From dd971805af003e481b1ef6b789a330e27f7ae223 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sat, 18 Aug 2018 22:29:22 +0200
Subject: [PATCH] - fixed: The viewpoint buffer was mapped write only but read
 from. On old hardware it wasn't even mapped.

Changed to cache the needed value in a CPU-side array so that the buffer access is not needed.
---
 src/gl/data/gl_viewpointbuffer.cpp | 6 ++++--
 src/gl/data/gl_viewpointbuffer.h   | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/gl/data/gl_viewpointbuffer.cpp b/src/gl/data/gl_viewpointbuffer.cpp
index 7b9039bf3a..611db9e407 100644
--- a/src/gl/data/gl_viewpointbuffer.cpp
+++ b/src/gl/data/gl_viewpointbuffer.cpp
@@ -41,6 +41,7 @@ GLViewpointBuffer::GLViewpointBuffer()
 	Allocate();
 	Clear();
 	mLastMappedIndex = UINT_MAX;
+	mClipPlaneInfo.Push(0);
 }
 
 GLViewpointBuffer::~GLViewpointBuffer()
@@ -121,10 +122,9 @@ int GLViewpointBuffer::Bind(unsigned int index)
 		glBindBufferRange(GL_UNIFORM_BUFFER, VIEWPOINT_BINDINGPOINT, mBufferId, index * mBlockAlign, mBlockAlign);
 
 		// Update the viewpoint-related clip plane setting.
-		auto *vp = (HWViewpointUniforms*)(((char*)mBufferPointer) + mUploadIndex * mBlockAlign);
 		if (!(gl.flags & RFL_NO_CLIP_PLANES))
 		{
-			if (index > 0 && (vp->mClipHeightDirection != 0.f || vp->mClipLine.X > -10000000.0f))
+			if (mClipPlaneInfo[index])
 			{
 				glEnable(GL_CLIP_DISTANCE0);
 			}
@@ -162,6 +162,7 @@ int GLViewpointBuffer::SetViewpoint(HWViewpointUniforms *vp)
 	memcpy(((char*)mBufferPointer) + mUploadIndex * mBlockAlign, vp, sizeof(*vp));
 	Unmap();
 
+	mClipPlaneInfo.Push(vp->mClipHeightDirection != 0.f || vp->mClipLine.X > -10000000.0f);
 	return Bind(mUploadIndex++);
 }
 
@@ -169,5 +170,6 @@ void GLViewpointBuffer::Clear()
 {
 	// Index 0 is reserved for the 2D projection.
 	mUploadIndex = 1;
+	mClipPlaneInfo.Resize(1);
 }
 
diff --git a/src/gl/data/gl_viewpointbuffer.h b/src/gl/data/gl_viewpointbuffer.h
index 208a42a5d9..3ec1093df5 100644
--- a/src/gl/data/gl_viewpointbuffer.h
+++ b/src/gl/data/gl_viewpointbuffer.h
@@ -12,6 +12,7 @@ class GLViewpointBuffer
 	unsigned int mLastMappedIndex;
 	unsigned int mByteSize;
 	void * mBufferPointer;
+	TArray<bool> mClipPlaneInfo;
 	
 	unsigned int m2DWidth = ~0u, m2DHeight = ~0u;