view test/testgamma.c @ 615:7ec821f3cbd0

Date: Thu, 17 Apr 2003 23:27:34 -0400 From: Darrell Walisser Subject: Yet another OS X cursor bug The synopsis: 1. Call SDL_ShowCursor(0); 2. Call SDL_SetVideoMode(); 3. Call SDL_GetEvent(); 3. Call SDL_ShowCursor(1); The result: Sometimes the cursor doesn't come back! Ack! Oddly enough, it does come back when mousing over the dock or clicking in the menu bar. But that's besides the point. The reason why this is happening is a flaw in the handling of activation/deactivation events. The short explanation is that the HideCursor() and ShowCursor() calls must be balanced, but if the cursor was initially hidden, HideCursor() was called again on the activate event - so now the next ShowCursor() fails (as does the next, and the next, for some reason). So, here's the patch. All it does is keep track of the HideCursor()/ShowCursor() calls so that they will always be balanced.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 20 Apr 2003 05:41:16 +0000
parents 74212992fb08
children be9c9c8f6d53
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"

/* 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());
		exit(1);
	}
	atexit(SDL_Quit);

	/* 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());
		exit(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());
		exit(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);

	return(0);
}