HWUI: reset buffer state after MakeCurrent
MakeCurrent call is not guaranteed to reset read/draw buffer state of
default framebuffer unless it's the first time the context is bound.
When the default framebuffer transitions from EGL_NO_SURFACE to a surface,
it's buffer state might stay GL_NONE.
This change make sure default framebuffer buffer state is GL_BACK after
MakeCurrent.
Change-Id: I9d8a402c6e66e8eca177d8dec8208db3abb155f2
diff --git a/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp b/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp
index 8e350d5..63c36f8 100644
--- a/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp
+++ b/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp
@@ -53,6 +53,8 @@
}
MakeCurrentResult SkiaOpenGLPipeline::makeCurrent() {
+ bool wasSurfaceless = mEglManager.isCurrent(EGL_NO_SURFACE);
+
// In case the surface was destroyed (e.g. a previous trimMemory call) we
// need to recreate it here.
if (!isSurfaceReady() && mNativeWindow) {
@@ -63,6 +65,37 @@
if (!mEglManager.makeCurrent(mEglSurface, &error)) {
return MakeCurrentResult::AlreadyCurrent;
}
+
+ // Make sure read/draw buffer state of default framebuffer is GL_BACK. Vendor implementations
+ // disagree on the draw/read buffer state if the default framebuffer transitions from a surface
+ // to EGL_NO_SURFACE and vice-versa. There was a related discussion within Khronos on this topic.
+ // See https://cvs.khronos.org/bugzilla/show_bug.cgi?id=13534.
+ // The discussion was not resolved with a clear consensus
+ if (error == 0 && wasSurfaceless && mEglSurface != EGL_NO_SURFACE) {
+ GLint curReadFB = 0;
+ GLint curDrawFB = 0;
+ glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &curReadFB);
+ glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &curDrawFB);
+
+ GLint buffer = GL_NONE;
+ glBindFramebuffer(GL_FRAMEBUFFER, 0);
+ glGetIntegerv(GL_DRAW_BUFFER0, &buffer);
+ if (buffer == GL_NONE) {
+ const GLenum drawBuffer = GL_BACK;
+ glDrawBuffers(1, &drawBuffer);
+ }
+
+ glGetIntegerv(GL_READ_BUFFER, &buffer);
+ if (buffer == GL_NONE) {
+ glReadBuffer(GL_BACK);
+ }
+
+ glBindFramebuffer(GL_READ_FRAMEBUFFER, curReadFB);
+ glBindFramebuffer(GL_DRAW_FRAMEBUFFER, curDrawFB);
+
+ GL_CHECKPOINT(LOW);
+ }
+
return error ? MakeCurrentResult::Failed : MakeCurrentResult::Succeeded;
}