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Unified Diff: cc/quads/draw_polygon.cc

Issue 1535833002: Delete CC. (Closed) Base URL: git@github.com:domokit/mojo.git@moz-5
Patch Set: rebase Created 4 years, 11 months ago
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Index: cc/quads/draw_polygon.cc
diff --git a/cc/quads/draw_polygon.cc b/cc/quads/draw_polygon.cc
deleted file mode 100644
index 6544b641acb237d07d6525015df5ae3abc93b369..0000000000000000000000000000000000000000
--- a/cc/quads/draw_polygon.cc
+++ /dev/null
@@ -1,363 +0,0 @@
-// 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 "cc/quads/draw_polygon.h"
-
-#include <vector>
-
-#include "cc/output/bsp_compare_result.h"
-#include "cc/quads/draw_quad.h"
-
-namespace {
-// This allows for some imperfection in the normal comparison when checking if
-// two pieces of geometry are coplanar.
-static const float coplanar_dot_epsilon = 0.001f;
-// This threshold controls how "thick" a plane is. If a point's distance is
-// <= |compare_threshold|, then it is considered on the plane. Only when this
-// boundary is crossed do we consider doing splitting.
-static const float compare_threshold = 1.0f;
-// |split_threshold| is lower in this case because we want the points created
-// during splitting to be well within the range of |compare_threshold| for
-// comparison purposes. The splitting operation will produce intersection points
-// that fit within a tighter distance to the splitting plane as a result of this
-// value. By using a value >= |compare_threshold| we run the risk of creating
-// points that SHOULD be intersecting the "thick plane", but actually fail to
-// test positively for it because |split_threshold| allowed them to be outside
-// this range.
-// This is really supposd to be compare_threshold / 2.0f, but that would
-// create another static initializer.
-static const float split_threshold = 0.5f;
-
-static const float normalized_threshold = 0.001f;
-} // namespace
-
-namespace cc {
-
-DrawPolygon::DrawPolygon() {
-}
-
-DrawPolygon::DrawPolygon(const DrawQuad* original,
- const std::vector<gfx::Point3F>& in_points,
- const gfx::Vector3dF& normal,
- int draw_order_index)
- : order_index_(draw_order_index), original_ref_(original), is_split_(true) {
- for (size_t i = 0; i < in_points.size(); i++) {
- points_.push_back(in_points[i]);
- }
- normal_ = normal;
-}
-
-// This takes the original DrawQuad that this polygon should be based on,
-// a visible content rect to make the 4 corner points from, and a transformation
-// to move it and its normal into screen space.
-DrawPolygon::DrawPolygon(const DrawQuad* original_ref,
- const gfx::RectF& visible_content_rect,
- const gfx::Transform& transform,
- int draw_order_index)
- : normal_(0.0f, 0.0f, 1.0f),
- order_index_(draw_order_index),
- original_ref_(original_ref),
- is_split_(false) {
- gfx::Point3F points[8];
- int num_vertices_in_clipped_quad;
- gfx::QuadF send_quad(visible_content_rect);
-
- // Doing this mapping here is very important, since we can't just transform
- // the points without clipping and not run into strange geometry issues when
- // crossing w = 0. At this point, in the constructor, we know that we're
- // working with a quad, so we can reuse the MathUtil::MapClippedQuad3d
- // function instead of writing a generic polygon version of it.
- MathUtil::MapClippedQuad3d(
- transform, send_quad, points, &num_vertices_in_clipped_quad);
- for (int i = 0; i < num_vertices_in_clipped_quad; i++) {
- points_.push_back(points[i]);
- }
- ApplyTransformToNormal(transform);
-}
-
-DrawPolygon::~DrawPolygon() {
-}
-
-scoped_ptr<DrawPolygon> DrawPolygon::CreateCopy() {
- scoped_ptr<DrawPolygon> new_polygon(new DrawPolygon());
- new_polygon->order_index_ = order_index_;
- new_polygon->original_ref_ = original_ref_;
- new_polygon->points_.reserve(points_.size());
- new_polygon->points_ = points_;
- new_polygon->normal_.set_x(normal_.x());
- new_polygon->normal_.set_y(normal_.y());
- new_polygon->normal_.set_z(normal_.z());
- return new_polygon.Pass();
-}
-
-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 A_BEFORE_B 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) {
- // Let's make sure that both of these are normalized.
- DCHECK_GE(normalized_threshold, std::abs(a.normal_.LengthSquared() - 1.0f));
- DCHECK_GE(normalized_threshold, std::abs(b.normal_.LengthSquared() - 1.0f));
- // Right away let's check if they're coplanar
- double dot = gfx::DotProduct(a.normal_, b.normal_);
- float sign = 0.0f;
- bool normal_match = false;
- // This check assumes that the normals are normalized.
- if (std::abs(dot) >= 1.0f - coplanar_dot_epsilon) {
- normal_match = true;
- // The normals are matching enough that we only have to test one point.
- sign = b.SignedPointDistance(a.points_[0]);
- // Is it on either side of the splitter?
- if (sign < -compare_threshold) {
- return BSP_BACK;
- }
-
- if (sign > compare_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;
- }
-
- int pos_count = 0;
- int neg_count = 0;
- for (size_t 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 < -compare_threshold) {
- ++neg_count;
- } else if (sign > compare_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 start_to_origin_vector = plane_origin - line_start;
- gfx::Vector3dF end_to_origin_vector = plane_origin - line_end;
-
- double start_distance = gfx::DotProduct(start_to_origin_vector, plane_normal);
- double end_distance = gfx::DotProduct(end_to_origin_vector, 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;
- float total_distance = std::abs(start_distance) + std::abs(end_distance);
- float lerp_factor = std::abs(start_distance) / total_distance;
-
- intersection->SetPoint(line_start.x() + (v.x() * lerp_factor),
- line_start.y() + (v.y() * lerp_factor),
- line_start.z() + (v.z() * lerp_factor));
-
- return true;
- }
- return false;
-}
-
-// This function is separate from ApplyTransform because it is often unnecessary
-// to transform the normal with the rest of the polygon.
-// When drawing these polygons, it is necessary to move them back into layer
-// space before sending them to OpenGL, which requires using ApplyTransform,
-// but normal information is no longer needed after sorting.
-void DrawPolygon::ApplyTransformToNormal(const gfx::Transform& transform) {
- // Now we use the inverse transpose of |transform| to transform the normal.
- gfx::Transform inverse_transform;
- bool inverted = transform.GetInverse(&inverse_transform);
- DCHECK(inverted);
- if (!inverted)
- return;
- inverse_transform.Transpose();
-
- gfx::Point3F new_normal(normal_.x(), normal_.y(), normal_.z());
- inverse_transform.TransformPoint(&new_normal);
- // Make sure our normal is still normalized.
- normal_ = gfx::Vector3dF(new_normal.x(), new_normal.y(), new_normal.z());
- float normal_magnitude = normal_.Length();
- if (normal_magnitude != 0 && normal_magnitude != 1) {
- normal_.Scale(1.0f / normal_magnitude);
- }
-}
-
-void DrawPolygon::ApplyTransform(const gfx::Transform& transform) {
- for (size_t i = 0; i < points_.size(); i++) {
- transform.TransformPoint(&points_[i]);
- }
-}
-
-// TransformToScreenSpace assumes we're moving a layer from its layer space
-// into 3D screen space, which for sorting purposes requires the normal to
-// be transformed along with the vertices.
-void DrawPolygon::TransformToScreenSpace(const gfx::Transform& transform) {
- ApplyTransform(transform);
- ApplyTransformToNormal(transform);
-}
-
-// In the case of TransformToLayerSpace, we assume that we are giving the
-// inverse transformation back to the polygon to move it back into layer space
-// but we can ignore the costly process of applying the inverse to the normal
-// since we know the normal will just reset to its original state.
-void DrawPolygon::TransformToLayerSpace(
- const gfx::Transform& inverse_transform) {
- ApplyTransform(inverse_transform);
- normal_ = gfx::Vector3dF(0.0f, 0.0f, -1.0f);
-}
-
-bool DrawPolygon::Split(const DrawPolygon& splitter,
- scoped_ptr<DrawPolygon>* front,
- scoped_ptr<DrawPolygon>* back) {
- gfx::Point3F intersections[2];
- std::vector<gfx::Point3F> out_points[2];
- // vertex_before stores the index of the vertex before its matching
- // intersection.
- // i.e. vertex_before[0] stores the vertex we saw before we crossed the plane
- // which resulted in the line/plane intersection giving us intersections[0].
- size_t vertex_before[2];
- size_t points_size = points_.size();
- size_t current_intersection = 0;
-
- size_t current_vertex = 0;
- // We will only have two intersection points because we assume all polygons
- // are convex.
- while (current_intersection < 2) {
- if (LineIntersectPlane(points_[(current_vertex % points_size)],
- points_[(current_vertex + 1) % points_size],
- splitter.points_[0],
- splitter.normal_,
- &intersections[current_intersection],
- split_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;
- }
- }
- if (current_vertex++ > (points_size)) {
- break;
- }
- }
- DCHECK_EQ(current_intersection, static_cast<size_t>(2));
-
- // Since we found both the intersection points, we can begin building the
- // vertex set for both our new polygons.
- size_t start1 = (vertex_before[0] + 1) % points_size;
- size_t start2 = (vertex_before[1] + 1) % points_size;
- size_t points_remaining = points_size;
-
- // First polygon.
- out_points[0].push_back(intersections[0]);
- DCHECK_GE(vertex_before[1], start1);
- for (size_t 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]);
- size_t index = start2;
- for (size_t 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.
- scoped_ptr<DrawPolygon> poly1(
- new DrawPolygon(original_ref_, out_points[0], normal_, order_index_));
- scoped_ptr<DrawPolygon> poly2(
- new DrawPolygon(original_ref_, out_points[1], normal_, order_index_));
-
- DCHECK_GE(poly1->points().size(), 3u);
- DCHECK_GE(poly2->points().size(), 3u);
-
- if (SideCompare(*poly1, splitter) == BSP_FRONT) {
- *front = poly1.Pass();
- *back = poly2.Pass();
- } else {
- *front = poly2.Pass();
- *back = poly1.Pass();
- }
- return true;
-}
-
-// This algorithm takes the first vertex in the polygon and uses that as a
-// pivot point to fan out and create quads from the rest of the vertices.
-// |offset| starts off as the second vertex, and then |op1| and |op2| indicate
-// offset+1 and offset+2 respectively.
-// After the first quad is created, the first vertex in the next quad is the
-// same as all the rest, the pivot point. The second vertex in the next quad is
-// the old |op2|, the last vertex added to the previous quad. This continues
-// until all points are exhausted.
-// The special case here is where there are only 3 points remaining, in which
-// case we use the same values for vertex 3 and 4 to make a degenerate quad
-// that represents a triangle.
-void DrawPolygon::ToQuads2D(std::vector<gfx::QuadF>* quads) const {
- if (points_.size() <= 2)
- return;
-
- gfx::PointF first(points_[0].x(), points_[0].y());
- size_t offset = 1;
- while (offset < points_.size() - 1) {
- size_t op1 = offset + 1;
- size_t 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;
- }
-}
-
-} // namespace cc
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