Fix problems with models and depth precision in ortho camera (interna…

…l-2152)

This PR fixes two problems with ortho projection, one when models are close to the camera and the precision was being lost, and the other when using transparent models being culled, (mostly visible with terrain enabled).

3d-style/render/draw_model.ts

@@ -289,11 +289,10 @@ function prepareMeshes(transform: Transform, node: ModelNode, modelMatrix: mat4,
             }
 
             const centroidPos = vec3.transformMat4([] as any, mesh.centroid, worldViewProjection);
-            // Filter meshes behind the camera
-            if (centroidPos[2] > 0.0) {
-                const transparentMesh: SortedMesh = {mesh, depth: centroidPos[2], modelIndex, worldViewProjection, nodeModelMatrix};
-                transparentMeshes.push(transparentMesh);
-            }
+            // Filter meshes behind the camera if in perspective mode
+            if (!transform.isOrthographic && centroidPos[2] <= 0.0) continue;
+            const transparentMesh: SortedMesh = {mesh, depth: centroidPos[2], modelIndex, worldViewProjection, nodeModelMatrix};
+            transparentMeshes.push(transparentMesh);
         }
     }
     if (node.children) {

src/geo/projection/far_z.ts

@@ -26,7 +26,9 @@ export function farthestPixelDistanceOnPlane(tr: Transform, pixelsPerMeter: numb
     // Due to precision of sources with low maxZoom, content is prone to flickering on zoom above 18.
     // Use larger furthest distance also on pitch before the horizon, especially on higher zoom to limit
     // the performance and depth range resolution impact.
-    if (!tr.elevation || tr.elevation.exaggeration() === 0) {
+    // In case of orthographic projection we don't want to extend the far clip plane as the
+    // depth is linear and we would be effectively decreasing precision.
+    if (!tr.isOrthographic && (!tr.elevation || tr.elevation.exaggeration() === 0)) {
         furthestDistance *= (1.0 + Math.max(tr.zoom - 17, 0));
     }
     return Math.min(furthestDistance * 1.01, horizonDistance);

test/integration/render-tests/model-layer/camera-projection/camera-orthographic-model-depth-terrain/style.json

@@ -0,0 +1,233 @@
+{
+  "version": 8,
+   "metadata": {
+    "test": {
+      "operations": [
+        [
+            "wait",
+            600
+        ]
+      ],
+      "width": 512,
+      "height": 512,
+      "allowed": 0.0008
+    }
+  },
+  "terrain": {
+    "source": "mapbox-dem",
+    "exaggeration": 1
+  },
+  "lights": [
+    {
+      "type": "ambient",
+      "id": "environment",
+      "properties": {
+        "color": "rgba(255.0, 255.0, 255.0, 1.0)",
+        "intensity": 0.5
+      }
+    },
+    {
+      "type": "directional",
+      "id": "sun_light",
+      "properties": {
+        "color": "rgba(255.0, 255.0, 255.0, 1.0)",
+        "intensity": 0.5,
+        "cast-shadows": false
+      }
+    }
+  ],
+  "sources": {
+     "mapbox-dem": {
+      "type": "raster-dem",
+      "maxzoom": 14,
+      "tileSize": 512,
+      "tiles": ["local://models/dem/14-8847-5550.terrain-512.png"]
+    },
+    "mapbox": {
+      "type": "vector",
+      "maxzoom": 16,
+      "tiles": [
+        "local://tiles/{z}-{x}-{y}.mvt"
+      ]
+    },
+    "model": {
+      "type": "model",
+      "models": {
+        "model-1" : {
+          "uri": "local://models/cubes-depth.gltf",
+          "position": [14.3946, 50.0834],
+          "orientation": [0, 0, 0]
+        }
+      }
+    }
+  },
+  "pitch": 0,
+  "zoom": 18.0,
+  "bearing": 0,
+  "center": [
+    14.3946,
+    50.0834
+  ],
+  "camera": {
+        "camera-projection": "orthographic"
+  },
+  "glyphs": "local://glyphs/{fontstack}/{range}.pbf",
+  "layers": [
+    {
+      "id": "background",
+      "type": "background",
+      "paint": {
+        "background-color": "lightgray"
+      }
+    },
+    {
+      "id": "land",
+      "type": "fill",
+      "source": "mapbox",
+      "source-layer": "water",
+      "paint": {
+        "fill-color": "lightblue"
+      }
+    },
+    {
+      "id": "road",
+      "type": "line",
+      "source": "mapbox",
+      "source-layer": "road",
+      "paint": {
+          "line-color": "lightyellow",
+          "line-width": 10
+      }
+    },
+    {
+      "id": "extrusion",
+      "type": "fill-extrusion",
+      "source": "mapbox",
+      "source-layer": "building",
+      "paint": {
+        "fill-extrusion-color": "white",
+        "fill-extrusion-height": ["get", "height"]
+      }
+    },
+    {
+      "filter": [
+        "match",
+        [
+          "get",
+          "class"
+        ],
+        [
+          "motorway",
+          "primary",
+          "secondary",
+          "street",
+          "street_limited",
+          "tertiary",
+          "trunk"
+        ],
+        true,
+        false
+      ],
+      "id": "road-label-simple",
+      "layout": {
+        "symbol-placement": "line",
+        "text-field": [
+          "format",
+          [
+            "coalesce",
+            [
+              "get",
+              "name_en"
+            ],
+            [
+              "get",
+              "name"
+            ]
+          ],
+          {}
+        ],
+        "text-font": [
+              "Open Sans Semibold",
+              "Arial Unicode MS Bold"
+        ],
+        "text-letter-spacing": 0.009999999776482582,
+        "text-max-angle": 30.0,
+        "text-padding": 1.0,
+        "text-pitch-alignment": "viewport",
+        "text-rotation-alignment": "map",
+        "text-size": [
+          "interpolate",
+          [
+            "linear"
+          ],
+          [
+            "zoom"
+          ],
+          10.0,
+          [
+            "match",
+            [
+              "get",
+              "class"
+            ],
+            [
+              "motorway",
+              "primary",
+              "secondary",
+              "tertiary",
+              "trunk"
+            ],
+            10.0,
+            9.0
+          ],
+          18.0,
+          [
+            "match",
+            [
+              "get",
+              "class"
+            ],
+            [
+              "motorway",
+              "primary",
+              "secondary",
+              "tertiary",
+              "trunk"
+            ],
+            16.0,
+            14.0
+          ]
+        ]
+      },
+      "minzoom": 12.0,
+      "paint": {
+        "text-color": [
+          "rgba",
+          154.0,
+          121.00000762939453,
+          55.000003814697269,
+          1.0
+        ],
+        "text-halo-color": [
+          "rgba",
+          255.0,
+          255.0,
+          255.0,
+          1.0
+        ],
+        "text-halo-width": 1.0
+      },
+      "source": "mapbox",
+      "source-layer": "road",
+      "type": "symbol"
+    },
+    {
+      "id": "model",
+      "type": "model",
+      "source": "model",
+      "paint" : {
+        "model-scale" : [4, 4, 4]
+      }
+    }
+  ]
+}