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e3cd0a3157
MozReview-Commit-ID: 1jESowJKdyp --HG-- extra : rebase_source : 3839cdea46729a9af05c777215cffcb9f42a2018
174 lines
5.9 KiB
C++
174 lines
5.9 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* vim: set ts=8 sts=4 et sw=4 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "DecomposeIntoNoRepeatTriangles.h"
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#include "gfxMatrix.h"
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namespace mozilla {
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namespace gl {
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void
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RectTriangles::AppendRectToCoordArray(InfallibleTArray<coord>& array,
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GLfloat x0, GLfloat y0,
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GLfloat x1, GLfloat y1)
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{
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coord* v = array.AppendElements(6);
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v[0].x = x0; v[0].y = y0;
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v[1].x = x1; v[1].y = y0;
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v[2].x = x0; v[2].y = y1;
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v[3].x = x0; v[3].y = y1;
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v[4].x = x1; v[4].y = y0;
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v[5].x = x1; v[5].y = y1;
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}
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void
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RectTriangles::addRect(GLfloat x0, GLfloat y0, GLfloat x1, GLfloat y1,
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GLfloat tx0, GLfloat ty0, GLfloat tx1, GLfloat ty1,
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bool flip_y /* = false */)
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{
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if (flip_y) {
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std::swap(ty0, ty1);
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}
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AppendRectToCoordArray(mVertexCoords, x0, y0, x1, y1);
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AppendRectToCoordArray(mTexCoords, tx0, ty0, tx1, ty1);
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}
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static GLfloat
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WrapTexCoord(GLfloat v)
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{
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// This should return values in range [0, 1.0)
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return v - floorf(v);
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}
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void
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DecomposeIntoNoRepeatTriangles(const gfx::IntRect& aTexCoordRect,
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const gfx::IntSize& aTexSize,
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RectTriangles& aRects,
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bool aFlipY /* = false */)
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{
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// normalize this
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gfx::IntRect tcr(aTexCoordRect);
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while (tcr.x >= aTexSize.width)
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tcr.x -= aTexSize.width;
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while (tcr.y >= aTexSize.height)
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tcr.y -= aTexSize.height;
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// Compute top left and bottom right tex coordinates
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GLfloat tl[2] =
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{ GLfloat(tcr.x) / GLfloat(aTexSize.width),
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GLfloat(tcr.y) / GLfloat(aTexSize.height) };
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GLfloat br[2] =
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{ GLfloat(tcr.XMost()) / GLfloat(aTexSize.width),
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GLfloat(tcr.YMost()) / GLfloat(aTexSize.height) };
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// then check if we wrap in either the x or y axis; if we do,
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// then also use fmod to figure out the "true" non-wrapping
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// texture coordinates.
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bool xwrap = false, ywrap = false;
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if (tcr.x < 0 || tcr.x > aTexSize.width ||
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tcr.XMost() < 0 || tcr.XMost() > aTexSize.width)
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{
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xwrap = true;
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tl[0] = WrapTexCoord(tl[0]);
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br[0] = WrapTexCoord(br[0]);
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}
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if (tcr.y < 0 || tcr.y > aTexSize.height ||
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tcr.YMost() < 0 || tcr.YMost() > aTexSize.height)
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{
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ywrap = true;
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tl[1] = WrapTexCoord(tl[1]);
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br[1] = WrapTexCoord(br[1]);
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}
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NS_ASSERTION(tl[0] >= 0.0f && tl[0] <= 1.0f &&
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tl[1] >= 0.0f && tl[1] <= 1.0f &&
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br[0] >= 0.0f && br[0] <= 1.0f &&
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br[1] >= 0.0f && br[1] <= 1.0f,
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"Somehow generated invalid texture coordinates");
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// If xwrap is false, the texture will be sampled from tl[0]
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// .. br[0]. If xwrap is true, then it will be split into tl[0]
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// .. 1.0, and 0.0 .. br[0]. Same for the Y axis. The
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// destination rectangle is also split appropriately, according
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// to the calculated xmid/ymid values.
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// There isn't a 1:1 mapping between tex coords and destination coords;
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// when computing midpoints, we have to take that into account. We
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// need to map the texture coords, which are (in the wrap case):
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// |tl->1| and |0->br| to the |0->1| range of the vertex coords. So
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// we have the length (1-tl)+(br) that needs to map into 0->1.
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// These are only valid if there is wrap involved, they won't be used
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// otherwise.
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GLfloat xlen = (1.0f - tl[0]) + br[0];
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GLfloat ylen = (1.0f - tl[1]) + br[1];
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NS_ASSERTION(!xwrap || xlen > 0.0f, "xlen isn't > 0, what's going on?");
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NS_ASSERTION(!ywrap || ylen > 0.0f, "ylen isn't > 0, what's going on?");
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NS_ASSERTION(aTexCoordRect.Width() <= aTexSize.width &&
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aTexCoordRect.Height() <= aTexSize.height, "tex coord rect would cause tiling!");
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if (!xwrap && !ywrap) {
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aRects.addRect(0.0f, 0.0f,
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1.0f, 1.0f,
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tl[0], tl[1],
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br[0], br[1],
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aFlipY);
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} else if (!xwrap && ywrap) {
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GLfloat ymid = (1.0f - tl[1]) / ylen;
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aRects.addRect(0.0f, 0.0f,
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1.0f, ymid,
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tl[0], tl[1],
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br[0], 1.0f,
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aFlipY);
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aRects.addRect(0.0f, ymid,
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1.0f, 1.0f,
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tl[0], 0.0f,
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br[0], br[1],
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aFlipY);
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} else if (xwrap && !ywrap) {
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GLfloat xmid = (1.0f - tl[0]) / xlen;
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aRects.addRect(0.0f, 0.0f,
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xmid, 1.0f,
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tl[0], tl[1],
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1.0f, br[1],
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aFlipY);
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aRects.addRect(xmid, 0.0f,
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1.0f, 1.0f,
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0.0f, tl[1],
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br[0], br[1],
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aFlipY);
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} else {
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GLfloat xmid = (1.0f - tl[0]) / xlen;
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GLfloat ymid = (1.0f - tl[1]) / ylen;
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aRects.addRect(0.0f, 0.0f,
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xmid, ymid,
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tl[0], tl[1],
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1.0f, 1.0f,
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aFlipY);
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aRects.addRect(xmid, 0.0f,
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1.0f, ymid,
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0.0f, tl[1],
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br[0], 1.0f,
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aFlipY);
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aRects.addRect(0.0f, ymid,
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xmid, 1.0f,
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tl[0], 0.0f,
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1.0f, br[1],
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aFlipY);
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aRects.addRect(xmid, ymid,
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1.0f, 1.0f,
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0.0f, 0.0f,
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br[0], br[1],
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aFlipY);
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}
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}
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} // namespace gl
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} // namespace mozilla
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