From b102f57bd43217866ba9b6f378ba5d3647982cd5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luis=20Pe=C3=B1aranda?= <luis.penaranda@gmx.com>
Date: Fri, 25 Jan 2013 16:44:31 -0200
Subject: [PATCH] some numerical stability

---
 openglcanvas.cpp | 77 ++++++++++++++++++++++++++----------------------
 1 file changed, 42 insertions(+), 35 deletions(-)

diff --git a/openglcanvas.cpp b/openglcanvas.cpp
index 6fa0b0b..e7a1851 100644
--- a/openglcanvas.cpp
+++ b/openglcanvas.cpp
@@ -22,6 +22,11 @@
 #define VERT_SHADER_FILE "test_vertex_shader.vert"
 #define FRAG_SHADER_FILE "fragment_shader.frag"
 
+#define CONST_PI        3.141592653589793238462
+#define CONST_PI_2      1.57079632679489661923
+#define CONST_PI_F      3.14159265358979f
+#define CONST_PI_2_F    1.570796326794897f // TODO: check this one
+
 OpenGLCanvas::OpenGLCanvas(QWidget *parent) :
     QGLWidget(parent)
 {
@@ -50,8 +55,8 @@ void OpenGLCanvas::change_fov(double f){
         fov=f;
     if (fov<=fov_max)
         scale=1.f;
-    else if (fov>295.f)
-        scale = 0.02f; // TODO: check this value wrt fov_max
+    //else if (fov>295.f)
+    //    scale = 0.02f; // TODO: check this value wrt fov_max
     else {
         if (fov_scale_relation == "Naive")
             scale=fov_max/fov;
@@ -69,7 +74,7 @@ void OpenGLCanvas::change_fov(double f){
 
 //    scale = 0.3f;
 
-    fprintf(stderr,"change fov=%f, fov_max=%f\n",fov,fov_max);
+    fprintf(stderr,"change fov, fov=%f, fov_max=%f, scale=%f\n",fov,fov_max,scale);
     emit fov_changed((int)fov);
 
     updateGL();
@@ -77,15 +82,17 @@ void OpenGLCanvas::change_fov(double f){
 }
 
 void OpenGLCanvas::change_fov(int new_fov){
-    change_fov((double)new_fov);
+    if(new_fov<=360&&new_fov>=1)
+            change_fov((double)new_fov);
 }
 
 void OpenGLCanvas::change_fov_max(int new_fov_max){
-    fov_max=(double)new_fov_max;
+    if(new_fov_max<=360&&new_fov_max>=0)
+            fov_max=(double)new_fov_max;
     if (fov<=fov_max)
         scale=1.f;
-    else if (fov>295.f)
-        scale = 0.02f; // TODO: check this value wrt fov_max
+    //else if (fov>295.f)
+    //    scale = 0.02f; // TODO: check this value wrt fov_max
     else {
         if (fov_scale_relation == "Naive")
             scale=fov_max/fov;
@@ -100,7 +107,7 @@ void OpenGLCanvas::change_fov_max(int new_fov_max){
         else if (fov_scale_relation == "Logarithm")
             scale=log(exp(1.f)+(1.f-exp(1.f))*(fov-fov_max)/(360.-2*fov_max));
     }
-    fprintf(stderr,"change fov_max=%f, new scale=%f\n",fov_max,scale);
+    fprintf(stderr,"change fov_max, fov=%f, fov_max=%f, new scale=%f\n",fov,fov_max,scale);
     emit max_fov_changed((int)fov_max);
     updateGL();
 }
@@ -114,7 +121,7 @@ void OpenGLCanvas::change_fov_max(int new_fov_max){
 
 void OpenGLCanvas::change_center_lambda(double lambda){
 
-    if (center_lambda!=lambda && lambda>=-3.14f && lambda<=3.14f) {
+    if (center_lambda!=lambda && lambda>=-CONST_PI && lambda<=CONST_PI) {
         center_lambda = lambda;
         updateGL();
     }
@@ -123,7 +130,7 @@ void OpenGLCanvas::change_center_lambda(double lambda){
 
 void OpenGLCanvas::change_center_phi(double phi){
 
-    if (center_phi!=phi && phi>=-1.57f && phi<=1.57f) {
+    if (center_phi!=phi && phi>=-CONST_PI_2 && phi<=CONST_PI_2) {
         center_phi = phi;
         updateGL();
     }
@@ -139,8 +146,8 @@ void OpenGLCanvas::re_center(){
 void OpenGLCanvas::change_fov_scale_relation(QString name){
 
    fov_scale_relation = name;
-   if (fov<60.f) scale = 1.f;
-   else if (fov>295.f) scale = 0.01f;
+   if (fov<fov_max) scale = 1.f;
+   //else if (fov>295.f) scale = 0.01f;
    else{
        if (fov_scale_relation == "Naive")
            scale=fov_max/fov;
@@ -278,7 +285,7 @@ void OpenGLCanvas::initializeGL(){
     if (texCoord == NULL){
         printf("problem allocating memory for texture coordinates \n");
     }
-    define_texture_coordinates(texCoord, m, n, -1.57f, 1.57f, -3.14f, 3.14f);
+    define_texture_coordinates(texCoord, m, n, -CONST_PI_2_F, CONST_PI_2_F, -CONST_PI_F, CONST_PI_F);
 
     //defining positions of the sphere vertices
     int meshNumVertices = m*n;
@@ -311,8 +318,8 @@ void OpenGLCanvas::define_texture_coordinates(float *texCoord, int m, int n, flo
 
     for (int i = 0; i<m; i++){
         for (int j = 0; j<n; j++){
-            texCoord[2*(j+i*n)] = (min_lambda+delta_lambda*j)/(6.2832) + 0.5;
-            texCoord[2*(j+i*n)+1] = (min_phi+delta_phi*i)/(3.1416) + 0.5;
+            texCoord[2*(j+i*n)] = (min_lambda+delta_lambda*j)/(2*CONST_PI_F) + 0.5;
+            texCoord[2*(j+i*n)+1] = (min_phi+delta_phi*i)/(CONST_PI_F) + 0.5;
         }
     }
 
@@ -320,10 +327,10 @@ void OpenGLCanvas::define_texture_coordinates(float *texCoord, int m, int n, flo
 
 void OpenGLCanvas::vertex_transformation(float *positions, int m, int n, float center_lambda, float center_phi, float fov_rads, float scale){
 
-    float min_lambda = -3.1415f;
-    float max_lambda = 3.1415f;
-    float min_phi = -1.5708f;
-    float max_phi = 1.5708f;
+    float min_lambda = -CONST_PI_F;
+    float max_lambda = CONST_PI_F;
+    float min_phi = -CONST_PI_2_F;
+    float max_phi = CONST_PI_2_F;
 
     float delta_lambda = (max_lambda-min_lambda)/(1.0*(n-1));
     float delta_phi = (max_phi-min_phi)/(1.0*(m-1));
@@ -391,8 +398,8 @@ void OpenGLCanvas::vertex_transformation(float *positions, int m, int n, float c
             y = (4.f*v)/(u*u+v*v+4.f);
             z = (u*u+v*v-4.f)/(u*u+v*v+4.f);
 
-            lambda = atan2(x,-z)/3.1415;
-            phi = asin(y)/1.5708;
+            lambda = atan2(x,-z)/CONST_PI_F;
+            phi = asin(y)/CONST_PI_2_F;
 
             u = x/(-z);
             v = y/(-z);
@@ -422,10 +429,10 @@ void OpenGLCanvas::vertex_transformation(float *positions, int m, int n, float c
 
 void OpenGLCanvas::load_sphere_mesh(float *positions, int m, int n){
 
-    float min_lambda = -3.1415f;
-    float max_lambda = 3.1415f;
-    float min_phi = -1.5708f;
-    float max_phi = 1.5708f;
+    float min_lambda = -CONST_PI_F;
+    float max_lambda = CONST_PI_F;
+    float min_phi = -CONST_PI_2_F;
+    float max_phi = CONST_PI_2_F;
 
     float delta_lambda = (max_lambda-min_lambda)/(1.0*(n-1));
     float delta_phi = (max_phi-min_phi)/(1.0*(m-1));
@@ -454,24 +461,24 @@ void OpenGLCanvas::load_sphere_mesh(float *positions, int m, int n){
 
 float OpenGLCanvas::calculate_extent(float fov_rads){
 
-    float lambda, phi, x, y, z, u, v, r, theta;
+    double lambda, phi, x, y, z, u, v, r, theta;
     //calculating the extent of the projection for the given FOV
     lambda = fov_rads;
-    phi = 0.f;
+    phi = 0.;
     // OpenGL: x is the vertical axes pointg downwards, and y is horizontal axes
     y = sin(phi);
     x = -sin(lambda)*cos(phi);
     z = -cos(lambda)*cos(phi);
-    u = 2.f*x/(-z+1.f);
-    v = 2.f*y/(-z+1.f);
+    u = 2.*x/(-z+1.);
+    v = 2.*y/(-z+1.);
     r = sqrt(u*u+v*v);
     theta = atan2(u,v);
     r *= scale;
     u = -r*sin(theta);
     v = r*cos(theta);
-    x = (4.f*u)/(u*u+v*v+4.f);
-    y = (4.f*v)/(u*u+v*v+4.f);
-    z = (u*u+v*v-4.f)/(u*u+v*v+4.f);
+    x = (4.*u)/(u*u+v*v+4.);
+    y = (4.*v)/(u*u+v*v+4.);
+    z = (u*u+v*v-4.)/(u*u+v*v+4.);
     u = x/(-z);
     v = y/(-z);
     return u;
@@ -670,8 +677,8 @@ void OpenGLCanvas::mouseMoveEvent(QMouseEvent *event){
     // scroll with the left button
     if(event->buttons()==Qt::LeftButton){
         // compute the delta and move the image
-        center_lambda+=(event->x()-lastPos.x())*3.1415926f/image_size_x;
-        center_phi+=(event->y()-lastPos.y())*3.1415926f/image_size_y;
+        center_lambda+=(event->x()-lastPos.x())*CONST_PI_F/image_size_x;
+        center_phi+=(event->y()-lastPos.y())*CONST_PI_F/image_size_y;
         lastPos=event->pos();
         updateGL();
     }
@@ -689,7 +696,7 @@ void OpenGLCanvas::wheelEvent(QWheelEvent *event){
 
 void OpenGLCanvas::paintGL(){
 
-    float fov_rads = (fov/180.f)*1.5708f;
+    float fov_rads = (fov/360.)*CONST_PI;
 
 //    // changing scale to generate the figures for the paper (remove it after)
 //    scale = 0.8;
-- 
GitLab