| /* |
| * 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)( GLcontext *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 & 0x3f) { |
| 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)( GLcontext *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 (mask & 0x3f) { |
| 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 ); |
| } |
| |
| |
| /* Clip a quad against the viewport and user clip planes. |
| */ |
| static INLINE void |
| TAG(clip_quad)( GLcontext *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 & 0x3f) { |
| 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 |
