Added samples per pixel gui param

src/consts.cu

@@ -55,3 +55,6 @@ __device__ float d_alphaAcumLimit;
 __device__ int d_tfComboSelected;
 __device__ int d_tfComboSelectedColor;
 __device__ float d_opacityConst;
+
+// ----------------------- Raycasting -----------------------
+__device__ int d_samplesPerPixel;

src/consts.h

@@ -30,9 +30,6 @@ 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 minAllowedDensity = 0.001f;
 
 const float stepSize = 0.02f;
@@ -74,6 +71,8 @@ extern __device__ int d_tfComboSelected;
 extern __device__ int d_tfComboSelectedColor;
 // constant opacity option
 extern __device__ float d_opacityConst;
+// samples per pixel
+extern __device__ int d_samplesPerPixel;
 
 const int lenStopsPythonLike = 5;
 const int lenStopsGrayscale = 2;

src/gui/input/Widget.cpp

@@ -25,6 +25,7 @@ Widget::Widget(GLFWwindow* window) {
   this->fps = (char*)malloc(512*sizeof(char));
   this->paused = true;
   this->renderOnce = false;
+  this->samplesPerPixel = 1;
 
   this->opacityK = 0;
   this->sigmoidShift = 0.5f;
@@ -101,6 +102,7 @@ void Widget::tick(double fps) {
   }
   sprintf(this->fps, "%.3f fps\n", fps);
   ImGui::Text(this->fps);
+  ImGui::DragInt("Samples per pixel", &this->samplesPerPixel, 1, 1, 16, "%d", ImGuiSliderFlags_AlwaysClamp);
   ImGui::End();
 
   ImGui::Begin("Camera Controls");
@@ -126,6 +128,8 @@ void Widget::copyToDevice() {
   cudaMemcpyToSymbol(&d_lightPos, &this->lightPos, sizeof(Point3));
   cudaMemcpyToSymbol(&d_backgroundColor, &this->bgColor, sizeof(Color3));
 
+  cudaMemcpyToSymbol(&d_samplesPerPixel, &this->samplesPerPixel, sizeof(int));
+  
   // cudaMemcpyToSymbol(&d_opacityK, &this->opacityK, sizeof(float));
   this->opacityKReal = std::pow(10.0f, (-10 + 0.1 * this->opacityK));
   cudaMemcpyToSymbol(&d_opacityK, &this->opacityKReal, sizeof(float));

src/gui/input/Widget.h

@@ -17,6 +17,7 @@ public:
   bool paused;
   bool renderOnce;
   char* fps;
+  int samplesPerPixel;
 
   int tfComboSelected;
   int tfComboSelectedColor;

src/illumination/Raycaster.cu

@@ -20,14 +20,14 @@ __global__ void raycastKernel(float* volumeData, FrameBuffer framebuffer, const
     float accumR = 0.0f;
     float accumG = 0.0f;
     float accumB = 0.0f;
-    float accumA = 1.0f * (float)SAMPLES_PER_PIXEL;
+    float accumA = 1.0f * (float)d_samplesPerPixel;
 
     // Initialize random state for ray scattering
     curandState randState;
     curand_init(1234, px + py * width, 0, &randState);
 
     // Multiple samples per pixel
-    for (int s = 0; s < SAMPLES_PER_PIXEL; s++) {
+    for (int s = 0; s < d_samplesPerPixel; s++) {
         // Map to [-1, 1]
         float jitterU = (curand_uniform(&randState) - 0.5f) / width;
         float jitterV = (curand_uniform(&randState) - 0.5f) / height;
@@ -71,11 +71,11 @@ __global__ void raycastKernel(float* volumeData, FrameBuffer framebuffer, const
         intersectAxis(d_cameraPos.z, rayDir.z, 0.0f, (float)VOLUME_DEPTH);
 
         if (tNear > tFar) {
-          // No intersection -> Set to brackground color (multiply by SAMPLES_PER_PIXEL because we divide by it later)
+          // No intersection -> Set to brackground color (multiply by d_samplesPerPixel because we divide by it later)
-          accumR = d_backgroundColor.x * (float)SAMPLES_PER_PIXEL;
+          accumR = d_backgroundColor.x * (float)d_samplesPerPixel;
-          accumG = d_backgroundColor.y * (float)SAMPLES_PER_PIXEL;
+          accumG = d_backgroundColor.y * (float)d_samplesPerPixel;
-          accumB = d_backgroundColor.z * (float)SAMPLES_PER_PIXEL;
+          accumB = d_backgroundColor.z * (float)d_samplesPerPixel;
-          accumA = 1.0f * (float)SAMPLES_PER_PIXEL;
+          accumA = 1.0f * (float)d_samplesPerPixel;
           
         } else {
           if (tNear < 0.0f) tNear = 0.0f;
@@ -130,10 +130,10 @@ __global__ void raycastKernel(float* volumeData, FrameBuffer framebuffer, const
 
 
     // Average samples
-    accumR /= (float)SAMPLES_PER_PIXEL;
+    accumR /= (float)d_samplesPerPixel;
-    accumG /= (float)SAMPLES_PER_PIXEL;
+    accumG /= (float)d_samplesPerPixel;
-    accumB /= (float)SAMPLES_PER_PIXEL;
+    accumB /= (float)d_samplesPerPixel;
-    accumA /= (float)SAMPLES_PER_PIXEL;
+    accumA /= (float)d_samplesPerPixel;
 
     // Final colour
     framebuffer.writePixel(px, py, accumR, accumG, accumB, accumA);