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/* |
* 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> |
*/ |
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#define CLIP_DOTPROD(K, A, B, C, D) X(K)*A + Y(K)*B + Z(K)*C + W(K)*D |
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#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) |
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#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) |
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/* 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; |
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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 ); |
} |
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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 ); |
} |
} |
} |
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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 ); |
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if (ctx->Light.ShadeModel == GL_FLAT) |
tnl->Driver.Render.CopyPV( ctx, newvert, v1 ); |
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v1 = newvert; |
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newvert++; |
} |
else { |
ASSERT(t1 == 0.0); |
} |
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tnl->Driver.Render.ClippedLine( ctx, v0, v1 ); |
} |
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/* 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; |
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ASSIGN_3V(inlist, v2, v0, v1 ); /* pv rotated to slot zero */ |
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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])); |
} |
} |
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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 ); |
} |
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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 ); |
} |
} |
} |
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if (ctx->Light.ShadeModel == GL_FLAT) { |
if (pv != inlist[0]) { |
ASSERT( inlist[0] >= VB->Count ); |
tnl->Driver.Render.CopyPV( ctx, inlist[0], pv ); |
} |
} |
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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]); |
} |
} |
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tnl->Driver.Render.ClippedPolygon( ctx, inlist, n ); |
} |
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/* 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; |
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ASSIGN_4V(inlist, v3, v0, v1, v2 ); /* pv rotated to slot zero */ |
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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 ); |
} |
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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 ); |
} |
} |
} |
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if (ctx->Light.ShadeModel == GL_FLAT) { |
if (pv != inlist[0]) { |
ASSERT( inlist[0] >= VB->Count ); |
tnl->Driver.Render.CopyPV( ctx, inlist[0], pv ); |
} |
} |
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tnl->Driver.Render.ClippedPolygon( ctx, inlist, n ); |
} |
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#undef W |
#undef Z |
#undef Y |
#undef X |
#undef SIZE |
#undef TAG |
#undef POLY_CLIP |
#undef LINE_CLIP |