view Xcode/TemplatesForXcodeTiger/SDL Cocoa Application/main.c @ 3333:b334b4f7dfa0

[SDL] Bad math in SDL_RenderCopy Mason Wheeler to sdl When I tried to render an image using something other than NULL for srcrect, it got horribly distorted. I traced it down to the fact that the math in the rectangle adjustments performed just before the call to renderer->RenderCopy is written inside out. It should look like this: if (dstrect->w != real_dstrect.w) { int deltax = (dstrect->x - real_dstrect.x); int deltaw = (dstrect->w - real_dstrect.w); real_srcrect.x += (deltax * real_srcrect.w) / dstrect->w; real_srcrect.w += (deltaw * real_srcrect.w) / dstrect->w; } if (dstrect->h != real_dstrect.h) { int deltay = (dstrect->y - real_dstrect.y); int deltah = (dstrect->h - real_dstrect.h); real_srcrect.y += (deltay * real_srcrect.h) / dstrect->h; real_srcrect.h += (deltah * real_srcrect.h) / dstrect->h;
author Sam Lantinga <slouken@libsdl.org>
date Sat, 03 Oct 2009 16:23:16 +0000
parents 232e5e00e398
children
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/* Simple program:  Create a blank window, wait for keypress, quit.

   Please see the SDL documentation for details on using the SDL API:
   /Developer/Documentation/SDL/docs.html
*/
   
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#include "SDL.h"

int main(int argc, char *argv[])
{
	Uint32 initflags = SDL_INIT_VIDEO;  /* See documentation for details */
	SDL_Surface *screen;
	Uint8  video_bpp = 0;
	Uint32 videoflags = SDL_SWSURFACE;
	int    done;
        SDL_Event event;

	/* Initialize the SDL library */
	if ( SDL_Init(initflags) < 0 ) {
		fprintf(stderr, "Couldn't initialize SDL: %s\n",
			SDL_GetError());
		exit(1);
	}

	/* Set 640x480 video mode */
	screen=SDL_SetVideoMode(640,480, video_bpp, videoflags);
        if (screen == NULL) {
		fprintf(stderr, "Couldn't set 640x480x%d video mode: %s\n",
                        video_bpp, SDL_GetError());
		SDL_Quit();
		exit(2);
	}

	done = 0;
	while ( !done ) {

		/* Check for events */
		while ( SDL_PollEvent(&event) ) {
			switch (event.type) {

				case SDL_MOUSEMOTION:
					break;
				case SDL_MOUSEBUTTONDOWN:
					break;
				case SDL_KEYDOWN:
					/* Any keypress quits the app... */
				case SDL_QUIT:
					done = 1;
					break;
				default:
					break;
			}
		}
	}
	
	/* Clean up the SDL library */
	SDL_Quit();
	return(0);
}