Reimplement drawing system with vertex buffers.

Now with 10000% more performance.

src/MultiImageVisualisation.cpp

@@ -0,0 +1,37 @@
+#include <glog/logging.h>
+#include "MultiImageVisualisation.hpp"
+#include "glutils.hpp"
+
+using namespace fmri;
+using namespace std;
+
+MultiImageVisualisation::MultiImageVisualisation(const fmri::LayerData &layer)
+{
+    auto dimensions = layer.shape();
+    CHECK_EQ(4, dimensions.size()) << "Should be image-like layer";
+
+    const auto images = dimensions[0],
+            channels = dimensions[1],
+            width = dimensions[2],
+            height = dimensions[3];
+
+    auto dataPtr = layer.data();
+    for (auto i = 0; i < images; ++i) {
+        for (auto j = 0; j < channels; ++j) {
+            textureReferences[make_pair(i, j)] = loadTexture(dataPtr, width, height);
+            dataPtr += width * height;
+        }
+    }
+}
+
+MultiImageVisualisation::~MultiImageVisualisation()
+{
+    for (auto entry : textureReferences) {
+        glDeleteTextures(0, &entry.second);
+    }
+}
+
+void MultiImageVisualisation::render()
+{
+    // TODO: do something.
+}