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author | rodri <rgl@antares-labs.eu> | 2024-06-14 15:01:15 +0000 |
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committer | rodri <rgl@antares-labs.eu> | 2024-06-14 15:01:15 +0000 |
commit | c69735e24f7c5926ed63ff8c5292be282aa8b240 (patch) | |
tree | 6c941bfd052eb0b603d591695034543a53b7f43d /render.c | |
parent | b1335875b19a4db2ae028f8d790784cddcffe8b5 (diff) | |
download | libgraphics-c69735e24f7c5926ed63ff8c5292be282aa8b240.tar.gz libgraphics-c69735e24f7c5926ed63ff8c5292be282aa8b240.tar.bz2 libgraphics-c69735e24f7c5926ed63ff8c5292be282aa8b240.zip |
fix the barycoords routine to avoid reporting false degenerates.
added a normals buffer for debugging.
Diffstat (limited to 'render.c')
-rw-r--r-- | render.c | 28 |
1 files changed, 27 insertions, 1 deletions
@@ -46,6 +46,15 @@ pixel(Framebuf *fb, Point p, Color c) dst[Dx(fb->r)*p.y + p.x] = col2ul(c); } +static void +pixeln(Framebuf *fb, Point p, Color c) +{ + ulong *dst; + + dst = fb->nb; + dst[Dx(fb->r)*p.y + p.x] = col2ul(c); +} + static int isvisible(Point3 p) { @@ -67,6 +76,21 @@ isfacingback(Primitive p) return sa <= 0; } +static Point3 +_barycoords(Triangle2 t, Point2 p) +{ + Point2 p0p1 = subpt2(t.p1, t.p0); + Point2 p0p2 = subpt2(t.p2, t.p0); + Point2 pp0 = subpt2(t.p0, p); + + Point3 v = crossvec3(Vec3(p0p2.x, p0p1.x, pp0.x), Vec3(p0p2.y, p0p1.y, pp0.y)); + + /* handle degenerate triangles—i.e. the ones where every point lies on the same line */ + if(fabs(v.z) < 1e-5) + return Pt3(-1,-1,-1,1); + return Pt3(1 - (v.x + v.y)/v.z, v.y/v.z, v.x/v.z, 1); +} + static void rasterize(Rastertask *task) { @@ -178,7 +202,7 @@ discard: for(p.y = bbox.min.y; p.y < bbox.max.y; p.y++) for(p.x = bbox.min.x; p.x < bbox.max.x; p.x++){ - bc = barycoords(t, Pt2(p.x,p.y,1)); + bc = _barycoords(t, Pt2(p.x,p.y,1)); if(bc.x < 0 || bc.y < 0 || bc.z < 0) continue; @@ -198,6 +222,8 @@ discard: fsp.p = p; c = params->fshader(&fsp); pixel(params->fb, p, c); + fsp.v.n.w = 1; + pixeln(params->fb, p, fsp.v.n); delvattrs(&fsp.v); } break; |