From 8becc0e78dbb53d9df660c0c440ce7e5c29bfb2b Mon Sep 17 00:00:00 2001
From: Christopher Bruns <cmbruns@rotatingpenguin.com>
Date: Tue, 26 Feb 2019 21:15:13 -0800
Subject: [PATCH] Enable menu blur in stereo 3d. Use more blitting to avoid
 confusing framebuffer state management in stereo 3D.

---
 src/rendering/gl/renderer/gl_postprocess.cpp  | 25 +++++++++++++------
 .../gl/renderer/gl_renderbuffers.cpp          | 24 +++++++++++++-----
 src/rendering/gl/renderer/gl_renderbuffers.h  |  2 +-
 src/rendering/gl/system/gl_framebuffer.cpp    |  4 +--
 4 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/src/rendering/gl/renderer/gl_postprocess.cpp b/src/rendering/gl/renderer/gl_postprocess.cpp
index d08443c574..6b8c5c2e64 100644
--- a/src/rendering/gl/renderer/gl_postprocess.cpp
+++ b/src/rendering/gl/renderer/gl_postprocess.cpp
@@ -120,7 +120,22 @@ void FGLRenderer::BlurScene(float gameinfobluramount)
 	mBuffers->CompileEffectShaders();
 	mBuffers->UpdateEffectTextures();
 
-	mBuffers->RenderEffect("BlurScene");
+	auto vrmode = VRMode::GetVRMode(true);
+	if (vrmode->mEyeCount == 1)
+	{
+		mBuffers->RenderEffect("BlurScene");
+	}
+	else
+	{
+		for (int eye_ix = 0; eye_ix < vrmode->mEyeCount; ++eye_ix)
+		{
+			FGLDebug::PushGroup("EyeBlur");
+			mBuffers->BlitFromEyeTexture(eye_ix);
+			mBuffers->RenderEffect("BlurScene");
+			mBuffers->BlitToEyeTexture(eye_ix);
+			FGLDebug::PopGroup();
+		}
+	}
 }
 
 void FGLRenderer::ClearTonemapPalette()
@@ -137,9 +152,6 @@ void FGLRenderer::ClearTonemapPalette()
 void FGLRenderer::Flush()
 {
 	auto vrmode = VRMode::GetVRMode(true);
-	const auto &mSceneViewport = screen->mSceneViewport;
-	const auto &mScreenViewport = screen->mScreenViewport;
-
 	if (vrmode->mEyeCount == 1)
 	{
 		CopyToBackbuffer(nullptr, true);
@@ -150,10 +162,9 @@ void FGLRenderer::Flush()
 		for (int eye_ix = 0; eye_ix < vrmode->mEyeCount; ++eye_ix)
 		{
 			FGLDebug::PushGroup("Eye2D");
-			mBuffers->BindEyeFB(eye_ix);
-			glViewport(mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
-			glScissor(mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
+			mBuffers->BlitFromEyeTexture(eye_ix);
 			screen->Draw2D();
+			mBuffers->BlitToEyeTexture(eye_ix);
 			FGLDebug::PopGroup();
 		}
 		screen->Clear2D();
diff --git a/src/rendering/gl/renderer/gl_renderbuffers.cpp b/src/rendering/gl/renderer/gl_renderbuffers.cpp
index 67d083a31c..4dd9f95be3 100644
--- a/src/rendering/gl/renderer/gl_renderbuffers.cpp
+++ b/src/rendering/gl/renderer/gl_renderbuffers.cpp
@@ -550,6 +550,24 @@ void FGLRenderBuffers::BlitToEyeTexture(int eye)
 	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 }
 
+void FGLRenderBuffers::BlitFromEyeTexture(int eye)
+{
+	CreateEyeBuffers(eye);
+
+	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mPipelineFB[mCurrentPipelineTexture].handle);
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, mEyeFBs[eye].handle);
+	glBlitFramebuffer(0, 0, mWidth, mHeight, 0, 0, mWidth, mHeight, GL_COLOR_BUFFER_BIT, GL_NEAREST);
+
+	if ((gl.flags & RFL_INVALIDATE_BUFFER) != 0)
+	{
+		GLenum attachments[2] = { GL_COLOR_ATTACHMENT0, GL_DEPTH_STENCIL_ATTACHMENT };
+		glInvalidateFramebuffer(GL_READ_FRAMEBUFFER, 2, attachments);
+	}
+
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+}
+
 void FGLRenderBuffers::BindEyeTexture(int eye, int texunit)
 {
 	CreateEyeBuffers(eye);
@@ -557,12 +575,6 @@ void FGLRenderBuffers::BindEyeTexture(int eye, int texunit)
 	glBindTexture(GL_TEXTURE_2D, mEyeTextures[eye].handle);
 }
 
-void FGLRenderBuffers::BindEyeFB(int eye, bool readBuffer)
-{
-	CreateEyeBuffers(eye);
-	glBindFramebuffer(readBuffer ? GL_READ_FRAMEBUFFER : GL_FRAMEBUFFER, mEyeFBs[eye].handle);
-}
-
 void FGLRenderBuffers::BindDitherTexture(int texunit)
 {
 	if (!mDitherTexture)
diff --git a/src/rendering/gl/renderer/gl_renderbuffers.h b/src/rendering/gl/renderer/gl_renderbuffers.h
index 10c4e37ed3..b4b0185169 100644
--- a/src/rendering/gl/renderer/gl_renderbuffers.h
+++ b/src/rendering/gl/renderer/gl_renderbuffers.h
@@ -88,8 +88,8 @@ public:
 	void BindOutputFB();
 
 	void BlitToEyeTexture(int eye);
+	void BlitFromEyeTexture(int eye);
 	void BindEyeTexture(int eye, int texunit);
-	void BindEyeFB(int eye, bool readBuffer = false);
 
 	void BindDitherTexture(int texunit);
 
diff --git a/src/rendering/gl/system/gl_framebuffer.cpp b/src/rendering/gl/system/gl_framebuffer.cpp
index 22e5c5fb32..6697c89d5e 100644
--- a/src/rendering/gl/system/gl_framebuffer.cpp
+++ b/src/rendering/gl/system/gl_framebuffer.cpp
@@ -448,9 +448,7 @@ void OpenGLFrameBuffer::Draw2D()
 	if (GLRenderer != nullptr)
 	{
 		FGLDebug::PushGroup("Draw2D");
-		if (VRMode::GetVRMode(true)->mEyeCount == 1)
-			GLRenderer->mBuffers->BindCurrentFB();
-
+		GLRenderer->mBuffers->BindCurrentFB();
 		::Draw2D(&m2DDrawer, gl_RenderState);
 		FGLDebug::PopGroup();
 	}