Renamed GUI elements

src/gui/input/Widget.cpp

@@ -49,14 +49,14 @@ void Widget::tick(double fps) {
   float min = -1, max = 1;
 
   ImGui::Begin("Transfer Function Controls");
-  ImGui::DragInt("k (log [1e-10, 1])", &this->opacityK, 1, 0, 100, "%d%%", ImGuiSliderFlags_AlwaysClamp);
+  ImGui::DragInt("Gradient exp. (log [1e-10, 1])", &this->opacityK, 1, 0, 100, "%d%%", ImGuiSliderFlags_AlwaysClamp);
   ImGui::DragFloat("sigmoidShift", &this->sigmoidShift, 0.01f, 0.0f, 1.0f, "%.2f");
   ImGui::InputFloat("sigmoidExp", &this->sigmoidExp, 10.0f, 100.0f, "%.0f");
   
   // the items[] contains the entries for the combobox. The selected index is stored as an int on this->tfComboSelected
   // the default entry is set in the constructor, so if you want that to be a specific entry just change it
   // whatever value is selected here is available on the gpu as d_tfComboSelected.
-  const char* items[] = {"First option", "Another option", "this is the third option", "..."};
+  const char* items[] = {"Opacity - gradient", "Opacity - sigmoid", "Opacity - constant", "..."};
   if (ImGui::BeginCombo("ComboBox for transferFunction", items[this->tfComboSelected]))
   {
     for (int n = 0; n < IM_ARRAYSIZE(items); n++)

src/illumination/transferFunction.cu

@@ -7,7 +7,7 @@
 
 __device__ float opacityFromGradient(const Vec3 &grad) {
     float gradMag = grad.length();
-    float alpha = 1.0f - expf(-1 * gradMag);  // TODO: This parameter probably has the wrong scale
+    float alpha = 1.0f - expf(-d_opacityK * gradMag);  // TODO: This parameter probably has the wrong scale
     return alpha;
 }
 
@@ -51,12 +51,26 @@ __device__ float4 transferFunction(float density, const Vec3& grad, const Point3
 
   // TODO: This is a Gui select element
   // TODO: Add a way to pick different function for alpha
-  float alpha = opacityFromGradient(grad);
-  // alpha = 0.1f;
-//   alpha = opacitySigmoid(normDensity);
-  // alpha = (1.0f - fabs(grad.normalize().dot(rayDir.normalize()))) * 0.8f + 0.2f;
+  float alpha;
+  switch (d_tfComboSelected) {
+  case 0:
+    alpha = opacityFromGradient(grad);
+    break;
   
-  float alphaSample = density * alpha * 0.1;
+  case 1:
+    alpha = opacitySigmoid(normDensity);
+    break;
+
+  case 2:
+    alpha = 0.1f;
+    break;
+  
+  default:
+    alpha = 1.0f;  // This should not be reached anyway
+    break;
+  }
+
+  float alphaSample = density * alpha * 0.1;  // TODO: Why is this still 0.1?
 
   // --------------------------- Shading ---------------------------
   // Apply Phong