src/video/SDL_pixels.c
changeset 0 74212992fb08
child 48 f97decee03a9
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/SDL_pixels.c	Thu Apr 26 16:45:43 2001 +0000
@@ -0,0 +1,619 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public
+    License along with this library; if not, write to the Free
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Sam Lantinga
+    slouken@devolution.com
+*/
+
+#ifdef SAVE_RCSID
+static char rcsid =
+ "@(#) $Id$";
+#endif
+
+/* General (mostly internal) pixel/color manipulation routines for SDL */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "SDL_error.h"
+#include "SDL_endian.h"
+#include "SDL_video.h"
+#include "SDL_sysvideo.h"
+#include "SDL_blit.h"
+#include "SDL_pixels_c.h"
+#include "SDL_RLEaccel_c.h"
+
+/* Helper functions */
+/*
+ * Allocate a pixel format structure and fill it according to the given info.
+ */
+SDL_PixelFormat *SDL_AllocFormat(int bpp,
+			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
+{
+	SDL_PixelFormat *format;
+	Uint32 mask;
+
+	/* Allocate an empty pixel format structure */
+	format = malloc(sizeof(*format));
+	if ( format == NULL ) {
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+	memset(format, 0, sizeof(*format));
+	format->alpha = SDL_ALPHA_OPAQUE;
+
+	/* Set up the format */
+	format->BitsPerPixel = bpp;
+	format->BytesPerPixel = (bpp+7)/8;
+	switch (bpp) {
+		case 1:
+			/* Create the 2 color black-white palette */
+			format->palette = (SDL_Palette *)malloc(
+							sizeof(SDL_Palette));
+			if ( format->palette == NULL ) {
+				SDL_FreeFormat(format);
+				SDL_OutOfMemory();
+				return(NULL);
+			}
+			(format->palette)->ncolors = 2;
+			(format->palette)->colors = (SDL_Color *)malloc(
+				(format->palette)->ncolors*sizeof(SDL_Color));
+			if ( (format->palette)->colors == NULL ) {
+				SDL_FreeFormat(format);
+				SDL_OutOfMemory();
+				return(NULL);
+			}
+			format->palette->colors[0].r = 0xFF;
+			format->palette->colors[0].g = 0xFF;
+			format->palette->colors[0].b = 0xFF;
+			format->palette->colors[1].r = 0x00;
+			format->palette->colors[1].g = 0x00;
+			format->palette->colors[1].b = 0x00;
+			format->Rloss = 8;
+			format->Gloss = 8;
+			format->Bloss = 8;
+			format->Aloss = 8;
+			format->Rshift = 0;
+			format->Gshift = 0;
+			format->Bshift = 0;
+			format->Ashift = 0;
+			format->Rmask = 0;
+			format->Gmask = 0;
+			format->Bmask = 0;
+			format->Amask = 0;
+			break;
+
+		case 4:
+			/* Create the 16 color VGA palette */
+			format->palette = (SDL_Palette *)malloc(
+							sizeof(SDL_Palette));
+			if ( format->palette == NULL ) {
+				SDL_FreeFormat(format);
+				SDL_OutOfMemory();
+				return(NULL);
+			}
+			(format->palette)->ncolors = 16;
+			(format->palette)->colors = (SDL_Color *)malloc(
+				(format->palette)->ncolors*sizeof(SDL_Color));
+			if ( (format->palette)->colors == NULL ) {
+				SDL_FreeFormat(format);
+				SDL_OutOfMemory();
+				return(NULL);
+			}
+			/* Punt for now, will this ever be used? */
+			memset((format->palette)->colors, 0,
+				(format->palette)->ncolors*sizeof(SDL_Color));
+
+			/* Palettized formats have no mask info */
+			format->Rloss = 8;
+			format->Gloss = 8;
+			format->Bloss = 8;
+			format->Aloss = 8;
+			format->Rshift = 0;
+			format->Gshift = 0;
+			format->Bshift = 0;
+			format->Ashift = 0;
+			format->Rmask = 0;
+			format->Gmask = 0;
+			format->Bmask = 0;
+			format->Amask = 0;
+			break;
+
+		case 8:
+			/* Create an empty 256 color palette */
+			format->palette = (SDL_Palette *)malloc(
+							sizeof(SDL_Palette));
+			if ( format->palette == NULL ) {
+				SDL_FreeFormat(format);
+				SDL_OutOfMemory();
+				return(NULL);
+			}
+			(format->palette)->ncolors = 256;
+			(format->palette)->colors = (SDL_Color *)malloc(
+				(format->palette)->ncolors*sizeof(SDL_Color));
+			if ( (format->palette)->colors == NULL ) {
+				SDL_FreeFormat(format);
+				SDL_OutOfMemory();
+				return(NULL);
+			}
+			memset((format->palette)->colors, 0,
+				(format->palette)->ncolors*sizeof(SDL_Color));
+
+			/* Palettized formats have no mask info */
+			format->Rloss = 8;
+			format->Gloss = 8;
+			format->Bloss = 8;
+			format->Aloss = 8;
+			format->Rshift = 0;
+			format->Gshift = 0;
+			format->Bshift = 0;
+			format->Ashift = 0;
+			format->Rmask = 0;
+			format->Gmask = 0;
+			format->Bmask = 0;
+			format->Amask = 0;
+			break;
+
+		default:
+			/* No palette, just packed pixel info */
+			format->palette = NULL;
+			format->Rshift = 0;
+			format->Rloss = 8;
+			if ( Rmask ) {
+				for ( mask = Rmask; !(mask&0x01); mask >>= 1 )
+					++format->Rshift;
+				for ( ; (mask&0x01); mask >>= 1 )
+					--format->Rloss;
+			}
+			format->Gshift = 0;
+			format->Gloss = 8;
+			if ( Gmask ) {
+				for ( mask = Gmask; !(mask&0x01); mask >>= 1 )
+					++format->Gshift;
+				for ( ; (mask&0x01); mask >>= 1 )
+					--format->Gloss;
+			}
+			format->Bshift = 0;
+			format->Bloss = 8;
+			if ( Bmask ) {
+				for ( mask = Bmask; !(mask&0x01); mask >>= 1 )
+					++format->Bshift;
+				for ( ; (mask&0x01); mask >>= 1 )
+					--format->Bloss;
+			}
+			format->Ashift = 0;
+			format->Aloss = 8;
+			if ( Amask ) {
+				for ( mask = Amask; !(mask&0x01); mask >>= 1 )
+					++format->Ashift;
+				for ( ; (mask&0x01); mask >>= 1 )
+					--format->Aloss;
+			}
+			format->Rmask = Rmask;
+			format->Gmask = Gmask;
+			format->Bmask = Bmask;
+			format->Amask = Amask;
+			break;
+	}
+	/* Calculate some standard bitmasks, if necessary 
+	 * Note:  This could conflict with an alpha mask, if given.
+	 */
+	if ( (bpp > 8) && !format->Rmask && !format->Gmask && !format->Bmask ) {
+		/* R-G-B */
+		if ( bpp > 24 )
+			bpp = 24;
+		format->Rloss = 8-(bpp/3);
+		format->Gloss = 8-(bpp/3)-(bpp%3);
+		format->Bloss = 8-(bpp/3);
+		format->Rshift = ((bpp/3)+(bpp%3))+(bpp/3);
+		format->Gshift = (bpp/3);
+		format->Bshift = 0;
+		format->Rmask = ((0xFF>>format->Rloss)<<format->Rshift);
+		format->Gmask = ((0xFF>>format->Gloss)<<format->Gshift);
+		format->Bmask = ((0xFF>>format->Bloss)<<format->Bshift);
+	}
+	return(format);
+}
+SDL_PixelFormat *SDL_ReallocFormat(SDL_Surface *surface, int bpp,
+			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
+{
+	if ( surface->format ) {
+		SDL_FreeFormat(surface->format);
+		SDL_FormatChanged(surface);
+	}
+	surface->format = SDL_AllocFormat(bpp, Rmask, Gmask, Bmask, Amask);
+	return surface->format;
+}
+
+/*
+ * Change any previous mappings from/to the new surface format
+ */
+void SDL_FormatChanged(SDL_Surface *surface)
+{
+	surface->format_version++;
+	SDL_InvalidateMap(surface->map);
+}
+/*
+ * Free a previously allocated format structure
+ */
+void SDL_FreeFormat(SDL_PixelFormat *format)
+{
+	if ( format ) {
+		if ( format->palette ) {
+			if ( format->palette->colors ) {
+				free(format->palette->colors);
+			}
+			free(format->palette);
+		}
+		free(format);
+	}
+}
+/*
+ * Calculate an 8-bit (3 red, 3 green, 2 blue) dithered palette of colors
+ */
+void SDL_DitherColors(SDL_Color *colors, int bpp)
+{
+	int i;
+	if(bpp != 8)
+		return;		/* only 8bpp supported right now */
+
+	for(i = 0; i < 256; i++) {
+		int r, g, b;
+		/* map each bit field to the full [0, 255] interval,
+		   so 0 is mapped to (0, 0, 0) and 255 to (255, 255, 255) */
+		r = i & 0xe0;
+		r |= r >> 3 | r >> 6;
+		colors[i].r = r;
+		g = (i << 3) & 0xe0;
+		g |= g >> 3 | g >> 6;
+		colors[i].g = g;
+		b = i & 0x3;
+		b |= b << 2;
+		b |= b << 4;
+		colors[i].b = b;
+	}
+}
+/* 
+ * Calculate the pad-aligned scanline width of a surface
+ */
+Uint16 SDL_CalculatePitch(SDL_Surface *surface)
+{
+	Uint16 pitch;
+
+	/* Surface should be 4-byte aligned for speed */
+	pitch = surface->w*surface->format->BytesPerPixel;
+	switch (surface->format->BitsPerPixel) {
+		case 1:
+			pitch = (pitch+7)/8;
+			break;
+		case 4:
+			pitch = (pitch+1)/2;
+			break;
+		default:
+			break;
+	}
+	pitch = (pitch + 3) & ~3;	/* 4-byte aligning */
+	return(pitch);
+}
+/*
+ * Match an RGB value to a particular palette index
+ */
+Uint8 SDL_FindColor(SDL_Palette *pal, Uint8 r, Uint8 g, Uint8 b)
+{
+	/* Do colorspace distance matching */
+	unsigned int smallest;
+	unsigned int distance;
+	int rd, gd, bd;
+	int i;
+	Uint8 pixel=0;
+		
+	smallest = ~0;
+	for ( i=0; i<pal->ncolors; ++i ) {
+		rd = pal->colors[i].r - r;
+		gd = pal->colors[i].g - g;
+		bd = pal->colors[i].b - b;
+		distance = (rd*rd)+(gd*gd)+(bd*bd);
+		if ( distance < smallest ) {
+			pixel = i;
+			if ( distance == 0 ) { /* Perfect match! */
+				break;
+			}
+			smallest = distance;
+		}
+	}
+	return(pixel);
+}
+
+/* Find the opaque pixel value corresponding to an RGB triple */
+Uint32 SDL_MapRGB(SDL_PixelFormat *format, Uint8 r, Uint8 g, Uint8 b)
+{
+	if ( format->palette == NULL ) {
+		return (r >> format->Rloss) << format->Rshift
+		       | (g >> format->Gloss) << format->Gshift
+		       | (b >> format->Bloss) << format->Bshift
+		       | format->Amask;
+	} else {
+		return SDL_FindColor(format->palette, r, g, b);
+	}
+}
+
+/* Find the pixel value corresponding to an RGBA quadruple */
+Uint32 SDL_MapRGBA(SDL_PixelFormat *format, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
+{
+	if ( format->palette == NULL ) {
+	        return (r >> format->Rloss) << format->Rshift
+		    | (g >> format->Gloss) << format->Gshift
+		    | (b >> format->Bloss) << format->Bshift
+		    | ((a >> format->Aloss) << format->Ashift & format->Amask);
+	} else {
+		return SDL_FindColor(format->palette, r, g, b);
+	}
+}
+
+void SDL_GetRGBA(Uint32 pixel, SDL_PixelFormat *fmt,
+		 Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a)
+{
+	if ( fmt->palette == NULL ) {
+	        /*
+		 * This makes sure that the result is mapped to the
+		 * interval [0..255], and the maximum value for each
+		 * component is 255. This is important to make sure
+		 * that white is indeed reported as (255, 255, 255),
+		 * and that opaque alpha is 255.
+		 * This only works for RGB bit fields at least 4 bit
+		 * wide, which is almost always the case.
+		 */
+	        unsigned rv, gv, bv, av;
+		rv = (pixel & fmt->Rmask) >> fmt->Rshift;
+		*r = (rv << fmt->Rloss) + (rv >> (8 - fmt->Rloss));
+		gv = (pixel & fmt->Gmask) >> fmt->Gshift;
+		*g = (gv << fmt->Gloss) + (gv >> (8 - fmt->Gloss));
+		bv = (pixel & fmt->Bmask) >> fmt->Bshift;
+		*b = (bv << fmt->Bloss) + (bv >> (8 - fmt->Bloss));
+		if(fmt->Amask) {
+		        av = (pixel & fmt->Amask) >> fmt->Ashift;
+			*a = (av << fmt->Aloss) + (av >> (8 - fmt->Aloss));
+		} else
+		        *a = SDL_ALPHA_OPAQUE;
+	} else {
+		*r = fmt->palette->colors[pixel].r;
+		*g = fmt->palette->colors[pixel].g;
+		*b = fmt->palette->colors[pixel].b;
+		*a = SDL_ALPHA_OPAQUE;
+	}
+}
+
+void SDL_GetRGB(Uint32 pixel, SDL_PixelFormat *fmt, Uint8 *r,Uint8 *g,Uint8 *b)
+{
+	if ( fmt->palette == NULL ) {
+	        /* the note for SDL_GetRGBA above applies here too */
+	        unsigned rv, gv, bv;
+		rv = (pixel & fmt->Rmask) >> fmt->Rshift;
+		*r = (rv << fmt->Rloss) + (rv >> (8 - fmt->Rloss));
+		gv = (pixel & fmt->Gmask) >> fmt->Gshift;
+		*g = (gv << fmt->Gloss) + (gv >> (8 - fmt->Gloss));
+		bv = (pixel & fmt->Bmask) >> fmt->Bshift;
+		*b = (bv << fmt->Bloss) + (bv >> (8 - fmt->Bloss));
+	} else {
+		*r = fmt->palette->colors[pixel].r;
+		*g = fmt->palette->colors[pixel].g;
+		*b = fmt->palette->colors[pixel].b;
+	}
+}
+
+/* Apply gamma to a set of colors - this is easy. :) */
+void SDL_ApplyGamma(Uint16 *gamma, SDL_Color *colors, SDL_Color *output,
+							int ncolors)
+{
+	int i;
+
+	for ( i=0; i<ncolors; ++i ) {
+		output[i].r = gamma[0*256 + colors[i].r] >> 8;
+		output[i].g = gamma[1*256 + colors[i].g] >> 8;
+		output[i].b = gamma[2*256 + colors[i].b] >> 8;
+	}
+}
+
+/* Map from Palette to Palette */
+static Uint8 *Map1to1(SDL_Palette *src, SDL_Palette *dst, int *identical)
+{
+	Uint8 *map;
+	int i;
+
+	if ( identical ) {
+		if ( src->ncolors <= dst->ncolors ) {
+			/* If an identical palette, no need to map */
+			if ( memcmp(src->colors, dst->colors, src->ncolors*
+						sizeof(SDL_Color)) == 0 ) {
+				*identical = 1;
+				return(NULL);
+			}
+		}
+		*identical = 0;
+	}
+	map = (Uint8 *)malloc(src->ncolors);
+	if ( map == NULL ) {
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+	for ( i=0; i<src->ncolors; ++i ) {
+		map[i] = SDL_FindColor(dst,
+			src->colors[i].r, src->colors[i].g, src->colors[i].b);
+	}
+	return(map);
+}
+/* Map from Palette to BitField */
+static Uint8 *Map1toN(SDL_Palette *src, SDL_PixelFormat *dst)
+{
+	Uint8 *map;
+	int i;
+	int  bpp;
+	unsigned alpha;
+
+	bpp = ((dst->BytesPerPixel == 3) ? 4 : dst->BytesPerPixel);
+	map = (Uint8 *)malloc(src->ncolors*bpp);
+	if ( map == NULL ) {
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+
+	alpha = dst->Amask ? SDL_ALPHA_OPAQUE : 0;
+	/* We memory copy to the pixel map so the endianness is preserved */
+	for ( i=0; i<src->ncolors; ++i ) {
+		ASSEMBLE_RGBA(&map[i*bpp], dst->BytesPerPixel, dst,
+			      src->colors[i].r, src->colors[i].g,
+			      src->colors[i].b, alpha);
+	}
+	return(map);
+}
+/* Map from BitField to Dithered-Palette to Palette */
+static Uint8 *MapNto1(SDL_PixelFormat *src, SDL_Palette *dst, int *identical)
+{
+	/* Generate a 256 color dither palette */
+	SDL_Palette dithered;
+	SDL_Color colors[256];
+
+	dithered.ncolors = 256;
+	SDL_DitherColors(colors, 8);
+	dithered.colors = colors;
+	return(Map1to1(&dithered, dst, identical));
+}
+
+SDL_BlitMap *SDL_AllocBlitMap(void)
+{
+	SDL_BlitMap *map;
+
+	/* Allocate the empty map */
+	map = (SDL_BlitMap *)malloc(sizeof(*map));
+	if ( map == NULL ) {
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+	memset(map, 0, sizeof(*map));
+
+	/* Allocate the software blit data */
+	map->sw_data = (struct private_swaccel *)malloc(sizeof(*map->sw_data));
+	if ( map->sw_data == NULL ) {
+		SDL_FreeBlitMap(map);
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+	memset(map->sw_data, 0, sizeof(*map->sw_data));
+
+	/* It's ready to go */
+	return(map);
+}
+void SDL_InvalidateMap(SDL_BlitMap *map)
+{
+	if ( ! map ) {
+		return;
+	}
+	map->dst = NULL;
+	map->format_version = (unsigned int)-1;
+	if ( map->table ) {
+		free(map->table);
+		map->table = NULL;
+	}
+}
+int SDL_MapSurface (SDL_Surface *src, SDL_Surface *dst)
+{
+	SDL_PixelFormat *srcfmt;
+	SDL_PixelFormat *dstfmt;
+	SDL_BlitMap *map;
+
+	/* Clear out any previous mapping */
+	map = src->map;
+	if ( (src->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
+		SDL_UnRLESurface(src, 1);
+	}
+	SDL_InvalidateMap(map);
+
+	/* Figure out what kind of mapping we're doing */
+	map->identity = 0;
+	srcfmt = src->format;
+	dstfmt = dst->format;
+	switch (srcfmt->BytesPerPixel) {
+	    case 1:
+		switch (dstfmt->BytesPerPixel) {
+		    case 1:
+			/* Palette --> Palette */
+			/* If both SDL_HWSURFACE, assume have same palette */
+			if ( ((src->flags & SDL_HWSURFACE) == SDL_HWSURFACE) &&
+			     ((dst->flags & SDL_HWSURFACE) == SDL_HWSURFACE) ) {
+				map->identity = 1;
+			} else {
+				map->table = Map1to1(srcfmt->palette,
+					dstfmt->palette, &map->identity);
+			}
+			if ( ! map->identity ) {
+				if ( map->table == NULL ) {
+					return(-1);
+				}
+			}
+			if (srcfmt->BitsPerPixel!=dstfmt->BitsPerPixel)
+				map->identity = 0;
+			break;
+
+		    default:
+			/* Palette --> BitField */
+			map->table = Map1toN(srcfmt->palette, dstfmt);
+			if ( map->table == NULL ) {
+				return(-1);
+			}
+			break;
+		}
+		break;
+	default:
+		switch (dstfmt->BytesPerPixel) {
+		    case 1:
+			/* BitField --> Palette */
+			map->table = MapNto1(srcfmt,
+					dstfmt->palette, &map->identity);
+			if ( ! map->identity ) {
+				if ( map->table == NULL ) {
+					return(-1);
+				}
+			}
+			map->identity = 0;	/* Don't optimize to copy */
+			break;
+		    default:
+			/* BitField --> BitField */
+			if ( FORMAT_EQUAL(srcfmt, dstfmt) )
+				map->identity = 1;
+			break;
+		}
+		break;
+	}
+
+	map->dst = dst;
+	map->format_version = dst->format_version;
+
+	/* Choose your blitters wisely */
+	return(SDL_CalculateBlit(src));
+}
+void SDL_FreeBlitMap(SDL_BlitMap *map)
+{
+	if ( map ) {
+		SDL_InvalidateMap(map);
+		if ( map->sw_data != NULL ) {
+			free(map->sw_data);
+		}
+		free(map);
+	}
+}