Implement showing interaction paths.

src/fmri/ActivityAnimation.cpp

@@ -5,6 +5,8 @@
 #include <caffe/util/math_functions.hpp>
 #include "Range.hpp"
 #include "ActivityAnimation.hpp"
+#include "RenderingState.hpp"
+#include "glutils.hpp"
 
 using namespace std;
 using namespace fmri;
@@ -29,11 +31,13 @@ ActivityAnimation::ActivityAnimation(
             const std::vector<std::pair<DType, std::pair<std::size_t, std::size_t>>> &interactions,
             const float *aPositions, const float *bPositions, ColoringFunction coloring)
         :
-        bufferLength(3 * interactions.size())
+        bufferLength(3 * interactions.size()),
+        delta(bufferLength)
 {
     CHECK(coloring) << "Invalid coloring function passed.";
     startingPos.reserve(bufferLength);
-    delta.reserve(bufferLength);
+    vector<float> endPos;
+    endPos.reserve(bufferLength);
     colorBuf.reserve(interactions.size());
 
     for (auto &entry : interactions) {
@@ -44,9 +48,16 @@ ActivityAnimation::ActivityAnimation(
 
         for (auto i : Range(3)) {
             startingPos.emplace_back(aPos[i]);
-            delta.emplace_back(bPos[i] - aPos[i] + (i % 3 ? 0 : LAYER_X_OFFSET));
+            endPos.emplace_back(bPos[i] + (i % 3 ? 0 : LAYER_X_OFFSET));
         }
     }
+
+    caffe::caffe_sub(endPos.size(), endPos.data(), startingPos.data(), delta.data());
+    startingPos.insert(startingPos.end(), endPos.begin(), endPos.end());
+    for (auto i : Range(interactions.size())) {
+        lineIndices.push_back(i);
+        lineIndices.push_back(i + interactions.size());
+    }
 }
 
 void ActivityAnimation::draw(float timeScale)
@@ -60,5 +71,11 @@ void ActivityAnimation::draw(float timeScale)
     glVertexPointer(3, GL_FLOAT, 0, vertexBuffer.data());
     glDrawArrays(GL_POINTS, 0, bufferLength / 3);
     glDisableClientState(GL_COLOR_ARRAY);
+    if (RenderingState::instance().renderInteractionPaths()) {
+        glColor4f(1, 1, 1, 0.1);
+        glVertexPointer(3, GL_FLOAT, 0, startingPos.data());
+        glDrawElements(GL_LINES, lineIndices.size(), GL_UNSIGNED_INT, lineIndices.data());
+        checkGLErrors();
+    }
     glDisableClientState(GL_VERTEX_ARRAY);
 }