v1.4.4

source/base/StarCellularLightArray.hpp

@@ -0,0 +1,590 @@
+#ifndef STAR_CELLULAR_LIGHT_ARRAY_HPP
+#define STAR_CELLULAR_LIGHT_ARRAY_HPP
+
+#include "StarList.hpp"
+#include "StarVector.hpp"
+
+namespace Star {
+
+// Operations for simple scalar lighting.
+struct ScalarLightTraits {
+  typedef float Value;
+
+  static float spread(float source, float dest, float drop);
+  static float subtract(float value, float drop);
+
+  static float maxIntensity(float value);
+  static float minIntensity(float value);
+
+  static float max(float v1, float v2);
+};
+
+// Operations for 3 component (colored) lighting.  Spread and subtract are
+// applied proportionally, so that color ratios stay the same, to prevent hues
+// changing as light spreads.
+struct ColoredLightTraits {
+  typedef Vec3F Value;
+
+  static Vec3F spread(Vec3F const& source, Vec3F const& dest, float drop);
+  static Vec3F subtract(Vec3F value, float drop);
+
+  static float maxIntensity(Vec3F const& value);
+  static float minIntensity(Vec3F const& value);
+
+  static Vec3F max(Vec3F const& v1, Vec3F const& v2);
+};
+
+template <typename LightTraits>
+class CellularLightArray {
+public:
+  typedef typename LightTraits::Value LightValue;
+
+  struct Cell {
+    LightValue light;
+    bool obstacle;
+  };
+
+  struct SpreadLight {
+    Vec2F position;
+    LightValue value;
+  };
+
+  struct PointLight {
+    Vec2F position;
+    LightValue value;
+    float beam;
+    float beamAngle;
+    float beamAmbience;
+  };
+
+  void setParameters(unsigned spreadPasses, float spreadMaxAir, float spreadMaxObstacle,
+      float pointMaxAir, float pointMaxObstacle, float pointObstacleBoost);
+
+  // The border around the target lighting array where initial lighting / light
+  // source data is required.  Based on parameters.
+  size_t borderCells() const;
+
+  // Begin a new calculation, setting internal storage to new width and height
+  // (if these are the same as last time this is cheap).  Always clears all
+  // existing light and collision data.
+  void begin(size_t newWidth, size_t newHeight);
+
+  // Position is in index space, spread lights will have no effect if they are
+  // outside of the array.  Integer points are assumed to be on the corners of
+  // the grid (not the center)
+  void addSpreadLight(SpreadLight const& spreadLight);
+  void addPointLight(PointLight const& pointLight);
+
+  // Directly set the lighting values for this position.
+  void setLight(size_t x, size_t y, LightValue const& light);
+
+  // Get current light value.  Call after calling calculate() to pull final
+  // data out.
+  LightValue getLight(size_t x, size_t y) const;
+
+  // Set obstacle values for this position
+  void setObstacle(size_t x, size_t y, bool obstacle);
+  bool getObstacle(size_t x, size_t y) const;
+
+  Cell const& cell(size_t x, size_t y) const;
+  Cell& cell(size_t x, size_t y);
+
+  Cell const& cellAtIndex(size_t index) const;
+  Cell& cellAtIndex(size_t index);
+
+  // Calculate lighting in the given sub-rect, in order to properly do spread
+  // lighting, and initial lighting must be given for the ambient border this
+  // given rect, and the array size must be at least that large.  xMax / yMax
+  // are not inclusive, the range is [xMin, xMax) and [yMin, yMax).
+  void calculate(size_t xMin, size_t yMin, size_t xMax, size_t yMax);
+
+private:
+  // Set 4 points based on interpolated light position and free space
+  // attenuation.
+  void setSpreadLightingPoints();
+
+  // Spreads light out in an octagonal based cellular automata
+  void calculateLightSpread(size_t xmin, size_t ymin, size_t xmax, size_t ymax);
+
+  // Loops through each light and adds light strength based on distance and
+  // obstacle attenuation.  Calculates within the given sub-rect
+  void calculatePointLighting(size_t xmin, size_t ymin, size_t xmax, size_t ymax);
+
+  // Run Xiaolin Wu's anti-aliased line drawing algorithm from start to end,
+  // summing each block that would be drawn to to produce an attenuation.  Not
+  // circularized.
+  float lineAttenuation(Vec2F const& start, Vec2F const& end, float perObstacleAttenuation, float maxAttenuation);
+
+  size_t m_width;
+  size_t m_height;
+  unique_ptr<Cell[]> m_cells;
+  List<SpreadLight> m_spreadLights;
+  List<PointLight> m_pointLights;
+
+  unsigned m_spreadPasses;
+  float m_spreadMaxAir;
+  float m_spreadMaxObstacle;
+  float m_pointMaxAir;
+  float m_pointMaxObstacle;
+  float m_pointObstacleBoost;
+};
+
+typedef CellularLightArray<ColoredLightTraits> ColoredCellularLightArray;
+typedef CellularLightArray<ScalarLightTraits> ScalarCellularLightArray;
+
+inline float ScalarLightTraits::spread(float source, float dest, float drop) {
+  return std::max(source - drop, dest);
+}
+
+inline float ScalarLightTraits::subtract(float c, float drop) {
+  return std::max(c - drop, 0.0f);
+}
+
+inline float ScalarLightTraits::maxIntensity(float value) {
+  return value;
+}
+
+inline float ScalarLightTraits::minIntensity(float value) {
+  return value;
+}
+
+inline float ScalarLightTraits::max(float v1, float v2) {
+  return std::max(v1, v2);
+}
+
+inline Vec3F ColoredLightTraits::spread(Vec3F const& source, Vec3F const& dest, float drop) {
+  float maxChannel = std::max(source[0], std::max(source[1], source[2]));
+  if (maxChannel <= 0.0f)
+    return dest;
+
+  drop /= maxChannel;
+  return Vec3F(
+      std::max(source[0] - source[0] * drop, dest[0]),
+      std::max(source[1] - source[1] * drop, dest[1]),
+      std::max(source[2] - source[2] * drop, dest[2])
+    );
+}
+
+inline Vec3F ColoredLightTraits::subtract(Vec3F c, float drop) {
+  float max = std::max(std::max(c[0], c[1]), c[2]);
+  if (max <= 0.0f)
+    return c;
+
+  for (size_t i = 0; i < 3; ++i) {
+    float pdrop = (drop * c[i]) / max;
+    if (c[i] > pdrop)
+      c[i] -= pdrop;
+    else
+      c[i] = 0;
+  }
+  return c;
+}
+
+inline float ColoredLightTraits::maxIntensity(Vec3F const& value) {
+  return value.max();
+}
+
+inline float ColoredLightTraits::minIntensity(Vec3F const& value) {
+  return value.min();
+}
+
+inline Vec3F ColoredLightTraits::max(Vec3F const& v1, Vec3F const& v2) {
+  return vmax(v1, v2);
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::setParameters(unsigned spreadPasses, float spreadMaxAir, float spreadMaxObstacle,
+    float pointMaxAir, float pointMaxObstacle, float pointObstacleBoost) {
+  m_spreadPasses = spreadPasses;
+  m_spreadMaxAir = spreadMaxAir;
+  m_spreadMaxObstacle = spreadMaxObstacle;
+  m_pointMaxAir = pointMaxAir;
+  m_pointMaxObstacle = pointMaxObstacle;
+  m_pointObstacleBoost = pointObstacleBoost;
+}
+
+template <typename LightTraits>
+size_t CellularLightArray<LightTraits>::borderCells() const {
+  return (size_t)ceil(max(0.0f, max(m_spreadMaxAir, m_pointMaxAir)));
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::begin(size_t newWidth, size_t newHeight) {
+  m_spreadLights.clear();
+  m_pointLights.clear();
+  starAssert(newWidth > 0 && newHeight > 0);
+
+  if (!m_cells || newWidth != m_width || newHeight != m_height) {
+    m_width = newWidth;
+    m_height = newHeight;
+
+    m_cells.reset(new Cell[m_width * m_height]());
+
+  } else {
+    std::fill(m_cells.get(), m_cells.get() + m_width * m_height, Cell{LightValue{}, false});
+  }
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::addSpreadLight(SpreadLight const& spreadLight) {
+  m_spreadLights.append(spreadLight);
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::addPointLight(PointLight const& pointLight) {
+  m_pointLights.append(pointLight);
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::setLight(size_t x, size_t y, LightValue const& lightValue) {
+  cell(x, y).light = lightValue;
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::setObstacle(size_t x, size_t y, bool obstacle) {
+  cell(x, y).obstacle = obstacle;
+}
+
+template <typename LightTraits>
+auto CellularLightArray<LightTraits>::getLight(size_t x, size_t y) const -> LightValue {
+  return cell(x, y).light;
+}
+
+template <typename LightTraits>
+bool CellularLightArray<LightTraits>::getObstacle(size_t x, size_t y) const {
+  return cell(x, y).obstacle;
+}
+
+template <typename LightTraits>
+auto CellularLightArray<LightTraits>::cell(size_t x, size_t y) const -> Cell const & {
+  starAssert(x < m_width && y < m_height);
+  return m_cells[x * m_height + y];
+}
+
+template <typename LightTraits>
+auto CellularLightArray<LightTraits>::cell(size_t x, size_t y) -> Cell & {
+  starAssert(x < m_width && y < m_height);
+  return m_cells[x * m_height + y];
+}
+
+template <typename LightTraits>
+auto CellularLightArray<LightTraits>::cellAtIndex(size_t index) const -> Cell const & {
+  starAssert(index < m_width * m_height);
+  return m_cells[index];
+}
+
+template <typename LightTraits>
+auto CellularLightArray<LightTraits>::cellAtIndex(size_t index) -> Cell & {
+  starAssert(index < m_width * m_height);
+  return m_cells[index];
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::calculate(size_t xMin, size_t yMin, size_t xMax, size_t yMax) {
+  setSpreadLightingPoints();
+  calculateLightSpread(xMin, yMin, xMax, yMax);
+  calculatePointLighting(xMin, yMin, xMax, yMax);
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::setSpreadLightingPoints() {
+  for (SpreadLight const& light : m_spreadLights) {
+    // - 0.5f to correct for lights being on the grid corners and not center
+    int minX = floor(light.position[0] - 0.5f);
+    int minY = floor(light.position[1] - 0.5f);
+    int maxX = minX + 1;
+    int maxY = minY + 1;
+
+    float xdist = light.position[0] - minX - 0.5f;
+    float ydist = light.position[1] - minY - 0.5f;
+
+    // Pick falloff here based on closest block obstacle value (probably not
+    // best)
+    Vec2I pos(light.position.floor());
+    float oneBlockAtt;
+    if (pos[0] >= 0 && pos[0] < (int)m_width && pos[1] >= 0 && pos[1] < (int)m_height && getObstacle(pos[0], pos[1]))
+      oneBlockAtt = 1.0f / m_spreadMaxObstacle;
+    else
+      oneBlockAtt = 1.0f / m_spreadMaxAir;
+
+    // "pre fall-off" a 2x2 area of blocks to smooth out floating point
+    // positions using the cellular algorithm
+
+    if (minX >= 0 && minX < (int)m_width && minY >= 0 && minY < (int)m_height)
+      setLight(minX, minY, LightTraits::max(getLight(minX, minY), LightTraits::subtract(light.value, oneBlockAtt * (2.0f - (1.0f - xdist) - (1.0f - ydist)))));
+
+    if (minX >= 0 && minX < (int)m_width && maxY >= 0 && maxY < (int)m_height)
+      setLight(minX, maxY, LightTraits::max(getLight(minX, maxY), LightTraits::subtract(light.value, oneBlockAtt * (2.0f - (1.0f - xdist) - (ydist)))));
+
+    if (maxX >= 0 && maxX < (int)m_width && minY >= 0 && minY < (int)m_height)
+      setLight(maxX, minY, LightTraits::max(getLight(maxX, minY), LightTraits::subtract(light.value, oneBlockAtt * (2.0f - (xdist) - (1.0f - ydist)))));
+
+    if (maxX >= 0 && maxX < (int)m_width && maxY >= 0 && maxY < (int)m_height)
+      setLight(maxX, maxY, LightTraits::max(getLight(maxX, maxY), LightTraits::subtract(light.value, oneBlockAtt * (2.0f - (xdist) - (ydist)))));
+  }
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::calculateLightSpread(size_t xMin, size_t yMin, size_t xMax, size_t yMax) {
+  starAssert(m_width > 0 && m_height > 0);
+
+  float dropoffAir = 1.0f / m_spreadMaxAir;
+  float dropoffObstacle = 1.0f / m_spreadMaxObstacle;
+  float dropoffAirDiag = 1.0f / m_spreadMaxAir * Constants::sqrt2;
+  float dropoffObstacleDiag = 1.0f / m_spreadMaxObstacle * Constants::sqrt2;
+
+  // enlarge x/y min/max taking into ambient spread of light
+  xMin = xMin - min(xMin, (size_t)ceil(m_spreadMaxAir));
+  yMin = yMin - min(yMin, (size_t)ceil(m_spreadMaxAir));
+  xMax = min(m_width, xMax + (size_t)ceil(m_spreadMaxAir));
+  yMax = min(m_height, yMax + (size_t)ceil(m_spreadMaxAir));
+
+  for (unsigned p = 0; p < m_spreadPasses; ++p) {
+    // Spread right and up and diag up right / diag down right
+    for (size_t x = xMin + 1; x < xMax - 1; ++x) {
+      size_t xCellOffset = x * m_height;
+      size_t xRightCellOffset = (x + 1) * m_height;
+
+      for (size_t y = yMin + 1; y < yMax - 1; ++y) {
+        auto cell = cellAtIndex(xCellOffset + y);
+        auto& cellRight = cellAtIndex(xRightCellOffset + y);
+        auto& cellUp = cellAtIndex(xCellOffset + y + 1);
+        auto& cellRightUp = cellAtIndex(xRightCellOffset + y + 1);
+        auto& cellRightDown = cellAtIndex(xRightCellOffset + y - 1);
+
+        float straightDropoff = cell.obstacle ? dropoffObstacle : dropoffAir;
+        float diagDropoff = cell.obstacle ? dropoffObstacleDiag : dropoffAirDiag;
+
+        cellRight.light = LightTraits::spread(cell.light, cellRight.light, straightDropoff);
+        cellUp.light = LightTraits::spread(cell.light, cellUp.light, straightDropoff);
+
+        cellRightUp.light = LightTraits::spread(cell.light, cellRightUp.light, diagDropoff);
+        cellRightDown.light = LightTraits::spread(cell.light, cellRightDown.light, diagDropoff);
+      }
+    }
+
+    // Spread left and down and diag up left / diag down left
+    for (size_t x = xMax - 2; x > xMin; --x) {
+      size_t xCellOffset = x * m_height;
+      size_t xLeftCellOffset = (x - 1) * m_height;
+
+      for (size_t y = yMax - 2; y > yMin; --y) {
+        auto cell = cellAtIndex(xCellOffset + y);
+        auto& cellLeft = cellAtIndex(xLeftCellOffset + y);
+        auto& cellDown = cellAtIndex(xCellOffset + y - 1);
+        auto& cellLeftUp = cellAtIndex(xLeftCellOffset + y + 1);
+        auto& cellLeftDown = cellAtIndex(xLeftCellOffset + y - 1);
+
+        float straightDropoff = cell.obstacle ? dropoffObstacle : dropoffAir;
+        float diagDropoff = cell.obstacle ? dropoffObstacleDiag : dropoffAirDiag;
+
+        cellLeft.light = LightTraits::spread(cell.light, cellLeft.light, straightDropoff);
+        cellDown.light = LightTraits::spread(cell.light, cellDown.light, straightDropoff);
+
+        cellLeftUp.light = LightTraits::spread(cell.light, cellLeftUp.light, diagDropoff);
+        cellLeftDown.light = LightTraits::spread(cell.light, cellLeftDown.light, diagDropoff);
+      }
+    }
+  }
+}
+
+template <typename LightTraits>
+void CellularLightArray<LightTraits>::calculatePointLighting(size_t xmin, size_t ymin, size_t xmax, size_t ymax) {
+  float perBlockObstacleAttenuation = 1.0f / m_pointMaxObstacle;
+  float perBlockAirAttenuation = 1.0f / m_pointMaxAir;
+
+  for (PointLight light : m_pointLights) {
+    if (light.position[0] < 0 || light.position[0] > m_width - 1 || light.position[1] < 0 || light.position[1] > m_height - 1)
+      continue;
+
+    float maxIntensity = LightTraits::maxIntensity(light.value);
+    Vec2F beamDirection = Vec2F(1, 0).rotate(light.beamAngle);
+
+    float maxRange = maxIntensity * m_pointMaxAir;
+    // The min / max considering the radius of the light
+    size_t lxmin = std::floor(std::max<float>(xmin, light.position[0] - maxRange));
+    size_t lymin = std::floor(std::max<float>(ymin, light.position[1] - maxRange));
+    size_t lxmax = std::ceil(std::min<float>(xmax, light.position[0] + maxRange));
+    size_t lymax = std::ceil(std::min<float>(ymax, light.position[1] + maxRange));
+
+    for (size_t x = lxmin; x < lxmax; ++x) {
+      for (size_t y = lymin; y < lymax; ++y) {
+        LightValue lvalue = getLight(x, y);
+        // + 0.5f to correct block position to center
+        Vec2F blockPos = Vec2F(x + 0.5f, y + 0.5f);
+
+        Vec2F relativeLightPosition = blockPos - light.position;
+        float distance = relativeLightPosition.magnitude();
+        if (distance == 0.0f) {
+          setLight(x, y, LightTraits::max(light.value, lvalue));
+          continue;
+        }
+
+        float attenuation = distance * perBlockAirAttenuation;
+        if (attenuation >= 1.0f)
+          continue;
+
+        Vec2F direction = relativeLightPosition / distance;
+        if (light.beam > 0.0f) {
+          attenuation += (1.0f - light.beamAmbience) * clamp(light.beam * (1.0f - direction * beamDirection), 0.0f, 1.0f);
+          if (attenuation >= 1.0f)
+            continue;
+        }
+
+        float remainingAttenuation = maxIntensity - LightTraits::minIntensity(lvalue) - attenuation;
+        if (remainingAttenuation <= 0.0f)
+          continue;
+
+        // Need to circularize manhattan attenuation here
+        float circularizedPerBlockObstacleAttenuation = perBlockObstacleAttenuation / max(fabs(direction[0]), fabs(direction[1]));
+        float blockAttenuation = lineAttenuation(blockPos, light.position, circularizedPerBlockObstacleAttenuation, remainingAttenuation);
+
+        // Apply single obstacle boost (determine single obstacle by one
+        // block unit of attenuation).
+        attenuation += blockAttenuation + min(blockAttenuation, circularizedPerBlockObstacleAttenuation) * m_pointObstacleBoost;
+
+        if (attenuation < 1.0f)
+          setLight(x, y, LightTraits::max(LightTraits::subtract(light.value, attenuation), lvalue));
+      }
+    }
+  }
+}
+
+template <typename LightTraits>
+float CellularLightArray<LightTraits>::lineAttenuation(Vec2F const& start, Vec2F const& end,
+    float perObstacleAttenuation, float maxAttenuation) {
+  // Run Xiaolin Wu's line algorithm from start to end, summing over colliding
+  // blocks using perObstacleAttenuation.
+  float obstacleAttenuation = 0.0;
+
+  // Apply correction because integer coordinates are lower left corner.
+  float x1 = start[0] - 0.5;
+  float y1 = start[1] - 0.5;
+  float x2 = end[0] - 0.5;
+  float y2 = end[1] - 0.5;
+
+  float dx = x2 - x1;
+  float dy = y2 - y1;
+
+  if (fabs(dx) < fabs(dy)) {
+    if (y2 < y1) {
+      swap(y1, y2);
+      swap(x1, x2);
+    }
+
+    float gradient = dx / dy;
+
+    // first end point
+    float yend = round(y1);
+    float xend = x1 + gradient * (yend - y1);
+    float ygap = rfpart(y1 + 0.5);
+    int ypxl1 = yend;
+    int xpxl1 = ipart(xend);
+
+    if (cell(xpxl1, ypxl1).obstacle)
+      obstacleAttenuation += rfpart(xend) * ygap * perObstacleAttenuation;
+
+    if (cell(xpxl1 + 1, ypxl1).obstacle)
+      obstacleAttenuation += fpart(xend) * ygap * perObstacleAttenuation;
+
+    if (obstacleAttenuation >= maxAttenuation)
+      return maxAttenuation;
+
+    float interx = xend + gradient;
+
+    // second end point
+    yend = round(y2);
+    xend = x2 + gradient * (yend - y2);
+    ygap = fpart(y2 + 0.5);
+    int ypxl2 = yend;
+    int xpxl2 = ipart(xend);
+
+    if (cell(xpxl2, ypxl2).obstacle)
+      obstacleAttenuation += rfpart(xend) * ygap * perObstacleAttenuation;
+
+    if (cell(xpxl2 + 1, ypxl2).obstacle)
+      obstacleAttenuation += fpart(xend) * ygap * perObstacleAttenuation;
+
+    if (obstacleAttenuation >= maxAttenuation)
+      return maxAttenuation;
+
+    for (int y = ypxl1 + 1; y < ypxl2; ++y) {
+      int interxIpart = ipart(interx);
+      float interxFpart = interx - interxIpart;
+      float interxRFpart = 1.0 - interxFpart;
+
+      if (cell(interxIpart, y).obstacle)
+        obstacleAttenuation += interxRFpart * perObstacleAttenuation;
+      if (cell(interxIpart + 1, y).obstacle)
+        obstacleAttenuation += interxFpart * perObstacleAttenuation;
+
+      if (obstacleAttenuation >= maxAttenuation)
+        return maxAttenuation;
+
+      interx += gradient;
+    }
+  } else {
+    if (x2 < x1) {
+      swap(x1, x2);
+      swap(y1, y2);
+    }
+
+    float gradient = dy / dx;
+
+    // first end point
+    float xend = round(x1);
+    float yend = y1 + gradient * (xend - x1);
+    float xgap = rfpart(x1 + 0.5);
+    int xpxl1 = xend;
+    int ypxl1 = ipart(yend);
+
+    if (cell(xpxl1, ypxl1).obstacle)
+      obstacleAttenuation += rfpart(yend) * xgap * perObstacleAttenuation;
+
+    if (cell(xpxl1, ypxl1 + 1).obstacle)
+      obstacleAttenuation += fpart(yend) * xgap * perObstacleAttenuation;
+
+    if (obstacleAttenuation >= maxAttenuation)
+      return maxAttenuation;
+
+    float intery = yend + gradient;
+
+    // second end point
+    xend = round(x2);
+    yend = y2 + gradient * (xend - x2);
+    xgap = fpart(x2 + 0.5);
+    int xpxl2 = xend;
+    int ypxl2 = ipart(yend);
+
+    if (cell(xpxl2, ypxl2).obstacle)
+      obstacleAttenuation += rfpart(yend) * xgap * perObstacleAttenuation;
+
+    if (cell(xpxl2, ypxl2 + 1).obstacle)
+      obstacleAttenuation += fpart(yend) * xgap * perObstacleAttenuation;
+
+    if (obstacleAttenuation >= maxAttenuation)
+      return maxAttenuation;
+
+    for (int x = xpxl1 + 1; x < xpxl2; ++x) {
+      int interyIpart = ipart(intery);
+      float interyFpart = intery - interyIpart;
+      float interyRFpart = 1.0 - interyFpart;
+
+      if (cell(x, interyIpart).obstacle)
+        obstacleAttenuation += interyRFpart * perObstacleAttenuation;
+      if (cell(x, interyIpart + 1).obstacle)
+        obstacleAttenuation += interyFpart * perObstacleAttenuation;
+
+      if (obstacleAttenuation >= maxAttenuation)
+        return maxAttenuation;
+
+      intery += gradient;
+    }
+  }
+
+  return min(obstacleAttenuation, maxAttenuation);
+}
+
+}
+
+#endif