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