Index: cc/quads/draw_polygon.cc |
diff --git a/cc/quads/draw_polygon.cc b/cc/quads/draw_polygon.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..c5f60f522e22ded5e9846b2b521f616b0d131bba |
--- /dev/null |
+++ b/cc/quads/draw_polygon.cc |
@@ -0,0 +1,313 @@ |
+// Copyright 2013 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 "cc/quads/draw_polygon.h" |
+ |
+#include <vector> |
+ |
+#include "cc/output/bsp_compare_result.h" |
+ |
+namespace { |
+// This allows for some imperfection in the normal comparison when checking if |
+// two pieces of geometry are coplanar. |
+const float coplanar_dot_epsilon = 0.99f; |
+} // namespace |
+ |
+namespace cc { |
+ |
+DrawPolygon::DrawPolygon() { |
+} |
+ |
+static float SignedArea(const DrawPolygon& polygon) { |
+ gfx::Vector3dF total; |
+ for (unsigned int i = 0; i < polygon.points.size(); i++) { |
+ unsigned int j = (i + 1) % polygon.points.size(); |
+ gfx::Vector3dF cross_prod = |
+ gfx::CrossProduct(gfx::Vector3dF(polygon.points[i].x(), |
+ polygon.points[i].y(), |
+ polygon.points[i].z()), |
+ gfx::Vector3dF(polygon.points[j].x(), |
+ polygon.points[j].y(), |
+ polygon.points[j].z())); |
+ total = total + cross_prod; |
+ } |
+ return 0.5f * std::abs(gfx::DotProduct(total, polygon.normal)); |
Ian Vollick
2014/07/22 16:12:15
The fns in DrawPolygon are probably the most invol
troyhildebrandt
2014/07/23 21:43:56
Changed and all part of the DrawPolygon patch sepa
|
+} |
+ |
+float Area(const DrawPolygon& polygon) { |
+ return std::abs(SignedArea(polygon)); |
+} |
+ |
+DrawPolygon::DrawPolygon(DrawQuad* original, |
+ gfx::Point3F* in_points, |
+ int num_vertices_in_polygon, |
+ int draw_order_index) |
+ : order_index(draw_order_index), original_ref(original) { |
+ for (int i = 0; i < num_vertices_in_polygon; i++) { |
+ points.push_back(in_points[i]); |
+ } |
+ |
+ if (num_vertices_in_polygon > 2) { |
+ gfx::Vector3dF c12 = in_points[1] - in_points[0]; |
+ gfx::Vector3dF c13 = in_points[2] - in_points[0]; |
+ normal = gfx::CrossProduct(c12, c13); |
+ normal.Scale(1.0f / normal.Length()); |
+ } |
+ area = Area(*this); |
+} |
+ |
+DrawPolygon::DrawPolygon(const DrawPolygon& other) { |
+ CopyFrom(other); |
+} |
+ |
+DrawPolygon::~DrawPolygon() { |
+} |
+ |
+DrawPolygon& DrawPolygon::operator=(const DrawPolygon& rhs) { |
+ CopyFrom(rhs); |
+ return *this; |
+} |
+ |
+void DrawPolygon::CopyFrom(const DrawPolygon& other) { |
+ order_index = other.order_index; |
+ original_ref = other.original_ref; |
+ points.reserve(other.points.size()); |
+ points = other.points; |
+ normal.set_x(other.normal.x()); |
+ normal.set_y(other.normal.y()); |
+ normal.set_z(other.normal.z()); |
+ area = other.area; |
+} |
+ |
+float DrawPolygon::SignedPointDistance(const gfx::Point3F& point) const { |
+ return gfx::DotProduct(point - points[0], normal); |
+} |
+ |
+// Checks whether or not shape a lies on the front or back side of b, or |
+// whether they should be considered coplanar. If on the back side, we |
+// say ABeforeB because it should be drawn in that order. |
+// Assumes that layers are split and there are no intersecting planes. |
+BspCompareResult DrawPolygon::SideCompare(const DrawPolygon& a, |
+ const DrawPolygon& b, |
+ float z_threshold) { |
+ // Right away let's check if they're coplanar |
+ double dot = gfx::DotProduct(a.normal, b.normal); |
+ float sign; |
+ bool normal_match = false; |
+ // This check assumes that the normals are normalized. |
+ if (std::abs(dot) >= coplanar_dot_epsilon) { |
+ normal_match = true; |
+ // The normals are matching enough that we only have to test one point. |
+ sign = gfx::DotProduct(a.points[0] - b.points[0], b.normal); |
+ // Is it on either side of the splitter? |
+ if (sign < -z_threshold) { |
+ return BSP_BACK; |
+ } |
+ |
+ if (sign > z_threshold) { |
+ return BSP_FRONT; |
+ } |
+ |
+ // No it wasn't, so the sign of the dot product of the normals |
+ // along with document order determines which side it goes on. |
+ if (dot >= 0.0f) { |
+ if (a.order_index < b.order_index) { |
+ return BSP_COPLANAR_FRONT; |
+ } |
+ return BSP_COPLANAR_BACK; |
+ } |
+ |
+ if (a.order_index < b.order_index) { |
+ return BSP_COPLANAR_BACK; |
+ } |
+ return BSP_COPLANAR_FRONT; |
+ } |
+ |
+ unsigned int pos_count = 0; |
+ unsigned int neg_count = 0; |
+ for (unsigned int i = 0; i < a.points.size(); i++) { |
+ if (!normal_match || (normal_match && i > 0)) { |
+ sign = gfx::DotProduct(a.points[i] - b.points[0], b.normal); |
+ } |
+ |
+ if (sign < -z_threshold) { |
+ ++neg_count; |
+ } else if (sign > z_threshold) { |
+ ++pos_count; |
+ } |
+ |
+ if (pos_count && neg_count) { |
+ return BSP_SPLIT; |
+ } |
+ } |
+ |
+ if (pos_count) { |
+ return BSP_FRONT; |
+ } |
+ return BSP_BACK; |
+} |
+ |
+static bool LineIntersectPlane(const gfx::Point3F& line_start, |
+ const gfx::Point3F& line_end, |
+ const gfx::Point3F& plane_origin, |
+ const gfx::Vector3dF& plane_normal, |
+ gfx::Point3F* intersection, |
+ float distance_threshold) { |
+ gfx::Vector3dF vec1 = plane_origin - line_start; |
+ gfx::Vector3dF vec2 = plane_origin - line_end; |
+ |
+ double start_distance = gfx::DotProduct(vec1, plane_normal); |
+ double end_distance = gfx::DotProduct(vec2, plane_normal); |
+ |
+ // The case where one vertex lies on the thick-plane and the other |
+ // is outside of it. |
+ if (std::abs(start_distance) < distance_threshold && |
+ std::abs(end_distance) > distance_threshold) { |
+ intersection->SetPoint(line_start.x(), line_start.y(), line_start.z()); |
+ return true; |
+ } |
+ |
+ // This is the case where we clearly cross the thick-plane. |
+ if ((start_distance > distance_threshold && |
+ end_distance < -distance_threshold) || |
+ (start_distance < -distance_threshold && |
+ end_distance > distance_threshold)) { |
+ gfx::Vector3dF v = line_end - line_start; |
+ |
+ v.Scale(1.f / v.Length()); |
+ double projected_length = gfx::DotProduct(v, plane_normal); |
+ if (!projected_length) |
+ return false; |
+ |
+ double scale = start_distance / projected_length; |
+ intersection->SetPoint(line_start.x() + (v.x() * scale), |
+ line_start.y() + (v.y() * scale), |
+ line_start.z() + (v.z() * scale)); |
+ |
+ return true; |
+ } |
+ return false; |
+} |
+ |
+bool DrawPolygon::ApplyTransform(const gfx::Transform& transform) { |
+ bool clipped = false; |
+ for (unsigned int i = 0; i < points.size(); i++) { |
+ points[i] = MathUtil::MapPoint(transform, points[i], &clipped); |
+ } |
+ return !clipped; |
+} |
+ |
+bool DrawPolygon::Split(const DrawPolygon& splitter, |
+ double plane_threshold, |
+ scoped_ptr<DrawPolygon>* front, |
+ scoped_ptr<DrawPolygon>* back) { |
+ gfx::Point3F intersections[2]; |
+ std::vector<gfx::Point3F> out_points[2]; |
+ int vertex_before[2]; |
+ int points_size = points.size(); |
+ int current_intersection = 0; |
+ |
+ int current_vertex = 0; |
+ while (current_intersection < 2) { |
+ if (current_intersection > 0 && |
+ vertex_before[0] == (current_vertex % points_size)) { |
+ continue; |
+ } |
+ |
+ if (LineIntersectPlane(points[(current_vertex % points_size)], |
+ points[(current_vertex + 1) % points_size], |
+ splitter.points[0], |
+ splitter.normal, |
+ &intersections[current_intersection], |
+ plane_threshold)) { |
+ vertex_before[current_intersection] = current_vertex % points_size; |
+ current_intersection++; |
+ // We found both intersection points so we're done already. |
+ if (current_intersection == 2) { |
+ break; |
+ } |
+ } |
+ ++current_vertex; |
+ // We've gone around one whole time, leave early. |
+ if (current_vertex > points_size) { |
+ break; |
+ } |
+ } |
+ if (current_intersection < 2) { |
+ return false; |
+ } |
+ |
+ // Since we found both the intersection points, we can begin building the |
+ // vertex set for both our new polygons. |
+ int start1 = (vertex_before[0] + 1) % points_size; |
+ int start2 = (vertex_before[1] + 1) % points_size; |
+ int points_remaining = points_size; |
+ |
+ // First polygon. |
+ out_points[0].push_back(intersections[0]); |
+ for (int i = start1; i <= vertex_before[1]; i++) { |
+ out_points[0].push_back(points[i]); |
+ --points_remaining; |
+ } |
+ out_points[0].push_back(intersections[1]); |
+ |
+ // Second polygon. |
+ out_points[1].push_back(intersections[1]); |
+ int index = start2; |
+ for (int i = 0; i < points_remaining; i++) { |
+ out_points[1].push_back(points[index % points_size]); |
+ ++index; |
+ } |
+ out_points[1].push_back(intersections[0]); |
+ |
+ // Give both polygons the original splitting polygon's ID, so that they'll |
+ // still be sorted properly in co-planar instances. |
+ // Send false as last parameter for is_original because they're split. |
+ scoped_ptr<DrawPolygon> poly1(new DrawPolygon(original_ref, |
+ &(out_points[0][0]), |
+ out_points[0].size(), |
+ this->order_index)); |
+ scoped_ptr<DrawPolygon> poly2(new DrawPolygon(original_ref, |
+ &(out_points[1][0]), |
+ out_points[1].size(), |
+ this->order_index)); |
+ |
+ if (SideCompare(*poly1, splitter, plane_threshold) == BSP_FRONT) { |
+ *front = poly1.Pass(); |
+ *back = poly2.Pass(); |
+ } else { |
+ *front = poly2.Pass(); |
+ *back = poly1.Pass(); |
+ } |
+ return true; |
+} |
+ |
+void DrawPolygon::ToQuads2D(std::vector<gfx::QuadF>* quads) const { |
+ if (points.size() == 0) |
+ return; |
+ |
+ // op1 = offset plus 1, op2 = offset plus 2. |
+ gfx::PointF first(points[0].x(), points[0].y()); |
+ unsigned int offset = 1; |
+ while (offset < points.size() - 1) { |
+ unsigned int op1 = offset + 1; |
+ unsigned int op2 = offset + 2; |
+ if (op2 >= points.size()) { |
+ // It's going to be a degenerate triangle. |
+ op2 = op1; |
+ } |
+ quads->push_back( |
+ gfx::QuadF(first, |
+ gfx::PointF(points[offset].x(), points[offset].y()), |
+ gfx::PointF(points[op1].x(), points[op1].y()), |
+ gfx::PointF(points[op2].x(), points[op2].y()))); |
+ offset = op2; |
+ } |
+} |
+ |
+bool DrawPolygon::GetInverseTransform(gfx::Transform* transform) const { |
+ return original_ref->quadTransform().GetInverse(transform); |
+} |
+ |
+} // namespace cc |