view test/testgamma.c @ 1768:814f9f2c7a33

Fixed bug #80 Date: 21 Apr 2003 17:20:20 +0100 From: Alan Swanson <swanson@uklinux.net> Subject: [SDL] New XFree 4.3 Video Mode Patch If you look at the unsorted list of modes returned by X, here's mine; 1280 x 1024 @ 85.0 > 1024 x 768 @ 100.3 > USER 800 x 600 @ 125.5 > SET 640 x 480 @ 124.9 > 1280 x 1024 @ 75.0 ] 1280 x 1024 @ 60.0 ] 1280 x 960 @ 85.0 ] X11 1280 x 960 @ 60.0 ] AUTO 1152 x 864 @ 75.0 ]=20 1152 x 768 @ 54.8 ] 960 x 720 @ 120.0 ] ... 640 x 400 @ 85.1 ] 256k 576 x 432 @ 150.0 ] 249k PIXEL 640 x 350 @ 85.1 ] 224k COUNT 576 x 384 @ 109.6 ] 221k ... The user set modes come first followed by X set modes which are ordered by decreasing number of pixels and refresh. The reason why every other library or program not using SDL working is due to SDL scanning the modes in reverse getting X11 provided modes modes with the lowest refresh.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 05 May 2006 05:50:26 +0000
parents be9c9c8f6d53
children 782fd950bd46 c121d94672cb
line wrap: on
line source


/* 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);
}