added the Zorin-Barr transformation

openglcanvas.cpp

@@ -40,6 +40,8 @@ OpenGLCanvas::OpenGLCanvas(QWidget *parent) :
     fov_scale_relation = "Naive";
     visualization = "Moebius";
     auto_fov_max=false;
+    zblambda=.1f; // Zorin-Barr transformation lambda
+    zbR=1.f; // Zorin-Barr transformation R
 
     time_frames = 0;
     time_timer.setInterval(0);
@@ -248,6 +250,19 @@ void OpenGLCanvas::read_config_file(){
                 auto_fov_max=atof(read_line);
                 fprintf(stderr,"auto_max_fov=%d\n",auto_fov_max);
             }
+            // check for the Zorin-Barr transformation parameters, lambda and R
+            if(!strncmp(line,"zblambda=",9)){
+                strcpy(read_line,line+9);
+                read_line[strlen(line)-10]='\0';
+                zblambda=atof(read_line);
+                fprintf(stderr,"zblambda=%f\n",zblambda);
+            }
+            if(!strncmp(line,"zbR=",4)){
+                strcpy(read_line,line+4);
+                read_line[strlen(line)-5]='\0';
+                zbR=atof(read_line);
+                fprintf(stderr,"zbR=%f\n",zbR);
+            }
         }
         fclose(rcfile);
     }
@@ -475,6 +490,24 @@ void OpenGLCanvas::vertex_transformation(float *positions, int m, int n, float c
                 positions[3*(j+i*n)+2] = z;
             }
 
+            // perspective
+            if (visualization=="Zorin-Barr"){
+                // perspective
+                u = x/(-z);
+                v = y/(-z);
+                // apply Z-B transformation to (u,v)
+                float lambda=.1f;
+                float R=1.f;
+                float alpha=atanf(v/u);
+                float r=hypotf(u,v);
+                float rhoprime=(lambda*r/R)+(1.f-lambda)*(R*(sqrtf(r*r+1.f)-1.f))/(r*(sqrtf(R*R+1.f)-1.f));
+                u=rhoprime*cosf(alpha);
+                v=rhoprime*sinf(alpha);
+                //
+                positions[3*(j+i*n)] = u/extent;
+                positions[3*(j+i*n)+1] = v/extent;
+                positions[3*(j+i*n)+2] = z;
+            }
         }
     }
 
@@ -546,6 +579,11 @@ float OpenGLCanvas::calculate_extent(float fov_rads){
         // Write now it's olny showing the entire panorama intead of
         // the corresponging FOV.
     }
+    if (visualization=="Zorin-Barr"){
+        // TODO: check whether this is correct
+        u = x/(-z);
+        v = y/(-z);
+    }
     return u;
 }
 
@@ -724,6 +762,7 @@ void OpenGLCanvas::paintGL(){
     else if (visualization=="Equi-Rectangular") vis_mode=3.0;
     else if (visualization=="Stereographic") vis_mode=4.0;
     else if (visualization=="Mercator") vis_mode=5.0;
+    else if (visualization=="Zorin-Barr") vis_mode=6.0;
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
     glOrtho(0.0, 2.0/extent, 0.0, 2.0/scale, 0.0, -2.0/vis_mode);

openglcanvas.h

@@ -71,6 +71,7 @@ private:
     QString fov_scale_relation;
     QString visualization;
     bool auto_fov_max;
+    float zblambda,zbR; // parameters of the Zorin-Barr transformation
 
     Chronos time_time;
     QTimer time_timer;

pano_interface_1.pro

@@ -76,3 +76,7 @@ HEADERS  += panowindow1.h \
     files.h
 
 FORMS    += panowindow1.ui
+
+OTHER_FILES += \
+    shaders/fragment_shader.frag \
+    shaders/test_vertex_shader.vert

panowindow1.ui

@@ -202,6 +202,11 @@
        <string>Mercator</string>
       </property>
      </item>
+     <item>
+      <property name="text">
+       <string>Zorin-Barr</string>
+      </property>
+     </item>
     </widget>
    </item>
    <item row="12" column="1">

shaders/test_vertex_shader.vert

@@ -4,6 +4,7 @@ float u, v, x, y, z;
 varying float r, theta, s;
 float lambda, phi;
 float extent, scale, vis_mode, center_lambda, center_phi;
+varying float zbu,zbv,zblambda,zbr,zbR,zbalpha,zbrho;
 
 void main(void){
 
@@ -58,23 +59,39 @@ void main(void){
     phi = asin(y)/1.5708;
 
     // Visualize using specified visualization (remove for timings in the paper! Use only "Perspective" in the paper!)
-    if (vis_mode==1.0) {
+    if (vis_mode==1.0) { // Moebius
         u = x/(-z);
         v = y/(-z);
         gl_Position = vec4(u/extent,v/extent,z,1.0);
     }
-    else if (vis_mode==2.0) gl_Position = vec4(0.9*x,0.9*y,z,1.0);
-    else if (vis_mode==3.0) gl_Position = vec4(lambda,phi,z,1.0);
-    else if (vis_mode==4.0) {
+    else if (vis_mode==2.0) // 3D Sphere
+        gl_Position = vec4(0.9*x,0.9*y,z,1.0);
+    else if (vis_mode==3.0) // Equi-Rectangular
+        gl_Position = vec4(lambda,phi,z,1.0);
+    else if (vis_mode==4.0) { // Stereographic
         u = 2.f*x/(-z+1);
         v = 2.f*y/(-z+1);
         gl_Position = vec4(u/extent,v/extent,z,1.0);
     }
-    else if (vis_mode==5.0) {
+    else if (vis_mode==5.0) { // Mercator
         u = lambda;
         v = log((1.0/cos(phi)) + tan(phi));
         gl_Position = vec4(u,v,z,1.0);
     }
+    else if (vis_mode==6.0) { // Zorin-Barr
+        // perspective projection
+        zbu = x/(-z);
+        zbv = y/(-z);
+        // Z-B transformation
+        zblambda=0.1;
+        zbR=1.0;
+        zbalpha=atan(zbv,zbu);
+        zbr=sqrt(zbu*zbu+zbv*zbv);
+        zbrho=(zblambda*zbr/zbR)+(1.0-zblambda)*(zbR*(sqrt(zbr*zbr+1.0)-1.0))/(zbr*(sqrt(zbR*zbR+1.0)-1.0));
+        u=zbrho*cos(zbalpha);
+        v=zbrho*sin(zbalpha);
+        gl_Position = vec4(u/extent,v/extent,z,1.0);
+    }
 
 //    gl_Position = vec4(u/2.0,v/2.0,z,1.0);