Hook up eye textures in renderer

src/gl/renderer/gl_postprocess.cpp

@@ -75,6 +75,7 @@
 #include "gl/shaders/gl_lensshader.h"
 #include "gl/shaders/gl_presentshader.h"
 #include "gl/renderer/gl_2ddrawer.h"
+#include "gl/stereo3d/gl_stereo3d.h"
 
 //==========================================================================
 //
@@ -375,6 +376,38 @@ void FGLRenderer::LensDistortScene()
 	FGLDebug::PopGroup();
 }
 
+//-----------------------------------------------------------------------------
+//
+// Copies the rendered screen to its final destination
+//
+//-----------------------------------------------------------------------------
+
+void FGLRenderer::Flush()
+{
+	const s3d::Stereo3DMode& stereo3dMode = s3d::Stereo3DMode::getCurrentMode();
+
+	if (stereo3dMode.IsMono() || !FGLRenderBuffers::IsEnabled())
+	{
+		CopyToBackbuffer(nullptr, true);
+	}
+	else
+	{
+		// Render 2D to eye textures
+		for (int eye_ix = 0; eye_ix < stereo3dMode.eye_count(); ++eye_ix)
+		{
+			FGLDebug::PushGroup("Eye2D");
+			mBuffers->BindEyeFB(eye_ix);
+			m2DDrawer->Flush(); // Draw the 2D
+			FGLDebug::PopGroup();
+		}
+
+		FGLPostProcessState savedState;
+		FGLDebug::PushGroup("PresentEyes");
+		stereo3dMode.Present();
+		FGLDebug::PopGroup();
+	}
+}
+
 //-----------------------------------------------------------------------------
 //
 // Gamma correct while copying to frame buffer

src/gl/renderer/gl_renderbuffers.cpp

@@ -122,12 +122,12 @@ void FGLRenderBuffers::ClearBloom()
 
 void FGLRenderBuffers::ClearEyeBuffers()
 {
-	for (auto handle : mEyeTextures)
-		DeleteTexture(handle);
-
 	for (auto handle : mEyeFBs)
 		DeleteFrameBuffer(handle);
 
+	for (auto handle : mEyeTextures)
+		DeleteTexture(handle);
+
 	mEyeTextures.Clear();
 	mEyeFBs.Clear();
 }
@@ -311,7 +311,7 @@ void FGLRenderBuffers::CreateEyeBuffers(int eye)
 	glGetIntegerv(GL_TEXTURE_BINDING_2D, &textureBinding);
 	glGetIntegerv(GL_FRAMEBUFFER_BINDING, &frameBufferBinding);
 
-	while (mEyeFBs.Size() < eye)
+	while (mEyeFBs.Size() <= eye)
 	{
 		GLuint texture = Create2DTexture("EyeTexture", GL_RGBA16F, mWidth, mHeight);
 		mEyeTextures.Push(texture);
@@ -546,10 +546,10 @@ void FGLRenderBuffers::BindEyeTexture(int eye, int texunit)
 	glBindTexture(GL_TEXTURE_2D, mEyeTextures[eye]);
 }
 
-void FGLRenderBuffers::BindEyeFB(int eye)
+void FGLRenderBuffers::BindEyeFB(int eye, bool readBuffer)
 {
 	CreateEyeBuffers(eye);
-	glBindFramebuffer(GL_FRAMEBUFFER, mEyeFBs[eye]);
+	glBindFramebuffer(readBuffer ? GL_READ_FRAMEBUFFER : GL_FRAMEBUFFER, mEyeFBs[eye]);
 }
 
 //==========================================================================

src/gl/renderer/gl_renderbuffers.h

@@ -34,7 +34,7 @@ public:
 
 	void BlitToEyeTexture(int eye);
 	void BindEyeTexture(int eye, int texunit);
-	void BindEyeFB(int eye);
+	void BindEyeFB(int eye, bool readBuffer = false);
 
 	enum { NumBloomLevels = 4 };
 	FGLBloomTextureLevel BloomLevels[NumBloomLevels];

src/gl/renderer/gl_renderer.h

@@ -173,7 +173,7 @@ public:
 	void ClearTonemapPalette();
 	void LensDistortScene();
 	void CopyToBackbuffer(const GL_IRECT *bounds, bool applyGamma);
-	void Flush() { CopyToBackbuffer(nullptr, true); }
+	void Flush();
 
 	void SetProjection(float fov, float ratio, float fovratio);
 	void SetProjection(VSMatrix matrix); // raw matrix input from stereo 3d modes

src/gl/scene/gl_scene.cpp

@@ -863,6 +863,8 @@ sector_t * FGLRenderer::RenderViewpoint (AActor * camera, GL_IRECT * bounds, flo
 			DrawBlend(lviewsector);
 		}
 		mDrawingScene2D = false;
+		if (!stereo3dMode.IsMono())
+			mBuffers->BlitToEyeTexture(eye_ix);
 		eye->TearDown();
 	}
 	stereo3dMode.TearDown();

src/gl/stereo3d/gl_stereo3d.cpp

@@ -36,6 +36,7 @@
 #include "gl/system/gl_system.h"
 #include "gl/stereo3d/gl_stereo3d.h"
 #include "gl/renderer/gl_renderer.h"
+#include "gl/renderer/gl_renderbuffers.h"
 #include "vectors.h" // RAD2DEG
 #include "doomtype.h" // M_PI
 
@@ -79,6 +80,28 @@ Stereo3DMode::~Stereo3DMode()
 {
 }
 
+void Stereo3DMode::Present() const
+{
+	// Example copying eye textures to the back buffer:
+
+	// The letterbox for the output destination.
+	// If stereo modes needs different dimensions then that needs to be added to FGLRenderer::SetOutputViewport.
+	const auto &box = GLRenderer->mOutputLetterbox;
+
+	GLRenderer->mBuffers->BindOutputFB();
+	glClearColor(0.0, 0.0, 0.0, 1.0);
+	glClear(GL_COLOR_BUFFER_BIT);
+	for (int eye_ix = 0; eye_ix < eye_count(); ++eye_ix)
+	{
+		GLRenderer->mBuffers->BindEyeFB(eye_ix, true);
+		int width = GLRenderer->mBuffers->GetWidth();
+		int height = GLRenderer->mBuffers->GetHeight();
+		glBlitFramebuffer(0, 0, width, height, box.left + eye_ix * box.width / eye_count(), box.top, box.left + (eye_ix + 1) * box.width / eye_count(), box.height, GL_COLOR_BUFFER_BIT, GL_LINEAR);
+	}
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+}
+
 // Avoid static initialization order fiasco by declaring first Mode type (Mono) here in the
 // same source file as Stereo3DMode::getCurrentMode()
 // https://isocpp.org/wiki/faq/ctors#static-init-order

src/gl/stereo3d/gl_stereo3d.h

@@ -85,6 +85,9 @@ public:
 	virtual void SetUp() const {};
 	virtual void TearDown() const {};
 
+	virtual bool IsMono() const { return false; }
+	virtual void Present() const;
+
 protected:
 	TArray<const EyePose *> eye_ptrs;
 
@@ -102,6 +105,8 @@ class MonoView : public Stereo3DMode
 public:
 	static const MonoView& getInstance();
 
+	bool IsMono() const override { return true; }
+
 protected:
 	MonoView() { eye_ptrs.Push(&centralEye); }
 	EyePose centralEye;