From: Erik Hofman <erik@ehofman.com>
Date: Wed, 26 Aug 2015 10:16:56 +0000 (+0200)
Subject: Thorsten Renk:
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=2910c6a77bd0870bcadc16b4e037ad540152b06e;p=simgear.git

Thorsten Renk:
Add a 4th layer to the sun (next to disc, inner halo and outer halo). While the inner/outer halos change with atmosphere conditions, the new layer is supposed to represent the effect of blinding brilliance - ideally it adds a suitable ray structure to the sun. The effect is most prominent in space (where I'm most keen on seeing it admittedly) because there all atmospheric halo effects are absent and we end with a really unrealistic white disc.

Some screenshots and discussion there

http://forum.flightgear.org/viewtopic.php?f=47&t=27216
---

diff --git a/simgear/scene/sky/oursun.cxx b/simgear/scene/sky/oursun.cxx
index f4b049ee..be78ca6c 100644
--- a/simgear/scene/sky/oursun.cxx
+++ b/simgear/scene/sky/oursun.cxx
@@ -216,6 +216,46 @@ SGSun::build( SGPath path, double sun_size, SGPropertyNode *property_tree_Node )
 
     sun_transform->addChild( geode );
 
+
+    // set up the brilliance state
+
+    geode = new osg::Geode;
+    stateSet = geode->getOrCreateStateSet();
+    stateSet->setRenderBinDetails(-9, "RenderBin");
+
+
+    texture = SGLoadTexture2D("brilliance.png", options.get());
+    stateSet->setTextureAttributeAndModes(0, texture);
+
+
+    // Build ssg structure
+    brilliance_cl = new osg::Vec4Array;
+    brilliance_cl->push_back(osg::Vec4(1, 1, 1, 1));
+
+    double brilliance_size = sun_size * 12.0;
+    osg::Vec3Array* brilliance_vl = new osg::Vec3Array;
+    brilliance_vl->push_back(osg::Vec3(-brilliance_size, 0, -brilliance_size));
+    brilliance_vl->push_back(osg::Vec3(brilliance_size, 0, -brilliance_size));
+    brilliance_vl->push_back(osg::Vec3(-brilliance_size, 0, brilliance_size));
+    brilliance_vl->push_back(osg::Vec3(brilliance_size, 0, brilliance_size));
+
+    osg::Vec2Array* brilliance_tl = new osg::Vec2Array;
+    brilliance_tl->push_back(osg::Vec2(0, 0));
+    brilliance_tl->push_back(osg::Vec2(1, 0));
+    brilliance_tl->push_back(osg::Vec2(0, 1));
+    brilliance_tl->push_back(osg::Vec2(1, 1));
+
+    geometry = new osg::Geometry;
+    geometry->setUseDisplayList(false);
+    geometry->setVertexArray(brilliance_vl);
+    geometry->setColorArray(brilliance_cl.get(), osg::Array::BIND_OVERALL);
+    geometry->setNormalBinding(osg::Geometry::BIND_OFF);
+    geometry->setTexCoordArray(0, brilliance_tl, osg::Array::BIND_PER_VERTEX);
+    geometry->addPrimitiveSet(new osg::DrawArrays(GL_TRIANGLE_STRIP, 0, 4));
+    geode->addDrawable(geometry);
+
+    sun_transform->addChild( geode );
+
     // force a repaint of the sun colors with arbitrary defaults
     repaint( 0.0, 1.0 );
 
@@ -262,7 +302,7 @@ bool SGSun::repaint( double sun_angle, double new_visibility ) {
         }
 
         // ok, now let's go and generate the sun and scene color
-        osg::Vec4 i_halo_color, o_halo_color, scene_color, sun_color;
+        osg::Vec4 i_halo_color, o_halo_color, scene_color, sun_color, brilliance_color;
 
         // Some comments:
         // * When the sunangle changes, light has to travel a longer
@@ -336,16 +376,29 @@ bool SGSun::repaint( double sun_angle, double new_visibility ) {
         if (o_halo_color[3] > 1) o_halo_color[3] = 1;
         if (o_halo_color[3] < 0) o_halo_color[3] = 0;
 
+	brilliance_color[0] = i_halo_color[0];
+	brilliance_color[1] = i_halo_color[1];
+	brilliance_color[2] = i_halo_color[2];
+
+	double norm = (i_halo_color[0] * i_halo_color[0] + i_halo_color[1] * i_halo_color[1] + i_halo_color[2] * i_halo_color[2])/1.732;
+
+	brilliance_color[3] = pow(norm, 6.0);
+	if (brilliance_color[3] < 0.0) {brilliance_color[3] = 0.0;}
+	
+
+
         gamma_correct_rgb( i_halo_color._v );
         gamma_correct_rgb( o_halo_color._v );
         gamma_correct_rgb( scene_color._v );
         gamma_correct_rgb( sun_color._v );
+        gamma_correct_rgb( brilliance_color._v );
 
 	if (sun_angle >91.0 * 3.1415/180.0 + horizon_angle)
 		{
 		sun_color[3] = 0;
 		o_halo_color[3]=0;
 		i_halo_color[3]=0;
+		brilliance_color[3]=0;
 		}
 
         (*sun_cl)[0] = sun_color;
@@ -356,6 +409,8 @@ bool SGSun::repaint( double sun_angle, double new_visibility ) {
         ihalo_cl->dirty();
         (*ohalo_cl)[0] = o_halo_color;
         ohalo_cl->dirty();
+	(*brilliance_cl)[0] = brilliance_color;
+        brilliance_cl->dirty();
     }
 
     return true;
diff --git a/simgear/scene/sky/oursun.hxx b/simgear/scene/sky/oursun.hxx
index bd1f3db1..e1e2b75c 100644
--- a/simgear/scene/sky/oursun.hxx
+++ b/simgear/scene/sky/oursun.hxx
@@ -45,6 +45,7 @@ class SGSun : public SGReferenced {
     osg::ref_ptr<osg::Vec4Array> scene_cl;
     osg::ref_ptr<osg::Vec4Array> ihalo_cl;
     osg::ref_ptr<osg::Vec4Array> ohalo_cl;
+    osg::ref_ptr<osg::Vec4Array> brilliance_cl;
 
     double visibility;
     double prev_sun_angle;