test/testgamma.c
author Sam Lantinga <slouken@lokigames.com>
Thu, 26 Apr 2001 16:45:43 +0000
changeset 0 74212992fb08
child 1151 be9c9c8f6d53
permissions -rw-r--r--
Initial revision
     1 
     2 /* Bring up a window and manipulate the gamma on it */
     3 
     4 #include <stdlib.h>
     5 #include <stdio.h>
     6 #include <string.h>
     7 #include <math.h>
     8 
     9 #include "SDL.h"
    10 
    11 /* Turn a normal gamma value into an appropriate gamma ramp */
    12 void CalculateGamma(double gamma, Uint16 *ramp)
    13 {
    14 	int i, value;
    15 
    16 	gamma = 1.0 / gamma;
    17 	for ( i=0; i<256; ++i ) {
    18 		value = (int)(pow((double)i/256.0, gamma)*65535.0 + 0.5);
    19 		if ( value > 65535 ) {
    20 			value = 65535;
    21 		}
    22 		ramp[i] = (Uint16)value;
    23 	}
    24 }
    25 
    26 /* This can be used as a general routine for all of the test programs */
    27 int get_video_args(char *argv[], int *w, int *h, int *bpp, Uint32 *flags)
    28 {
    29 	int i;
    30 
    31 	*w = 640;
    32 	*h = 480;
    33 	*bpp = 0;
    34 	*flags = SDL_SWSURFACE;
    35 
    36 	for ( i=1; argv[i]; ++i ) {
    37 		if ( strcmp(argv[i], "-width") == 0 ) {
    38 			if ( argv[i+1] ) {
    39 				*w = atoi(argv[++i]);
    40 			}
    41 		} else
    42 		if ( strcmp(argv[i], "-height") == 0 ) {
    43 			if ( argv[i+1] ) {
    44 				*h = atoi(argv[++i]);
    45 			}
    46 		} else
    47 		if ( strcmp(argv[i], "-bpp") == 0 ) {
    48 			if ( argv[i+1] ) {
    49 				*bpp = atoi(argv[++i]);
    50 			}
    51 		} else
    52 		if ( strcmp(argv[i], "-fullscreen") == 0 ) {
    53 			*flags |= SDL_FULLSCREEN;
    54 		} else
    55 		if ( strcmp(argv[i], "-hw") == 0 ) {
    56 			*flags |= SDL_HWSURFACE;
    57 		} else
    58 		if ( strcmp(argv[i], "-hwpalette") == 0 ) {
    59 			*flags |= SDL_HWPALETTE;
    60 		} else
    61 			break;
    62 	}
    63 	return i;
    64 }
    65 
    66 int main(int argc, char *argv[])
    67 {
    68 	SDL_Surface *screen;
    69 	SDL_Surface *image;
    70 	float gamma;
    71 	int i;
    72 	int w, h, bpp;
    73 	Uint32 flags;
    74 	Uint16 ramp[256];
    75 	Uint16 red_ramp[256];
    76 	Uint32 then, timeout;
    77 
    78 	/* Check command line arguments */
    79 	argv += get_video_args(argv, &w, &h, &bpp, &flags);
    80 
    81 	/* Initialize SDL */
    82 	if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
    83 		fprintf(stderr,
    84 			"Couldn't initialize SDL: %s\n", SDL_GetError());
    85 		exit(1);
    86 	}
    87 	atexit(SDL_Quit);
    88 
    89 	/* Initialize the display, always use hardware palette */
    90 	screen = SDL_SetVideoMode(w, h, bpp, flags | SDL_HWPALETTE);
    91 	if ( screen == NULL ) {
    92 		fprintf(stderr, "Couldn't set %dx%d video mode: %s\n",
    93 						w, h, SDL_GetError());
    94 		exit(1);
    95 	}
    96 
    97 	/* Set the window manager title bar */
    98 	SDL_WM_SetCaption("SDL gamma test", "testgamma");
    99 
   100 	/* Set the desired gamma, if any */
   101 	gamma = 1.0f;
   102 	if ( *argv ) {
   103 		gamma = (float)atof(*argv);
   104 	}
   105 	if ( SDL_SetGamma(gamma, gamma, gamma) < 0 ) {
   106 		fprintf(stderr, "Unable to set gamma: %s\n", SDL_GetError());
   107 		exit(1);
   108 	}
   109 
   110 #if 0 /* This isn't supported.  Integrating the gamma ramps isn't exact */
   111 	/* See what gamma was actually set */
   112 	float real[3];
   113 	if ( SDL_GetGamma(&real[0], &real[1], &real[2]) < 0 ) {
   114 		printf("Couldn't get gamma: %s\n", SDL_GetError());
   115 	} else {
   116 		printf("Set gamma values: R=%2.2f, G=%2.2f, B=%2.2f\n",
   117 			real[0], real[1], real[2]);
   118 	}
   119 #endif
   120 
   121 	/* Do all the drawing work */
   122 	image = SDL_LoadBMP("sample.bmp");
   123 	if ( image ) {
   124 		SDL_Rect dst;
   125 
   126 		dst.x = (screen->w - image->w)/2;
   127 		dst.y = (screen->h - image->h)/2;
   128 		dst.w = image->w;
   129 		dst.h = image->h;
   130 		SDL_BlitSurface(image, NULL, screen, &dst);
   131 		SDL_UpdateRects(screen, 1, &dst);
   132 	}
   133 
   134 	/* Wait a bit, handling events */
   135 	then = SDL_GetTicks();
   136 	timeout = (5*1000);
   137 	while ( (SDL_GetTicks()-then) < timeout ) {
   138 		SDL_Event event;
   139 
   140 		while ( SDL_PollEvent(&event) ) {
   141 			switch (event.type) {
   142 			    case SDL_QUIT:	/* Quit now */
   143 				timeout = 0;
   144 				break;
   145 			    case SDL_KEYDOWN:
   146 				switch (event.key.keysym.sym) {
   147 				    case SDLK_SPACE:	/* Go longer.. */
   148 					timeout += (5*1000);
   149 					break;
   150 				    case SDLK_UP:
   151 					gamma += 0.2f;
   152 					SDL_SetGamma(gamma, gamma, gamma);
   153 					break;
   154 				    case SDLK_DOWN:
   155 					gamma -= 0.2f;
   156 					SDL_SetGamma(gamma, gamma, gamma);
   157 					break;
   158 				    case SDLK_ESCAPE:
   159 					timeout = 0;
   160 					break;
   161 				    default:
   162 					break;
   163 				}
   164 				break;
   165 			}
   166 		}
   167 	}
   168 
   169 	/* Perform a gamma flash to red using color ramps */
   170 	while ( gamma < 10.0 ) {
   171 		/* Increase the red gamma and decrease everything else... */
   172 		gamma += 0.1f;
   173 		CalculateGamma(gamma, red_ramp);
   174 		CalculateGamma(1.0/gamma, ramp);
   175 		SDL_SetGammaRamp(red_ramp, ramp, ramp);
   176 	}
   177 	/* Finish completely red */
   178 	memset(red_ramp, 255, sizeof(red_ramp));
   179 	memset(ramp, 0, sizeof(ramp));
   180 	SDL_SetGammaRamp(red_ramp, ramp, ramp);
   181 
   182 	/* Now fade out to black */
   183 	for ( i=(red_ramp[0] >> 8); i >= 0; --i ) {
   184 		memset(red_ramp, i, sizeof(red_ramp));
   185 		SDL_SetGammaRamp(red_ramp, NULL, NULL);
   186 	}
   187 	SDL_Delay(1*1000);
   188 
   189 	return(0);
   190 }