WIP BSP Tree for 3D Layer Sorting

cc/output/bsp_tree_unittest.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "cc/base/scoped_ptr_vector.h"
+#include "cc/output/bsp_controller.h"
+#include "cc/output/bsp_tree.h"
+#include "cc/output/bsp_walk_action.h"
+#include "cc/quads/draw_polygon.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace cc {
+namespace {
+
+#define EXPECT_SORTED_LISTS_EQ(polygon_list, compare_list)        \
+  do {                                                            \
+    EXPECT_EQ(polygon_list.size(), compare_list.size());          \
+    for (unsigned int i = 0; i < polygon_list.size(); i++) {      \
+      EXPECT_EQ(polygon_list[i]->order_index(), compare_list[i]); \
+    }                                                             \
+  } while (false);
+
+#define INT_VECTOR_FROM_ARRAY(array) \
+  std::vector<int>(array, array + arraysize(array))
+
+#define CREATE_DRAW_POLYGON(vertex_vector, polygon_id) \
+  new DrawPolygon(NULL, vertex_vector, polygon_id)
+
+class BspTreeTest {
+ public:
+  static void RunTest(ScopedPtrVector<DrawPolygon>* test_polygons,
+                      const std::vector<int>& compare_list) {
+    BspController bsp_controller;
+    BspTree bsp_tree(&bsp_controller, test_polygons);
+
+    std::vector<DrawPolygon*> sorted_list;
+    BspWalkActionToVector action_handler(&sorted_list);
+    bsp_tree.TraverseWithActionHandler(&action_handler);
+
+    EXPECT_SORTED_LISTS_EQ(sorted_list, compare_list);
+    EXPECT_TRUE(VerifySidedness(bsp_tree.root()));
+  }
+
+  static bool VerifySidedness(const scoped_ptr<BspNode>& node) {
+    // We check if both the front and back child nodes have geometry that is
+    // completely on the expected side of the current node.
+    bool front_ok = true;
+    bool back_ok = true;
+    if (node->back_child) {
+      // Make sure the back child lies entirely behind this node.
+      BspCompareResult result = DrawPolygon::SideCompare(
+          *(node->back_child->node_data), *(node->node_data));
+      if (result != BSP_BACK) {
+        return false;
+      }
+      back_ok = VerifySidedness(node->back_child);
+    }
+    // Make sure the front child lies entirely in front of this node.
+    if (node->front_child) {
+      BspCompareResult result = DrawPolygon::SideCompare(
+          *(node->front_child->node_data), *(node->node_data));
+      if (result != BSP_FRONT) {
+        return false;
+      }
+      front_ok = VerifySidedness(node->front_child);
+    }
+    if (!back_ok || !front_ok) {
+      return false;
+    }
+
+    // Now we need to make sure our coplanar geometry is all actually coplanar.
+    for (unsigned int i = 0; i < node->coplanars_front.size(); i++) {
+      BspCompareResult result = DrawPolygon::SideCompare(
+          *(node->coplanars_front[i]), *(node->node_data));
+      if (result != BSP_COPLANAR_FRONT) {
+        return false;
+      }
+    }
+    for (unsigned int i = 0; i < node->coplanars_back.size(); i++) {

[enne (OOO), 2014/07/28 21:38:20]

unsigned int => size_t

[troyhildebrandt, 2014/07/29 00:04:33]

Done.

+      BspCompareResult result = DrawPolygon::SideCompare(
+          *(node->coplanars_back[i]), *(node->node_data));
+      if (result != BSP_COPLANAR_BACK) {
+        return false;
+      }
+    }
+    return true;
+  }
+};
+
+// Simple standing quads all parallel with each other, causing no splits.
+TEST(BspTreeTest, NoSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(0.0f, 10.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 10.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(0.0f, 10.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, 0.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(10.0f, 0.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(10.0f, 10.0f, -5.0f));
+  std::vector<gfx::Point3F> vertices_c;
+  vertices_c.push_back(gfx::Point3F(0.0f, 10.0f, 5.0f));
+  vertices_c.push_back(gfx::Point3F(0.0f, 0.0f, 5.0f));
+  vertices_c.push_back(gfx::Point3F(10.0f, 0.0f, 5.0f));
+  vertices_c.push_back(gfx::Point3F(10.0f, 10.0f, 5.0f));
+
+  scoped_ptr<DrawPolygon> polygon_a(CREATE_DRAW_POLYGON(vertices_a, 0));
+  scoped_ptr<DrawPolygon> polygon_b(CREATE_DRAW_POLYGON(vertices_b, 1));
+  scoped_ptr<DrawPolygon> polygon_c(CREATE_DRAW_POLYGON(vertices_c, 2));
+  polygon_a->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_b->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_c->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+
+  ScopedPtrVector<DrawPolygon> polygon_list;
+  polygon_list.push_back(polygon_a.Pass());
+  polygon_list.push_back(polygon_b.Pass());
+  polygon_list.push_back(polygon_c.Pass());
+
+  int compare_ids[] = {1, 0, 2};
+  std::vector<int> compare_list = INT_VECTOR_FROM_ARRAY(compare_ids);
+  BspTreeTest::RunTest(&polygon_list, compare_list);
+}
+
+// Basic two polygon split, can be viewed as a + from above.
+TEST(BspTreeTest, BasicSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(-5.0f, -5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(-5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, -5.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(0.0f, -5.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, 5.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, 5.0f, 5.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, -5.0f, 5.0f));
+
+  scoped_ptr<DrawPolygon> polygon_a(CREATE_DRAW_POLYGON(vertices_a, 0));
+  scoped_ptr<DrawPolygon> polygon_b(CREATE_DRAW_POLYGON(vertices_b, 1));
+  polygon_a->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_b->SetNormal(gfx::Vector3dF(-1.0f, 0.0f, 0.0f));
+
+  ScopedPtrVector<DrawPolygon> polygon_list;
+  polygon_list.push_back(polygon_a.Pass());
+  polygon_list.push_back(polygon_b.Pass());
+
+  int compare_ids[] = {1, 0, 1};
+  std::vector<int> compare_list = INT_VECTOR_FROM_ARRAY(compare_ids);
+  BspTreeTest::RunTest(&polygon_list, compare_list);
+}
+
+// Same as above with the second quad offset so it doesn't intersect. One quad
+// should be very clearly on one side of the other, and no splitting should
+// occur.
+TEST(BspTreeTest, QuadOffset) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(-5.0f, -5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(-5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, -5.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(0.0f, 5.0f, -15.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, -5.0f, -15.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, -5.0f, -10.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, 5.0f, -10.0f));
+
+  scoped_ptr<DrawPolygon> polygon_a(CREATE_DRAW_POLYGON(vertices_a, 0));
+  scoped_ptr<DrawPolygon> polygon_b(CREATE_DRAW_POLYGON(vertices_b, 1));
+  polygon_a->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_b->SetNormal(gfx::Vector3dF(-1.0f, 0.0f, 0.0f));
+
+  ScopedPtrVector<DrawPolygon> polygon_list;
+  polygon_list.push_back(polygon_a.Pass());
+  polygon_list.push_back(polygon_b.Pass());
+
+  int compare_ids[] = {1, 0};
+  std::vector<int> compare_list = INT_VECTOR_FROM_ARRAY(compare_ids);
+  BspTreeTest::RunTest(&polygon_list, compare_list);
+}
+
+// Same as above, but this time we change the order in which the quads are
+// inserted into the tree, causing one to actually cross the plane of the other
+// and cause a split.
+TEST(BspTreeTest, QuadOffsetSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(-5.0f, -5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(-5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, -5.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(0.0f, -5.0f, -15.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, 5.0f, -15.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, 5.0f, -10.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, -5.0f, -10.0f));
+
+  scoped_ptr<DrawPolygon> polygon_a(CREATE_DRAW_POLYGON(vertices_a, 0));
+  scoped_ptr<DrawPolygon> polygon_b(CREATE_DRAW_POLYGON(vertices_b, 1));
+  polygon_a->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_b->SetNormal(gfx::Vector3dF(-1.0f, 0.0f, 0.0f));
+
+  ScopedPtrVector<DrawPolygon> polygon_list;
+  polygon_list.push_back(polygon_b.Pass());
+  polygon_list.push_back(polygon_a.Pass());
+
+  int compare_ids[] = {0, 1, 0};
+  std::vector<int> compare_list = INT_VECTOR_FROM_ARRAY(compare_ids);
+  BspTreeTest::RunTest(&polygon_list, compare_list);
+}
+
+// In addition to what can be viewed as a + from above, another piece of
+// geometry is inserted to cut these pieces right in the middle, viewed as
+// a quad from overhead.
+TEST(BspTreeTest, ThreeWaySplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(-5.0f, -5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(-5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, -5.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(0.0f, -5.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, 5.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, 5.0f, 5.0f));
+  vertices_b.push_back(gfx::Point3F(0.0f, -5.0f, 5.0f));
+  std::vector<gfx::Point3F> vertices_c;
+  vertices_c.push_back(gfx::Point3F(-5.0f, 0.0f, -5.0f));
+  vertices_c.push_back(gfx::Point3F(-5.0f, 0.0f, 5.0f));
+  vertices_c.push_back(gfx::Point3F(5.0f, 0.0f, 5.0f));
+  vertices_c.push_back(gfx::Point3F(5.0f, 0.0f, -5.0f));
+
+  scoped_ptr<DrawPolygon> polygon_a(CREATE_DRAW_POLYGON(vertices_a, 0));
+  scoped_ptr<DrawPolygon> polygon_b(CREATE_DRAW_POLYGON(vertices_b, 1));
+  scoped_ptr<DrawPolygon> polygon_c(CREATE_DRAW_POLYGON(vertices_c, 2));
+  polygon_a->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_b->SetNormal(gfx::Vector3dF(-1.0f, 0.0f, 0.0f));
+  polygon_c->SetNormal(gfx::Vector3dF(0.0f, 1.0f, 0.0f));
+
+  ScopedPtrVector<DrawPolygon> polygon_list;
+  polygon_list.push_back(polygon_a.Pass());
+  polygon_list.push_back(polygon_b.Pass());
+  polygon_list.push_back(polygon_c.Pass());
+
+  int compare_ids[] = {2, 1, 2, 0, 2, 1, 2};
+  std::vector<int> compare_list = INT_VECTOR_FROM_ARRAY(compare_ids);
+  BspTreeTest::RunTest(&polygon_list, compare_list);
+}
+
+// This test checks whether coplanar geometry, when inserted into the tree in
+// order, comes back in the same order as it should.
+TEST(BspTreeTest, Coplanar) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(-5.0f, -5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(-5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, -5.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(-4.0f, -4.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(-4.0f, 4.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(4.0f, 4.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(4.0f, -4.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_c;
+  vertices_c.push_back(gfx::Point3F(-3.0f, -3.0f, 0.0f));
+  vertices_c.push_back(gfx::Point3F(-3.0f, 3.0f, 0.0f));
+  vertices_c.push_back(gfx::Point3F(3.0f, 3.0f, 0.0f));
+  vertices_c.push_back(gfx::Point3F(3.0f, -3.0f, 0.0f));
+
+  scoped_ptr<DrawPolygon> polygon_a(CREATE_DRAW_POLYGON(vertices_a, 0));
+  scoped_ptr<DrawPolygon> polygon_b(CREATE_DRAW_POLYGON(vertices_b, 1));
+  scoped_ptr<DrawPolygon> polygon_c(CREATE_DRAW_POLYGON(vertices_c, 2));
+  polygon_a->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_b->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_c->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+
+  ScopedPtrVector<DrawPolygon> polygon_list;

[enne (OOO), 2014/07/28 21:38:20]

Can you insert these same quads in a different order and verify that they come
back in that new order too?

[troyhildebrandt, 2014/07/29 00:04:33]

Done. They don't come in the new order, however, because if the order_index of
one polygon is less than that of the other, it comes in front of that one in the
sorting process, so we get back the exact same 0,1,2 ordering despite the
different input order.

+  polygon_list.push_back(polygon_a.Pass());
+  polygon_list.push_back(polygon_b.Pass());
+  polygon_list.push_back(polygon_c.Pass());
+
+  int compare_ids[] = {0, 1, 2};
+  std::vector<int> compare_list = INT_VECTOR_FROM_ARRAY(compare_ids);
+  BspTreeTest::RunTest(&polygon_list, compare_list);
+}
+
+// A bunch of coplanar geometry should end up sharing a single node, and
+// result in the final piece of geometry splitting into just two pieces on
+// either side of the shared plane.
+TEST(BspTreeTest, CoplanarSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(-5.0f, -5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(-5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, 5.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(5.0f, -5.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(-4.0f, -4.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(-4.0f, 4.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(4.0f, 4.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(4.0f, -4.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_c;
+  vertices_c.push_back(gfx::Point3F(-3.0f, -3.0f, 0.0f));
+  vertices_c.push_back(gfx::Point3F(-3.0f, 3.0f, 0.0f));
+  vertices_c.push_back(gfx::Point3F(3.0f, 3.0f, 0.0f));
+  vertices_c.push_back(gfx::Point3F(3.0f, -3.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_d;
+  vertices_d.push_back(gfx::Point3F(0.0f, -15.0f, -15.0f));
+  vertices_d.push_back(gfx::Point3F(0.0f, 15.0f, -15.0f));
+  vertices_d.push_back(gfx::Point3F(0.0f, 15.0f, 15.0f));
+  vertices_d.push_back(gfx::Point3F(0.0f, -15.0f, 15.0f));
+
+  scoped_ptr<DrawPolygon> polygon_a(CREATE_DRAW_POLYGON(vertices_a, 0));
+  scoped_ptr<DrawPolygon> polygon_b(CREATE_DRAW_POLYGON(vertices_b, 1));
+  scoped_ptr<DrawPolygon> polygon_c(CREATE_DRAW_POLYGON(vertices_c, 2));
+  scoped_ptr<DrawPolygon> polygon_d(CREATE_DRAW_POLYGON(vertices_d, 3));
+  polygon_a->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_b->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_c->SetNormal(gfx::Vector3dF(0.0f, 0.0f, 1.0f));
+  polygon_d->SetNormal(gfx::Vector3dF(-1.0f, 0.0f, 0.0f));
+
+  ScopedPtrVector<DrawPolygon> polygon_list;
+  polygon_list.push_back(polygon_a.Pass());
+  polygon_list.push_back(polygon_b.Pass());
+  polygon_list.push_back(polygon_c.Pass());
+  polygon_list.push_back(polygon_d.Pass());
+
+  int compare_ids[] = {3, 0, 1, 2, 3};
+  std::vector<int> compare_list = INT_VECTOR_FROM_ARRAY(compare_ids);
+  BspTreeTest::RunTest(&polygon_list, compare_list);
+}
+
+}  // namespace
+}  // namespace cc