Updates to 3D clouds to use the new shading parameters.

Docs/README.3DClouds

@@ -43,8 +43,6 @@ The cloud is defined by the following properties:
 <height-map-texture>  - whether to choose the vertical texture index based on
                         sprite height within the clouds (default false)
 <num-sprites>         - Number of sprite to generate for the cloud (default 20)
-<bottom-shade>        - Light multiplier for sprites at the bottom of the cloud
-                        (default 1.0)
 <min-sprite-width-m>  - minimum width of the sprites used to create the cloud
                         (default 200)
 <max-sprite-width-m>  - maximum width of the sprites used to create the cloud
@@ -56,7 +54,39 @@ The cloud is defined by the following properties:
 <z-scale>             - vertical scaling factor to apply to to the sprite after
                         billboarding. A small value would create a sprite that
                         looks squashed when viewed from the side. (default 1.0)
+<min-bottom-lighting-factor> - See Shading below (default 1.0)
+<max-bottom-lighting-factor> - See Shading below (default min-...-factor + 0.1)
+<min-middle-lighting-factor> - See Shading below (default 1.0)
+<max-middle-lighting-factor> - See Shading below (default min-...-factor + 0.1)
+<min-top-lighting-factor>    - See Shading below (default 1.0)
+<max-top-lighting-factor>    - See Shading below (default min-...-factor + 0.1)
+<min-shade-lighting-factor>  - See Shading below (default 0.5)
+<max-shade-lighting-factor>  - See Shading below (default min-...-factor + 0.1)
                                                 
+Shading
+-------
+
+the [min|max]-...-lighting-factor properties allow you to define diffuse lighting 
+multipliers to the bottom, middle, top, sunny and shaded parts of the cloud. In 
+each case, individual clouds will have a random multiplier between the min and 
+max values used to allow for some variation between individual clouds.
+
+The top, middle and bottom lighting factors are applied based on the pixels vertical 
+positon in the cloud. A linear interpolation is used either between top/middle (if
+the pixel is above the middle of the cloud) or middle/bottom (if the pixel is below
+the middle of the cloud). 
+
+The top factor is also applied to _all_ pixels on the sunny side of the cloud. The
+shade factor is applied based on the pixel position away from the sun, linearly
+interpolated from top to shade. E.g this is not a straight linear interpolation
+from top to shade across the entire cloud.
+
+The final lighting factor is determined by the minimum of the vertical factor and
+the sunny/shade factor. Note that this is applied to the individual pixels, not
+sprites.
+
+Textures
+--------
 
 The texture to use for the sprites is defined in the <texture> tag.
 To allow some variation, you can create a texture file containing multiple

Effects/cloud.eff

@@ -60,6 +60,10 @@
           <name>usrAttr2</name>
           <index>11</index>
         </attribute>
+        <attribute>
+          <name>usrAttr3</name>
+          <index>12</index>
+        </attribute>
       </program>
       <uniform>
         <name>baseTexture</name>

Environment/cloudlayers.xml

@@ -35,33 +35,29 @@ ns = Nimbostratus (Rain cloud)
   <clouds>
     <cb-large>
       <min-cloud-width-m>1600</min-cloud-width-m>
-      <max-cloud-width-m>2000</max-cloud-width-m>
       <min-cloud-height-m>4000</min-cloud-height-m>
-      <max-cloud-height-m>3000</max-cloud-height-m>
       <num-sprites>10</num-sprites>
       <texture>cl_cumulus.png</texture>
       <num-textures-x>4</num-textures-x>
       <num-textures-y>4</num-textures-y>
-      <bottom-shade>0.3</bottom-shade>
+      <min-bottom-lighting-factor>0.3</min-bottom-lighting-factor>
+      <min-shade-lighting-factor>0.4</min-shade-lighting-factor>
       <min-sprite-width-m>800</min-sprite-width-m>
-      <max-sprite-width-m>1200</max-sprite-width-m>
       <min-sprite-height-m>800</min-sprite-height-m>
-      <max-sprite-height-m>1200</max-sprite-height-m>
+      <height-map-texture>true</height-map-texture>
     </cb-large>
     <cb-small>
       <min-cloud-width-m>800</min-cloud-width-m>
-      <max-cloud-width-m>400</max-cloud-width-m>
+      <min-cloud-height-m>800</min-cloud-height-m>
-      <min-cloud-height-m>500</min-cloud-height-m>
-      <max-cloud-height-m>200</max-cloud-height-m>
       <num-sprites>10</num-sprites>
       <texture>cl_cumulus.png</texture>
       <num-textures-x>4</num-textures-x>
       <num-textures-y>4</num-textures-y>
-      <bottom-shade>0.3</bottom-shade>
+      <min-bottom-lighting-factor>0.3</min-bottom-lighting-factor>
+      <min-shade-lighting-factor>0.4</min-shade-lighting-factor>
       <min-sprite-width-m>400</min-sprite-width-m>
-      <max-sprite-width-m>800</max-sprite-width-m>
       <min-sprite-height-m>400</min-sprite-height-m>
-      <max-sprite-height-m>800</max-sprite-height-m>
+      <height-map-texture>true</height-map-texture>
     </cb-small>
     <cu-large>
       <min-cloud-width-m>600</min-cloud-width-m>
@@ -69,89 +65,95 @@ ns = Nimbostratus (Rain cloud)
       <min-cloud-height-m>400</min-cloud-height-m>
       <max-cloud-height-m>800</max-cloud-height-m>
       <num-sprites>20</num-sprites>
-      <texture>cl_cumulus.png</texture>
+      <texture>cl_cumulus2.png</texture>
       <num-textures-x>4</num-textures-x>
       <num-textures-y>4</num-textures-y>
-      <bottom-shade>0.6</bottom-shade>
+      <min-bottom-lighting-factor>0.2</min-bottom-lighting-factor>
+      <min-shade-lighting-factor>0.3</min-shade-lighting-factor>
       <min-sprite-width-m>400</min-sprite-width-m>
       <max-sprite-width-m>700</max-sprite-width-m>
       <min-sprite-height-m>300</min-sprite-height-m>
       <max-sprite-height-m>700</max-sprite-height-m>
+      <height-map-texture>true</height-map-texture>
     </cu-large>
     <cu-small>
-      <min-cloud-width-m>300</min-cloud-width-m>
+      <min-cloud-width-m>600</min-cloud-width-m>
-      <max-cloud-width-m>800</max-cloud-width-m>
+      <max-cloud-width-m>900</max-cloud-width-m>
-      <min-cloud-height-m>200</min-cloud-height-m>
+      <min-cloud-height-m>400</min-cloud-height-m>
-      <max-cloud-height-m>300</max-cloud-height-m>
+      <max-cloud-height-m>600</max-cloud-height-m>
-      <num-sprites>10</num-sprites>
+      <num-sprites>20</num-sprites>
-      <texture>cl_cumulus.png</texture>
+      <texture>cl_cumulus2.png</texture>
       <num-textures-x>4</num-textures-x>
       <num-textures-y>4</num-textures-y>
-      <bottom-shade>0.7</bottom-shade>
+      <min-bottom-lighting-factor>0.4</min-bottom-lighting-factor>
-      <min-sprite-width-m>200</min-sprite-width-m>
+      <min-shade-lighting-factor>0.5</min-shade-lighting-factor>
+      <min-sprite-width-m>300</min-sprite-width-m>
       <max-sprite-width-m>400</max-sprite-width-m>
-      <min-sprite-height-m>150</min-sprite-height-m>
+      <min-sprite-height-m>200</min-sprite-height-m>
       <max-sprite-height-m>300</max-sprite-height-m>
+      <height-map-texture>true</height-map-texture>
     </cu-small>
     <ns-large>
       <min-cloud-width-m>1200</min-cloud-width-m>
       <max-cloud-width-m>3000</max-cloud-width-m>
-      <min-cloud-height-m>200</min-cloud-height-m>
+      <min-cloud-height-m>400</min-cloud-height-m>
-      <max-cloud-height-m>400</max-cloud-height-m>
+      <max-cloud-height-m>800</max-cloud-height-m>
       <num-sprites>40</num-sprites>
       <texture>cl_st.png</texture>
       <num-textures-x>1</num-textures-x>
       <num-textures-y>1</num-textures-y>
-      <bottom-shade>0.2</bottom-shade>
+      <min-bottom-lighting-factor>0.2</min-bottom-lighting-factor>
       <min-sprite-width-m>300</min-sprite-width-m>
       <max-sprite-width-m>600</max-sprite-width-m>
       <min-sprite-height-m>100</min-sprite-height-m>
       <max-sprite-height-m>200</max-sprite-height-m>
+      <height-map-texture>false</height-map-texture>
+      <z-scale>0.5</z-scale>
     </ns-large>
     <ns-white>
       <min-cloud-width-m>600</min-cloud-width-m>
       <max-cloud-width-m>2000</max-cloud-width-m>
-      <min-cloud-height-m>200</min-cloud-height-m>
+      <min-cloud-height-m>400</min-cloud-height-m>
-      <max-cloud-height-m>300</max-cloud-height-m>
+      <max-cloud-height-m>600</max-cloud-height-m>
       <num-sprites>40</num-sprites>
       <texture>cl_st.png</texture>
       <num-textures-x>1</num-textures-x>
       <num-textures-y>1</num-textures-y>
-      <bottom-shade>0.3</bottom-shade>
+      <min-bottom-lighting-factor>0.3</min-bottom-lighting-factor>
       <min-sprite-width-m>300</min-sprite-width-m>
       <max-sprite-width-m>600</max-sprite-width-m>
       <min-sprite-height-m>100</min-sprite-height-m>
       <max-sprite-height-m>200</max-sprite-height-m>
+      <height-map-texture>false</height-map-texture>
+      <z-scale>0.5</z-scale>
     </ns-white>
     <st-small>
-      <min-cloud-width-m>800</min-cloud-width-m>
+      <min-cloud-width-m>1000</min-cloud-width-m>
-      <max-cloud-width-m>1500</max-cloud-width-m>
-      <min-cloud-height-m>100</min-cloud-height-m>
-      <max-cloud-height-m>200</max-cloud-height-m>
-      <num-sprites>40</num-sprites>
-      <texture>cl_st.png</texture>
-      <num-textures-x>1</num-textures-x>
-      <num-textures-y>1</num-textures-y>
-      <bottom-shade>0.9</bottom-shade>
-      <min-sprite-width-m>300</min-sprite-width-m>
-      <max-sprite-width-m>600</max-sprite-width-m>
-      <min-sprite-height-m>200</min-sprite-height-m>
-      <max-sprite-height-m>400</max-sprite-height-m>
-    </st-small>
-    <st-large>
-      <min-cloud-width-m>1800</min-cloud-width-m>
-      <max-cloud-width-m>2500</max-cloud-width-m>
       <min-cloud-height-m>200</min-cloud-height-m>
-      <max-cloud-height-m>400</max-cloud-height-m>
       <num-sprites>40</num-sprites>
-      <texture>cl_st.png</texture>
+      <texture>cl_cumulus.png</texture>
-      <num-textures-x>1</num-textures-x>
+      <num-textures-x>4</num-textures-x>
-      <num-textures-y>1</num-textures-y>
+      <num-textures-y>4</num-textures-y>
-      <bottom-shade>0.9</bottom-shade>
+      <min-bottom-lighting-factor>0.9</min-bottom-lighting-factor>
       <min-sprite-width-m>400</min-sprite-width-m>
       <max-sprite-width-m>800</max-sprite-width-m>
-      <min-sprite-height-m>300</min-sprite-height-m>
+      <min-sprite-height-m>400</min-sprite-height-m>
-      <max-sprite-height-m>500</max-sprite-height-m>
+      <max-sprite-height-m>800</max-sprite-height-m>
+      <height-map-texture>false</height-map-texture>
+      <z-scale>0.3</z-scale>
+    </st-small>
+    <st-large>
+      <min-cloud-width-m>2000</min-cloud-width-m>
+      <min-cloud-height-m>1000</min-cloud-height-m>
+      <num-sprites>40</num-sprites>
+      <texture>cl_st.png</texture>
+      <num-textures-x>1</num-textures-x>
+      <num-textures-y>1</num-textures-y>
+      <min-bottom-lighting-factor>0.9</min-bottom-lighting-factor>
+      <min-sprite-width-m>600</min-sprite-width-m>
+      <min-sprite-height-m>600</min-sprite-height-m>
+      <height-map-texture>false</height-map-texture>
+      <z-scale>0.4</z-scale>
     </st-large>
   </clouds>
   <boxes>

Shaders/3dcloud.vert

@@ -7,13 +7,17 @@ uniform float range; // From /sim/rendering/clouds3d-vis-range
 
 attribute vec3 usrAttr1;
 attribute vec3 usrAttr2;
+attribute vec3 usrAttr3;
 
 float textureIndexX = usrAttr1.r;
 float textureIndexY = usrAttr1.g;
 float wScale = usrAttr1.b;
 float hScale = usrAttr2.r;
-float shade = usrAttr2.g;
+float shade_factor = usrAttr2.g;
 float cloud_height = usrAttr2.b;
+float bottom_factor = usrAttr3.r;
+float middle_factor = usrAttr3.g;
+float top_factor = usrAttr3.b;
 
 void main(void)
 {
@@ -34,11 +38,12 @@ void main(void)
   gl_Position.xyz = gl_Vertex.x * u;
   gl_Position.xyz += gl_Vertex.y * r * wScale;
   gl_Position.xyz += gl_Vertex.z * w  * hScale;
-  gl_Position.xyz += gl_Color.xyz;
-  
   // Apply Z scaling to allow sprites to be squashed in the z-axis
   gl_Position.z = gl_Position.z * gl_Color.w;
 
+  // Now shift the sprite to the correct position in the cloud.
+  gl_Position.xyz += gl_Color.xyz;
+
   // Determine a lighting normal based on the vertex position from the
   // center of the cloud, so that sprite on the opposite side of the cloud to the sun are darker.
   float n = dot(normalize(-gl_LightSource[0].position.xyz),
@@ -48,21 +53,29 @@ void main(void)
   vec3 ecPosition = vec3(gl_ModelViewMatrix * gl_Position);
   float fogCoord = abs(ecPosition.z);
   
-  // Determine fractional height of vertex from 0 at the bottom, and 1 at mid-height.
+  // Determine the shading of the vertex. We shade it based on it's position
-  // Used to determine shading.
+  // in the cloud relative to the sun, and it's vertical position in the cloud.
-  float fract = smoothstep(0.0, cloud_height, gl_Position.z + cloud_height);
+  float shade = mix(shade_factor, top_factor,  smoothstep(-0.3, 0.0, n));
+  //if (n < 0) {
+  //  shade = mix(top_factor, shade_factor, abs(n));
+  //} 
+  
+  float h = gl_Position.z;
+  shade = min(shade,
+              min(mix(bottom_factor, middle_factor, smoothstep(0.0, 0.5 * h, h)),
+                  mix(middle_factor, top_factor, smoothstep(0.5 * h, h, h))      ) );
+                
+  //float h = gl_Position.z / cloud_height;
+  //if (h < 0.5) {
+  //  shade = min(shade, mix(bottom_factor, middle_factor, smoothstep(0.0, 0.5, h)));
+  //} else {
+  //  shade = min(shade, mix(middle_factor, top_factor, smoothstep(2.0 * (h - 0.5)));    
+ // }
   
   // Final position of the sprite
   gl_Position = gl_ModelViewProjectionMatrix * gl_Position;
   
-  // Determine the shading of the sprite based on its vertical position and position relative to the sun.
+  gl_FrontColor = gl_LightSource[0].diffuse * shade + gl_FrontLightModelProduct.sceneColor;
-  n = min(smoothstep(-0.5, 0.0, n), fract);
-  
-  // Determine the shading based on a mixture from the backlight to the front
-  vec4 backlight = gl_LightSource[0].diffuse * shade;
-
-  gl_FrontColor = mix(backlight, gl_LightSource[0].diffuse, n);
-  gl_FrontColor += gl_FrontLightModelProduct.sceneColor;
 
   // As we get within 100m of the sprite, it is faded out. Equally at large distances it also fades out.
   gl_FrontColor.a = min(smoothstep(10.0, 100.0, fogCoord), 1.0 - smoothstep(range*0.8, range, fogCoord));