Cache the results of get_pixel_formats_to_try

Choosing pixel formats is quite slow (depending on driver?). We were
doing this once per context, and it added up. On my desktop windows
machine, this saves another 7 seconds in `dm --config gl --src gm`.

Actual times:
  37s -> 30s (not writing PNGs)
  47s -> 39.5s (writing PNGs)

We always called this with MSAA sample count set to zero, so I cleaned
up the code to make that clearer. Also included a comment about the
theoretical risk, although I think that outside of a multi-GPU system,
we're fine.

Bug: skia:
Change-Id: I50927ebfaf6fe8d88a63674427fbf9e06e4ab059
Reviewed-on: https://skia-review.googlesource.com/35763
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
This commit is contained in:
Brian Osman 2017-08-17 12:58:28 -04:00 committed by Skia Commit-Bot
parent 1591c38d13
commit de3b710913
3 changed files with 40 additions and 20 deletions

View File

@ -143,8 +143,8 @@ HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, bool deepColor, SkWGLConte
*/
class SkWGLPbufferContext : public SkRefCnt {
public:
static SkWGLPbufferContext* Create(HDC parentDC, int msaaSampleCount,
SkWGLContextRequest contextType, HGLRC shareContext);
static SkWGLPbufferContext* Create(HDC parentDC, SkWGLContextRequest contextType,
HGLRC shareContext);
virtual ~SkWGLPbufferContext();

View File

@ -438,8 +438,7 @@ HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, bool deepColor,
return create_gl_context(dc, extensions, contextType, shareContext);
}
SkWGLPbufferContext* SkWGLPbufferContext::Create(HDC parentDC, int msaaSampleCount,
SkWGLContextRequest contextType,
SkWGLPbufferContext* SkWGLPbufferContext::Create(HDC parentDC, SkWGLContextRequest contextType,
HGLRC shareContext) {
SkWGLExtensions extensions;
if (!extensions.hasExtension(parentDC, "WGL_ARB_pixel_format") ||
@ -447,24 +446,45 @@ SkWGLPbufferContext* SkWGLPbufferContext::Create(HDC parentDC, int msaaSampleCou
return nullptr;
}
// We cache the pixel formats once, and then reuse them. That's possibly incorrect if
// there are multiple GPUs, but this function is always called with a freshly made,
// identically constructed HDC (see WinGLTestContext).
//
// We only store two potential pixel formats, one for single buffer, one for double buffer.
// We never ask for MSAA, so we don't need the second pixel format for each buffering state.
static int gPixelFormats[2] = { -1, -1 };
static SkOnce once;
once([=] {
{
// Single buffer
int pixelFormatsToTry[2] = { -1, -1 };
get_pixel_formats_to_try(parentDC, extensions, false, 0, false, pixelFormatsToTry);
gPixelFormats[0] = pixelFormatsToTry[0];
}
{
// Double buffer
int pixelFormatsToTry[2] = { -1, -1 };
get_pixel_formats_to_try(parentDC, extensions, true, 0, false, pixelFormatsToTry);
gPixelFormats[1] = pixelFormatsToTry[0];
}
});
// try for single buffer first
for (int dblBuffer = 0; dblBuffer < 2; ++dblBuffer) {
int pixelFormatsToTry[] = { -1, -1 };
get_pixel_formats_to_try(parentDC, extensions, (0 != dblBuffer), msaaSampleCount,
false, pixelFormatsToTry);
for (int f = 0; -1 != pixelFormatsToTry[f] && f < SK_ARRAY_COUNT(pixelFormatsToTry); ++f) {
HPBUFFER pbuf = extensions.createPbuffer(parentDC, pixelFormatsToTry[f], 1, 1, nullptr);
if (0 != pbuf) {
HDC dc = extensions.getPbufferDC(pbuf);
if (dc) {
HGLRC glrc = create_gl_context(dc, extensions, contextType, shareContext);
if (glrc) {
return new SkWGLPbufferContext(pbuf, dc, glrc);
}
extensions.releasePbufferDC(pbuf, dc);
for (int pixelFormat : gPixelFormats) {
if (-1 == pixelFormat) {
continue;
}
HPBUFFER pbuf = extensions.createPbuffer(parentDC, pixelFormat, 1, 1, nullptr);
if (0 != pbuf) {
HDC dc = extensions.getPbufferDC(pbuf);
if (dc) {
HGLRC glrc = create_gl_context(dc, extensions, contextType, shareContext);
if (glrc) {
return new SkWGLPbufferContext(pbuf, dc, glrc);
}
extensions.destroyPbuffer(pbuf);
extensions.releasePbufferDC(pbuf, dc);
}
extensions.destroyPbuffer(pbuf);
}
}
return nullptr;

View File

@ -90,7 +90,7 @@ WinGLTestContext::WinGLTestContext(GrGLStandard forcedGpuAPI, WinGLTestContext*
winShareContext = shareContext->fPbufferContext ? shareContext->fPbufferContext->getGLRC()
: shareContext->fGlRenderContext;
}
fPbufferContext = SkWGLPbufferContext::Create(fDeviceContext, 0, contextType, winShareContext);
fPbufferContext = SkWGLPbufferContext::Create(fDeviceContext, contextType, winShareContext);
HDC dc;
HGLRC glrc;