
+ */
bool save(Common::WriteStream &stream);
+ /** Load the table from a stream. */
bool load(Common::SeekableReadStream &stream);
private:
- byte _depth1, _depth2;
- byte _shift;
+ byte _depth1; //!< The table's depth for one dimension.
+ byte _depth2; //!< The table's depth for two dimensions.
+ byte _shift; //!< Amount to shift to adjust for the table's depth.
- uint32 _dim1, _dim2, _dim3;
+ uint32 _dim1; //!< The table's entry offset for one dimension.
+ uint32 _dim2; //!< The table's entry offset for two dimensions.
+ uint32 _dim3; //!< The table's entry offset for three dimensions.
- PaletteFormat _format;
- byte _lutPal[768];
- byte _realPal[768];
+ PaletteFormat _format; //!< The table's palette format.
+ byte _lutPal[768]; //!< The palette used for looking up a color.
+ byte _realPal[768]; //!< The original palette.
- uint32 _got;
- byte *_gots;
- byte *_lut;
+ uint32 _got; //!< Number of slices generated.
+ byte *_gots; //!< Map of generated slices.
+ byte *_lut; //!< The lookup table.
+ /** Building a specified slice. */
void build(int d1);
+ /** Calculates the index into the lookup table for a given color. */
inline int getIndex(byte c1, byte c2, byte c3) const;
- inline void plotEntry(int x, int y, int z, byte e, byte *filled, int &free);
};
-// The Sierra-2-4A ("Filter Light") dithering algorithm
+/** The Sierra-2-4A ("Filter Light") error distribution dithering algorithm.
+ *
+ * The image will be dithered line by line and pixel by pixel, without earlier
+ * values having to be changed.
+*/
class SierraLight {
public:
- SierraLight(int16 width, int16 height, PaletteLUT *palLUT);
+ /** Constructor.
+ *
+ * @param width The width of the image to dither.
+ * @param palLUT The palette to which to dither.
+ */
+ SierraLight(int16 width, PaletteLUT *palLUT);
~SierraLight();
+ /** Signals that a new frame or image is about to be dithered.
+ *
+ * This clears all collected errors, so that a new image (of the same
+ * height and with the same palette) can be dithered.
+ */
void newFrame();
+ /** Signals that a new line is about the begin.
+ *
+ * The current line's errors will be forgotten and values collected for the
+ * next line will now count as the current line's.
+ */
void nextLine();
+ /** Dither a pixel.
+ *
+ * @param c1 The first color component of the pixel.
+ * @param c2 The second color component of the pixel.
+ * @param c3 The third color component of the pixel.
+ * @param x The pixel's x coordinate within the image.
+ */
byte dither(byte c1, byte c2, byte c3, uint32 x);
protected:
- int16 _width, _height;
+ int16 _width; //!< The image's width.
- PaletteLUT *_palLUT;
+ PaletteLUT *_palLUT; //!< The palette against which to dither.
- int32 *_errorBuf;
- int32 *_errors[2];
- int _curLine;
+ int32 *_errorBuf; //!< Big buffer for all collected errors.
+ int32 *_errors[2]; //!< Pointers into the error buffer for two lines.
+ int _curLine; //!< Which one is the current line?
+ /** Querying a pixel's errors. */
inline void getErrors(uint32 x, int32 &eC1, int32 &eC2, int32 &eC3);
+ /** Adding a pixel's errors. */
inline void addErrors(uint32 x, int32 eC1, int32 eC2, int32 eC3);
};
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