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/*
* Mesa 3-D graphics library
* Version: 3.5
*
* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* Authors:
* Keith Whitwell <keith_whitwell@yahoo.com>
*/
/* Template to build clipping routines to support t_dd_imm_primtmp.h.
*
* The TAG(draw_line) and TAG(draw_triangle) routines are called in
* clipping and fallback scenarios, and when the native hardware
* primitive (eg polygons) is unavailable.
*/
#define CLIP_DOTPROD(K, A, B, C, D) \
(CLIP_X(K)*A + CLIP_Y(K)*B + \
CLIP_Z(K)*C + CLIP_W(K)*D)
#define POLY_CLIP( PLANE, A, B, C, D ) \
do { \
if (mask & PLANE) { \
TNL_VERTEX **indata = inlist[in]; \
TNL_VERTEX **outdata = inlist[in ^= 1]; \
TNL_VERTEX *J = indata[0]; \
GLfloat dpJ = CLIP_DOTPROD(J, A, B, C, D ); \
GLuint outcount = 0; \
GLuint i; \
\
indata[n] = indata[0]; /* prevent rotation of vertices */ \
for (i = 1; i <= n; i++) { \
TNL_VERTEX *I = indata[i]; \
GLfloat dpI = CLIP_DOTPROD(idx, A, B, C, D ); \
\
if (!NEGATIVE(dpPrev)) { \
outdata[outcount++] = J; \
} \
\
if (DIFFERENT_SIGNS(dpI, dpJ)) { \
TNL_VERTEX *O = verts++; \
outdata[outcount++] = O; \
if (NEGATIVE(dpI)) { \
/* Going out of bounds. Avoid division by zero as we \
* know dp != dpPrev from DIFFERENT_SIGNS, above. \
*/ \
GLfloat t = dpI / (dpI - dpJ); \
INTERP( ctx, t, O, I, J ); \
} else { \
/* Coming back in. \
*/ \
GLfloat t = dpJ / (dpJ - dpI); \
INTERP( ctx, t, O, J, I ); \
} \
} \
\
J = I; \
dpJ = dpI; \
} \
\
if (outcount < 3) \
return; \
\
nr = outcount; \
} \
} while (0)
#define LINE_CLIP(PLANE, A, B, C, D ) \
do { \
if (mask & PLANE) { \
GLfloat dpI = CLIP_DOTPROD( I, A, B, C, D ); \
GLfloat dpJ = CLIP_DOTPROD( J, A, B, C, D ); \
\
if (DIFFERENT_SIGNS(dpI, dpJ)) { \
TNL_VERTEX *O = verts++; \
if (NEGATIVE(dpJ)) { \
GLfloat t = dpI / (dpI - dpJ); \
INTERP( ctx, t, O, I, J ); \
J = O; \
} else { \
GLfloat t = dpJ / (dpJ - dpI); \
INTERP( ctx, t, O, J, I ); \
I = O; \
} \
} \
else if (NEGATIVE(dpI)) \
return; \
} \
} while (0)
/* Clip a line against the viewport and user clip planes.
*/
static void TAG(clip_draw_line)( struct gl_context *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 );
}
/* Clip a triangle against the viewport and user clip planes.
*/
static void TAG(clip_draw_triangle)( struct gl_context *ctx,
TNL_VERTEX *v0,
TNL_VERTEX *v1,
TNL_VERTEX *v2,
GLuint mask )
{
LOCAL_VARS;
GET_INTERP_FUNC;
TNL_VERTEX tmp[MAX_CLIPPED_VERTICES];
TNL_VERTEX *verts = tmp;
TNL_VERTEX *(inlist[2][MAX_CLIPPED_VERTICES]);
TNL_VERTEX **out;
GLuint in = 0;
GLuint n = 3;
GLuint i;
ASSIGN_3V(inlist, v2, v0, v1 ); /* pv rotated to slot zero */
POLY_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 );
POLY_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 );
POLY_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 );
POLY_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 );
POLY_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 );
POLY_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 );
if ((ctx->_TriangleCaps & DD_FLATSHADE) && v2 != inlist[0])
COPY_PV( ctx, inlist[0], v2 );
out = inlist[in];
DRAW_POLYGON( out, n );
}
static __inline void TAG(draw_triangle)( struct gl_context *ctx,
TNL_VERTEX *v0,
TNL_VERTEX *v1,
TNL_VERTEX *v2 )
{
LOCAL_VARS;
GLubyte ormask = (v0->mask | v1->mask | v2->mask);
if ( !ormask ) {
DRAW_TRI( v0, v1, v2 );
} else if ( !(v0->mask & v1->mask & v2->mask) ) {
TAG(clip_draw_triangle)( ctx, v0, v1, v2, ormask );
}
}
static __inline void TAG(draw_line)( struct gl_context *ctx,
TNL_VERTEX *v0,
TNL_VERTEX *v1 )
{
LOCAL_VARS;
GLubyte ormask = (v0->mask | v1->mask);
if ( !ormask ) {
DRAW_LINE( v0, v1 );
} else if ( !(v0->mask & v1->mask) ) {
TAG(clip_draw_line)( ctx, v0, v1, ormask );
}
}
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