/*
* Mesa 3-D graphics library
* Version: 6.5.2
*
* Copyright (C) 1999-2006 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@tungstengraphics.com>
*/
#define CLIP_DOTPROD(K, A, B, C, D) X(K)*A + Y(K)*B + Z(K)*C + W(K)*D
#define POLY_CLIP( PLANE_BIT, A, B, C, D ) \
do { \
if (mask & PLANE_BIT) { \
GLuint idxPrev = inlist[0]; \
GLfloat dpPrev = CLIP_DOTPROD(idxPrev, A, B, C, D ); \
GLuint outcount = 0; \
GLuint i; \
\
inlist[n] = inlist[0]; /* prevent rotation of vertices */ \
for (i = 1; i <= n; i++) { \
GLuint idx = inlist[i]; \
GLfloat dp = CLIP_DOTPROD(idx, A, B, C, D ); \
\
if (!IS_NEGATIVE(dpPrev)) { \
outlist[outcount++] = idxPrev; \
} \
\
if (DIFFERENT_SIGNS(dp, dpPrev)) { \
if (IS_NEGATIVE(dp)) { \
/* Going out of bounds. Avoid division by zero as we \
* know dp != dpPrev from DIFFERENT_SIGNS, above. \
*/ \
GLfloat t = dp / (dp - dpPrev); \
INTERP_4F( t, coord[newvert], coord[idx], coord[idxPrev]); \
interp( ctx, t, newvert, idx, idxPrev, GL_TRUE ); \
} else { \
/* Coming back in. \
*/ \
GLfloat t = dpPrev / (dpPrev - dp); \
INTERP_4F( t, coord[newvert], coord[idxPrev], coord[idx]); \
interp( ctx, t, newvert, idxPrev, idx, GL_FALSE ); \
} \
outlist[outcount++] = newvert++; \
} \
\
idxPrev = idx; \
dpPrev = dp; \
} \
\
if (outcount < 3) \
return; \
\
{ \
GLuint *tmp = inlist; \
inlist = outlist; \
outlist = tmp; \
n = outcount; \
} \
} \
} while (0)
#define LINE_CLIP(PLANE_BIT, A, B, C, D ) \
do { \
if (mask & PLANE_BIT) { \
const GLfloat dp0 = CLIP_DOTPROD( v0, A, B, C, D ); \
const GLfloat dp1 = CLIP_DOTPROD( v1, A, B, C, D ); \
const GLboolean neg_dp0 = IS_NEGATIVE(dp0); \
const GLboolean neg_dp1 = IS_NEGATIVE(dp1); \
\
/* For regular clipping, we know from the clipmask that one \
* (or both) of these must be negative (otherwise we wouldn't \
* be here). \
* For userclip, there is only a single bit for all active \
* planes, so we can end up here when there is nothing to do, \
* hence the second IS_NEGATIVE() test: \
*/ \
if (neg_dp0 && neg_dp1) \
return; /* both vertices outside clip plane: discard */ \
\
if (neg_dp1) { \
GLfloat t = dp1 / (dp1 - dp0); \
if (t > t1) t1 = t; \
} else if (neg_dp0) { \
GLfloat t = dp0 / (dp0 - dp1); \
if (t > t0) t0 = t; \
} \
if (t0 + t1 >= 1.0) \
return; /* discard */ \
} \
} while (0)
/* Clip a line against the viewport and user clip planes.
*/
static INLINE void
TAG(clip_line)( struct gl_context *ctx, GLuint v0, GLuint v1, GLubyte mask )
{
TNLcontext *tnl = TNL_CONTEXT(ctx);
struct vertex_buffer *VB = &tnl->vb;
tnl_interp_func interp = tnl->Driver.Render.Interp;
GLfloat (*coord)[4] = VB->ClipPtr->data;
GLuint newvert = VB->Count;
GLfloat t0 = 0;
GLfloat t1 = 0;
GLuint p;
const GLuint v0_orig = v0;
if (mask & CLIP_FRUSTUM_BITS) {
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 (mask & CLIP_USER_BIT) {
for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
const GLfloat a = ctx->Transform._ClipUserPlane[p][0];
const GLfloat b = ctx->Transform._ClipUserPlane[p][1];
const GLfloat c = ctx->Transform._ClipUserPlane[p][2];
const GLfloat d = ctx->Transform._ClipUserPlane[p][3];
LINE_CLIP( CLIP_USER_BIT, a, b, c, d );
}
}
}
if (VB->ClipMask[v0]) {
INTERP_4F( t0, coord[newvert], coord[v0], coord[v1] );
interp( ctx, t0, newvert, v0, v1, GL_FALSE );
v0 = newvert;
newvert++;
}
else {
ASSERT(t0 == 0.0);
}
/* 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!
*/
if (VB->ClipMask[v1]) {
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 );
v1 = newvert;
newvert++;
}
else {
ASSERT(t1 == 0.0);
}
tnl->Driver.Render.ClippedLine( ctx, v0, v1 );
}
/* Clip a triangle against the viewport and user clip planes.
*/
static INLINE void
TAG(clip_tri)( struct gl_context *ctx, GLuint v0, GLuint v1, GLuint v2, GLubyte mask )
{
TNLcontext *tnl = TNL_CONTEXT(ctx);
struct vertex_buffer *VB = &tnl->vb;
tnl_interp_func interp = tnl->Driver.Render.Interp;
GLuint newvert = VB->Count;
GLfloat (*coord)[4] = VB->ClipPtr->data;
GLuint pv = v2;
GLuint vlist[2][MAX_CLIPPED_VERTICES];
GLuint *inlist = vlist[0], *outlist = vlist[1];
GLuint p;
GLuint n = 3;
ASSIGN_3V(inlist, v2, v0, v1 ); /* pv rotated to slot zero */
if (0) {
/* print pre-clip vertex coords */
GLuint i, j;
printf("pre clip:\n");
for (i = 0; i < n; i++) {
j = inlist[i];
printf(" %u: %u: %f, %f, %f, %f\n",
i, j,
coord[j][0], coord[j][1], coord[j][2], coord[j][3]);
assert(!IS_INF_OR_NAN(coord[j][0]));
assert(!IS_INF_OR_NAN(coord[j][1]));
assert(!IS_INF_OR_NAN(coord[j][2]));
assert(!IS_INF_OR_NAN(coord[j][3]));
}
}
if (mask & CLIP_FRUSTUM_BITS) {
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 (mask & CLIP_USER_BIT) {
for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
const GLfloat a = ctx->Transform._ClipUserPlane[p][0];
const GLfloat b = ctx->Transform._ClipUserPlane[p][1];
const GLfloat c = ctx->Transform._ClipUserPlane[p][2];
const GLfloat d = ctx->Transform._ClipUserPlane[p][3];
POLY_CLIP( CLIP_USER_BIT, a, b, c, d );
}
}
}
if (ctx->Light.ShadeModel == GL_FLAT) {
if (pv != inlist[0]) {
ASSERT( inlist[0] >= VB->Count );
tnl->Driver.Render.CopyPV( ctx, inlist[0], pv );
}
}
if (0) {
/* print post-clip vertex coords */
GLuint i, j;
printf("post clip:\n");
for (i = 0; i < n; i++) {
j = inlist[i];
printf(" %u: %u: %f, %f, %f, %f\n",
i, j,
coord[j][0], coord[j][1], coord[j][2], coord[j][3]);
}
}
tnl->Driver.Render.ClippedPolygon( ctx, inlist, n );
}
/* Clip a quad against the viewport and user clip planes.
*/
static INLINE void
TAG(clip_quad)( struct gl_context *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint v3,
GLubyte mask )
{
TNLcontext *tnl = TNL_CONTEXT(ctx);
struct vertex_buffer *VB = &tnl->vb;
tnl_interp_func interp = tnl->Driver.Render.Interp;
GLuint newvert = VB->Count;
GLfloat (*coord)[4] = VB->ClipPtr->data;
GLuint pv = v3;
GLuint vlist[2][MAX_CLIPPED_VERTICES];
GLuint *inlist = vlist[0], *outlist = vlist[1];
GLuint p;
GLuint n = 4;
ASSIGN_4V(inlist, v3, v0, v1, v2 ); /* pv rotated to slot zero */
if (mask & CLIP_FRUSTUM_BITS) {
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 (mask & CLIP_USER_BIT) {
for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
const GLfloat a = ctx->Transform._ClipUserPlane[p][0];
const GLfloat b = ctx->Transform._ClipUserPlane[p][1];
const GLfloat c = ctx->Transform._ClipUserPlane[p][2];
const GLfloat d = ctx->Transform._ClipUserPlane[p][3];
POLY_CLIP( CLIP_USER_BIT, a, b, c, d );
}
}
}
if (ctx->Light.ShadeModel == GL_FLAT) {
if (pv != inlist[0]) {
ASSERT( inlist[0] >= VB->Count );
tnl->Driver.Render.CopyPV( ctx, inlist[0], pv );
}
}
tnl->Driver.Render.ClippedPolygon( ctx, inlist, n );
}
#undef W
#undef Z
#undef Y
#undef X
#undef SIZE
#undef TAG
#undef POLY_CLIP
#undef LINE_CLIP