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[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 355632dca928
children
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<HTML
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>SDL_GetVideoSurface</TITLE
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>SDL_GetVideoSurface</H1
><DIV
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><H2
>Name</H2
>SDL_GetVideoSurface&nbsp;--&nbsp;returns a pointer to the current display surface</DIV
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><H2
>Synopsis</H2
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><P
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><PRE
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>#include "SDL.h"</PRE
><P
><CODE
><CODE
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>SDL_Surface *<B
CLASS="FSFUNC"
>SDL_GetVideoSurface</B
></CODE
>(void);</CODE
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><H2
>Description</H2
><P
>This function returns a pointer to the current display surface.
If SDL is doing format conversion on the display surface, this
function returns the publicly visible surface, not the real video
surface.</P
></DIV
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>SDL_Surface</SPAN
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