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#include "UnityPrefix.h"
#include "VramLimits.h"
#include "Runtime/Shaders/GraphicsCaps.h"
int ChooseSuitableFSAALevel( int width, int height, int backbufferBPP, int frontbufferBPP, int depthBPP, int fsaa )
{
// no AA support?
if( !gGraphicsCaps.hasMultiSample )
return 0;
// figure out appropriate AA level based on VRAM and screen size
int vramKB = int(gGraphicsCaps.videoMemoryMB * 1024);
const int vramAllowedByPortion = int(vramKB * 0.5f); // allow max. 50% of total VRAM for screen
const int vramAllowedMax = 256 * 1024; // max 256MB for screen
// Make sure at least this amount of free of VRAM left after the screen.
// E.g. on a 32MB VRAM PPC MacMini, going 1280x960 2xAA still corrupts the screen (VRAM taken: 23.5MB).
// So we need to keep somewhat more free than 8MB... 16MB works.
const int vramAllowedWithKeepingSomeFree = int(vramKB - 16*1024);
int vramAllowedKB = std::min(vramAllowedByPortion, std::min(vramAllowedMax,vramAllowedWithKeepingSomeFree));
int vramNeededKB;
do {
vramNeededKB = width * height * (std::max(fsaa,1) * (backbufferBPP+depthBPP) + frontbufferBPP) / 1024;
if( vramNeededKB < vramAllowedKB )
break;
#if !UNITY_RELEASE
printf_console("Screen %ix%i at %ixAA won't fit, reducing AA (needed mem=%i allowedmem=%i)\n", width, height, fsaa, vramNeededKB, vramAllowedKB );
#endif
fsaa /= 2;
} while( fsaa > 1 );
if( fsaa == 1 )
fsaa = 0;
return fsaa;
}
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