From a204b2fbd9b9efc8ae5a65c1fc3abdf1a3042849 Mon Sep 17 00:00:00 2001
From: SmileTheory <SmileTheory@gmail.com>
Date: Mon, 16 Sep 2013 23:20:44 -0700
Subject: OpenGL2: Speed up fog shader slightly.

---
 src/renderergl2/glsl/fogpass_vp.glsl | 17 +++++++----------
 src/renderergl2/glsl/generic_vp.glsl | 15 ++++++---------
 2 files changed, 13 insertions(+), 19 deletions(-)

(limited to 'src/renderergl2')

diff --git a/src/renderergl2/glsl/fogpass_vp.glsl b/src/renderergl2/glsl/fogpass_vp.glsl
index f18bc707..40d14d9f 100644
--- a/src/renderergl2/glsl/fogpass_vp.glsl
+++ b/src/renderergl2/glsl/fogpass_vp.glsl
@@ -85,16 +85,13 @@ float CalcFog(vec4 position)
 	float s = dot(position, u_FogDistance) * 8.0;
 	float t = dot(position, u_FogDepth);
 
-	if (t < 1.0)
-	{
-		t = step(step(0.0, -u_FogEyeT), t);
-	}
-	else
-	{
-		t /= t - min(u_FogEyeT, 0.0);
-	}
-	
-	return s * t;
+	bool eyeOutside = u_FogEyeT < 0.0;
+	float t2 = float(t >= float(eyeOutside));
+
+	if (eyeOutside)
+		t2 *= t / (t - u_FogEyeT);
+
+	return s * t2;
 }
 
 void main()
diff --git a/src/renderergl2/glsl/generic_vp.glsl b/src/renderergl2/glsl/generic_vp.glsl
index 67360b1b..9ad4489b 100644
--- a/src/renderergl2/glsl/generic_vp.glsl
+++ b/src/renderergl2/glsl/generic_vp.glsl
@@ -194,16 +194,13 @@ float CalcFog(vec4 position)
 	float s = dot(position, u_FogDistance) * 8.0;
 	float t = dot(position, u_FogDepth);
 
-	if (t < 1.0)
-	{
-		t = step(step(0.0, -u_FogEyeT), t);
-	}
-	else
-	{
-		t /= t - min(u_FogEyeT, 0.0);
-	}
+	bool eyeOutside = u_FogEyeT < 0.0;
+	float t2 = float(t >= float(eyeOutside));
+
+	if (eyeOutside)
+		t2 *= t / (t - u_FogEyeT);
 
-	return s * t;
+	return s * t2;
 }
 #endif
 
-- 
cgit