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

1 files changed, 8 insertions, 4 deletions

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 } };
 }