Add API for flushing surfaces with gpu semaphores

BUG=skia:

Change-Id: Ia4bfef784cd5f2516ceccafce958be18a86f91d1
Reviewed-on: https://skia-review.googlesource.com/11488
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Forrest Reiling <freiling@google.com>

2 files changed, 94 insertions, 0 deletions

diff --git a/include/core/SkSurface.h b/include/core/SkSurface.h
index efa2428ccb..6fad21721e 100644
--- a/include/core/SkSurface.h
+++ b/include/core/SkSurface.h
@@ -15,6 +15,7 @@
 class SkCanvas;
 class SkPaint;
 class GrBackendRenderTarget;
+class GrBackendSemaphore;
 class GrContext;
 class GrRenderTarget;
 
@@ -323,9 +324,33 @@ public:
 
     /**
      * Issue any pending surface IO to the current backend 3D API and resolve any surface MSAA.
+     *
+     * The flush calls below are the new preferred way to flush calls to a surface, and this call
+     * will eventually be removed.
      */
     void prepareForExternalIO();
 
+    /**
+     * Issue any pending surface IO to the current backend 3D API
+     */
+    void flush();
+
+    /**
+     * Issue any pending surface IO to the current backend 3D API. After issuing all commands, we
+     * will issue numSemaphore semaphores for the gpu to signal. We will then fill in the array
+     * signalSemaphores with the info on the semaphores we submitted. The client is reposonsible for
+     * allocating enough space in signalSemaphores to handle numSemaphores of GrBackendSemaphores.
+     * The client will also take ownership of the returned underlying backend semaphores.
+     */
+    void flushAndSignalSemaphores(int numSemaphores, GrBackendSemaphore* signalSemaphores);
+
+    /**
+     * Inserts a list of GPU semaphores that the current backend 3D API must wait on before
+     * executing any more commands on the GPU for this surface. Skia will take ownership of the
+     * underlying semaphores and delete them once they have been signaled and waited on.
+     */
+    void wait(int numSemaphores, const GrBackendSemaphore* waitSemaphores);
+
 protected:
     SkSurface(int width, int height, const SkSurfaceProps*);
     SkSurface(const SkImageInfo&, const SkSurfaceProps*);
diff --git a/include/gpu/GrBackendSemaphore.h b/include/gpu/GrBackendSemaphore.h
new file mode 100644
index 0000000000..668f6bb1c9
--- /dev/null
+++ b/include/gpu/GrBackendSemaphore.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrBackendSemaphore_DEFINED
+#define GrBackendSemaphore_DEFINED
+
+#include "GrTypes.h"
+
+#include "gl/GrGLTypes.h"
+
+#ifdef SK_VULKAN
+#include "vk/GrVkTypes.h"
+#endif
+
+/**
+ * Wrapper class for passing into and receiving data from Ganesh about a backend semaphore object.
+ */
+class GrBackendSemaphore {
+public:
+    // For convenience we just set the backend here to OpenGL. The GrBackendSemaphore cannot be used
+    // until either initGL or initVulkan are called which will set the appropriate GrBackend.
+    GrBackendSemaphore() : fBackend(kOpenGL_GrBackend), fGLSync(0), fIsInitialized(false) {}
+
+    void initGL(GrGLsync sync) {
+        fBackend = kOpenGL_GrBackend;
+        fGLSync = sync;
+        fIsInitialized = true;
+    }
+
+#ifdef SK_VULKAN
+    void initVulkan(VkSemaphore semaphore) {
+        fBackend = kVulkan_GrBackend;
+        fVkSemaphore = semaphore;
+        fIsInitialized = true;
+    }
+#endif
+
+    GrGLsync glSync() const {
+        if (!fIsInitialized || kOpenGL_GrBackend != fBackend) {
+            return 0;
+        }
+        return fGLSync;
+    }
+
+#ifdef SK_VULKAN
+    VkSemaphore vkSemaphore() const {
+        if (!fIsInitialized || kVulkan_GrBackend != fBackend) {
+            return VK_NULL_HANDLE;
+        }
+        return fVkSemaphore;
+    }
+#endif
+
+private:
+    GrBackend fBackend;
+    union {
+        GrGLsync    fGLSync;
+#ifdef SK_VULKAN
+        VkSemaphore fVkSemaphore;
+#endif
+    };
+    bool fIsInitialized;
+};
+
+#endif