3 * Mesa 3-D graphics library
6 * Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the "Software"),
10 * to deal in the Software without restriction, including without limitation
11 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
12 * and/or sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following conditions:
15 * The above copyright notice and this permission notice shall be included
16 * in all copies or substantial portions of the Software.
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
22 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
23 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26 * Keith Whitwell <keith_whitwell@yahoo.com>
29 /* Template to build clipping routines to support t_dd_imm_primtmp.h.
31 * The TAG(draw_line) and TAG(draw_triangle) routines are called in
32 * clipping and fallback scenarios, and when the native hardware
33 * primitive (eg polygons) is unavailable.
37 #define CLIP_DOTPROD(K, A, B, C, D) \
38 (CLIP_X(K)*A + CLIP_Y(K)*B + \
39 CLIP_Z(K)*C + CLIP_W(K)*D)
41 #define POLY_CLIP( PLANE, A, B, C, D ) \
44 TNL_VERTEX **indata = inlist[in]; \
45 TNL_VERTEX **outdata = inlist[in ^= 1]; \
46 TNL_VERTEX *J = indata[0]; \
47 GLfloat dpJ = CLIP_DOTPROD(J, A, B, C, D ); \
48 GLuint outcount = 0; \
51 indata[n] = indata[0]; /* prevent rotation of vertices */ \
52 for (i = 1; i <= n; i++) { \
53 TNL_VERTEX *I = indata[i]; \
54 GLfloat dpI = CLIP_DOTPROD(idx, A, B, C, D ); \
56 if (!NEGATIVE(dpPrev)) { \
57 outdata[outcount++] = J; \
60 if (DIFFERENT_SIGNS(dpI, dpJ)) { \
61 TNL_VERTEX *O = verts++; \
62 outdata[outcount++] = O; \
63 if (NEGATIVE(dpI)) { \
64 /* Going out of bounds. Avoid division by zero as we \
65 * know dp != dpPrev from DIFFERENT_SIGNS, above. \
67 GLfloat t = dpI / (dpI - dpJ); \
68 INTERP( ctx, t, O, I, J ); \
72 GLfloat t = dpJ / (dpJ - dpI); \
73 INTERP( ctx, t, O, J, I ); \
89 #define LINE_CLIP(PLANE, A, B, C, D ) \
92 GLfloat dpI = CLIP_DOTPROD( I, A, B, C, D ); \
93 GLfloat dpJ = CLIP_DOTPROD( J, A, B, C, D ); \
95 if (DIFFERENT_SIGNS(dpI, dpJ)) { \
96 TNL_VERTEX *O = verts++; \
97 if (NEGATIVE(dpJ)) { \
98 GLfloat t = dpI / (dpI - dpJ); \
99 INTERP( ctx, t, O, I, J ); \
102 GLfloat t = dpJ / (dpJ - dpI); \
103 INTERP( ctx, t, O, J, I ); \
107 else if (NEGATIVE(dpI)) \
114 /* Clip a line against the viewport and user clip planes.
116 static void TAG(clip_draw_line
)( struct gl_context
*ctx
,
123 TNL_VERTEX tmp
[MAX_CLIPPED_VERTICES
];
124 TNL_VERTEX
*verts
= tmp
;
127 LINE_CLIP( CLIP_RIGHT_BIT
, -1, 0, 0, 1 );
128 LINE_CLIP( CLIP_LEFT_BIT
, 1, 0, 0, 1 );
129 LINE_CLIP( CLIP_TOP_BIT
, 0, -1, 0, 1 );
130 LINE_CLIP( CLIP_BOTTOM_BIT
, 0, 1, 0, 1 );
131 LINE_CLIP( CLIP_FAR_BIT
, 0, 0, -1, 1 );
132 LINE_CLIP( CLIP_NEAR_BIT
, 0, 0, 1, 1 );
134 if ((ctx
->_TriangleCaps
& DD_FLATSHADE
) && J
!= pv
)
135 COPY_PV( ctx
, J
, pv
);
141 /* Clip a triangle against the viewport and user clip planes.
143 static void TAG(clip_draw_triangle
)( struct gl_context
*ctx
,
151 TNL_VERTEX tmp
[MAX_CLIPPED_VERTICES
];
152 TNL_VERTEX
*verts
= tmp
;
153 TNL_VERTEX
*(inlist
[2][MAX_CLIPPED_VERTICES
]);
159 ASSIGN_3V(inlist
, v2
, v0
, v1
); /* pv rotated to slot zero */
161 POLY_CLIP( CLIP_RIGHT_BIT
, -1, 0, 0, 1 );
162 POLY_CLIP( CLIP_LEFT_BIT
, 1, 0, 0, 1 );
163 POLY_CLIP( CLIP_TOP_BIT
, 0, -1, 0, 1 );
164 POLY_CLIP( CLIP_BOTTOM_BIT
, 0, 1, 0, 1 );
165 POLY_CLIP( CLIP_FAR_BIT
, 0, 0, -1, 1 );
166 POLY_CLIP( CLIP_NEAR_BIT
, 0, 0, 1, 1 );
168 if ((ctx
->_TriangleCaps
& DD_FLATSHADE
) && v2
!= inlist
[0])
169 COPY_PV( ctx
, inlist
[0], v2
);
172 DRAW_POLYGON( out
, n
);
176 static __inline
void TAG(draw_triangle
)( struct gl_context
*ctx
,
182 GLubyte ormask
= (v0
->mask
| v1
->mask
| v2
->mask
);
185 DRAW_TRI( v0
, v1
, v2
);
186 } else if ( !(v0
->mask
& v1
->mask
& v2
->mask
) ) {
187 TAG(clip_draw_triangle
)( ctx
, v0
, v1
, v2
, ormask
);
191 static __inline
void TAG(draw_line
)( struct gl_context
*ctx
,
196 GLubyte ormask
= (v0
->mask
| v1
->mask
);
200 } else if ( !(v0
->mask
& v1
->mask
) ) {
201 TAG(clip_draw_line
)( ctx
, v0
, v1
, ormask
);