diff options
Diffstat (limited to 'src/libnr/nr-gradient.cpp')
| -rw-r--r-- | src/libnr/nr-gradient.cpp | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/src/libnr/nr-gradient.cpp b/src/libnr/nr-gradient.cpp index fa4f9f91f..9e9360147 100644 --- a/src/libnr/nr-gradient.cpp +++ b/src/libnr/nr-gradient.cpp @@ -114,6 +114,17 @@ nr_rgradient_render_block_end(NRRenderer *r, NRPixBlock *pb, NRPixBlock *m) nr_blit_pixblock_mask_rgba32(pb, m, (c[0] << 24) | (c[1] << 16) | (c[2] << 8) | c[3]); } +float fast_sqrt (float in) +{ + float x = in; + float xhalf = 0.5f*x; + int i = *(int*)&x; + i = 0x5f3759df - (i >> 1); // This line hides a LOT of math! + x = *(float*)&i; + x = x*(1.5f - xhalf*x*x); // repeat this statement for a better approximation + return x * in; +} + /* * The archetype is following * @@ -150,7 +161,7 @@ nr_rgradient_render_generic_symmetric(NRRGradientRenderer *rgr, NRPixBlock *pb) NR::Coord gx = rgr->px2gs.c[0] * pb->area.x0 + rgr->px2gs.c[2] * y + rgr->px2gs.c[4]; NR::Coord gy = rgr->px2gs.c[1] * pb->area.x0 + rgr->px2gs.c[3] * y + rgr->px2gs.c[5]; for (int x = pb->area.x0; x < pb->area.x1; x++) { - NR::Coord const pos = hypot(gx, gy); + float const pos = fast_sqrt((gx*gx) + (gy*gy)); int idx; if (rgr->spread == NR_GRADIENT_SPREAD_REFLECT) { idx = (int) ((long long) pos & NRG_2MASK); @@ -176,7 +187,7 @@ nr_rgradient_render_generic_symmetric(NRRGradientRenderer *rgr, NRPixBlock *pb) NR::Coord gx = rgr->px2gs.c[0] * pb->area.x0 + rgr->px2gs.c[2] * y + rgr->px2gs.c[4]; NR::Coord gy = rgr->px2gs.c[1] * pb->area.x0 + rgr->px2gs.c[3] * y + rgr->px2gs.c[5]; for (int x = pb->area.x0; x < pb->area.x1; x++) { - NR::Coord const pos = hypot(gx, gy); + float pos = fast_sqrt((gx*gx) + (gy*gy)); int idx; if (rgr->spread == NR_GRADIENT_SPREAD_REFLECT) { idx = (int) ((long long) pos & NRG_2MASK); @@ -221,7 +232,7 @@ nr_rgradient_render_generic_symmetric(NRRGradientRenderer *rgr, NRPixBlock *pb) NR::Coord gx = rgr->px2gs.c[0] * pb->area.x0 + rgr->px2gs.c[2] * y + rgr->px2gs.c[4]; NR::Coord gy = rgr->px2gs.c[1] * pb->area.x0 + rgr->px2gs.c[3] * y + rgr->px2gs.c[5]; for (int x = pb->area.x0; x < pb->area.x1; x++) { - NR::Coord const pos = hypot(gx, gy); + NR::Coord const pos = fast_sqrt((gx*gx) + (gy*gy)); int idx; if (rgr->spread == NR_GRADIENT_SPREAD_REFLECT) { idx = (int) ((long long) pos & NRG_2MASK); |