Improvements to flame effect

Effects/thrust-flame.eff

@@ -7,19 +7,29 @@
     <texture n="0">
       	<type>white</type>
     </texture>
-    <thrust_collimation>0.1</thrust_collimation>
-    <thrust_density>0.5</thrust_density>
-    <shock_frequency>0.5</shock_frequency>
-    <noise_strength>0.2</noise_strength>
-    <noise_scale>0.1</noise_scale>
+
+    <thrust_collimation type="float">0.1</thrust_collimation>
+    <thrust_density type="float">0.5</thrust_density>
+    <base_flame_density type="float">1.0</base_flame_density>
+    <shock_frequency type="float">0.5</shock_frequency>
+    <noise_strength type="float">0.2</noise_strength>
+    <noise_scale type="float">0.1</noise_scale>
     <flame_color_low_r type="float">0.95</flame_color_low_r>
     <flame_color_low_g type="float">0.55</flame_color_low_g>
     <flame_color_low_b type="float">0.0</flame_color_low_b>
     <flame_color_high_r type="float">1.0</flame_color_high_r>
     <flame_color_high_g type="float">0.8</flame_color_high_g>
     <flame_color_high_b type="float">0.3</flame_color_high_b>
+    <base_flame_r type="float">1.0</base_flame_r>
+    <base_flame_g type="float">0.8</base_flame_g>
+    <base_flame_b type="float">0.3</base_flame_b>
     <use_shocks type="int">1</use_shocks>
     <use_noise type="int">1</use_noise>
+    <visibility><use>/environment/ground-visibility-m</use></visibility>
+    <avisibility><use>/environment/visibility-m</use></avisibility>
+    <lthickness><use>/environment/ground-haze-thickness-m</use></lthickness>
+    <terrain_alt><use>/environment/mean-terrain-elevation-m</use></terrain_alt>
+    <eye_alt><use>/sim/rendering/eye-altitude-m</use></eye_alt>
 </parameters>
 
 <technique n="4">
@@ -95,6 +105,11 @@
         <type>float</type>
         <value><use>thrust_density</use></value>
       </uniform>
+      <uniform>
+        <name>base_flame_density</name>
+        <type>float</type>
+        <value><use>base_flame_density</use></value>
+      </uniform>
       <uniform>
         <name>shock_frequency</name>
         <type>float</type>
@@ -140,6 +155,21 @@
         <type>float</type>
         <value><use>flame_color_high_b</use></value>
       </uniform>
+      <uniform>
+        <name>base_flame_r</name>
+        <type>float</type>
+        <value><use>base_flame_r</use></value>
+      </uniform>
+      <uniform>
+        <name>base_flame_g</name>
+        <type>float</type>
+        <value><use>base_flame_g</use></value>
+      </uniform>
+      <uniform>
+        <name>base_flame_b</name>
+        <type>float</type>
+        <value><use>base_flame_b</use></value>
+      </uniform>
      
 
       <uniform>

Shaders/thrustflame-ALS.frag

@@ -1,5 +1,6 @@
 // -*-C++-*-
 
+#version 120
 
 varying vec3 vertex;
 varying vec3 viewDir;
@@ -7,6 +8,7 @@ varying vec3 viewDir;
 uniform float osg_SimulationTime;
 uniform float thrust_collimation;
 uniform float thrust_density;
+uniform float base_flame_density;
 uniform float shock_frequency;
 uniform float noise_strength;
 uniform float noise_scale;
@@ -19,56 +21,61 @@ uniform float flame_color_high_r;
 uniform float flame_color_high_g;
 uniform float flame_color_high_b;
 
+uniform float base_flame_r;
+uniform float base_flame_g;
+uniform float base_flame_b;
+
 uniform int use_shocks;
 uniform int use_noise;
 
 float Noise3D(in vec3 coord, in float wavelength);
 float Noise2D(in vec2 coord, in float wavelength);
 
-const int n_steps = 100;
+const int n_steps = 15;
 
 float spherical_smoothstep (in vec3 pos)
 {
 
-float noise = Noise3D(vec3(pos.x - osg_SimulationTime * 5.0 , pos.y, pos.z), 0.3);
+float l = length(vec3 (pos.x/2.0, pos.y,pos.z) );
 
-pos *=4.0;
+return 10.0 * thrust_density * base_flame_density *  (1.0 - smoothstep(0.1, 0.2, l));
 
-pos.x *=0.5;
-float d = length(pos);
-
-
-
-return 3.0 * (1.0 - smoothstep(0.3, 0.7, d)) /float(n_steps)* (0.5 + 0.5 * noise);
 }
 
-float spherical_smoothstep1 (in vec3 pos)
-{
-pos.x *=0.2;
-float d = length(pos);
 
-return 1.0 * (1.0 - smoothstep(0.3, 0.7, d)) /float(n_steps);
-}
 
 float thrust_flame (in vec3 pos)
 {
 
 
 //float noise = Noise3D(vec3(pos.x - osg_SimulationTime * 20.0 , pos.y, pos.z), 0.3);
-float noise = Noise2D(vec2(pos.x - osg_SimulationTime * 30.0 , length(pos.yz)), noise_scale);
+float noise = 0.0;
 
-float d = 1.0 - pos.x/2.5 ;
-float radius = 0.2 + thrust_collimation * 1.4 * pow((pos.x+0.1),0.5);
+float d_rad = length(pos.yz);
+//float longFade = smoothstep(0.0, 5.0, pos.x) ;
+float longFade = pos.x/5.0;
 
-d *= (1.0 - smoothstep(0.125, radius, length(pos.yz))) * (1.0 - noise_strength + noise_strength* noise);
+float density = 1.0 - longFade;
+float radius = 0.2 + thrust_collimation * 1.2 * pow((pos.x+0.1),0.5);
+
+if (d_rad > radius) {return 0.0;}
+
+
+if (use_noise ==1)
+	{
+	noise = Noise2D(vec2(pos.x - osg_SimulationTime * 30.0 , d_rad), noise_scale);
+	}
+
+density *= (1.0 - smoothstep(0.125, radius, d_rad)) * (1.0 - noise_strength + noise_strength* noise);
 
 if (use_shocks == 1)
 	{
-	float shock = sin(pos.x * 20.0 * shock_frequency);
-	d += shock * shock * shock * shock * (1.0 - pos.x/2.5) * (1.0 - smoothstep(0.05, 0.1, length(pos.yz))) *  (1.0 - smoothstep(0.0, 1.0, thrust_collimation));
+	float shock = sin(pos.x * 10.0 * shock_frequency);
+	density += shock * shock * shock * shock * (1.0 - longFade) * (1.0 - smoothstep(0.05, 0.1, d_rad)) *  (1.0 - smoothstep(0.0, 1.0, thrust_collimation));
 	}
 
-return 10.0 * thrust_density *  d / (radius/0.2);
+
+return 10.0 * thrust_density *  density / (radius/0.2);
 }
 
 
@@ -76,14 +83,21 @@ return 10.0 * thrust_density *  d / (radius/0.2);
 void main()
 {
 
-float t_x = 2.0 * abs(vertex.x) / max(viewDir.x, 0.0001);
-float t_y = 2.0 * abs(vertex.y) / max(viewDir.y, 0.0001);
-float t_z = 2.0 * abs(vertex.z) / max(viewDir.z, 0.0001);
+vec3 vDir = normalize(viewDir);
+
+float x_E, y_E, z_E;
+
+if (vDir.x > 0.0) {x_E = 5.0;} else {x_E = 0.0;}
+if (vDir.y > 0.0) {y_E = 1.0;} else {y_E = -1.0;}
+if (vDir.z > 0.0) {z_E = 1.0;} else {z_E = -1.0;}
+
+float t_x = (x_E - vertex.x) / vDir.x;
+float t_y = (y_E - vertex.y) / vDir.y;
+float t_z = (z_E - vertex.z) / vDir.z;
 
 float t_min = min(t_x, t_y);
 t_min = min(t_min, t_z);
 
-t_min = 5.0;
 
 float dt = t_min  / float(n_steps);
 
@@ -98,11 +112,7 @@ float density2 = 0.0;
 for (int i = 0; i < n_steps; i++)
 	{
 	pos = pos + step;
-	if ((pos.x > 5.0) || (pos.x <0.0)) {break;} 
-	if ((pos.y > 1.0) || (pos.y <-1.0)) {break;} 
-	if ((pos.z > 1.0) || (pos.z <-1.0)) {break;} 
-	//density1 += spherical_smoothstep(pos);
-	//density2 += spherical_smoothstep1(pos);
+	density1 += spherical_smoothstep(pos) * dt;
 	density2 += thrust_flame(pos) * dt;
 	}
 
@@ -110,13 +120,18 @@ for (int i = 0; i < n_steps; i++)
 
 
 float density = density1 + density2;
-density = clamp(density,0.0,1.0);
+//density = clamp(density,0.0,1.0);
+density = 1.0 - exp(-density);
+
+density1 = 1.0 - exp(-density1);
+density2 = 1.0 - exp(-density2);
 
 
 vec3 flame_color_low = vec3 (flame_color_low_r, flame_color_low_g, flame_color_low_b);
 vec3 flame_color_high = vec3 (flame_color_high_r, flame_color_high_g, flame_color_high_b);
 
-vec3 color = mix(flame_color_low, flame_color_high, density2+density1);
+vec3 color = mix(flame_color_low, flame_color_high, density2);
+color = mix(color, vec3(0.8, 1.0, 1.0), density1);
 
 vec4 finalColor = vec4 (color.rgb, density);
 

Shaders/thrustflame-ALS.vert

@@ -1,5 +1,7 @@
 // -*-C++-*-
 
+#version 120
+
 varying vec3 vertex;
 varying vec3 viewDir;