[core] Render fill-extrusion layers (#8431)

1 files changed, 36 insertions, 12 deletions

diff --git a/src/mbgl/renderer/render_tile.cpp b/src/mbgl/renderer/render_tile.cpp
index 5c7c491be0..ce59186e61 100644
--- a/src/mbgl/renderer/render_tile.cpp
+++ b/src/mbgl/renderer/render_tile.cpp
@@ -5,11 +5,12 @@ namespace mbgl {
 
 using namespace style;
 
-mat4 RenderTile::translatedMatrix(const std::array<float, 2>& translation,
-                                  TranslateAnchorType anchor,
-                                  const TransformState& state) const {
+mat4 RenderTile::translateVtxMatrix(const mat4& tileMatrix,
+                                    const std::array<float, 2>& translation,
+                                    TranslateAnchorType anchor,
+                                    const TransformState& state) const {
     if (translation[0] == 0 && translation[1] == 0) {
-        return matrix;
+        return tileMatrix;
     }
 
     mat4 vtxMatrix;
@@ -17,18 +18,41 @@ mat4 RenderTile::translatedMatrix(const std::array<float, 2>& translation,
     if (anchor == TranslateAnchorType::Viewport) {
         const double sin_a = std::sin(-state.getAngle());
         const double cos_a = std::cos(-state.getAngle());
-        matrix::translate(vtxMatrix, matrix,
-                id.pixelsToTileUnits(translation[0] * cos_a - translation[1] * sin_a, state.getZoom()),
-                id.pixelsToTileUnits(translation[0] * sin_a + translation[1] * cos_a, state.getZoom()),
-                0);
+        matrix::translate(vtxMatrix, tileMatrix,
+                          id.pixelsToTileUnits(translation[0] * cos_a - translation[1] * sin_a, state.getZoom()),
+                          id.pixelsToTileUnits(translation[0] * sin_a + translation[1] * cos_a, state.getZoom()),
+                          0);
     } else {
-        matrix::translate(vtxMatrix, matrix,
-                id.pixelsToTileUnits(translation[0], state.getZoom()),
-                id.pixelsToTileUnits(translation[1], state.getZoom()),
-                0);
+        matrix::translate(vtxMatrix, tileMatrix,
+                          id.pixelsToTileUnits(translation[0], state.getZoom()),
+                          id.pixelsToTileUnits(translation[1], state.getZoom()),
+                          0);
     }
 
     return vtxMatrix;
 }
 
+mat4 RenderTile::translatedMatrix(const std::array<float, 2>& translation,
+                                  TranslateAnchorType anchor,
+                                  const TransformState& state) const {
+    return translateVtxMatrix(matrix, translation, anchor, state);
+}
+
+mat4 RenderTile::translatedClipMatrix(const std::array<float, 2>& translation,
+                                      TranslateAnchorType anchor,
+                                      const TransformState& state) const {
+    return translateVtxMatrix(nearClippedMatrix, translation, anchor, state);
+}
+
+void RenderTile::calculateMatrices(const mat4& projMatrix,
+                                   const mat4& projClipMatrix,
+                                   const TransformState& transform) {
+    // Calculate two matrices for this tile: matrix is the standard tile matrix; nearClippedMatrix
+    // clips the near plane to 100 to save depth buffer precision
+    transform.matrixFor(matrix, id);
+    transform.matrixFor(nearClippedMatrix, id);
+    matrix::multiply(matrix, projMatrix, matrix);
+    matrix::multiply(nearClippedMatrix, projClipMatrix, nearClippedMatrix);
+}
+
 } // namespace mbgl