Fix layers rendering after fill-extrusion

This fixes following issues:
* Fix some false passing combinations/fill-extrusion-translucent--XXXX tests
* Fix and enable other, failing but ignored, combinations/fill-extrusion-translucent--XXXX tests
* Fix rendering of layers that are on top of fill-extrusion layers

state.getProjMatrix(nearClippedProjMatrix, 100) caused that tests with size 64x64 were not
rendering fill extrusions: far plane calculated as 96.9 and near plane set to 100 was the cause.
near plane is changed from hardcoded 100 to depend on state.getCameraToCenterDistance() - producing
similar value but one that follows max zoom.

This caused that e.g. combinations/fill-extrusion-translucent--fill-opaque was falsely passing as
only fill-opaque layer got rendered.

combinations/fill-extrusion-translucent--XXXX tests expose regression https://github.com/mapbox/mapbox-gl-native/issues/14844#issuecomment-503600034 in #14844, #14779.

Fix (opaquePassCutoff, is3D) is ported from https://github.com/mapbox/mapbox-gl-js/pull/7821

Fixes: #14844, #14779, #15039

10 files changed, 31 insertions, 15 deletions

diff --git a/src/mbgl/renderer/layers/render_fill_extrusion_layer.cpp b/src/mbgl/renderer/layers/render_fill_extrusion_layer.cpp
index b8d195cfa1..5ad2e53a5b 100644
--- a/src/mbgl/renderer/layers/render_fill_extrusion_layer.cpp
+++ b/src/mbgl/renderer/layers/render_fill_extrusion_layer.cpp
@@ -55,6 +55,10 @@ bool RenderFillExtrusionLayer::hasCrossfade() const {
     return getCrossfade<FillExtrusionLayerProperties>(evaluatedProperties).t != 1;
 }
 
+bool RenderFillExtrusionLayer::is3D() const {
+    return true;
+}
+
 void RenderFillExtrusionLayer::render(PaintParameters& parameters) {
     assert(renderTiles);
     if (parameters.pass != RenderPass::Translucent) {
diff --git a/src/mbgl/renderer/layers/render_fill_extrusion_layer.hpp b/src/mbgl/renderer/layers/render_fill_extrusion_layer.hpp
index 9118601581..8bd1f52adf 100644
--- a/src/mbgl/renderer/layers/render_fill_extrusion_layer.hpp
+++ b/src/mbgl/renderer/layers/render_fill_extrusion_layer.hpp
@@ -17,6 +17,7 @@ private:
     void evaluate(const PropertyEvaluationParameters&) override;
     bool hasTransition() const override;
     bool hasCrossfade() const override;
+    bool is3D() const override;
     void render(PaintParameters&) override;
 
     bool queryIntersectsFeature(
diff --git a/src/mbgl/renderer/layers/render_fill_layer.cpp b/src/mbgl/renderer/layers/render_fill_layer.cpp
index 6a3c247fbb..c2bf149582 100644
--- a/src/mbgl/renderer/layers/render_fill_layer.cpp
+++ b/src/mbgl/renderer/layers/render_fill_layer.cpp
@@ -130,11 +130,10 @@ void RenderFillLayer::render(PaintParameters& parameters) {
                 );
             };
 
-            // Only draw the fill when it's opaque and we're drawing opaque fragments,
-            // or when it's translucent and we're drawing translucent fragments.
-            if (bucket.triangleIndexBuffer &&
-              (evaluated.get<FillColor>().constantOr(Color()).a >= 1.0f &&
-               evaluated.get<FillOpacity>().constantOr(0) >= 1.0f) == (parameters.pass == RenderPass::Opaque)) {
+            auto fillRenderPass = (evaluated.get<FillColor>().constantOr(Color()).a >= 1.0f
+                && evaluated.get<FillOpacity>().constantOr(0) >= 1.0f
+                && parameters.currentLayer >= parameters.opaquePassCutoff) ? RenderPass::Opaque : RenderPass::Translucent;
+            if (bucket.triangleIndexBuffer && parameters.pass == fillRenderPass) {
                 draw(parameters.programs.getFillLayerPrograms().fill,
                      gfx::Triangles(),
                      parameters.depthModeForSublayer(1, parameters.pass == RenderPass::Opaque
diff --git a/src/mbgl/renderer/paint_parameters.cpp b/src/mbgl/renderer/paint_parameters.cpp
index 1539c0fbcb..6c6abc008b 100644
--- a/src/mbgl/renderer/paint_parameters.cpp
+++ b/src/mbgl/renderer/paint_parameters.cpp
@@ -19,10 +19,11 @@ TransformParameters::TransformParameters(const TransformState& state_)
     // odd viewport sizes.
     state.getProjMatrix(alignedProjMatrix, 1, true);
 
-    // Calculate a second projection matrix with the near plane clipped to 100 so as
-    // not to waste lots of depth buffer precision on very close empty space, for layer
-    // types (fill-extrusion) that use the depth buffer to emulate real-world space.
-    state.getProjMatrix(nearClippedProjMatrix, 100);
+    // Calculate a second projection matrix with the near plane moved further,
+    // to a tenth of the far value, so as not to waste depth buffer precision on
+    // very close empty space, for layer types (fill-extrusion) that use the
+    // depth buffer to emulate real-world space.
+    state.getProjMatrix(nearClippedProjMatrix, 0.1 * state.getCameraToCenterDistance());
 }
 
 PaintParameters::PaintParameters(gfx::Context& context_,
@@ -72,6 +73,9 @@ mat4 PaintParameters::matrixForTile(const UnwrappedTileID& tileID, bool aligned)
 }
 
 gfx::DepthMode PaintParameters::depthModeForSublayer(uint8_t n, gfx::DepthMaskType mask) const {
+    if (currentLayer < opaquePassCutoff) {
+        return gfx::DepthMode::disabled();
+    }
     float depth = depthRangeSize + ((1 + currentLayer) * numSublayers + n) * depthEpsilon;
     return gfx::DepthMode { gfx::DepthFunctionType::LessEqual, mask, { depth, depth } };
 }
diff --git a/src/mbgl/renderer/paint_parameters.hpp b/src/mbgl/renderer/paint_parameters.hpp
index a0d26df7c5..a043ad5578 100644
--- a/src/mbgl/renderer/paint_parameters.hpp
+++ b/src/mbgl/renderer/paint_parameters.hpp
@@ -104,8 +104,7 @@ public:
     uint32_t currentLayer;
     float depthRangeSize;
     const float depthEpsilon = 1.0f / (1 << 16);
-
-
+    uint32_t opaquePassCutoff = 0;
     float symbolFadeChange;
 };
 
diff --git a/src/mbgl/renderer/render_layer.hpp b/src/mbgl/renderer/render_layer.hpp
index c7efdceab4..fe8b7c6529 100644
--- a/src/mbgl/renderer/render_layer.hpp
+++ b/src/mbgl/renderer/render_layer.hpp
@@ -66,6 +66,9 @@ public:
     // Returns true if the layer has a pattern property and is actively crossfading.
     virtual bool hasCrossfade() const = 0;
 
+    // Returns true if layer writes to depth buffer by drawing using PaintParameters::depthModeFor3D().
+    virtual bool is3D() const { return false; }
+
     // Returns true is the layer is subject to placement.
     bool needsPlacement() const;
 
diff --git a/src/mbgl/renderer/render_orchestrator.cpp b/src/mbgl/renderer/render_orchestrator.cpp
index 7df74cda71..c70ce63c76 100644
--- a/src/mbgl/renderer/render_orchestrator.cpp
+++ b/src/mbgl/renderer/render_orchestrator.cpp
@@ -342,12 +342,16 @@ std::unique_ptr<RenderTree> RenderOrchestrator::createRenderTree(const UpdatePar
         }
     }
 
-    for (auto& renderItem : layerRenderItems) {
-        RenderLayer& renderLayer = renderItem.layer;
-        renderLayer.prepare({renderItem.source, *imageManager, *patternAtlas, *lineAtlas, updateParameters.transformState});
+    uint32_t i = static_cast<uint32_t>(layerRenderItems.size()) - 1;
+    for (auto it = layerRenderItems.begin(); it != layerRenderItems.end(); ++it, --i) {
+        RenderLayer& renderLayer = it->layer;
+        renderLayer.prepare({it->source, *imageManager, *patternAtlas, *lineAtlas, updateParameters.transformState});
         if (renderLayer.needsPlacement()) {
             layersNeedPlacement.emplace_back(renderLayer);
         }
+        if (renderLayer.is3D() && renderTreeParameters->opaquePassCutOff == 0) {
+            renderTreeParameters->opaquePassCutOff = i;
+        }
     }
     // Symbol placement.
     {
diff --git a/src/mbgl/renderer/render_tile.cpp b/src/mbgl/renderer/render_tile.cpp
index fbb2ae81de..65a6cb9f30 100644
--- a/src/mbgl/renderer/render_tile.cpp
+++ b/src/mbgl/renderer/render_tile.cpp
@@ -121,7 +121,7 @@ void RenderTile::prepare(const SourcePrepareParameters& parameters) {
     }
 
     // Calculate two matrices for this tile: matrix is the standard tile matrix; nearClippedMatrix
-    // clips the near plane to 100 to save depth buffer precision
+    // has near plane moved further, to enhance depth buffer precision
     const auto& transform = parameters.transform;
     transform.state.matrixFor(matrix, id);
     transform.state.matrixFor(nearClippedMatrix, id);
diff --git a/src/mbgl/renderer/render_tree.hpp b/src/mbgl/renderer/render_tree.hpp
index 4266ddec6d..cf62ccb03e 100644
--- a/src/mbgl/renderer/render_tree.hpp
+++ b/src/mbgl/renderer/render_tree.hpp
@@ -47,6 +47,7 @@ public:
     TimePoint timePoint;
     EvaluatedLight light;
     bool has3D = false;
+    uint32_t opaquePassCutOff = 0;
     Color backgroundColor;
     float symbolFadeChange = 0.0f;
     bool needsRepaint = false;
diff --git a/src/mbgl/renderer/renderer_impl.cpp b/src/mbgl/renderer/renderer_impl.cpp
index c536497c30..990d9cd3ab 100644
--- a/src/mbgl/renderer/renderer_impl.cpp
+++ b/src/mbgl/renderer/renderer_impl.cpp
@@ -77,6 +77,7 @@ void Renderer::Impl::render(const RenderTree& renderTree) {
     };
 
     parameters.symbolFadeChange = renderTreeParameters.symbolFadeChange;
+    parameters.opaquePassCutoff = renderTreeParameters.opaquePassCutOff;
     const auto& sourceRenderItems = renderTree.getSourceRenderItems();
     const auto& layerRenderItems = renderTree.getLayerRenderItems();