Add line shadow shader

shader/lighting/wall.geom

@@ -14,15 +14,15 @@ vec4 shiftCloser (vec4 v)
 { return vec4 (v.xy , v.z-0.0001 , v.w) ; }
 void main()
 {
-vec4 p1 = vec4 (gl_in[0].gl_Position.xy,0.1,1);
-vec4 p2 = vec4 (gl_in[0].gl_Position.zw,0.1,1);
+vec4 p1 = vec4 (gl_in[0].gl_Position.xy,0,1);
+vec4 p2 = vec4 (gl_in[0].gl_Position.zw,0,1);
 if (isLHS (p1.xy - lightPos.xy, p2.xy - lightPos.xy) < 0)
 {
     lum = radLum.y;
     float rad = radLum.x;
 
-    vec4 p3 = vec4 (p1.xy,-0.3,1);
-    vec4 p4 = vec4 (p2.xy,-0.3,1);
+    vec4 p3 = vec4 (p1.xy,100,1);
+    vec4 p4 = vec4 (p2.xy,100,1);
 
     vec2 d1 = p1.xy - lightPos.xy;
     vec2 d2 = p2.xy - lightPos.xy;
@@ -32,16 +32,16 @@ if (isLHS (p1.xy - lightPos.xy, p2.xy - lightPos.xy) < 0)
     vec4 a3 = shiftCloser( theMat * p3 );
     vec4 a4 = shiftCloser( theMat * p4 );
     
-    dField = vec3( d1.x/rad, d1.y/rad, 100.0/rad);
+    dField = (p1.xyz - lightPos) / rad;
     gl_Position = a1; 
     EmitVertex();
-    dField = vec3( d1.x/rad, d1.y/rad, -300.0/rad);
+    dField = (p3.xyz - lightPos) / rad;
     gl_Position = a3; 
     EmitVertex();
-    dField = vec3( d2.x/rad, d2.y/rad, 100.0/rad);
+    dField = (p2.xyz - lightPos) / rad;
     gl_Position = a2; 
     EmitVertex();
-    dField = vec3( d2.x/rad, d2.y/rad, -300.0/rad);
+    dField = (p4.xyz - lightPos) / rad;
     gl_Position = a4; 
     EmitVertex();