From 04c5f2c36a98399da797ea9fa7c2a58bb5bc4e9b Mon Sep 17 00:00:00 2001
From: ehofman <ehofman>
Date: Tue, 24 May 2005 08:13:09 +0000
Subject: [PATCH] Melchior FRANZ:

Turn the material animation's <transparency> property into a group, with
members <alpha-prop>/<alpha>, <offset-prop>/<offset>, <factor-prop>/<factor>,
<min>, and <max>. The "material" animation can now fully replace "blend" and
"alpha-test" (--> <threshold>) animations, with enhanced possibilities:
The "material" animation can be used for one or more explicit objects (like
"blend"), but also for all objects that share one material (<global>), which
avoids problems with objects being forced together into one tree. Also, an
object doesn't have to be semitransparent or textured with a semitransparent
texture to make blending work. Unlike the "blend" animation, the "material"
animation also makes fully opaque and untextured objects transparent. (This
fixes the bo105's formerly semi-transparent rotor.)

Erik:
The blend animation and alpha-test animation are depreciated as of now.
---
 simgear/scene/model/animation.cxx | 41 +++++++++++++++++++++++--------
 simgear/scene/model/animation.hxx | 18 ++++++++++++--
 2 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/simgear/scene/model/animation.cxx b/simgear/scene/model/animation.cxx
index cf18f9b6..f1b06acc 100644
--- a/simgear/scene/model/animation.cxx
+++ b/simgear/scene/model/animation.cxx
@@ -1146,9 +1146,25 @@ SGMaterialAnimation::SGMaterialAnimation( SGPropertyNode *prop_root,
     if (_shi >= 0.0)
         _update |= SHININESS;
 
-    _trans = props->getFloatValue("transparency", -1.0);
-    if (_trans >= 0.0)
-        _update |= TRANSPARENCY;
+    SGPropertyNode_ptr group = props->getChild("transparency");
+    if (group) {
+        _trans.value = group->getFloatValue("alpha", -1.0);
+        _trans.factor = group->getFloatValue("factor", 1.0);
+        _trans.offset = group->getFloatValue("offset", 0.0);
+        _trans.min = group->getFloatValue("min", 0.0);
+        _trans.max = group->getFloatValue("max", 1.0);
+        if (_trans.dirty())
+            _update |= TRANSPARENCY;
+
+        n = group->getChild("alpha-prop");
+        _trans.value_prop = n ? _prop_root->getNode(path(n->getStringValue()), true) : 0;
+        n = group->getChild("factor-prop");
+        _trans.factor_prop = n ? _prop_root->getNode(path(n->getStringValue()), true) : 0;
+        n = group->getChild("offset-prop");
+        _trans.offset_prop = n ? _prop_root->getNode(path(n->getStringValue()), true) : 0;
+        if (_trans.live())
+            _read |= TRANSPARENCY;
+    }
 
     _thresh = props->getFloatValue("threshold", -1.0);
     if (_thresh >= 0.0)
@@ -1163,8 +1179,6 @@ SGMaterialAnimation::SGMaterialAnimation( SGPropertyNode *prop_root,
 
     n = props->getChild("shininess-prop");
     _shi_prop = n ? _prop_root->getNode(path(n->getStringValue()), true) : 0;
-    n = props->getChild("transparency-prop");
-    _trans_prop = n ? _prop_root->getNode(path(n->getStringValue()), true) : 0;
     n = props->getChild("threshold-prop");
     _thresh_prop = n ? _prop_root->getNode(path(n->getStringValue()), true) : 0;
     n = props->getChild("texture-prop");
@@ -1226,10 +1240,15 @@ int SGMaterialAnimation::update()
         if (_shi != f)
             _update |= SHININESS;
     }
-    if (_trans_prop) {
-        f = _trans;
-        _trans = _trans_prop->getFloatValue();
-        if (_trans != f)
+    if (_read & TRANSPARENCY) {
+        PropSpec tmp = _trans;
+        if (_trans.value_prop)
+            _trans.value = _trans.value_prop->getFloatValue();
+        if (_trans.factor_prop)
+            _trans.factor = _trans.factor_prop->getFloatValue();
+        if (_trans.offset_prop)
+            _trans.offset = _trans.offset_prop->getFloatValue();
+        if (_trans != tmp)
             _update |= TRANSPARENCY;
     }
     if (_thresh_prop) {
@@ -1319,7 +1338,9 @@ void SGMaterialAnimation::setMaterialBranch(ssgBranch *b)
         s->setShininess(clamp(_shi, 0.0, 128.0));
     if (_update & TRANSPARENCY) {
         SGfloat *v = s->getMaterial(GL_DIFFUSE);
-        s->setMaterial(GL_DIFFUSE, v[0], v[1], v[2], 1.0 - clamp(_trans));
+        float trans = _trans.value * _trans.factor + _trans.offset;
+        trans = trans < _trans.min ? _trans.min : trans > _trans.max ? _trans.max : trans;
+        s->setMaterial(GL_DIFFUSE, v[0], v[1], v[2], trans);
     }
     if (_update & THRESHOLD)
         s->setAlphaClamp(clamp(_thresh));
diff --git a/simgear/scene/model/animation.hxx b/simgear/scene/model/animation.hxx
index 491d8bd9..fd7ec8c5 100644
--- a/simgear/scene/model/animation.hxx
+++ b/simgear/scene/model/animation.hxx
@@ -488,6 +488,21 @@ private:
             return val < 0.0 ? 0.0 : val > 1.0 ? 1.0 : val;
         }
     };
+    struct PropSpec {
+        float value;
+        float factor;
+        float offset;
+        float min;
+	float max;
+        SGPropertyNode_ptr value_prop;
+        SGPropertyNode_ptr factor_prop;
+        SGPropertyNode_ptr offset_prop;
+        inline bool dirty() { return value >= 0.0; }
+        inline bool live() { return value_prop || factor_prop || offset_prop; }
+        inline bool operator!=(PropSpec& a) {
+            return value != a.value || factor != a.factor || offset != a.offset;
+        }
+    };
     SGCondition *_condition;
     SGPropertyNode *_prop_root;
     string _prop_base;
@@ -504,12 +519,11 @@ private:
     ColorSpec _emis;
     ColorSpec _spec;
     float _shi;
-    float _trans;
+    PropSpec _trans;
     float _thresh;	// alpha_clamp (see man glAlphaFunc)
     string _tex;
     string _tmpstr;
     SGPropertyNode_ptr _shi_prop;
-    SGPropertyNode_ptr _trans_prop;
     SGPropertyNode_ptr _thresh_prop;
     SGPropertyNode_ptr _tex_prop;
 
-- 
2.39.5