Vassilii KHACHATUROV: rain fix, cleanup, read formerly hard-coded values

                      from provided node

"* minor redundant gl call in DrawCone2 optimized away (twice per frame)
* corrected the glRotatef() order in drawRain even further (a less
obvious mistake than before, which is noticed by looking skywards and wiggling
the mouse in the view direction change mode)
* all the "magic numbers" used in the rain rendering code have been
provided a default (based on the old hardcoded value) in a form of a
define, and a meaningfully named static member in SGEnviro"

diff --git a/simgear/environment/visual_enviro.cxx b/simgear/environment/visual_enviro.cxx
index 1c265f7f1fde3fba4a0d9bc36fea5b730208dc50..d3888f5c50b880c52e85a37b123773e66f75958f 100644 (file)
--- a/simgear/environment/visual_enviro.cxx
+++ b/simgear/environment/visual_enviro.cxx
@@ -34,6 +34,7 @@
 #include <simgear/sound/soundmgr_openal.hxx>
 #include <simgear/scene/sky/cloudfield.hxx>
 #include <simgear/scene/sky/newcloud.hxx>
+#include <simgear/props/props.hxx>
 #include "visual_enviro.hxx"
 
 #include <vector>
@@ -51,6 +52,85 @@ typedef struct {
 static float rainpos[MAX_RAIN_SLICE];
 #define MAX_LT_TREE_SEG        400
 
+#define DFL_MIN_LIGHT 0.35
+sgVec3 SGEnviro::min_light = {DFL_MIN_LIGHT, DFL_MIN_LIGHT, DFL_MIN_LIGHT};
+#define DFL_STREAK_BRIGHT_NEARMOST_LAYER 0.9
+SGfloat SGEnviro::streak_bright_nearmost_layer = DFL_STREAK_BRIGHT_NEARMOST_LAYER;
+#define DFL_STREAK_BRIGHT_FARMOST_LAYER 0.5
+SGfloat SGEnviro::streak_bright_farmost_layer = DFL_STREAK_BRIGHT_FARMOST_LAYER;
+#define DFL_STREAK_PERIOD_MAX 2.5
+SGfloat SGEnviro::streak_period_max = DFL_STREAK_PERIOD_MAX;
+#define DFL_STREAK_PERIOD_CHANGE_PER_KT 0.005
+SGfloat SGEnviro::streak_period_change_per_kt = DFL_STREAK_PERIOD_CHANGE_PER_KT;
+#define DFL_STREAK_PERIOD_MIN 1.0
+SGfloat SGEnviro::streak_period_min = DFL_STREAK_PERIOD_MIN;
+#define DFL_STREAK_LENGTH_MIN 0.03
+SGfloat SGEnviro::streak_length_min = DFL_STREAK_LENGTH_MIN;
+#define DFL_STREAK_LENGTH_CHANGE_PER_KT 0.0005
+SGfloat SGEnviro::streak_length_change_per_kt = DFL_STREAK_LENGTH_CHANGE_PER_KT;
+#define DFL_STREAK_LENGTH_MAX 0.1
+SGfloat SGEnviro::streak_length_max = DFL_STREAK_LENGTH_MAX;
+#define DFL_STREAK_COUNT_MIN 40
+int SGEnviro::streak_count_min = DFL_STREAK_COUNT_MIN;
+#define DFL_STREAK_COUNT_MAX 190
+#if (DFL_STREAK_COUNT_MAX > MAX_RAIN_SLICE)
+#error "Bad default!"
+#endif
+int SGEnviro::streak_count_max = DFL_STREAK_COUNT_MAX;
+#define DFL_CONE_BASE_RADIUS 15.0
+SGfloat SGEnviro::cone_base_radius = DFL_CONE_BASE_RADIUS;
+#define DFL_CONE_HEIGHT 30.0
+SGfloat SGEnviro::cone_height = DFL_CONE_HEIGHT;
+
+
+void SGEnviro::config(const SGPropertyNode* n)
+{
+       if (!n)
+               return;
+
+       const float ml = n->getFloatValue("min-light", DFL_MIN_LIGHT);
+       sgSetVec3(min_light, ml, ml, ml);
+
+       streak_bright_nearmost_layer = n->getFloatValue(
+                       "streak-brightness-nearmost-layer",
+                       DFL_STREAK_BRIGHT_NEARMOST_LAYER);
+       streak_bright_farmost_layer = n->getFloatValue(
+                       "streak-brightness-farmost-layer",
+                       DFL_STREAK_BRIGHT_FARMOST_LAYER);
+
+       streak_period_max = n->getFloatValue(
+                       "streak-period-max",
+                       DFL_STREAK_PERIOD_MAX);
+       streak_period_min = n->getFloatValue(
+                       "streak-period-min",
+                       DFL_STREAK_PERIOD_MIN);
+       streak_period_change_per_kt = n->getFloatValue(
+                       "streak-period-change-per-kt",
+                       DFL_STREAK_PERIOD_CHANGE_PER_KT);
+
+       streak_length_max = n->getFloatValue(
+                       "streak-length-max",
+                       DFL_STREAK_LENGTH_MAX);
+       streak_length_min = n->getFloatValue(
+                       "streak-length-min",
+                       DFL_STREAK_LENGTH_MIN);
+       streak_length_change_per_kt = n->getFloatValue(
+                       "streak-length-change-per-kt",
+                       DFL_STREAK_LENGTH_CHANGE_PER_KT);
+
+       streak_count_min = n->getIntValue(
+                       "streak-count-min", DFL_STREAK_COUNT_MIN);
+       streak_count_max = n->getIntValue(
+                       "streak-count-max", DFL_STREAK_COUNT_MAX);
+       if (streak_count_max > MAX_RAIN_SLICE)
+               streak_count_max = MAX_RAIN_SLICE;
+
+       cone_base_radius = n->getFloatValue(
+                       "cone-base-radius", DFL_CONE_BASE_RADIUS);
+       cone_height = n->getFloatValue("cone_height", DFL_CONE_HEIGHT);
+}
+
+
 /**
  * A class to render lightnings.
  */
@@ -362,24 +442,24 @@ list_of_SGWxRadarEcho *SGEnviro::get_radar_echo(void) {
 // precipitation rendering code
 void SGEnviro::DrawCone2(float baseRadius, float height, int slices, bool down, double rain_norm, double speed) {
        sgVec3 light;
-       sgVec3 min_light = {0.35, 0.35, 0.35};
        sgAddVec3( light, fog_color, min_light );
        float da = SG_PI * 2.0f / (float) slices;
        // low number = faster
-       float speedf = 2.5f - speed / 200.0;
-       if( speedf < 1.0f )
-               speedf = 1.0f;
-       float lenf = 0.03f + speed / 2000.0;
-       if( lenf > 0.10f )
-               lenf = 0.10f;
+       float speedf = streak_period_max - speed * streak_period_change_per_kt;
+       if( speedf < streak_period_min )
+               speedf = streak_period_min;
+       float lenf = streak_length_min + speed * streak_length_change_per_kt;
+       if( lenf > streak_length_max )
+               lenf = streak_length_max;
     float t = fmod((float) elapsed_time, speedf) / speedf;
 //     t = 0.1f;
        if( !down )
                t = 1.0f - t;
        float angle = 0.0f;
-       glColor4f(1.0f, 0.7f, 0.7f, 0.9f);
+       //glColor4f(1.0f, 0.7f, 0.7f, 0.9f); // XXX unneeded? overriden below
        glBegin(GL_LINES);
-       int rainpos_indice = 0;
+       if (slices >  MAX_RAIN_SLICE)
+               slices = MAX_RAIN_SLICE; // should never happen
        for( int i = 0 ; i < slices ; i++ ) {
                float x = cos(angle) * baseRadius;
                float y = sin(angle) * baseRadius;
@@ -387,12 +467,14 @@ void SGEnviro::DrawCone2(float baseRadius, float height, int slices, bool down,
                sgVec3 dir = {x, -height, y};
 
                // rain drops at 2 different speed to simulate depth
-               float t1 = (i & 1 ? t : t + t) + rainpos[rainpos_indice];
+               float t1 = (i & 1 ? t : t + t) + rainpos[i];
                if(t1 > 1.0f)   t1 -= 1.0f;
                if(t1 > 1.0f)   t1 -= 1.0f;
 
                // distant raindrops are more transparent
-               float c = (i & 1 ? t1 * 0.5f : t1 * 0.9f);
+               float c = t1 * (i & 1 ?
+                               streak_bright_farmost_layer
+                               : streak_bright_nearmost_layer);
                glColor4f(c * light[0], c * light[1], c * light[2], c);
                sgVec3 p1, p2;
                sgScaleVec3(p1, dir, t1);
@@ -402,8 +484,6 @@ void SGEnviro::DrawCone2(float baseRadius, float height, int slices, bool down,
 
                glVertex3f(p1[0], p1[1] + height, p1[2]);
                glVertex3f(p2[0], p2[1] + height, p2[2]);
-               if( ++rainpos_indice >= MAX_RAIN_SLICE )
-                       rainpos_indice = 0;
        }
        glEnd();
 }
@@ -414,13 +494,13 @@ void SGEnviro::drawRain(double pitch, double roll, double heading, double hspeed
        static int debug_period = 0;
        if (debug_period++ == 50) {
                debug_period = 0;
-               cout << "drawRain(" 
-                       << pitch << ", " 
-                       << roll  << ", " 
-                       << heading << ", " 
-                       << hspeed << ", " 
+               cout << "drawRain("
+                       << pitch << ", "
+                       << roll  << ", "
+                       << heading << ", "
+                       << hspeed << ", "
                        << rain_norm << ");"
-                       //" angle = " << angle 
+                       //" angle = " << angle
                        //<< " raindrop(KTS) = " << raindrop_speed_kts
                        << endl;
        }
@@ -437,14 +517,15 @@ void SGEnviro::drawRain(double pitch, double roll, double heading, double hspeed
        glDisable(GL_LIGHTING);
 
        int slice_count = static_cast<int>(
-                               (40.0 + rain_norm*150.0)* precipitation_density / 100.0);
+                       (streak_count_min + rain_norm*(streak_count_max-streak_count_min))
+                               * precipitation_density / 100.0);
 
        // www.wonderquest.com/falling-raindrops.htm says that
        // Raindrop terminal velocity is 5 to 20mph
        // Rather than model it accurately (temp, pressure, diameter), and make it
        // smaller than terminal when closer to the precipitation cloud base,
        // we interpolate in the 5-20mph range according to rain_norm.
-       double raindrop_speed_kts 
+       double raindrop_speed_kts
                = (5.0 + rain_norm*15.0) * SG_MPH_TO_MPS * SG_MPS_TO_KT;
 
        float angle = atanf(hspeed / raindrop_speed_kts) * SG_RADIANS_TO_DEGREES;
@@ -456,10 +537,12 @@ void SGEnviro::drawRain(double pitch, double roll, double heading, double hspeed
                glRotatef(angle, 1.0, 0.0, 0.0);
 
                // up cone
-               DrawCone2(15.0, 30.0, slice_count, true, rain_norm, hspeed);
+               DrawCone2(cone_base_radius, cone_height, 
+                               slice_count, true, rain_norm, hspeed);
                // down cone (usually not visible)
                if(angle > 0.0 || heading != 0.0)
-                       DrawCone2(15.0, -30.0, slice_count, false, rain_norm, hspeed);
+                       DrawCone2(cone_base_radius, -cone_height, 
+                                       slice_count, false, rain_norm, hspeed);
 
        glPopMatrix();
 

diff --git a/simgear/environment/visual_enviro.hxx b/simgear/environment/visual_enviro.hxx
index cdb4655a81131e442830d6038b32903b717c1e8f..1c901b098734cb9005cd78ac70264463c75b2934 100644 (file)
--- a/simgear/environment/visual_enviro.hxx
+++ b/simgear/environment/visual_enviro.hxx
@@ -90,11 +90,31 @@ private:
 
        /** a list of all the radar echo. */
        list_of_SGWxRadarEcho radarEcho;
+       static sgVec3 min_light;
+       static SGfloat streak_bright_nearmost_layer,
+                                  streak_bright_farmost_layer,
+                                  streak_period_max,
+                                  streak_period_change_per_kt,
+                                  streak_period_min,
+                                  streak_length_min,
+                                  streak_length_change_per_kt,
+                                  streak_length_max;
+       static int streak_count_min, streak_count_max;
+       static SGfloat cone_base_radius,
+                                  cone_height;
 
 public:
        SGEnviro();
        ~SGEnviro();
 
+       /** Read the config from the precipitation rendering config properties.
+        * @param precip_rendering_cfgNode "/sim/rendering/precipitation" in fg
+        * Set from whatever info present in the
+        * subnodes passed, substituting hardwired defaults for missing fields.
+        * If NULL is given, do nothing.
+        */
+       void config(const class SGPropertyNode* precip_rendering_cfgNode);
+
     /**
      * Forward a few states used for renderings.
      */