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Cache the results of WglContext::selectBestPixelFormat to speed up context creation on systems where pixel format selection is an expensive operation. Closes #2508

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binary1248 2023-07-14 04:14:00 +02:00 committed by Chris Thrasher
parent 78973e4a06
commit f6612dd1f0
1 changed files with 40 additions and 5 deletions
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45
src/SFML/Window/Win32/WglContext.cpp
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@ -277,6 +277,36 @@ void WglContext::setVerticalSyncEnabled(bool enabled)
////////////////////////////////////////////////////////////
int WglContext::selectBestPixelFormat(HDC deviceContext, unsigned int bitsPerPixel, const ContextSettings& settings, bool pbuffer)
{
// Selecting a pixel format can be an expensive process on some implementations
// Since the same pixel format should always be selected for a specific combination of inputs
// we can cache the result of the lookup instead of having to perform it multiple times for the same inputs
struct PixelFormatCacheEntry
{
unsigned int bitsPerPixel;
unsigned int depthBits;
unsigned int stencilBits;
unsigned int antialiasingLevel;
bool pbuffer;
int bestFormat;
};
static std::mutex cacheMutex;
static std::vector<PixelFormatCacheEntry> pixelFormatCache;
// Check if we have already previously found a pixel format for
// the current inputs and return it if one has been previously found
{
const std::lock_guard lock(cacheMutex);
for (const auto& entry : pixelFormatCache)
{
if (bitsPerPixel == entry.bitsPerPixel && settings.depthBits == entry.depthBits &&
settings.stencilBits == entry.stencilBits && settings.antialiasingLevel == entry.antialiasingLevel &&
pbuffer == entry.pbuffer)
return entry.bestFormat;
}
}
WglContextImpl::ensureInit();
// Let's find a suitable pixel format -- first try with wglChoosePixelFormatARB
@ -393,12 +423,9 @@ int WglContext::selectBestPixelFormat(HDC deviceContext, unsigned int bitsPerPix
}
}
// ChoosePixelFormat doesn't support pbuffers
if (pbuffer)
return bestFormat;
// Find a pixel format with ChoosePixelFormat, if wglChoosePixelFormatARB is not supported
if (bestFormat == 0)
// ChoosePixelFormat doesn't support pbuffers
if ((bestFormat == 0) && !pbuffer)
{
// Setup a pixel format descriptor from the rendering settings
PIXELFORMATDESCRIPTOR descriptor;
@ -417,6 +444,14 @@ int WglContext::selectBestPixelFormat(HDC deviceContext, unsigned int bitsPerPix
bestFormat = ChoosePixelFormat(deviceContext, &descriptor);
}
// If we get this far, the format wasn't found in the cache so add it here
{
const std::lock_guard lock(cacheMutex);
pixelFormatCache.emplace_back(
PixelFormatCacheEntry{bitsPerPixel, settings.depthBits, settings.stencilBits, settings.antialiasingLevel, pbuffer, bestFormat});
}
return bestFormat;
}