diff options
Diffstat (limited to 'src/mesa/tnl/t_vb_cliptmp.h')
| -rw-r--r-- | src/mesa/tnl/t_vb_cliptmp.h | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/src/mesa/tnl/t_vb_cliptmp.h b/src/mesa/tnl/t_vb_cliptmp.h index f3776e7eeb6..8dfa018aab7 100644 --- a/src/mesa/tnl/t_vb_cliptmp.h +++ b/src/mesa/tnl/t_vb_cliptmp.h @@ -125,6 +125,7 @@ TAG(clip_line)( GLcontext *ctx, GLuint v0, GLuint v1, GLubyte mask ) GLfloat t0 = 0; GLfloat t1 = 0; GLuint p; + const GLuint v0_orig = v0; if (mask & 0x3f) { LINE_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 ); @@ -153,12 +154,18 @@ TAG(clip_line)( GLcontext *ctx, GLuint v0, GLuint v1, GLubyte mask ) v0 = newvert; newvert++; } - else + else { ASSERT(t0 == 0.0); + } if (VB->ClipMask[v1]) { - INTERP_4F( t1, coord[newvert], coord[v1], coord[v0] ); - interp( ctx, t1, newvert, v1, v0, GL_FALSE ); + /* Note: we need to use vertex v0_orig when computing the new + * interpolated/clipped vertex position, not the current v0 which + * may have got set when we clipped the other end of the line! + */ + + INTERP_4F( t1, coord[newvert], coord[v1], coord[v0_orig] ); + interp( ctx, t1, newvert, v1, v0_orig, GL_FALSE ); if (ctx->Light.ShadeModel == GL_FLAT) tnl->Driver.Render.CopyPV( ctx, newvert, v1 ); @@ -167,8 +174,9 @@ TAG(clip_line)( GLcontext *ctx, GLuint v0, GLuint v1, GLubyte mask ) newvert++; } - else + else { ASSERT(t1 == 0.0); + } tnl->Driver.Render.ClippedLine( ctx, v0, v1 ); } |