Implement SkGLContext swapBuffers with fence syncs
Improves the GPU measuring accuracy of nanobench by using fence syncs.
Fence syncs are very widely supported and available on almost every
platform.
NO_MERGE_BUILDS
BUG=skia:
Review URL: https://codereview.chromium.org/1194783003
diff --git a/include/gpu/gl/GrGLInterface.h b/include/gpu/gl/GrGLInterface.h
index e510551..8c72526 100644
--- a/include/gpu/gl/GrGLInterface.h
+++ b/include/gpu/gl/GrGLInterface.h
@@ -30,6 +30,8 @@
* comments in GrGLConfig.h
*/
+typedef void(*GrGLFuncPtr)();
+
struct GrGLInterface;
const GrGLInterface* GrGLDefaultInterface();
diff --git a/include/gpu/gl/SkGLContext.h b/include/gpu/gl/SkGLContext.h
index 6ca7bf5..8209c31 100644
--- a/include/gpu/gl/SkGLContext.h
+++ b/include/gpu/gl/SkGLContext.h
@@ -9,6 +9,7 @@
#define SkGLContext_DEFINED
#include "GrGLInterface.h"
+#include "../../src/gpu/SkGpuFenceSync.h"
/**
* Create an offscreen opengl context with an RGBA8 / 8bit stencil FBO.
@@ -25,19 +26,32 @@
const GrGLInterface* gl() const { return fGL.get(); }
- virtual void makeCurrent() const = 0;
+ bool fenceSyncSupport() const { return SkToBool(fFenceSync); }
+
+ bool getMaxGpuFrameLag(int* maxFrameLag) const {
+ if (!fFenceSync) {
+ return false;
+ }
+ *maxFrameLag = kMaxFrameLag;
+ return true;
+ }
+
+ void makeCurrent() const;
/**
- * The primary purpose of this function it to provide a means of scheduling
+ * The only purpose of this function it to provide a means of scheduling
* work on the GPU (since all of the subclasses create primary buffers for
* testing that are small and not meant to be rendered to the screen).
*
- * If the drawing surface provided by the platform is double buffered this
- * call will cause the platform to swap which buffer is currently being
- * targeted. If the current surface does not include a back buffer, this
- * call has no effect.
+ * If the platform supports fence sync (OpenGL 3.2+ or EGL_KHR_fence_sync),
+ * this will not swap any buffers, but rather emulate triple buffer
+ * synchronization using fences.
+ *
+ * Otherwise it will call the platform SwapBuffers method. This may or may
+ * not perform some sort of synchronization, depending on whether the
+ * drawing surface provided by the platform is double buffered.
*/
- virtual void swapBuffers() const = 0;
+ void swapBuffers();
/**
* This notifies the context that we are deliberately testing abandoning
@@ -47,13 +61,37 @@
*/
void testAbandon();
+ class GLFenceSync; // SkGpuFenceSync implementation that uses the OpenGL functionality.
+
protected:
SkGLContext();
+ /*
+ * Methods that sublcasses must call from their constructors and destructors.
+ */
+ void init(const GrGLInterface*, SkGpuFenceSync* = NULL);
+ void teardown();
+
+ /*
+ * Operations that have a platform-dependent implementation.
+ */
+ virtual void onPlatformMakeCurrent() const = 0;
+ virtual void onPlatformSwapBuffers() const = 0;
+ virtual GrGLFuncPtr onPlatformGetProcAddress(const char*) const = 0;
+
+private:
+ enum { kMaxFrameLag = 3 };
+
+ SkAutoTDelete<SkGpuFenceSync> fFenceSync;
+ SkPlatformGpuFence fFrameFences[kMaxFrameLag - 1];
+ int fCurrentFenceIdx;
+
/** Subclass provides the gl interface object if construction was
* successful. */
SkAutoTUnref<const GrGLInterface> fGL;
+ friend class GLFenceSync; // For onPlatformGetProcAddress.
+
typedef SkRefCnt INHERITED;
};
diff --git a/include/gpu/gl/SkNullGLContext.h b/include/gpu/gl/SkNullGLContext.h
index ca71dde..1f63438 100644
--- a/include/gpu/gl/SkNullGLContext.h
+++ b/include/gpu/gl/SkNullGLContext.h
@@ -13,8 +13,6 @@
class SK_API SkNullGLContext : public SkGLContext {
public:
~SkNullGLContext() override;
- void makeCurrent() const override;
- void swapBuffers() const override {};
static SkNullGLContext* Create(GrGLStandard);
@@ -23,6 +21,10 @@
private:
SkNullGLContext();
+ void onPlatformMakeCurrent() const override;
+ void onPlatformSwapBuffers() const override {}
+ GrGLFuncPtr onPlatformGetProcAddress(const char*) const override { return NULL; }
+
ContextState* fState;
};
diff --git a/include/gpu/gl/angle/SkANGLEGLContext.h b/include/gpu/gl/angle/SkANGLEGLContext.h
index f54f29e..8850cd0 100644
--- a/include/gpu/gl/angle/SkANGLEGLContext.h
+++ b/include/gpu/gl/angle/SkANGLEGLContext.h
@@ -15,8 +15,6 @@
class SkANGLEGLContext : public SkGLContext {
public:
~SkANGLEGLContext() override;
- void makeCurrent() const override;
- void swapBuffers() const override;
static SkANGLEGLContext* Create(GrGLStandard forcedGpuAPI) {
if (kGL_GrGLStandard == forcedGpuAPI) {
@@ -37,6 +35,10 @@
SkANGLEGLContext();
void destroyGLContext();
+ void onPlatformMakeCurrent() const override;
+ void onPlatformSwapBuffers() const override;
+ GrGLFuncPtr onPlatformGetProcAddress(const char* name) const override;
+
void* fContext;
void* fDisplay;
void* fSurface;