From efce88ff12164e34cefdc9761e692bcf5beec2cf Mon Sep 17 00:00:00 2001
From: curt <curt>
Date: Tue, 11 Jan 2005 16:02:39 +0000
Subject: [PATCH] - Fix a couple oops's in cloud.cxx - In sky.cxx blend low
 density cloud layers (few/scattered) into nothing (but   don't touch
 visibility distance) as we approach them so we can fly through   clean. - For
 high density cloud layers (broken/overcast) we do not fade the layers   out,
 but we fade visibility to nearly nothing as we approach the layer.

---
 simgear/scene/sky/cloud.cxx | 18 +++++++++---------
 simgear/scene/sky/sky.cxx   | 37 +++++++++++++++++++++++++++----------
 2 files changed, 36 insertions(+), 19 deletions(-)

diff --git a/simgear/scene/sky/cloud.cxx b/simgear/scene/sky/cloud.cxx
index d567f729..24b03e96 100644
--- a/simgear/scene/sky/cloud.cxx
+++ b/simgear/scene/sky/cloud.cxx
@@ -633,25 +633,25 @@ bool SGCloudLayer::repaint( sgVec3 fog_color ) {
         for ( int i = 0; i < 4; i++ ) {
             color = cl[i]->get( 0 );
             sgCopyVec3( color, fog_color );
-            color[3] = (i == 0) ? 0.0f : 0.15f;
+            color[3] = (i == 0) ? 0.0f : cloud_alpha * 0.15f;
 
             for ( int j = 0; j < 4; ++j ) {
-                color = cl[i]->get( (2*j) );
-                sgCopyVec3( color, fog_color );
-                color[3] = 
-                    ((j == 0) || (i == 3)) ?
-                    ((j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f;
-
                 color = cl[i]->get( (2*j) + 1 );
                 sgCopyVec3( color, fog_color );
+                color[3] = 
+                    ((j == 0) || (i == 3)) ?
+                    ((j == 0) && (i == 3)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
+
+                color = cl[i]->get( (2*j) + 2 );
+                sgCopyVec3( color, fog_color );
                 color[3] = 
                     ((j == 3) || (i == 0)) ?
-                    ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f;
+                    ((j == 3) && (i == 0)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
             }
 
             color = cl[i]->get( 9 );
             sgCopyVec3( color, fog_color );
-            color[3] = (i == 3) ? 0.0f : 0.15f;
+            color[3] = (i == 3) ? 0.0f : cloud_alpha * 0.15f;
         }
     }
 
diff --git a/simgear/scene/sky/sky.cxx b/simgear/scene/sky/sky.cxx
index ae1a2c0a..53ff7314 100644
--- a/simgear/scene/sky/sky.cxx
+++ b/simgear/scene/sky/sky.cxx
@@ -266,10 +266,7 @@ void SGSky::modify_vis( float alt, float time_factor ) {
 
 	double ratio = 1.0;
 
-        if ( cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_CLEAR ||
-             cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_FEW ||
-             cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_SCATTERED)
-        {
+        if ( cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_CLEAR ) {
 	    // less than 50% coverage -- assume we're in the clear for now
 	    ratio = 1.0;
         } else if ( alt < asl - transition ) {
@@ -289,13 +286,33 @@ void SGSky::modify_vis( float alt, float time_factor ) {
 	    ratio = 1.0;
 	}
 
-        // set the alpha fade value for the cloud layer
-        float temp = ratio * 2.0;
-        if ( temp > 1.0 ) { temp = 1.0; }
-        cloud_layers[i]->setAlpha( temp );
+        if ( cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_CLEAR ) {
+            // do nothing, clear layers aren't drawn, don't affect
+            // visibility andn dont' need to be faded in or out.
+        } else if ( (cloud_layers[i]->getCoverage() == 
+                     SGCloudLayer::SG_CLOUD_FEW)
+                    || (cloud_layers[i]->getCoverage() ==
+                        SGCloudLayer::SG_CLOUD_SCATTERED) )
+        {
+            // set the alpha fade value for the cloud layer.  For less
+            // dense cloud layers we fade the layer to nothing as we
+            // approach it because we stay clear visibility-wise as we
+            // pass through it.
+            float temp = ratio * 2.0;
+            if ( temp > 1.0 ) { temp = 1.0; }
+            cloud_layers[i]->setAlpha( temp );
 
-	// accumulate effects from multiple cloud layers
-	effvis *= ratio;
+            // don't touch visibility
+        } else {
+            // maintain full alpha for denser cloud layer types.
+            // Let's set the value explicitly in case someone changed
+            // the layer type.
+            cloud_layers[i]->setAlpha( 1.0 );
+
+            // lower visibility as we approach the cloud layer.
+            // accumulate effects from multiple cloud layers
+            effvis *= ratio;
+        }
 
 #if 0
 	if ( ratio < 1.0 ) {