Category : C Source Code
Archive   : POLY3DRS.ZIP
Filename : COLORTBL.C

/*****************************************************************************
* Routines to prpepare the color table for the given scene. Each color *
* get equal share in the map table, so its modules does: *
* 1. Scans all objects and retrieve all possible colors. *
* 2. Create a color map table, of the specified size (in ShadingInfo global *
* structure) and interpolate intensity levels for each color into it. *
* 3. Update the objects for their index into the color map. *
* *
* Written by: Gershon Elber Ver 2.0, Mar. 1990 *
*****************************************************************************/

#ifdef __MSDOS__
#include
#endif /* __MSDOS__ */

#include
#include
#include
#include "program.h"
#include "parser.h"
#include "gif_lib.h"

/* The colors can be specified as indices in which we must convert to RGB: */
/* We uses the EGA convension (see also TC 2.0 graphics.h file). */
static int TransColorTable[][4] = {
{ /* BLACK */ 0, 0, 0, 0 },
{ /* BLUE */ 1, 0, 0, 255 },
{ /* GREEN */ 2, 0, 255, 0 },
{ /* CYAN */ 3, 0, 255, 255 },
{ /* RED */ 4, 255, 0, 0 },
{ /* MAGENTA */ 5, 255, 0, 255 },
{ /* BROWN */ 20, 50, 0, 0 },
{ /* LIGHTGRAY */ 7, 127, 127, 127 },
{ /* DARKGRAY */ 56, 63, 63, 63 },
{ /* LIGHTBLUE */ 57, 0, 0, 255 },
{ /* LIGHTGREEN */ 58, 0, 255, 0 },
{ /* LIGHTCYAN */ 59, 0, 255, 255 },
{ /* LIGHTRED */ 60, 255, 0, 0 },
{ /* LIGHTMAGENTA */ 61, 255, 0, 255 },
{ /* YELLOW */ 62, 255, 255, 0 },
{ /* WHITE */ 63, 255, 255, 255 },
{ -1, 0, 0, 0 }
};


static void PrepareAllObjects1(FileDescription **FD, GifColorType *Colors,
int *NumColors);
static void VisitObjectTree1(BinTree *PBinTree, GifColorType *Colors,
int *NumColors);
static void InsertColor(ObjectStruct *PObject, GifColorType *Colors,
int *NumColors);
static void PrepareAllObjects2(FileDescription **FD, GifColorType *Colors,
int NumColors);
static void VisitObjectTree2(BinTree *PBinTree, GifColorType *Colors,
int NumColors);
static void UpdateColorIndex(ObjectStruct *PObject, GifColorType *Colors,
int NumColors);

/*****************************************************************************
* Routine to prepare color map for the given scene. *
*****************************************************************************/
void PrepareColorTable(FileDescription **FD, int NumOfObjects,
int RealNumOfObjects, char **Objects)
{
int i, j, NumColors = 0, ColorMapSize, Levels, *MinIntensityIndex;
float DIntensity, CrntIntensity;
GifColorType *Colors, *ColorMap;
struct ObjectStruct *PObject;

Colors = (GifColorType *) MyMalloc(sizeof(GifColorType) * RealNumOfObjects);

if (NumOfObjects > 0) /* There was something on command line... */
for (i=0; i
if ((PObject = SearchObject(FD, *Objects)) != NULL)
InsertColor(PObject, Colors, &NumColors);
}
else { /* Prepare all objects by scanning object trees. */
PrepareAllObjects1(FD, Colors, &NumColors);
}

/* Allocate color table and fill it in: */
ColorMapSize = (1 << ShadingInfo.BitsPerPixel);
ShadingInfo.PColorMap = ColorMap =
(GifColorType *) MyMalloc(sizeof(GifColorType) * ColorMapSize);
ShadingInfo.MinIntensityIndex = MinIntensityIndex =
(int *) MyMalloc(sizeof(int) * ColorMapSize);

/* Save one place to hold the back ground color: */
if (NumColors == 0) {
fprintf(stderr, "No color allocated - that is really wierd!\n");
MyExit(1);
}
ShadingInfo.LevelsPerColor = Levels = (ColorMapSize - 1) / NumColors;
if (Levels == 0) {
fprintf(stderr, "Too many colors (%d) for color map size (%d), exit\n",
NumColors, ColorMapSize);
MyExit(1);
}

/* Insert the back ground color in: */
for (i=0; TransColorTable[i][0] >= 0; i++)
if (TransColorTable[i][0] == ShadingInfo.BackGroundColor) break;
if (TransColorTable[i][0] < 0) {
fprintf(stderr,
"Undefined color required (%d) for background, default selected instead.\n",
PObject -> Color);
PObject -> Color = ShadingInfo.DefaultColor;
}
ColorMap[0].Red = TransColorTable[i][1];
ColorMap[0].Green = TransColorTable[i][2];
ColorMap[0].Blue = TransColorTable[i][3];

/* O.k. time to interpolate the colors. Each given color intensities are */
/* interplated between the ambient light and full intensity (1.0): */
DIntensity = (1.0 - ShadingInfo.Ambient) / Levels;
for (i=0; i CrntIntensity = 1.0;
for (j=0; j ColorMap[i * Levels + j + 1].Red =
(int) (Colors[i].Red * CrntIntensity);
ColorMap[i * Levels + j + 1].Green =
(int) (Colors[i].Green * CrntIntensity);
ColorMap[i * Levels + j + 1].Blue =
(int) (Colors[i].Blue * CrntIntensity);
MinIntensityIndex[i * Levels + j + 1] = (i + 1) * Levels;
CrntIntensity -= DIntensity;
}
}

/* Now the final step - let the objects know where their color is mapped */
/* to in the color table. */
if (NumOfObjects > 0) /* There was something on command line... */
for (i=0; i if ((PObject = SearchObject(FD, *Objects)) != NULL)
UpdateColorIndex(PObject, Colors, NumColors);
}
else { /* Prepare all objects by scanning object trees. */
PrepareAllObjects2(FD, Colors, NumColors);
}

free((char *) Colors);
}

/*****************************************************************************
* Scan all objects. *
*****************************************************************************/
static void PrepareAllObjects1(FileDescription **FD, GifColorType *Colors,
int *NumColors)
{
while (*FD) VisitObjectTree1((*FD++) -> ObjectPointer, Colors, NumColors);
}

/*****************************************************************************
* Scanning all the object in tree PBinTree and prepare them. *
*****************************************************************************/
static void VisitObjectTree1(BinTree *PBinTree, GifColorType *Colors,
int *NumColors)
{
if (PBinTree == (BinTree *) NULL) return;

VisitObjectTree1(PBinTree -> right, Colors, NumColors);

InsertColor(PBinTree -> Data.PObject, Colors, NumColors);

VisitObjectTree1(PBinTree -> left, Colors, NumColors);
}

/*****************************************************************************
* Scanning all the object in tree PBinTree and prepare them. *
*****************************************************************************/
static void InsertColor(ObjectStruct *PObject, GifColorType *Colors,
int *NumColors)
{
int i;

if (PObject -> Color != RGB_COLOR_GIVEN) {
/* Translate the color into RGB form: */
for (i=0; TransColorTable[i][0] >= 0; i++)
if (TransColorTable[i][0] == PObject -> Color) break;
if (TransColorTable[i][0] < 0) {
fprintf(stderr,
"Undefined color required (%d), default selected instead.\n",
PObject -> Color);
PObject -> Color = ShadingInfo.DefaultColor;
}
PObject -> RGBColor[0] = TransColorTable[i][1];
PObject -> RGBColor[1] = TransColorTable[i][2];
PObject -> RGBColor[2] = TransColorTable[i][3];
}

/* Lets see if this color exists in table already, and if so do nothing: */
for (i=0; i<*NumColors; i++)
if (PObject -> RGBColor[0] == Colors[i].Red &&
PObject -> RGBColor[1] == Colors[i].Green &&
PObject -> RGBColor[2] == Colors[i].Blue) return;

/* Its a new color - add it to out colors table to allocate: */
Colors[*NumColors].Red = PObject -> RGBColor[0];
Colors[*NumColors].Green = PObject -> RGBColor[1];
Colors[(*NumColors)++].Blue = PObject -> RGBColor[2];
}

/*****************************************************************************
* Scan all objects. *
*****************************************************************************/
static void PrepareAllObjects2(FileDescription **FD, GifColorType *Colors,
int NumColors)
{
while (*FD) VisitObjectTree2((*FD++) -> ObjectPointer, Colors, NumColors);
}

/*****************************************************************************
* Scanning all the object in tree PBinTree and prepare them. *
*****************************************************************************/
static void VisitObjectTree2(BinTree *PBinTree, GifColorType *Colors,
int NumColors)
{
if (PBinTree == (BinTree *) NULL) return;

VisitObjectTree2(PBinTree -> right, Colors, NumColors);

UpdateColorIndex(PBinTree -> Data.PObject, Colors, NumColors);

VisitObjectTree2(PBinTree -> left, Colors, NumColors);
}

/*****************************************************************************
* Update object with the index to its color in the color map. *
*****************************************************************************/
static void UpdateColorIndex(ObjectStruct *PObject, GifColorType *Colors,
int NumColors)
{
int i;

/* Find this color in table (must be in it...): */
for (i=0; i if (PObject -> RGBColor[0] == Colors[i].Red &&
PObject -> RGBColor[1] == Colors[i].Green &&
PObject -> RGBColor[2] == Colors[i].Blue) break;

/* Color table hold this object color, with decreasing intensity, from */
/* this index up to (i + 1) * ShadingInfo.LevelsPerColor. */
PObject -> Color = i * ShadingInfo.LevelsPerColor + 1;
}