[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;

.TH "SDL_Rect" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_Rect \- Defines a rectangular area
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Sint16 x, y;
  Uint16 w, h;
} SDL_Rect;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBx, y\fR
Position of the upper-left corner of the rectangle
.TP 20
\fBw, h\fR
The width and height of the rectangle
.SH "DESCRIPTION"
.PP
A \fBSDL_Rect\fR defines a rectangular area of pixels\&. It is used by \fI\fBSDL_BlitSurface\fP\fR to define blitting regions and by several other video functions\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_BlitSurface\fP\fR, \fI\fBSDL_UpdateRect\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01