Mercurial > sdl-ios-xcode
view test/testgamma.c @ 5154:8ef640410ac9
SDL doesn't actually support the physical/logical palette split anymore.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Tue, 01 Feb 2011 21:51:09 -0800 |
parents | c121d94672cb |
children |
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/* Bring up a window and manipulate the gamma on it */ #include <stdlib.h> #include <stdio.h> #include <string.h> #include <math.h> #include "SDL.h" /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */ static void quit(int rc) { SDL_Quit(); exit(rc); } /* Turn a normal gamma value into an appropriate gamma ramp */ void CalculateGamma(double gamma, Uint16 * ramp) { int i, value; gamma = 1.0 / 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; } } /* This can be used as a general routine for all of the test programs */ int get_video_args(char *argv[], int *w, int *h, int *bpp, Uint32 * flags) { int i; *w = 640; *h = 480; *bpp = 0; *flags = SDL_SWSURFACE; for (i = 1; argv[i]; ++i) { if (strcmp(argv[i], "-width") == 0) { if (argv[i + 1]) { *w = atoi(argv[++i]); } } else if (strcmp(argv[i], "-height") == 0) { if (argv[i + 1]) { *h = atoi(argv[++i]); } } else if (strcmp(argv[i], "-bpp") == 0) { if (argv[i + 1]) { *bpp = atoi(argv[++i]); } } else if (strcmp(argv[i], "-fullscreen") == 0) { *flags |= SDL_FULLSCREEN; } else if (strcmp(argv[i], "-hw") == 0) { *flags |= SDL_HWSURFACE; } else if (strcmp(argv[i], "-hwpalette") == 0) { *flags |= SDL_HWPALETTE; } else break; } return i; } int main(int argc, char *argv[]) { SDL_Surface *screen; SDL_Surface *image; float gamma; int i; int w, h, bpp; Uint32 flags; Uint16 ramp[256]; Uint16 red_ramp[256]; Uint32 then, timeout; /* Check command line arguments */ argv += get_video_args(argv, &w, &h, &bpp, &flags); /* Initialize SDL */ if (SDL_Init(SDL_INIT_VIDEO) < 0) { fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError()); return (1); } /* Initialize the display, always use hardware palette */ screen = SDL_SetVideoMode(w, h, bpp, flags | SDL_HWPALETTE); if (screen == NULL) { fprintf(stderr, "Couldn't set %dx%d video mode: %s\n", w, h, SDL_GetError()); quit(1); } /* Set the window manager title bar */ SDL_WM_SetCaption("SDL gamma test", "testgamma"); /* Set the desired gamma, if any */ gamma = 1.0f; if (*argv) { gamma = (float) atof(*argv); } if (SDL_SetGamma(gamma, gamma, gamma) < 0) { fprintf(stderr, "Unable to set gamma: %s\n", SDL_GetError()); quit(1); } #if 0 /* This isn't supported. Integrating the gamma ramps isn't exact */ /* See what gamma was actually set */ float real[3]; if (SDL_GetGamma(&real[0], &real[1], &real[2]) < 0) { printf("Couldn't get gamma: %s\n", SDL_GetError()); } else { printf("Set gamma values: R=%2.2f, G=%2.2f, B=%2.2f\n", real[0], real[1], real[2]); } #endif /* Do all the drawing work */ image = SDL_LoadBMP("sample.bmp"); if (image) { SDL_Rect dst; dst.x = (screen->w - image->w) / 2; dst.y = (screen->h - image->h) / 2; dst.w = image->w; dst.h = image->h; SDL_BlitSurface(image, NULL, screen, &dst); SDL_UpdateRects(screen, 1, &dst); } /* Wait a bit, handling events */ then = SDL_GetTicks(); timeout = (5 * 1000); while ((SDL_GetTicks() - then) < timeout) { SDL_Event event; while (SDL_PollEvent(&event)) { switch (event.type) { case SDL_QUIT: /* Quit now */ timeout = 0; break; case SDL_KEYDOWN: switch (event.key.keysym.sym) { case SDLK_SPACE: /* Go longer.. */ timeout += (5 * 1000); break; case SDLK_UP: gamma += 0.2f; SDL_SetGamma(gamma, gamma, gamma); break; case SDLK_DOWN: gamma -= 0.2f; SDL_SetGamma(gamma, gamma, gamma); break; case SDLK_ESCAPE: timeout = 0; break; default: break; } break; } } } /* Perform a gamma flash to red using color ramps */ while (gamma < 10.0) { /* Increase the red gamma and decrease everything else... */ gamma += 0.1f; CalculateGamma(gamma, red_ramp); CalculateGamma(1.0 / gamma, ramp); SDL_SetGammaRamp(red_ramp, ramp, ramp); } /* Finish completely red */ memset(red_ramp, 255, sizeof(red_ramp)); memset(ramp, 0, sizeof(ramp)); SDL_SetGammaRamp(red_ramp, ramp, ramp); /* Now fade out to black */ for (i = (red_ramp[0] >> 8); i >= 0; --i) { memset(red_ramp, i, sizeof(red_ramp)); SDL_SetGammaRamp(red_ramp, NULL, NULL); } SDL_Delay(1 * 1000); SDL_Quit(); return (0); }