--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/libsdl-trunk/src/video/SDL_gamma.c Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,233 @@
+/*
+ SDL - Simple DirectMedia Layer
+ Copyright (C) 1997-2006 Sam Lantinga
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+ Sam Lantinga
+ slouken@libsdl.org
+*/
+#include "SDL_config.h"
+
+/* Gamma correction support */
+
+#ifdef HAVE_MATH_H
+#include <math.h> /* Used for calculating gamma ramps */
+#else
+/* Math routines from uClibc: http://www.uclibc.org */
+#include "math_private.h"
+#include "e_sqrt.h"
+#include "e_pow.h"
+#include "e_log.h"
+#define pow(x, y) __ieee754_pow(x, y)
+#define log(x) __ieee754_log(x)
+#endif
+
+#include "SDL_sysvideo.h"
+
+
+static void CalculateGammaRamp(float gamma, Uint16 *ramp)
+{
+ int i;
+
+ /* 0.0 gamma is all black */
+ if ( gamma <= 0.0f ) {
+ for ( i=0; i<256; ++i ) {
+ ramp[i] = 0;
+ }
+ return;
+ } else
+ /* 1.0 gamma is identity */
+ if ( gamma == 1.0f ) {
+ for ( i=0; i<256; ++i ) {
+ ramp[i] = (i << 8) | i;
+ }
+ return;
+ } else
+ /* Calculate a real gamma ramp */
+ { int value;
+ gamma = 1.0f / gamma;
+ for ( i=0; i<256; ++i ) {
+ value = (int)(pow((double)i/256.0, gamma)*65535.0+0.5);
+ if ( value > 65535 ) {
+ value = 65535;
+ }
+ ramp[i] = (Uint16)value;
+ }
+ }
+}
+static void CalculateGammaFromRamp(float *gamma, Uint16 *ramp)
+{
+ /* The following is adapted from a post by Garrett Bass on OpenGL
+ Gamedev list, March 4, 2000.
+ */
+ float sum = 0.0f;
+ int i, count = 0;
+
+ *gamma = 1.0;
+ for ( i = 1; i < 256; ++i ) {
+ if ( (ramp[i] != 0) && (ramp[i] != 65535) ) {
+ double B = (double)i / 256.0;
+ double A = ramp[i] / 65535.0;
+ sum += (float) ( log(A) / log(B) );
+ count++;
+ }
+ }
+ if ( count && sum > 0.0f ) {
+ *gamma = 1.0f / (sum / count);
+ }
+}
+
+int SDL_SetGamma(float red, float green, float blue)
+{
+ int succeeded;
+ SDL_VideoDevice *video = current_video;
+ SDL_VideoDevice *this = current_video;
+
+ succeeded = -1;
+ /* Prefer using SetGammaRamp(), as it's more flexible */
+ {
+ Uint16 ramp[3][256];
+
+ CalculateGammaRamp(red, ramp[0]);
+ CalculateGammaRamp(green, ramp[1]);
+ CalculateGammaRamp(blue, ramp[2]);
+ succeeded = SDL_SetGammaRamp(ramp[0], ramp[1], ramp[2]);
+ }
+ if ( (succeeded < 0) && video->SetGamma ) {
+ SDL_ClearError();
+ succeeded = video->SetGamma(this, red, green, blue);
+ }
+ return succeeded;
+}
+
+/* Calculating the gamma by integrating the gamma ramps isn't exact,
+ so this function isn't officially supported.
+*/
+int SDL_GetGamma(float *red, float *green, float *blue)
+{
+ int succeeded;
+ SDL_VideoDevice *video = current_video;
+ SDL_VideoDevice *this = current_video;
+
+ succeeded = -1;
+ /* Prefer using GetGammaRamp(), as it's more flexible */
+ {
+ Uint16 ramp[3][256];
+
+ succeeded = SDL_GetGammaRamp(ramp[0], ramp[1], ramp[2]);
+ if ( succeeded >= 0 ) {
+ CalculateGammaFromRamp(red, ramp[0]);
+ CalculateGammaFromRamp(green, ramp[1]);
+ CalculateGammaFromRamp(blue, ramp[2]);
+ }
+ }
+ if ( (succeeded < 0) && video->GetGamma ) {
+ SDL_ClearError();
+ succeeded = video->GetGamma(this, red, green, blue);
+ }
+ return succeeded;
+}
+
+int SDL_SetGammaRamp(const Uint16 *red, const Uint16 *green, const Uint16 *blue)
+{
+ int succeeded;
+ SDL_VideoDevice *video = current_video;
+ SDL_VideoDevice *this = current_video;
+ SDL_Surface *screen = SDL_PublicSurface;
+
+ /* Verify the screen parameter */
+ if ( !screen ) {
+ SDL_SetError("No video mode has been set");
+ return -1;
+ }
+
+ /* Lazily allocate the gamma tables */
+ if ( ! video->gamma ) {
+ SDL_GetGammaRamp(0, 0, 0);
+ }
+
+ /* Fill the gamma table with the new values */
+ if ( red ) {
+ SDL_memcpy(&video->gamma[0*256], red, 256*sizeof(*video->gamma));
+ }
+ if ( green ) {
+ SDL_memcpy(&video->gamma[1*256], green, 256*sizeof(*video->gamma));
+ }
+ if ( blue ) {
+ SDL_memcpy(&video->gamma[2*256], blue, 256*sizeof(*video->gamma));
+ }
+
+ /* Gamma correction always possible on split palettes */
+ if ( (screen->flags & SDL_HWPALETTE) == SDL_HWPALETTE ) {
+ SDL_Palette *pal = screen->format->palette;
+
+ /* If physical palette has been set independently, use it */
+ if(video->physpal)
+ pal = video->physpal;
+
+ SDL_SetPalette(screen, SDL_PHYSPAL,
+ pal->colors, 0, pal->ncolors);
+ return 0;
+ }
+
+ /* Try to set the gamma ramp in the driver */
+ succeeded = -1;
+ if ( video->SetGammaRamp ) {
+ succeeded = video->SetGammaRamp(this, video->gamma);
+ } else {
+ SDL_SetError("Gamma ramp manipulation not supported");
+ }
+ return succeeded;
+}
+
+int SDL_GetGammaRamp(Uint16 *red, Uint16 *green, Uint16 *blue)
+{
+ SDL_VideoDevice *video = current_video;
+ SDL_VideoDevice *this = current_video;
+
+ /* Lazily allocate the gamma table */
+ if ( ! video->gamma ) {
+ video->gamma = SDL_malloc(3*256*sizeof(*video->gamma));
+ if ( ! video->gamma ) {
+ SDL_OutOfMemory();
+ return -1;
+ }
+ if ( video->GetGammaRamp ) {
+ /* Get the real hardware gamma */
+ video->GetGammaRamp(this, video->gamma);
+ } else {
+ /* Assume an identity gamma */
+ int i;
+ for ( i=0; i<256; ++i ) {
+ video->gamma[0*256+i] = (i << 8) | i;
+ video->gamma[1*256+i] = (i << 8) | i;
+ video->gamma[2*256+i] = (i << 8) | i;
+ }
+ }
+ }
+
+ /* Just copy from our internal table */
+ if ( red ) {
+ SDL_memcpy(red, &video->gamma[0*256], 256*sizeof(*red));
+ }
+ if ( green ) {
+ SDL_memcpy(green, &video->gamma[1*256], 256*sizeof(*green));
+ }
+ if ( blue ) {
+ SDL_memcpy(blue, &video->gamma[2*256], 256*sizeof(*blue));
+ }
+ return 0;
+}