test/testgamma.c
changeset 0 74212992fb08
child 1151 be9c9c8f6d53
equal deleted inserted replaced
-1:000000000000 0:74212992fb08
       
     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 }