void ClipLine(int *indices)
{
int mask = 0;
int clip_mask[2] = { 0, 0 };
for (int i = 0; i < 2; ++i)
{
clip_mask[i] = CalcClipMask(Vertices[i]);
mask |= clip_mask[i];
}
if (mask == 0)
return;
float t0 = 0;
float t1 = 0;
// Mark unused in case of early termination
// of the macros below. (When fully clipped)
indices[0] = SKIP_FLAG;
indices[1] = SKIP_FLAG;
LINE_CLIP(CLIP_POS_X_BIT, -1, 0, 0, 1);
LINE_CLIP(CLIP_NEG_X_BIT, 1, 0, 0, 1);
LINE_CLIP(CLIP_POS_Y_BIT, 0, -1, 0, 1);
LINE_CLIP(CLIP_NEG_Y_BIT, 0, 1, 0, 1);
LINE_CLIP(CLIP_POS_Z_BIT, 0, 0, -1, 1);
LINE_CLIP(CLIP_NEG_Z_BIT, 0, 0, 1, 1);
// Restore the old values as this line
// was not fully clipped.
indices[0] = 0;
indices[1] = 1;
int numVertices = 2;
if (clip_mask[0])
{
indices[0] = numVertices;
AddInterpolatedVertex(t0, 0, 1, numVertices);
}
if (clip_mask[1])
{
indices[1] = numVertices;
AddInterpolatedVertex(t1, 1, 0, numVertices);
}
}
/* Clip a line against the viewport and user clip planes.
*/
static void TAG(clip_draw_line)( GLcontext *ctx,
TNL_VERTEX *I,
TNL_VERTEX *J,
GLuint mask )
{
LOCAL_VARS;
GET_INTERP_FUNC;
TNL_VERTEX tmp[MAX_CLIPPED_VERTICES];
TNL_VERTEX *verts = tmp;
TNL_VERTEX *pv = J;
LINE_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 );
LINE_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 );
LINE_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 );
LINE_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 );
LINE_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 );
LINE_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 );
if ((ctx->_TriangleCaps & DD_FLATSHADE) && J != pv)
COPY_PV( ctx, J, pv );
DRAW_LINE( I, J );
}
