The Tor Browser: gfx/gl/DecomposeIntoNoRepeatTriangles.cpp@97036ab72558 (annotated)

gfx/gl/DecomposeIntoNoRepeatTriangles.cpp@97036ab72558 (annotated)

gfx/gl/DecomposeIntoNoRepeatTriangles.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* vim: set ts=8 sts=4 et sw=4 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "DecomposeIntoNoRepeatTriangles.h"
 #include "gfxMatrix.h"
 namespace mozilla {
 namespace gl {
 void
 RectTriangles::AppendRectToCoordArray(InfallibleTArray<coord>& array,
                                       GLfloat x0, GLfloat y0,
                                       GLfloat x1, GLfloat y1)
 {
     coord* v = array.AppendElements(6);
     v[0].x = x0; v[0].y = y0;
     v[1].x = x1; v[1].y = y0;
     v[2].x = x0; v[2].y = y1;
     v[3].x = x0; v[3].y = y1;
     v[4].x = x1; v[4].y = y0;
     v[5].x = x1; v[5].y = y1;
 }
 void
 RectTriangles::addRect(GLfloat x0, GLfloat y0, GLfloat x1, GLfloat y1,
                        GLfloat tx0, GLfloat ty0, GLfloat tx1, GLfloat ty1,
                        bool flip_y /* = false */)
 {
     if (flip_y) {
         std::swap(ty0, ty1);
     }
     AppendRectToCoordArray(mVertexCoords, x0, y0, x1, y1);
     AppendRectToCoordArray(mTexCoords, tx0, ty0, tx1, ty1);
 }
 bool
 RectTriangles::isSimpleQuad(gfx3DMatrix& aOutTextureTransform) const
 {
     if (mVertexCoords.Length() == 6 &&
         mVertexCoords[0].x == 0.0f &&
         mVertexCoords[0].y == 0.0f &&
         mVertexCoords[5].x == 1.0f &&
         mVertexCoords[5].y == 1.0f)
     {
         GLfloat tx0 = mTexCoords[0].x;
         GLfloat ty0 = mTexCoords[0].y;
         GLfloat tx1 = mTexCoords[5].x;
         GLfloat ty1 = mTexCoords[5].y;
         aOutTextureTransform = gfx3DMatrix::From2D(gfxMatrix(tx1 - tx0, 0, 0, ty1 - ty0, tx0, ty0));
         return true;
     }
     return false;
 }
 static GLfloat
 WrapTexCoord(GLfloat v)
 {
     // fmodf gives negative results for negative numbers;
     // that is, fmodf(0.75, 1.0) == 0.75, but
     // fmodf(-0.75, 1.0) == -0.75.  For the negative case,
     // the result we need is 0.25, so we add 1.0f.
     if (v < 0.0f) {
         return 1.0f + fmodf(v, 1.0f);
     }
     return fmodf(v, 1.0f);
 }
 void
 DecomposeIntoNoRepeatTriangles(const nsIntRect& aTexCoordRect,
                                const nsIntSize& aTexSize,
                                RectTriangles& aRects,
                                bool aFlipY /* = false */)
 {
     // normalize this
     nsIntRect tcr(aTexCoordRect);
     while (tcr.x >= aTexSize.width)
         tcr.x -= aTexSize.width;
     while (tcr.y >= aTexSize.height)
         tcr.y -= aTexSize.height;
     // Compute top left and bottom right tex coordinates
     GLfloat tl[2] =
         { GLfloat(tcr.x) / GLfloat(aTexSize.width),
           GLfloat(tcr.y) / GLfloat(aTexSize.height) };
     GLfloat br[2] =
         { GLfloat(tcr.XMost()) / GLfloat(aTexSize.width),
           GLfloat(tcr.YMost()) / GLfloat(aTexSize.height) };
     // then check if we wrap in either the x or y axis; if we do,
     // then also use fmod to figure out the "true" non-wrapping
     // texture coordinates.
     bool xwrap = false, ywrap = false;
     if (tcr.x < 0 || tcr.x > aTexSize.width ||
         tcr.XMost() < 0 || tcr.XMost() > aTexSize.width)
     {
         xwrap = true;
         tl[0] = WrapTexCoord(tl[0]);
         br[0] = WrapTexCoord(br[0]);
     }
     if (tcr.y < 0 || tcr.y > aTexSize.height ||
         tcr.YMost() < 0 || tcr.YMost() > aTexSize.height)
     {
         ywrap = true;
         tl[1] = WrapTexCoord(tl[1]);
         br[1] = WrapTexCoord(br[1]);
     }
     NS_ASSERTION(tl[0] >= 0.0f && tl[0] <= 1.0f &&
                  tl[1] >= 0.0f && tl[1] <= 1.0f &&
                  br[0] >= 0.0f && br[0] <= 1.0f &&
                  br[1] >= 0.0f && br[1] <= 1.0f,
                  "Somehow generated invalid texture coordinates");
     // If xwrap is false, the texture will be sampled from tl[0]
     // .. br[0].  If xwrap is true, then it will be split into tl[0]
     // .. 1.0, and 0.0 .. br[0].  Same for the Y axis.  The
     // destination rectangle is also split appropriately, according
     // to the calculated xmid/ymid values.
     // There isn't a 1:1 mapping between tex coords and destination coords;
     // when computing midpoints, we have to take that into account.  We
     // need to map the texture coords, which are (in the wrap case):
     // |tl->1| and |0->br| to the |0->1| range of the vertex coords.  So
     // we have the length (1-tl)+(br) that needs to map into 0->1.
     // These are only valid if there is wrap involved, they won't be used
     // otherwise.
     GLfloat xlen = (1.0f - tl[0]) + br[0];
     GLfloat ylen = (1.0f - tl[1]) + br[1];
     NS_ASSERTION(!xwrap || xlen > 0.0f, "xlen isn't > 0, what's going on?");
     NS_ASSERTION(!ywrap || ylen > 0.0f, "ylen isn't > 0, what's going on?");
     NS_ASSERTION(aTexCoordRect.width <= aTexSize.width &&
                  aTexCoordRect.height <= aTexSize.height, "tex coord rect would cause tiling!");
     if (!xwrap && !ywrap) {
         aRects.addRect(0.0f, 0.0f,
 .0f, 1.0f,
                        tl[0], tl[1],
                        br[0], br[1],
                        aFlipY);
     } else if (!xwrap && ywrap) {
         GLfloat ymid = (1.0f - tl[1]) / ylen;
         aRects.addRect(0.0f, 0.0f,
 .0f, ymid,
                        tl[0], tl[1],
                        br[0], 1.0f,
                        aFlipY);
         aRects.addRect(0.0f, ymid,
 .0f, 1.0f,
                        tl[0], 0.0f,
                        br[0], br[1],
                        aFlipY);
     } else if (xwrap && !ywrap) {
         GLfloat xmid = (1.0f - tl[0]) / xlen;
         aRects.addRect(0.0f, 0.0f,
                        xmid, 1.0f,
                        tl[0], tl[1],
 .0f, br[1],
                        aFlipY);
         aRects.addRect(xmid, 0.0f,
 .0f, 1.0f,
 .0f, tl[1],
                        br[0], br[1],
                        aFlipY);
     } else {
         GLfloat xmid = (1.0f - tl[0]) / xlen;
         GLfloat ymid = (1.0f - tl[1]) / ylen;
         aRects.addRect(0.0f, 0.0f,
                        xmid, ymid,
                        tl[0], tl[1],
 .0f, 1.0f,
                        aFlipY);
         aRects.addRect(xmid, 0.0f,
 .0f, ymid,
 .0f, tl[1],
                        br[0], 1.0f,
                        aFlipY);
         aRects.addRect(0.0f, ymid,
                        xmid, 1.0f,
                        tl[0], 0.0f,
 .0f, br[1],
                        aFlipY);
         aRects.addRect(xmid, ymid,
 .0f, 1.0f,
 .0f, 0.0f,
                        br[0], br[1],
                        aFlipY);
     }
 }
 }
 }

The Tor Browser / annotate

gfx/gl/DecomposeIntoNoRepeatTriangles.cpp@97036ab72558 (annotated)

gfx/gl/DecomposeIntoNoRepeatTriangles.cpp