From e4336b6757e55d465ba09beb10dd8d96ca965a94 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 15 Feb 2018 16:07:13 +0100
Subject: [PATCH] Actually use the same node positions internally and
 externally.

---
 src/ActivityAnimation.cpp      |  4 +-
 src/FlatLayerVisualisation.cpp | 89 +++++++++++++++-------------------
 src/FlatLayerVisualisation.hpp | 18 +++++++
 3 files changed, 60 insertions(+), 51 deletions(-)

diff --git a/src/ActivityAnimation.cpp b/src/ActivityAnimation.cpp
index 51de794..5825b15 100644
--- a/src/ActivityAnimation.cpp
+++ b/src/ActivityAnimation.cpp
@@ -16,8 +16,8 @@ ActivityAnimation::ActivityAnimation(const vector<pair<DType, pair<size_t, size_
     delta.reserve(bufferLength);
 
     for (auto &entry : interactions) {
-        auto *aPos = &aPositions[entry.second.first];
-        auto *bPos = &bPositions[entry.second.second];
+        auto *aPos = &aPositions[3 * entry.second.first];
+        auto *bPos = &bPositions[3 * entry.second.second];
 
         for (auto i : Range(3)) {
             startingPos.emplace_back(aPos[i]);
diff --git a/src/FlatLayerVisualisation.cpp b/src/FlatLayerVisualisation.cpp
index d5b549a..0c1f006 100644
--- a/src/FlatLayerVisualisation.cpp
+++ b/src/FlatLayerVisualisation.cpp
@@ -24,7 +24,7 @@ static inline void computeColor(float intensity, float limit, float* destination
 FlatLayerVisualisation::FlatLayerVisualisation(const LayerData &layer, Ordering ordering) :
         LayerVisualisation(layer.numEntries()),
         ordering(ordering),
-        faceCount(layer.numEntries() * 4),
+        faceCount(layer.numEntries() * NODE_FACES.size() / 3),
         vertexBuffer(new float[faceCount * 3]),
         colorBuffer(new float[faceCount * 3]),
         indexBuffer(new int[faceCount * 3])
@@ -33,6 +33,8 @@ FlatLayerVisualisation::FlatLayerVisualisation(const LayerData &layer, Ordering
     CHECK_EQ(shape.size(), 2) << "layer should be flat!" << endl;
     CHECK_EQ(shape[0], 1) << "Only single images supported." << endl;
 
+    initializeNodePositions();
+
     const auto limit = (int) layer.numEntries();
     auto data = layer.data();
     const auto [minElem, maxElem] = minmax_element(data, data + limit);
@@ -41,28 +43,18 @@ FlatLayerVisualisation::FlatLayerVisualisation(const LayerData &layer, Ordering
 
     int v = 0;
     for (int i : Range(limit)) {
-        setVertexPositions(i, vertexBuffer.get() + 12 * i);
-        const int vertexBase = i * 4;
+        setVertexPositions(i, vertexBuffer.get() + NODE_FACES.size() * i);
+        const auto vertexBase = static_cast<int>(i * NODE_FACES.size() / 3);
 
         // Define the colors for the vertices
-        for (int c = 0; c < 4; ++c) {
-            computeColor(data[i], scalingMax, &colorBuffer[12 * i + 3 * c]);
+        for (auto c : Range(NODE_SHAPE.size() / 3)) {
+            computeColor(data[i], scalingMax, &colorBuffer[NODE_FACES.size() * i + 3 * c]);
         }
 
-        // Create the index set for the faces
-        // Simply connect all vertices in ascending order and it works.
-        indexBuffer[v++] = vertexBase;
-        indexBuffer[v++] = vertexBase + 1;
-        indexBuffer[v++] = vertexBase + 2;
-        indexBuffer[v++] = vertexBase;
-        indexBuffer[v++] = vertexBase + 1;
-        indexBuffer[v++] = vertexBase + 3;
-        indexBuffer[v++] = vertexBase;
-        indexBuffer[v++] = vertexBase + 2;
-        indexBuffer[v++] = vertexBase + 3;
-        indexBuffer[v++] = vertexBase + 1;
-        indexBuffer[v++] = vertexBase + 2;
-        indexBuffer[v++] = vertexBase + 3;
+        // Set the face nodes indices
+        for (auto faceNode : NODE_FACES) {
+            indexBuffer[v++] = vertexBase + faceNode;
+        }
     }
     assert(v == (int) faceCount * 3);
 }
@@ -82,42 +74,41 @@ void FlatLayerVisualisation::render()
 
 void FlatLayerVisualisation::setVertexPositions(const int vertexNo, float *destination)
 {
-    int j = 0;
-    float zOffset;
-    float yOffset;
+    for (auto i : Range(NODE_SHAPE.size())) {
+        destination[i] = NODE_SHAPE[i] + nodePositions_[3 * vertexNo + (i % 3)];
+    }
+}
 
+void FlatLayerVisualisation::initializeNodePositions()
+{
     switch (ordering) {
         case Ordering::LINE:
-            zOffset = -2 * vertexNo;
-            yOffset = 0;
+            computeNodePositionsLine();
             break;
 
         case Ordering::SQUARE:
-            const auto nodes = faceCount / 4;
-            auto columns = static_cast<int>(numCols(nodes));
-
-            zOffset = -2 * (vertexNo % columns);
-            yOffset = 2 * (vertexNo / columns);
+            computeNodePositionsSquare();
             break;
     }
-
-    nodePositions_[3 * vertexNo] = 0;
-    nodePositions_[3 * vertexNo + 1] = yOffset;
-    nodePositions_[3 * vertexNo + 2] = zOffset;
-    // TODO: actually compute from this rather than copying to destination.
-    // Side note: should move this out of this function anyway.
-
-    // Create the 4 vertices for the pyramid
-    destination[j++] = -0.5f;
-    destination[j++] = 0 + yOffset; 
-    destination[j++] = 0.5f + zOffset;
-    destination[j++] = 0;
-    destination[j++] = 0 + yOffset;
-    destination[j++] = -0.5f + zOffset;
-    destination[j++] = 0;
-    destination[j++] = 1 + yOffset;
-    destination[j++] = 0 + zOffset;
-    destination[j++] = 0.5;
-    destination[j++] = 0 + yOffset;
-    destination[j++] = 0.5f + zOffset;
+}
+
+void FlatLayerVisualisation::computeNodePositionsSquare()
+{
+    const auto nodes = static_cast<int>(faceCount / 4);
+    const auto columns = numCols(nodes);
+
+    for (auto i : Range(nodes)) {
+        nodePositions_[3 * i + 0] = 0;
+        nodePositions_[3 * i + 1] = 2 * (i / columns);
+        nodePositions_[3 * i + 2] = -2 * (i % columns);
+    }
+}
+
+void FlatLayerVisualisation::computeNodePositionsLine()
+{
+    for (auto i : Range(static_cast<int>(faceCount / 4))) {
+        nodePositions_[3 * i + 0] = 0;
+        nodePositions_[3 * i + 1] = 0;
+        nodePositions_[3 * i + 2] = -2.0f * i;
+    }
 }
diff --git a/src/FlatLayerVisualisation.hpp b/src/FlatLayerVisualisation.hpp
index 4a6da11..7090851 100644
--- a/src/FlatLayerVisualisation.hpp
+++ b/src/FlatLayerVisualisation.hpp
@@ -26,6 +26,24 @@ namespace fmri
         std::unique_ptr<float[]> colorBuffer;
         std::unique_ptr<int[]> indexBuffer;
 
+        static constexpr const std::array<float, 12> NODE_SHAPE = {
+                -0.5f, 0, 0.5f,
+                0, 0, -0.5f,
+                0, 1, 0,
+                0.5f, 0, 0.5f
+        };
+        static constexpr const std::array<int, 12> NODE_FACES = {
+                0, 1, 2,
+                0, 1, 3,
+                0, 2, 3,
+                1, 2, 3
+        };
+
         void setVertexPositions(int vertexNo, float *destination);
+
+        // Various functions defining the way the nodes will be aligned.
+        void initializeNodePositions();
+        void computeNodePositionsLine();
+        void computeNodePositionsSquare();
     };
 }