From 2152780806c73b8103dc1a07831d876f63bf4bc5 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sat, 19 Oct 2019 18:14:13 +0200
Subject: [PATCH] - added some hackery to render voxels properly again.

Something about their data preparation is not right, their depth looks totally off and causes fog to become to dense.
One more reason to reconstruct the renderer in a sane fashion.
---
 source/build/src/voxmodel.cpp                     |  3 +++
 source/glbackend/glbackend.cpp                    |  5 +++++
 source/glbackend/glbackend.h                      |  1 +
 wadsrc/static/demolition/shaders/glsl/polymost.fp | 10 ++++++----
 4 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/source/build/src/voxmodel.cpp b/source/build/src/voxmodel.cpp
index 2da0859e7..eba530d35 100644
--- a/source/build/src/voxmodel.cpp
+++ b/source/build/src/voxmodel.cpp
@@ -1098,6 +1098,8 @@ int32_t polymost_voxdraw(voxmodel_t *m, tspriteptr_t const tspr)
             GLInterface.EnableBlend(true);  // else GLInterface.EnableBlend(false);
     }
     else pc[3] = 1.f;
+	GLInterface.SetFadeDisable(true); // disable depth fading. The voxel code is somewhat broken and messes this up.
+	GLInterface.SetShade(0, numshades);
     //------------
 
     //transform to Build coords
@@ -1186,6 +1188,7 @@ int32_t polymost_voxdraw(voxmodel_t *m, tspriteptr_t const tspr)
 	}
 	VSMatrix identity(0);
 	GLInterface.SetMatrix(Matrix_ModelView, &identity);
+	GLInterface.SetFadeDisable(false);
 	GLInterface.SetTinting(0, 0, PalEntry(255, 255, 255));
 	return 1;
 }
diff --git a/source/glbackend/glbackend.cpp b/source/glbackend/glbackend.cpp
index 29443b355..da783174c 100644
--- a/source/glbackend/glbackend.cpp
+++ b/source/glbackend/glbackend.cpp
@@ -392,6 +392,11 @@ void GLInstance::SetFadeColor(PalEntry color)
 	renderState.FogColor[2] = color.b * (1 / 255.f);
 };
 
+void GLInstance::SetFadeDisable(bool on)
+{
+	renderState.FogColor[3] = on;
+}
+
 void GLInstance::SetColorMask(bool on)
 {
 	glColorMask(on, on, on, on);
diff --git a/source/glbackend/glbackend.h b/source/glbackend/glbackend.h
index e41c3277a..c9dc3e2b9 100644
--- a/source/glbackend/glbackend.h
+++ b/source/glbackend/glbackend.h
@@ -279,6 +279,7 @@ public:
 
 	void SetDepthFunc(int func);
 	void SetFadeColor(PalEntry color);
+	void SetFadeDisable(bool on);
 	void SetColorMask(bool on);
 	void SetDepthMask(bool on);
 	void SetBlendFunc(int src, int dst);
diff --git a/wadsrc/static/demolition/shaders/glsl/polymost.fp b/wadsrc/static/demolition/shaders/glsl/polymost.fp
index ae4fb1a2d..1259d5f9e 100644
--- a/wadsrc/static/demolition/shaders/glsl/polymost.fp
+++ b/wadsrc/static/demolition/shaders/glsl/polymost.fp
@@ -183,10 +183,12 @@ void main()
 		else
 		{
 			color.rgb *= detailColor.rgb;
-			shade = clamp(shade / (u_numShades-2), 0.0, 1.0);
-			// Apply the shade as a linear depth fade ramp.
-			color.rgb = mix(color.rgb, u_fogColor.rgb, shade);
-
+			if (u_fogColor.a == 0.0)
+			{
+				shade = clamp(shade / (u_numShades-2), 0.0, 1.0);
+				// Apply the shade as a linear depth fade ramp.
+				color.rgb = mix(color.rgb, u_fogColor.rgb, shade);
+			}
 		}
 		if (fullbright == 0.0) color.rgb *= v_color.rgb;
 		color.a *= v_color.a;