| Index: cc/CCLayerSorter.cpp
|
| diff --git a/cc/CCLayerSorter.cpp b/cc/CCLayerSorter.cpp
|
| deleted file mode 100644
|
| index cf8577797211258877e2df9c020e41952027e814..0000000000000000000000000000000000000000
|
| --- a/cc/CCLayerSorter.cpp
|
| +++ /dev/null
|
| @@ -1,445 +0,0 @@
|
| -// Copyright 2011 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 "config.h"
|
| -
|
| -#include "CCLayerSorter.h"
|
| -
|
| -#include "CCMathUtil.h"
|
| -#include "CCRenderSurface.h"
|
| -#include <limits.h>
|
| -#include <public/WebTransformationMatrix.h>
|
| -#include <wtf/Deque.h>
|
| -
|
| -using namespace std;
|
| -using WebKit::WebTransformationMatrix;
|
| -
|
| -#define LOG_CHANNEL_PREFIX Log
|
| -#define SHOW_DEBUG_LOG 0
|
| -
|
| -#if !defined( NDEBUG )
|
| -#if SHOW_DEBUG_LOG
|
| -static WTFLogChannel LogCCLayerSorter = { 0x00000000, "", WTFLogChannelOn };
|
| -#else
|
| -static WTFLogChannel LogCCLayerSorter = { 0x00000000, "", WTFLogChannelOff };
|
| -#endif
|
| -#endif
|
| -
|
| -namespace cc {
|
| -
|
| -inline static float perpProduct(const FloatSize& u, const FloatSize& v)
|
| -{
|
| - return u.width() * v.height() - u.height() * v.width();
|
| -}
|
| -
|
| -// Tests if two edges defined by their endpoints (a,b) and (c,d) intersect. Returns true and the
|
| -// point of intersection if they do and false otherwise.
|
| -static bool edgeEdgeTest(const FloatPoint& a, const FloatPoint& b, const FloatPoint& c, const FloatPoint& d, FloatPoint& r)
|
| -{
|
| - FloatSize u = b - a;
|
| - FloatSize v = d - c;
|
| - FloatSize w = a - c;
|
| -
|
| - float denom = perpProduct(u, v);
|
| -
|
| - // If denom == 0 then the edges are parallel. While they could be overlapping
|
| - // we don't bother to check here as the we'll find their intersections from the
|
| - // corner to quad tests.
|
| - if (!denom)
|
| - return false;
|
| -
|
| - float s = perpProduct(v, w) / denom;
|
| - if (s < 0 || s > 1)
|
| - return false;
|
| -
|
| - float t = perpProduct(u, w) / denom;
|
| - if (t < 0 || t > 1)
|
| - return false;
|
| -
|
| - u.scale(s);
|
| - r = a + u;
|
| - return true;
|
| -}
|
| -
|
| -CCLayerSorter::GraphNode::GraphNode(CCLayerImpl* cclayer)
|
| - : layer(cclayer)
|
| - , incomingEdgeWeight(0)
|
| -{
|
| -}
|
| -
|
| -CCLayerSorter::GraphNode::~GraphNode()
|
| -{
|
| -}
|
| -
|
| -CCLayerSorter::CCLayerSorter()
|
| - : m_zRange(0)
|
| -{
|
| -}
|
| -
|
| -CCLayerSorter::~CCLayerSorter()
|
| -{
|
| -}
|
| -
|
| -// Checks whether layer "a" draws on top of layer "b". The weight value returned is an indication of
|
| -// the maximum z-depth difference between the layers or zero if the layers are found to be intesecting
|
| -// (some features are in front and some are behind).
|
| -CCLayerSorter::ABCompareResult CCLayerSorter::checkOverlap(LayerShape* a, LayerShape* b, float zThreshold, float& weight)
|
| -{
|
| - weight = 0;
|
| -
|
| - // Early out if the projected bounds don't overlap.
|
| - if (!a->projectedBounds.intersects(b->projectedBounds))
|
| - return None;
|
| -
|
| - FloatPoint aPoints[4] = {a->projectedQuad.p1(), a->projectedQuad.p2(), a->projectedQuad.p3(), a->projectedQuad.p4() };
|
| - FloatPoint bPoints[4] = {b->projectedQuad.p1(), b->projectedQuad.p2(), b->projectedQuad.p3(), b->projectedQuad.p4() };
|
| -
|
| - // Make a list of points that inside both layer quad projections.
|
| - Vector<FloatPoint> overlapPoints;
|
| -
|
| - // Check all four corners of one layer against the other layer's quad.
|
| - for (int i = 0; i < 4; ++i) {
|
| - if (a->projectedQuad.containsPoint(bPoints[i]))
|
| - overlapPoints.append(bPoints[i]);
|
| - if (b->projectedQuad.containsPoint(aPoints[i]))
|
| - overlapPoints.append(aPoints[i]);
|
| - }
|
| -
|
| - // Check all the edges of one layer for intersection with the other layer's edges.
|
| - FloatPoint r;
|
| - for (int ea = 0; ea < 4; ++ea)
|
| - for (int eb = 0; eb < 4; ++eb)
|
| - if (edgeEdgeTest(aPoints[ea], aPoints[(ea + 1) % 4],
|
| - bPoints[eb], bPoints[(eb + 1) % 4],
|
| - r))
|
| - overlapPoints.append(r);
|
| -
|
| - if (!overlapPoints.size())
|
| - return None;
|
| -
|
| - // Check the corresponding layer depth value for all overlap points to determine
|
| - // which layer is in front.
|
| - float maxPositive = 0;
|
| - float maxNegative = 0;
|
| - for (unsigned o = 0; o < overlapPoints.size(); o++) {
|
| - float za = a->layerZFromProjectedPoint(overlapPoints[o]);
|
| - float zb = b->layerZFromProjectedPoint(overlapPoints[o]);
|
| -
|
| - float diff = za - zb;
|
| - if (diff > maxPositive)
|
| - maxPositive = diff;
|
| - if (diff < maxNegative)
|
| - maxNegative = diff;
|
| - }
|
| -
|
| - float maxDiff = (fabsf(maxPositive) > fabsf(maxNegative) ? maxPositive : maxNegative);
|
| -
|
| - // If the results are inconsistent (and the z difference substantial to rule out
|
| - // numerical errors) then the layers are intersecting. We will still return an
|
| - // order based on the maximum depth difference but with an edge weight of zero
|
| - // these layers will get priority if a graph cycle is present and needs to be broken.
|
| - if (maxPositive > zThreshold && maxNegative < -zThreshold)
|
| - weight = 0;
|
| - else
|
| - weight = fabsf(maxDiff);
|
| -
|
| - // Maintain relative order if the layers have the same depth at all intersection points.
|
| - if (maxDiff <= 0)
|
| - return ABeforeB;
|
| -
|
| - return BBeforeA;
|
| -}
|
| -
|
| -CCLayerSorter::LayerShape::LayerShape()
|
| -{
|
| -}
|
| -
|
| -CCLayerSorter::LayerShape::LayerShape(float width, float height, const WebTransformationMatrix& drawTransform)
|
| -{
|
| - FloatQuad layerQuad(FloatRect(0, 0, width, height));
|
| -
|
| - // Compute the projection of the layer quad onto the z = 0 plane.
|
| -
|
| - FloatPoint clippedQuad[8];
|
| - int numVerticesInClippedQuad;
|
| - CCMathUtil::mapClippedQuad(drawTransform, layerQuad, clippedQuad, numVerticesInClippedQuad);
|
| -
|
| - if (numVerticesInClippedQuad < 3) {
|
| - projectedBounds = FloatRect();
|
| - return;
|
| - }
|
| -
|
| - projectedBounds = CCMathUtil::computeEnclosingRectOfVertices(clippedQuad, numVerticesInClippedQuad);
|
| -
|
| - // NOTE: it will require very significant refactoring and overhead to deal with
|
| - // generalized polygons or multiple quads per layer here. For the sake of layer
|
| - // sorting it is equally correct to take a subsection of the polygon that can be made
|
| - // into a quad. This will only be incorrect in the case of intersecting layers, which
|
| - // are not supported yet anyway.
|
| - projectedQuad.setP1(clippedQuad[0]);
|
| - projectedQuad.setP2(clippedQuad[1]);
|
| - projectedQuad.setP3(clippedQuad[2]);
|
| - if (numVerticesInClippedQuad >= 4)
|
| - projectedQuad.setP4(clippedQuad[3]);
|
| - else
|
| - projectedQuad.setP4(clippedQuad[2]); // this will be a degenerate quad that is actually a triangle.
|
| -
|
| - // Compute the normal of the layer's plane.
|
| - bool clipped = false;
|
| - FloatPoint3D c1 = CCMathUtil::mapPoint(drawTransform, FloatPoint3D(0, 0, 0), clipped);
|
| - FloatPoint3D c2 = CCMathUtil::mapPoint(drawTransform, FloatPoint3D(0, 1, 0), clipped);
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| - FloatPoint3D c3 = CCMathUtil::mapPoint(drawTransform, FloatPoint3D(1, 0, 0), clipped);
|
| - // FIXME: Deal with clipping.
|
| - FloatPoint3D c12 = c2 - c1;
|
| - FloatPoint3D c13 = c3 - c1;
|
| - layerNormal = c13.cross(c12);
|
| -
|
| - transformOrigin = c1;
|
| -}
|
| -
|
| -// Returns the Z coordinate of a point on the layer that projects
|
| -// to point p which lies on the z = 0 plane. It does it by computing the
|
| -// intersection of a line starting from p along the Z axis and the plane
|
| -// of the layer.
|
| -float CCLayerSorter::LayerShape::layerZFromProjectedPoint(const FloatPoint& p) const
|
| -{
|
| - const FloatPoint3D zAxis(0, 0, 1);
|
| - FloatPoint3D w = FloatPoint3D(p) - transformOrigin;
|
| -
|
| - float d = layerNormal.dot(zAxis);
|
| - float n = -layerNormal.dot(w);
|
| -
|
| - // Check if layer is parallel to the z = 0 axis which will make it
|
| - // invisible and hence returning zero is fine.
|
| - if (!d)
|
| - return 0;
|
| -
|
| - // The intersection point would be given by:
|
| - // p + (n / d) * u but since we are only interested in the
|
| - // z coordinate and p's z coord is zero, all we need is the value of n/d.
|
| - return n / d;
|
| -}
|
| -
|
| -void CCLayerSorter::createGraphNodes(LayerList::iterator first, LayerList::iterator last)
|
| -{
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "Creating graph nodes:\n");
|
| -#endif
|
| - float minZ = FLT_MAX;
|
| - float maxZ = -FLT_MAX;
|
| - for (LayerList::const_iterator it = first; it < last; it++) {
|
| - m_nodes.append(GraphNode(*it));
|
| - GraphNode& node = m_nodes.at(m_nodes.size() - 1);
|
| - CCRenderSurface* renderSurface = node.layer->renderSurface();
|
| - if (!node.layer->drawsContent() && !renderSurface)
|
| - continue;
|
| -
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "Layer %d (%d x %d)\n", node.layer->id(), node.layer->bounds().width(), node.layer->bounds().height());
|
| -#endif
|
| -
|
| - WebTransformationMatrix drawTransform;
|
| - float layerWidth, layerHeight;
|
| - if (renderSurface) {
|
| - drawTransform = renderSurface->drawTransform();
|
| - layerWidth = renderSurface->contentRect().width();
|
| - layerHeight = renderSurface->contentRect().height();
|
| - } else {
|
| - drawTransform = node.layer->drawTransform();
|
| - layerWidth = node.layer->contentBounds().width();
|
| - layerHeight = node.layer->contentBounds().height();
|
| - }
|
| -
|
| - node.shape = LayerShape(layerWidth, layerHeight, drawTransform);
|
| -
|
| - maxZ = max(maxZ, node.shape.transformOrigin.z());
|
| - minZ = min(minZ, node.shape.transformOrigin.z());
|
| - }
|
| -
|
| - m_zRange = fabsf(maxZ - minZ);
|
| -}
|
| -
|
| -void CCLayerSorter::createGraphEdges()
|
| -{
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "Edges:\n");
|
| -#endif
|
| - // Fraction of the total zRange below which z differences
|
| - // are not considered reliable.
|
| - const float zThresholdFactor = 0.01f;
|
| - float zThreshold = m_zRange * zThresholdFactor;
|
| -
|
| - for (unsigned na = 0; na < m_nodes.size(); na++) {
|
| - GraphNode& nodeA = m_nodes[na];
|
| - if (!nodeA.layer->drawsContent() && !nodeA.layer->renderSurface())
|
| - continue;
|
| - for (unsigned nb = na + 1; nb < m_nodes.size(); nb++) {
|
| - GraphNode& nodeB = m_nodes[nb];
|
| - if (!nodeB.layer->drawsContent() && !nodeB.layer->renderSurface())
|
| - continue;
|
| - float weight = 0;
|
| - ABCompareResult overlapResult = checkOverlap(&nodeA.shape, &nodeB.shape, zThreshold, weight);
|
| - GraphNode* startNode = 0;
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| - GraphNode* endNode = 0;
|
| - if (overlapResult == ABeforeB) {
|
| - startNode = &nodeA;
|
| - endNode = &nodeB;
|
| - } else if (overlapResult == BBeforeA) {
|
| - startNode = &nodeB;
|
| - endNode = &nodeA;
|
| - }
|
| -
|
| - if (startNode) {
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "%d -> %d\n", startNode->layer->id(), endNode->layer->id());
|
| -#endif
|
| - m_edges.append(GraphEdge(startNode, endNode, weight));
|
| - }
|
| - }
|
| - }
|
| -
|
| - for (unsigned i = 0; i < m_edges.size(); i++) {
|
| - GraphEdge& edge = m_edges[i];
|
| - m_activeEdges.add(&edge, &edge);
|
| - edge.from->outgoing.append(&edge);
|
| - edge.to->incoming.append(&edge);
|
| - edge.to->incomingEdgeWeight += edge.weight;
|
| - }
|
| -}
|
| -
|
| -// Finds and removes an edge from the list by doing a swap with the
|
| -// last element of the list.
|
| -void CCLayerSorter::removeEdgeFromList(GraphEdge* edge, Vector<GraphEdge*>& list)
|
| -{
|
| - size_t edgeIndex = list.find(edge);
|
| - ASSERT(edgeIndex != notFound);
|
| - if (list.size() == 1) {
|
| - ASSERT(!edgeIndex);
|
| - list.clear();
|
| - return;
|
| - }
|
| - if (edgeIndex != list.size() - 1)
|
| - list[edgeIndex] = list[list.size() - 1];
|
| -
|
| - list.removeLast();
|
| -}
|
| -
|
| -// Sorts the given list of layers such that they can be painted in a back-to-front
|
| -// order. Sorting produces correct results for non-intersecting layers that don't have
|
| -// cyclical order dependencies. Cycles and intersections are broken (somewhat) aribtrarily.
|
| -// Sorting of layers is done via a topological sort of a directed graph whose nodes are
|
| -// the layers themselves. An edge from node A to node B signifies that layer A needs to
|
| -// be drawn before layer B. If A and B have no dependency between each other, then we
|
| -// preserve the ordering of those layers as they were in the original list.
|
| -//
|
| -// The draw order between two layers is determined by projecting the two triangles making
|
| -// up each layer quad to the Z = 0 plane, finding points of intersection between the triangles
|
| -// and backprojecting those points to the plane of the layer to determine the corresponding Z
|
| -// coordinate. The layer with the lower Z coordinate (farther from the eye) needs to be rendered
|
| -// first.
|
| -//
|
| -// If the layer projections don't intersect, then no edges (dependencies) are created
|
| -// between them in the graph. HOWEVER, in this case we still need to preserve the ordering
|
| -// of the original list of layers, since that list should already have proper z-index
|
| -// ordering of layers.
|
| -//
|
| -void CCLayerSorter::sort(LayerList::iterator first, LayerList::iterator last)
|
| -{
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "Sorting start ----\n");
|
| -#endif
|
| - createGraphNodes(first, last);
|
| -
|
| - createGraphEdges();
|
| -
|
| - Vector<GraphNode*> sortedList;
|
| - Deque<GraphNode*> noIncomingEdgeNodeList;
|
| -
|
| - // Find all the nodes that don't have incoming edges.
|
| - for (NodeList::iterator la = m_nodes.begin(); la < m_nodes.end(); la++) {
|
| - if (!la->incoming.size())
|
| - noIncomingEdgeNodeList.append(la);
|
| - }
|
| -
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "Sorted list: ");
|
| -#endif
|
| - while (m_activeEdges.size() || noIncomingEdgeNodeList.size()) {
|
| - while (noIncomingEdgeNodeList.size()) {
|
| -
|
| - // It is necessary to preserve the existing ordering of layers, when there are
|
| - // no explicit dependencies (because this existing ordering has correct
|
| - // z-index/layout ordering). To preserve this ordering, we process Nodes in
|
| - // the same order that they were added to the list.
|
| - GraphNode* fromNode = noIncomingEdgeNodeList.takeFirst();
|
| -
|
| - // Add it to the final list.
|
| - sortedList.append(fromNode);
|
| -
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "%d, ", fromNode->layer->id());
|
| -#endif
|
| -
|
| - // Remove all its outgoing edges from the graph.
|
| - for (unsigned i = 0; i < fromNode->outgoing.size(); i++) {
|
| - GraphEdge* outgoingEdge = fromNode->outgoing[i];
|
| -
|
| - m_activeEdges.remove(outgoingEdge);
|
| - removeEdgeFromList(outgoingEdge, outgoingEdge->to->incoming);
|
| - outgoingEdge->to->incomingEdgeWeight -= outgoingEdge->weight;
|
| -
|
| - if (!outgoingEdge->to->incoming.size())
|
| - noIncomingEdgeNodeList.append(outgoingEdge->to);
|
| - }
|
| - fromNode->outgoing.clear();
|
| - }
|
| -
|
| - if (!m_activeEdges.size())
|
| - break;
|
| -
|
| - // If there are still active edges but the list of nodes without incoming edges
|
| - // is empty then we have run into a cycle. Break the cycle by finding the node
|
| - // with the smallest overall incoming edge weight and use it. This will favor
|
| - // nodes that have zero-weight incoming edges i.e. layers that are being
|
| - // occluded by a layer that intersects them.
|
| - float minIncomingEdgeWeight = FLT_MAX;
|
| - GraphNode* nextNode = 0;
|
| - for (unsigned i = 0; i < m_nodes.size(); i++) {
|
| - if (m_nodes[i].incoming.size() && m_nodes[i].incomingEdgeWeight < minIncomingEdgeWeight) {
|
| - minIncomingEdgeWeight = m_nodes[i].incomingEdgeWeight;
|
| - nextNode = &m_nodes[i];
|
| - }
|
| - }
|
| - ASSERT(nextNode);
|
| - // Remove all its incoming edges.
|
| - for (unsigned e = 0; e < nextNode->incoming.size(); e++) {
|
| - GraphEdge* incomingEdge = nextNode->incoming[e];
|
| -
|
| - m_activeEdges.remove(incomingEdge);
|
| - removeEdgeFromList(incomingEdge, incomingEdge->from->outgoing);
|
| - }
|
| - nextNode->incoming.clear();
|
| - nextNode->incomingEdgeWeight = 0;
|
| - noIncomingEdgeNodeList.append(nextNode);
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "Breaking cycle by cleaning up incoming edges from %d (weight = %f)\n", nextNode->layer->id(), minIncomingEdgeWeight);
|
| -#endif
|
| - }
|
| -
|
| - // Note: The original elements of the list are in no danger of having their ref count go to zero
|
| - // here as they are all nodes of the layer hierarchy and are kept alive by their parent nodes.
|
| - int count = 0;
|
| - for (LayerList::iterator it = first; it < last; it++)
|
| - *it = sortedList[count++]->layer;
|
| -
|
| -#if !defined( NDEBUG )
|
| - LOG(CCLayerSorter, "Sorting end ----\n");
|
| -#endif
|
| -
|
| - m_nodes.clear();
|
| - m_edges.clear();
|
| - m_activeEdges.clear();
|
| -}
|
| -
|
| -}
|
|
|