1 files changed, 69 insertions, 0 deletions
diff --git a/source/game/terrain/StarDisplacementSelector.cpp b/source/game/terrain/StarDisplacementSelector.cpp
new file mode 100644
index 0000000..9047f3a
--- /dev/null
+++ b/source/game/terrain/StarDisplacementSelector.cpp
@@ -0,0 +1,69 @@
+#include "StarDisplacementSelector.hpp"
+#include "StarRandom.hpp"
+#include "StarJsonExtra.hpp"
+
+namespace Star {
+
+char const* const DisplacementSelector::Name = "displacement";
+
+DisplacementSelector::DisplacementSelector(
+    Json const& config, TerrainSelectorParameters const& parameters, TerrainDatabase const* database)
+  : TerrainSelector(Name, config, parameters) {
+  RandomSource random(parameters.seed);
+
+  auto xType = PerlinTypeNames.getLeft(config.getString("xType"));
+  auto xOctaves = config.getFloat("xOctaves");
+  auto xFreq = config.getFloat("xFreq");
+  auto xAmp = config.getFloat("xAmp");
+  auto xBias = config.getFloat("xBias", 0.0f);
+  auto xAlpha = config.getFloat("xAlpha", 2.0f);
+  auto xBeta = config.getFloat("xBeta", 2.0f);
+
+  xDisplacementFunction = PerlinF(xType, xOctaves, xFreq, xAmp, xBias, xAlpha, xBeta, random.randu64());
+
+  auto yType = PerlinTypeNames.getLeft(config.getString("yType"));
+  auto yOctaves = config.getFloat("yOctaves");
+  auto yFreq = config.getFloat("yFreq");
+  auto yAmp = config.getFloat("yAmp");
+  auto yBias = config.getFloat("yBias", 0.0f);
+  auto yAlpha = config.getFloat("yAlpha", 2.0f);
+  auto yBeta = config.getFloat("yBeta", 2.0f);
+
+  yDisplacementFunction = PerlinF(yType, yOctaves, yFreq, yAmp, yBias, yAlpha, yBeta, random.randu64());
+
+  xXInfluence = config.getFloat("xXInfluence", 1.0f);
+  xYInfluence = config.getFloat("xYInfluence", 1.0f);
+  yXInfluence = config.getFloat("yXInfluence", 1.0f);
+  yYInfluence = config.getFloat("yYInfluence", 1.0f);
+
+  yClamp = config.contains("yClamp");
+  if (yClamp) {
+    yClampRange = jsonToVec2F(config.get("yClamp"));
+    yClampSmoothing = config.getFloat("yClampSmoothing", 0);
+  }
+
+  auto sourceConfig = config.get("source");
+  String sourceType = sourceConfig.getString("type");
+  m_source = database->createSelectorType(sourceType, sourceConfig, parameters);
+}
+
+float DisplacementSelector::get(int x, int y) const {
+  auto x_ = x + xDisplacementFunction.get(x * xXInfluence, y * xYInfluence);
+  auto y_ = y + clampY(yDisplacementFunction.get(x * yXInfluence, y * yYInfluence));
+  return m_source->get(x_, y_);
+}
+
+float DisplacementSelector::clampY(float v) const {
+  if (!yClamp)
+    return v;
+  if (yClampSmoothing == 0)
+    return clamp(v, yClampRange[0], yClampRange[1]);
+
+  return 0.2f * (clamp(v - yClampSmoothing, yClampRange[0], yClampRange[1])
+      + clamp(v - 0.5f * yClampSmoothing, yClampRange[0], yClampRange[1])
+      + clamp(v, yClampRange[0], yClampRange[1])
+      + clamp(v + 0.5f * yClampSmoothing, yClampRange[0], yClampRange[1])
+      + clamp(v + yClampSmoothing, yClampRange[0], yClampRange[1]));
+}
+
+}