Added alpha accum gui param

src/consts.cu

@@ -51,6 +51,7 @@ void copyConstantsToDevice() {
 __device__ float d_opacityK;
 __device__ float d_sigmoidShift;
 __device__ float d_sigmoidExp;
+__device__ float d_alphaAcumLimit;
 __device__ int d_tfComboSelected;
 __device__ int d_tfComboSelectedColor;
 __device__ float d_opacityConst;

src/consts.h

@@ -32,7 +32,7 @@ const float MAX_SPEED = 14.0f;
 // --------------------------- Raycasting Constants ---------------------------
 const int SAMPLES_PER_PIXEL = 4;
 
-const float alphaAcumLimit = 0.4f;   // TODO: Atm, this only works with sigmoid
+// const float alphaAcumLimit = 0.4f;   // TODO: Atm, this only works with sigmoid
 const float minAllowedDensity = 0.001f;
 
 const float stepSize = 0.02f;
@@ -67,6 +67,8 @@ extern __device__ float d_opacityK;
 // sigmoid function variables
 extern __device__ float d_sigmoidShift;
 extern __device__ float d_sigmoidExp;
+// alpha accumulation limit
+extern __device__ float d_alphaAcumLimit;
 // combo box index
 extern __device__ int d_tfComboSelected;
 extern __device__ int d_tfComboSelectedColor;

src/gui/input/Widget.cpp

@@ -29,6 +29,7 @@ Widget::Widget(GLFWwindow* window) {
   this->opacityK = 0;
   this->sigmoidShift = 0.5f;
   this->sigmoidExp = -250.0f;
+  this->alphaAcumLimit = 0.4f;
   this->tfComboSelected = 0;
   this->opacityConst = 100;
 };
@@ -53,6 +54,7 @@ void Widget::tick(double fps) {
   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");
+  ImGui::DragFloat("Alpha accumulation limit", &this->alphaAcumLimit, 0.01f, 0.0f, 1.0f, "%.2f");
   ImGui::DragInt("Opacity constant (log [1e-5, 1])", &this->opacityConst, 1, 0, 100, "%d%%", ImGuiSliderFlags_AlwaysClamp);
   
   // the items[] contains the entries for the combobox. The selected index is stored as an int on this->tfComboSelected
@@ -130,6 +132,7 @@ void Widget::copyToDevice() {
 
   cudaMemcpyToSymbol(&d_sigmoidShift, &this->sigmoidShift, sizeof(float));
   cudaMemcpyToSymbol(&d_sigmoidExp, &this->sigmoidExp, sizeof(float));
+  cudaMemcpyToSymbol(&d_alphaAcumLimit, &this->alphaAcumLimit, sizeof(float));
   cudaMemcpyToSymbol(&d_tfComboSelected, &this->tfComboSelected, sizeof(int));
 
   this->opacityConstReal = std::pow(10.0f, (-5 + 0.05 * this->opacityConst));

src/gui/input/Widget.h

@@ -24,6 +24,7 @@ public:
   float opacityKReal;
   float sigmoidShift;
   float sigmoidExp;
+  float alphaAcumLimit;
   int opacityConst;
   float opacityConstReal;
 

src/illumination/Raycaster.cu

@@ -84,7 +84,7 @@ __global__ void raycastKernel(float* volumeData, FrameBuffer framebuffer, const
           float alphaAccum = 0.0f;
 
           float t = tNear;  // Front to back
-          while (t < tFar && alphaAccum < alphaAcumLimit) {
+          while (t < tFar && alphaAccum < d_alphaAcumLimit) {
               Point3 pos = d_cameraPos + rayDir * t;
 
               // Convert to volume indices