ExtentCalculation.h

#pragma once
 
#include "ClipmapState.h"
#include "ClipmapLevel.h"
#include "Raster/RasterLevel.h"
 
namespace Cogs
{
  inline void updateImageryExtent(Cogs::ClipmapLevel & imageryLevel, const Cogs::ClipmapLevel & terrainLevel)
  {
    const int imageryWest = (int)imageryLevel.rasterLevel->longitudeToIndex(terrainLevel.rasterLevel->indexToLongitude(terrainLevel.nextExtent.west));
    const int imagerySouth = (int)imageryLevel.rasterLevel->latitudeToIndex(terrainLevel.rasterLevel->indexToLatitude(terrainLevel.nextExtent.south));
 
    imageryLevel.nextExtent.west = imageryWest;
    imageryLevel.nextExtent.east = imageryWest + imageryLevel.renderTexture.width - 1;
    imageryLevel.nextExtent.south = imagerySouth;
    imageryLevel.nextExtent.north = imagerySouth + imageryLevel.renderTexture.height - 1;
  }
 
  inline void calculateNextExtent(double longitude, double latitude, const Cogs::ClipmapState & clipmapState, Cogs::ClipmapLevel & firstTerrainLevel)
  {
    const double longitudeIndex = firstTerrainLevel.rasterLevel->longitudeToIndex(longitude);
    const double latitudeIndex = firstTerrainLevel.rasterLevel->latitudeToIndex(latitude);
 
    int west = (int)(longitudeIndex - clipmapState.clipmapPosts / 2);
    int south = (int)(latitudeIndex - clipmapState.clipmapPosts / 2);
 
    // Ensure the finest clipmap is always positioned at even coordinates.
    if ((west % 2) != 0) ++west;
    if ((south % 2) != 0) ++south;
 
    firstTerrainLevel.nextExtent.west = west;
    firstTerrainLevel.nextExtent.east = west + static_cast<int>(clipmapState.clipmapSegments);
    firstTerrainLevel.nextExtent.south = south;
    firstTerrainLevel.nextExtent.north = south + static_cast<int>(clipmapState.clipmapSegments);
  }
 
  inline void calculateLevelNextExtent(Cogs::ClipmapLevel & terrainLevel, const Cogs::ClipmapLevel & finerLevel, const Cogs::ClipmapState & clipmapState)
  {
    terrainLevel.nextExtent.west = finerLevel.nextExtent.west / 2 - static_cast<int>(clipmapState.fillPatchSegments);
    terrainLevel.offsetStripOnEast = (terrainLevel.nextExtent.west % 2) == 0;
 
    if (!terrainLevel.offsetStripOnEast) {
      --terrainLevel.nextExtent.west;
    }
 
    terrainLevel.nextExtent.east = terrainLevel.nextExtent.west + static_cast<int>(clipmapState.clipmapSegments);
 
    terrainLevel.nextExtent.south = finerLevel.nextExtent.south / 2 - static_cast<int>(clipmapState.fillPatchSegments);
    terrainLevel.offsetStripOnNorth = (terrainLevel.nextExtent.south % 2) == 0;
 
    if (!terrainLevel.offsetStripOnNorth) {
      --terrainLevel.nextExtent.south;
    }
 
    terrainLevel.nextExtent.north = terrainLevel.nextExtent.south + static_cast<int>(clipmapState.clipmapSegments);
  }
}