Cache render targets that render to wrapped textures

src/gpu/gl/GrGLGpu.cpp

Index: src/gpu/gl/GrGLGpu.cpp
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index b94991b6915f241918dd4baf541946da967b5d8a..1d53b49e092d06a57f62333718fbc1304348ef45 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -698,21 +698,19 @@ GrRenderTarget* GrGLGpu::onWrapBackendRenderTarget(const GrBackendRenderTargetDe
     return GrGLRenderTarget::CreateWrapped(this, desc, idDesc, wrapDesc.fStencilBits);
 }
 
-GrRenderTarget* GrGLGpu::onWrapBackendTextureAsRenderTarget(const GrBackendTextureDesc& desc) {
+static bool backend_texture_to_tex_info(const GrBackendTextureDesc& desc,
+                                        GrGLTextureInfo* outInfo) {
 #ifdef SK_IGNORE_GL_TEXTURE_TARGET
     if (!desc.fTextureHandle) {
-        return nullptr;
+        return false;
     }
 #else
     const GrGLTextureInfo* info = reinterpret_cast<const GrGLTextureInfo*>(desc.fTextureHandle);
     if (!info || !info->fID) {
-        return nullptr;
+        return false;
     }
 #endif
-
     GrGLTextureInfo texInfo;
-    GrSurfaceDesc surfDesc;
-
 #ifdef SK_IGNORE_GL_TEXTURE_TARGET
     texInfo.fID = static_cast<GrGLuint>(desc.fTextureHandle);
     // We only support GL_TEXTURE_2D at the moment.
@@ -726,9 +724,63 @@ GrRenderTarget* GrGLGpu::onWrapBackendTextureAsRenderTarget(const GrBackendTextu
         // Only texture rectangle and texture 2d are supported. We do not check whether texture
         // rectangle is supported by Skia - if the caller provided us with a texture rectangle,
         // we assume the necessary support exists.
+        return false;
+    }
+    *outInfo = texInfo;
+    return true;
+}
+
+static void compute_backend_texture_key_for_wrap_as_render_target(const GrBackendTextureDesc& desc,
+                                                              GrUniqueKey* key) {
+    GrGLTextureInfo texInfo;
+    if (!backend_texture_to_tex_info(desc, &texInfo)) {
+        return;
+    }
+    static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
+    GrUniqueKey::Builder builder(key, kDomain, 3);
+    builder[0] = desc.fWidth;
+    builder[1] = desc.fHeight;
+    builder[2] = desc.fConfig | (desc.fFlags << 5) | (desc.fSampleCnt << 6) | (desc.fOrigin << 14)
+            | ((texInfo.fTarget == GR_GL_TEXTURE_2D) << 16);
+    builder.finish();
+}
+
+void GrGLGpu::onComputeBackendTextureKeyForWrapAsRenderTarget(const GrBackendTextureDesc& desc,
+                                                              GrUniqueKey* key) {
+    compute_backend_texture_key_for_wrap_as_render_target(desc, key);
+}
+
+bool GrGLGpu::onRewrapRenderTargetWithBackendTexture(const GrBackendTextureDesc& desc,
+                                                     GrRenderTarget* rt) {
+    GrGLTextureInfo texInfo;
+    SkAssertResult(backend_texture_to_tex_info(desc, &texInfo));
+
+
+    GrGLRenderTarget* glRT = static_cast<GrGLRenderTarget*>(rt);
+    SkASSERT(glRT);
+    fStats.incRenderTargetBinds();
+    GL_CALL(BindFramebuffer(GR_GL_FRAMEBUFFER, glRT->textureFBOID()));
+    if (this->glCaps().usesImplicitMSAAResolve() && desc.fSampleCnt > 0) {
+        GL_CALL(FramebufferTexture2DMultisample(GR_GL_FRAMEBUFFER,
+                                                GR_GL_COLOR_ATTACHMENT0,
+                                                texInfo.fTarget,
+                                                texInfo.fID, 0, desc.fSampleCnt));
+    } else {
+        GL_CALL(FramebufferTexture2D(GR_GL_FRAMEBUFFER,
+                                     GR_GL_COLOR_ATTACHMENT0,
+                                     texInfo.fTarget,
+                                     texInfo.fID, 0));
+    }
+    return true;
+}
+
+GrRenderTarget* GrGLGpu::onWrapBackendTextureAsRenderTarget(const GrBackendTextureDesc& desc) {
+    GrGLTextureInfo texInfo;
+    if (!backend_texture_to_tex_info(desc, &texInfo)) {
         return nullptr;
     }
 
+    GrSurfaceDesc surfDesc;
     surfDesc.fFlags = (GrSurfaceFlags) desc.fFlags;
     surfDesc.fWidth = desc.fWidth;
     surfDesc.fHeight = desc.fHeight;
@@ -748,7 +800,11 @@ GrRenderTarget* GrGLGpu::onWrapBackendTextureAsRenderTarget(const GrBackendTextu
     if (!this->createRenderTargetObjects(surfDesc, texInfo, &rtIDDesc)) {
         return nullptr;
     }
-    return GrGLRenderTarget::CreateWrapped(this, surfDesc, rtIDDesc, 0);
+    GrGLRenderTarget* rt = GrGLRenderTarget::CreateWrapped(this, surfDesc, rtIDDesc, 0);
+    GrUniqueKey key;
+    compute_backend_texture_key_for_wrap_as_render_target(desc, &key);
+    rt->resourcePriv().setUniqueKey(key);
+    return rt;
 }
 
 ////////////////////////////////////////////////////////////////////////////////