/* * 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