Fixed #1 (black tile issue) and drafted building model gen code

core/src/main/kotlin/com/decosegfault/atlas/map/BuildingGenerator.kt

@@ -1,10 +1,19 @@
 package com.decosegfault.atlas.map
 
+import com.badlogic.gdx.graphics.Color
+import com.badlogic.gdx.graphics.GL20
+import com.badlogic.gdx.graphics.VertexAttributes
+import com.badlogic.gdx.graphics.g3d.Material
+import com.badlogic.gdx.graphics.g3d.Model
 import com.badlogic.gdx.graphics.g3d.ModelCache
-import com.badlogic.gdx.math.DelaunayTriangulator
+import com.badlogic.gdx.graphics.g3d.ModelInstance
+import com.badlogic.gdx.graphics.g3d.utils.ModelBuilder
+import com.badlogic.gdx.graphics.g3d.utils.shapebuilders.BoxShapeBuilder
+import com.badlogic.gdx.math.MathUtils
 import com.badlogic.gdx.math.Vector2
-import com.badlogic.gdx.math.Vector3
+import com.decosegfault.atlas.util.Triangle
 import io.github.sebasbaumh.postgis.PGgeometry
+import net.mgsx.gltf.scene3d.attributes.PBRColorAttribute
 import org.postgresql.PGConnection
 import org.postgresql.geometric.PGpolygon
 import org.tinylog.kotlin.Logger
@@ -35,6 +44,12 @@ object BuildingGenerator {
     /** Approximate height in metres of one storey. Source: https://en.wikipedia.org/wiki/Storey#Overview */
     private const val STOREY_HEIGHT = 4.3f
 
+    /**
+     * The tallest building in Brisbane is currently the Brisbane Skytower which is 90 storeys tall
+     * We clamp building storeys to this many in case of OSM data misinputs so they're not mega tall
+     */
+    private const val MAX_STOREYS = 90f
+
     /**
      * Query to find polygons and tags for OSM buildings in a bounding box. Assumes coordinates in Web
      * Mercator (EPSG coord ID 3857), which is true for this osm2pgsql generated PostGIS DB.
@@ -49,6 +64,12 @@ object BuildingGenerator {
         |AND building IS NOT NULL;
     """.trimMargin()
 
+    private val BUILDING_COLOUR = Color.LIGHT_GRAY
+
+    private val BUILDING_MATERIAL = Material().apply {
+        set(PBRColorAttribute.createBaseColorFactor(BUILDING_COLOUR))
+    }
+
     private lateinit var conn: Connection
 
     /** Prepared statement consisting of [BUILDING_QUERY] */
@@ -117,12 +138,42 @@ object BuildingGenerator {
         return buildings
     }
 
+    /**
+     * Extrudes the given triangulated base of a building into a 3D model
+     * @param height height in metres
+     */
+    private fun extrudeToModel(tris: List<Triangle>, height: Float): Model {
+        val modelBuilder = ModelBuilder()
+        val mpb = modelBuilder.part(
+            "building", GL20.GL_TRIANGLES,
+            VertexAttributes.Usage.Position.toLong() or VertexAttributes.Usage.Normal.toLong(),
+            BUILDING_MATERIAL
+        )
+        BoxShapeBuilder.build(mpb, 5f, height, 5f)
+        return modelBuilder.end()
+    }
+
     /**
      * Generates a building chunk. Buildings are packaged together into a ModelCache.
      */
-    fun generateBuildingChunk(chunk: Vector3): ModelCache {
+    fun generateBuildingChunk(buildings: Set<Building>): ModelCache {
         val cache = ModelCache()
         cache.begin()
+
+        for (building in buildings) {
+            // calculate the triangulation of the floor plan
+            val triangles = building.triangulate()
+
+            // limit the height of buildings in case of errors, and if a height is missing give a default
+            // height of 1 floor
+            val height = MathUtils.clamp(building.floors.toFloat(), 1f, MAX_STOREYS) * STOREY_HEIGHT
+
+            // extrude the triangulation into a 3D model and insert into cache
+            val model = extrudeToModel(triangles, height) // FIXME: memory leak here (need to free model)
+            val instance = ModelInstance(model)
+            cache.add(instance)
+        }
+
         cache.end()
         return cache
     }

core/src/main/kotlin/com/decosegfault/atlas/map/GCBuildingCache.kt

@@ -1,6 +1,7 @@
 package com.decosegfault.atlas.map
 
 import com.badlogic.gdx.graphics.g3d.ModelCache
+import com.badlogic.gdx.math.MathUtils
 import com.badlogic.gdx.math.Vector2
 import com.badlogic.gdx.math.Vector3
 import com.decosegfault.atlas.util.AbstractGarbageCollectedCache
@@ -48,6 +49,9 @@ object GCBuildingCache : AbstractGarbageCollectedCache<Vector3, ModelCache>(
         // now we have the actual list of buildings to process on this thread, register them
         buildingAssignments[key] = buildings.toList()
 
+        // process buildings
+        val chunk = BuildingGenerator.generateBuildingChunk(buildings)
+
         throw NotImplementedError()
     }
 

core/src/main/kotlin/com/decosegfault/atlas/screens/SimulationScreen.kt

@@ -277,7 +277,7 @@ class SimulationScreen(private val game: Game) : ScreenAdapter() {
             isDebugDraw = !isDebugDraw
         } else if (Gdx.input.isKeyJustPressed(Input.Keys.RIGHT_BRACKET)) {
             // forces tile cache GC
-            GCTileCache.garbageCollect(true)
+            GCTileCache.gcNextFrame()
         } else if (Gdx.input.isKeyJustPressed(Input.Keys.ENTER)) {
             // toggle fullscreen
             if (Gdx.graphics.isFullscreen) {

core/src/main/kotlin/com/decosegfault/atlas/util/AbstractGarbageCollectedCache.kt

@@ -62,6 +62,7 @@ abstract class AbstractGarbageCollectedCache<K, V : Disposable>(
     private var hits = 0
     private var misses = 0
     private var total = 0
+    private var shouldGcNextFrame = false
 
     /** Implementers should override this function to instantiate a new item. Can block for as long as you want. */
     abstract fun newItem(key: K): V
@@ -72,7 +73,6 @@ abstract class AbstractGarbageCollectedCache<K, V : Disposable>(
      */
     fun retrieve(item: K, onRetrieved: (V) -> Unit) {
         val begin = System.nanoTime()
-        garbageCollect()
         val maybeItem = cache[item]
         if (maybeItem != null) {
             // tile was already in cache
@@ -129,11 +129,23 @@ abstract class AbstractGarbageCollectedCache<K, V : Disposable>(
         }
     }
 
-    /** Clears items in use for the next frame */
+    /** Performs garbage collection and clears items in use for next frame */
     fun nextFrame() {
+        if (shouldGcNextFrame) {
+            Logger.debug("Forcing GC this frame")
+            garbageCollect(true)
+            shouldGcNextFrame = false
+        } else {
+            garbageCollect()
+        }
         itemsInUse.clear()
     }
 
+    /** Tells the garbage collector to GC on the next frame */
+    fun gcNextFrame() {
+        shouldGcNextFrame = true
+    }
+
     /** Tells the cache that the item is in use and should not be GCd */
     fun markUsed(item: K) {
         itemsInUse.add(item)

docs/atlas_buildings_design.md

@@ -75,3 +75,21 @@ database is entirely in Web Mercator coords, which is great for us. Sources:
 **Extrusion**
 
 TODO
+
+**Coordinates**
+
+Centre of Brisbane in Atlas is: `-27.410786,153.01758`
+
+Convert to EPSG 3857 Web Mercator (from WGS84 to Web Mercator):
+https://epsg.io/transform#s_srs=4326&t_srs=3857&x=153.0175800&y=-27.4107860
+
+Yields: `x=17033839.088019006, y=-3174888.4441493554`
+
+Subtract these from the PostGIS database to centre the buildings
+
+---
+
+random building web mercator: `17042011.25221322 -3178371.2622345123`
+
+actual in game: `27370.577 11667.356`
+