| /************************************************************************** |
| * |
| * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas. |
| * 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, sub license, 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 (including the |
| * next paragraph) 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 NON-INFRINGEMENT. |
| * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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. |
| * |
| **************************************************************************/ |
| |
| /** |
| * \brief Clipping stage |
| * |
| * \author Keith Whitwell <keith@tungstengraphics.com> |
| */ |
| |
| |
| #include "util/u_memory.h" |
| #include "util/u_math.h" |
| |
| #include "pipe/p_shader_tokens.h" |
| |
| #include "draw_vs.h" |
| #include "draw_pipe.h" |
| #include "draw_fs.h" |
| |
| |
| #ifndef IS_NEGATIVE |
| #define IS_NEGATIVE(X) ((X) < 0.0) |
| #endif |
| |
| #ifndef DIFFERENT_SIGNS |
| #define DIFFERENT_SIGNS(x, y) ((x) * (y) <= 0.0F && (x) - (y) != 0.0F) |
| #endif |
| |
| #define MAX_CLIPPED_VERTICES ((2 * (6 + PIPE_MAX_CLIP_PLANES))+1) |
| |
| |
| |
| struct clip_stage { |
| struct draw_stage stage; /**< base class */ |
| |
| /* List of the attributes to be flatshaded. */ |
| uint num_flat_attribs; |
| uint flat_attribs[PIPE_MAX_SHADER_OUTPUTS]; |
| |
| /* Mask of attributes in noperspective mode */ |
| boolean noperspective_attribs[PIPE_MAX_SHADER_OUTPUTS]; |
| |
| float (*plane)[4]; |
| }; |
| |
| |
| /** Cast wrapper */ |
| static INLINE struct clip_stage *clip_stage( struct draw_stage *stage ) |
| { |
| return (struct clip_stage *)stage; |
| } |
| |
| |
| #define LINTERP(T, OUT, IN) ((OUT) + (T) * ((IN) - (OUT))) |
| |
| |
| /* All attributes are float[4], so this is easy: |
| */ |
| static void interp_attr( float dst[4], |
| float t, |
| const float in[4], |
| const float out[4] ) |
| { |
| dst[0] = LINTERP( t, out[0], in[0] ); |
| dst[1] = LINTERP( t, out[1], in[1] ); |
| dst[2] = LINTERP( t, out[2], in[2] ); |
| dst[3] = LINTERP( t, out[3], in[3] ); |
| } |
| |
| |
| /** |
| * Copy flat shaded attributes src vertex to dst vertex. |
| */ |
| static void copy_flat( struct draw_stage *stage, |
| struct vertex_header *dst, |
| const struct vertex_header *src ) |
| { |
| const struct clip_stage *clipper = clip_stage(stage); |
| uint i; |
| for (i = 0; i < clipper->num_flat_attribs; i++) { |
| const uint attr = clipper->flat_attribs[i]; |
| COPY_4FV(dst->data[attr], src->data[attr]); |
| } |
| } |
| |
| |
| |
| /* Interpolate between two vertices to produce a third. |
| */ |
| static void interp( const struct clip_stage *clip, |
| struct vertex_header *dst, |
| float t, |
| const struct vertex_header *out, |
| const struct vertex_header *in ) |
| { |
| const unsigned nr_attrs = draw_current_shader_outputs(clip->stage.draw); |
| const unsigned pos_attr = draw_current_shader_position_output(clip->stage.draw); |
| const unsigned clip_attr = draw_current_shader_clipvertex_output(clip->stage.draw); |
| unsigned j; |
| float t_nopersp; |
| |
| /* Vertex header. |
| */ |
| dst->clipmask = 0; |
| dst->edgeflag = 0; /* will get overwritten later */ |
| dst->have_clipdist = in->have_clipdist; |
| dst->vertex_id = UNDEFINED_VERTEX_ID; |
| |
| /* Interpolate the clip-space coords. |
| */ |
| interp_attr(dst->clip, t, in->clip, out->clip); |
| /* interpolate the clip-space position */ |
| interp_attr(dst->pre_clip_pos, t, in->pre_clip_pos, out->pre_clip_pos); |
| |
| /* Do the projective divide and viewport transformation to get |
| * new window coordinates: |
| */ |
| { |
| const float *pos = dst->pre_clip_pos; |
| const float *scale = clip->stage.draw->viewport.scale; |
| const float *trans = clip->stage.draw->viewport.translate; |
| const float oow = 1.0f / pos[3]; |
| |
| dst->data[pos_attr][0] = pos[0] * oow * scale[0] + trans[0]; |
| dst->data[pos_attr][1] = pos[1] * oow * scale[1] + trans[1]; |
| dst->data[pos_attr][2] = pos[2] * oow * scale[2] + trans[2]; |
| dst->data[pos_attr][3] = oow; |
| } |
| |
| /** |
| * Compute the t in screen-space instead of 3d space to use |
| * for noperspective interpolation. |
| * |
| * The points can be aligned with the X axis, so in that case try |
| * the Y. When both points are at the same screen position, we can |
| * pick whatever value (the interpolated point won't be in front |
| * anyway), so just use the 3d t. |
| */ |
| { |
| int k; |
| t_nopersp = t; |
| for (k = 0; k < 2; k++) |
| if (in->data[pos_attr][k] != out->data[pos_attr][k]) { |
| t_nopersp = (dst->data[pos_attr][k] - out->data[pos_attr][k]) / |
| (in->data[pos_attr][k] - out->data[pos_attr][k]); |
| break; |
| } |
| } |
| |
| /* Other attributes |
| */ |
| for (j = 0; j < nr_attrs; j++) { |
| if (j != pos_attr && j != clip_attr) { |
| if (clip->noperspective_attribs[j]) |
| interp_attr(dst->data[j], t_nopersp, in->data[j], out->data[j]); |
| else |
| interp_attr(dst->data[j], t, in->data[j], out->data[j]); |
| } |
| } |
| } |
| |
| |
| /** |
| * Emit a post-clip polygon to the next pipeline stage. The polygon |
| * will be convex and the provoking vertex will always be vertex[0]. |
| */ |
| static void emit_poly( struct draw_stage *stage, |
| struct vertex_header **inlist, |
| const boolean *edgeflags, |
| unsigned n, |
| const struct prim_header *origPrim) |
| { |
| struct prim_header header; |
| unsigned i; |
| ushort edge_first, edge_middle, edge_last; |
| |
| if (stage->draw->rasterizer->flatshade_first) { |
| edge_first = DRAW_PIPE_EDGE_FLAG_0; |
| edge_middle = DRAW_PIPE_EDGE_FLAG_1; |
| edge_last = DRAW_PIPE_EDGE_FLAG_2; |
| } |
| else { |
| edge_first = DRAW_PIPE_EDGE_FLAG_2; |
| edge_middle = DRAW_PIPE_EDGE_FLAG_0; |
| edge_last = DRAW_PIPE_EDGE_FLAG_1; |
| } |
| |
| if (!edgeflags[0]) |
| edge_first = 0; |
| |
| /* later stages may need the determinant, but only the sign matters */ |
| header.det = origPrim->det; |
| header.flags = DRAW_PIPE_RESET_STIPPLE | edge_first | edge_middle; |
| header.pad = 0; |
| |
| for (i = 2; i < n; i++, header.flags = edge_middle) { |
| /* order the triangle verts to respect the provoking vertex mode */ |
| if (stage->draw->rasterizer->flatshade_first) { |
| header.v[0] = inlist[0]; /* the provoking vertex */ |
| header.v[1] = inlist[i-1]; |
| header.v[2] = inlist[i]; |
| } |
| else { |
| header.v[0] = inlist[i-1]; |
| header.v[1] = inlist[i]; |
| header.v[2] = inlist[0]; /* the provoking vertex */ |
| } |
| |
| if (!edgeflags[i-1]) { |
| header.flags &= ~edge_middle; |
| } |
| |
| if (i == n - 1 && edgeflags[i]) |
| header.flags |= edge_last; |
| |
| if (0) { |
| const struct draw_vertex_shader *vs = stage->draw->vs.vertex_shader; |
| uint j, k; |
| debug_printf("Clipped tri: (flat-shade-first = %d)\n", |
| stage->draw->rasterizer->flatshade_first); |
| for (j = 0; j < 3; j++) { |
| for (k = 0; k < vs->info.num_outputs; k++) { |
| debug_printf(" Vert %d: Attr %d: %f %f %f %f\n", j, k, |
| header.v[j]->data[k][0], |
| header.v[j]->data[k][1], |
| header.v[j]->data[k][2], |
| header.v[j]->data[k][3]); |
| } |
| } |
| } |
| |
| stage->next->tri( stage->next, &header ); |
| } |
| } |
| |
| |
| static INLINE float |
| dot4(const float *a, const float *b) |
| { |
| return (a[0] * b[0] + |
| a[1] * b[1] + |
| a[2] * b[2] + |
| a[3] * b[3]); |
| } |
| |
| /* |
| * this function extracts the clip distance for the current plane, |
| * it first checks if the shader provided a clip distance, otherwise |
| * it works out the value using the clipvertex |
| */ |
| static INLINE float getclipdist(const struct clip_stage *clipper, |
| struct vertex_header *vert, |
| int plane_idx) |
| { |
| const float *plane; |
| float dp; |
| if (vert->have_clipdist && plane_idx >= 6) { |
| /* pick the correct clipdistance element from the output vectors */ |
| int _idx = plane_idx - 6; |
| int cdi = _idx >= 4; |
| int vidx = cdi ? _idx - 4 : _idx; |
| dp = vert->data[draw_current_shader_clipdistance_output(clipper->stage.draw, cdi)][vidx]; |
| } else { |
| plane = clipper->plane[plane_idx]; |
| dp = dot4(vert->clip, plane); |
| } |
| return dp; |
| } |
| |
| /* Clip a triangle against the viewport and user clip planes. |
| */ |
| static void |
| do_clip_tri( struct draw_stage *stage, |
| struct prim_header *header, |
| unsigned clipmask ) |
| { |
| struct clip_stage *clipper = clip_stage( stage ); |
| struct vertex_header *a[MAX_CLIPPED_VERTICES]; |
| struct vertex_header *b[MAX_CLIPPED_VERTICES]; |
| struct vertex_header **inlist = a; |
| struct vertex_header **outlist = b; |
| unsigned tmpnr = 0; |
| unsigned n = 3; |
| unsigned i; |
| boolean aEdges[MAX_CLIPPED_VERTICES]; |
| boolean bEdges[MAX_CLIPPED_VERTICES]; |
| boolean *inEdges = aEdges; |
| boolean *outEdges = bEdges; |
| |
| inlist[0] = header->v[0]; |
| inlist[1] = header->v[1]; |
| inlist[2] = header->v[2]; |
| |
| /* |
| * Note: at this point we can't just use the per-vertex edge flags. |
| * We have to observe the edge flag bits set in header->flags which |
| * were set during primitive decomposition. Put those flags into |
| * an edge flags array which parallels the vertex array. |
| * Later, in the 'unfilled' pipeline stage we'll draw the edge if both |
| * the header.flags bit is set AND the per-vertex edgeflag field is set. |
| */ |
| inEdges[0] = !!(header->flags & DRAW_PIPE_EDGE_FLAG_0); |
| inEdges[1] = !!(header->flags & DRAW_PIPE_EDGE_FLAG_1); |
| inEdges[2] = !!(header->flags & DRAW_PIPE_EDGE_FLAG_2); |
| |
| while (clipmask && n >= 3) { |
| const unsigned plane_idx = ffs(clipmask)-1; |
| const boolean is_user_clip_plane = plane_idx >= 6; |
| struct vertex_header *vert_prev = inlist[0]; |
| boolean *edge_prev = &inEdges[0]; |
| float dp_prev; |
| unsigned outcount = 0; |
| |
| dp_prev = getclipdist(clipper, vert_prev, plane_idx); |
| clipmask &= ~(1<<plane_idx); |
| |
| assert(n < MAX_CLIPPED_VERTICES); |
| if (n >= MAX_CLIPPED_VERTICES) |
| return; |
| inlist[n] = inlist[0]; /* prevent rotation of vertices */ |
| inEdges[n] = inEdges[0]; |
| |
| for (i = 1; i <= n; i++) { |
| struct vertex_header *vert = inlist[i]; |
| boolean *edge = &inEdges[i]; |
| |
| float dp = getclipdist(clipper, vert, plane_idx); |
| |
| if (!IS_NEGATIVE(dp_prev)) { |
| assert(outcount < MAX_CLIPPED_VERTICES); |
| if (outcount >= MAX_CLIPPED_VERTICES) |
| return; |
| outEdges[outcount] = *edge_prev; |
| outlist[outcount++] = vert_prev; |
| } |
| |
| if (DIFFERENT_SIGNS(dp, dp_prev)) { |
| struct vertex_header *new_vert; |
| boolean *new_edge; |
| |
| assert(tmpnr < MAX_CLIPPED_VERTICES + 1); |
| if (tmpnr >= MAX_CLIPPED_VERTICES + 1) |
| return; |
| new_vert = clipper->stage.tmp[tmpnr++]; |
| |
| assert(outcount < MAX_CLIPPED_VERTICES); |
| if (outcount >= MAX_CLIPPED_VERTICES) |
| return; |
| |
| new_edge = &outEdges[outcount]; |
| outlist[outcount++] = new_vert; |
| |
| if (IS_NEGATIVE(dp)) { |
| /* Going out of bounds. Avoid division by zero as we |
| * know dp != dp_prev from DIFFERENT_SIGNS, above. |
| */ |
| float t = dp / (dp - dp_prev); |
| interp( clipper, new_vert, t, vert, vert_prev ); |
| |
| /* Whether or not to set edge flag for the new vert depends |
| * on whether it's a user-defined clipping plane. We're |
| * copying NVIDIA's behaviour here. |
| */ |
| if (is_user_clip_plane) { |
| /* we want to see an edge along the clip plane */ |
| *new_edge = TRUE; |
| new_vert->edgeflag = TRUE; |
| } |
| else { |
| /* we don't want to see an edge along the frustum clip plane */ |
| *new_edge = *edge_prev; |
| new_vert->edgeflag = FALSE; |
| } |
| } |
| else { |
| /* Coming back in. |
| */ |
| float t = dp_prev / (dp_prev - dp); |
| interp( clipper, new_vert, t, vert_prev, vert ); |
| |
| /* Copy starting vert's edgeflag: |
| */ |
| new_vert->edgeflag = vert_prev->edgeflag; |
| *new_edge = *edge_prev; |
| } |
| } |
| |
| vert_prev = vert; |
| edge_prev = edge; |
| dp_prev = dp; |
| } |
| |
| /* swap in/out lists */ |
| { |
| struct vertex_header **tmp = inlist; |
| inlist = outlist; |
| outlist = tmp; |
| n = outcount; |
| } |
| { |
| boolean *tmp = inEdges; |
| inEdges = outEdges; |
| outEdges = tmp; |
| } |
| |
| } |
| |
| /* If flat-shading, copy provoking vertex color to polygon vertex[0] |
| */ |
| if (n >= 3) { |
| if (clipper->num_flat_attribs) { |
| if (stage->draw->rasterizer->flatshade_first) { |
| if (inlist[0] != header->v[0]) { |
| assert(tmpnr < MAX_CLIPPED_VERTICES + 1); |
| if (tmpnr >= MAX_CLIPPED_VERTICES + 1) |
| return; |
| inlist[0] = dup_vert(stage, inlist[0], tmpnr++); |
| copy_flat(stage, inlist[0], header->v[0]); |
| } |
| } |
| else { |
| if (inlist[0] != header->v[2]) { |
| assert(tmpnr < MAX_CLIPPED_VERTICES + 1); |
| if (tmpnr >= MAX_CLIPPED_VERTICES + 1) |
| return; |
| inlist[0] = dup_vert(stage, inlist[0], tmpnr++); |
| copy_flat(stage, inlist[0], header->v[2]); |
| } |
| } |
| } |
| |
| /* Emit the polygon as triangles to the setup stage: |
| */ |
| emit_poly( stage, inlist, inEdges, n, header ); |
| } |
| } |
| |
| |
| /* Clip a line against the viewport and user clip planes. |
| */ |
| static void |
| do_clip_line( struct draw_stage *stage, |
| struct prim_header *header, |
| unsigned clipmask ) |
| { |
| const struct clip_stage *clipper = clip_stage( stage ); |
| struct vertex_header *v0 = header->v[0]; |
| struct vertex_header *v1 = header->v[1]; |
| float t0 = 0.0F; |
| float t1 = 0.0F; |
| struct prim_header newprim; |
| |
| while (clipmask) { |
| const unsigned plane_idx = ffs(clipmask)-1; |
| const float dp0 = getclipdist(clipper, v0, plane_idx); |
| const float dp1 = getclipdist(clipper, v1, plane_idx); |
| |
| if (dp1 < 0.0F) { |
| float t = dp1 / (dp1 - dp0); |
| t1 = MAX2(t1, t); |
| } |
| |
| if (dp0 < 0.0F) { |
| float t = dp0 / (dp0 - dp1); |
| t0 = MAX2(t0, t); |
| } |
| |
| if (t0 + t1 >= 1.0F) |
| return; /* discard */ |
| |
| clipmask &= ~(1 << plane_idx); /* turn off this plane's bit */ |
| } |
| |
| if (v0->clipmask) { |
| interp( clipper, stage->tmp[0], t0, v0, v1 ); |
| copy_flat(stage, stage->tmp[0], v0); |
| newprim.v[0] = stage->tmp[0]; |
| } |
| else { |
| newprim.v[0] = v0; |
| } |
| |
| if (v1->clipmask) { |
| interp( clipper, stage->tmp[1], t1, v1, v0 ); |
| newprim.v[1] = stage->tmp[1]; |
| } |
| else { |
| newprim.v[1] = v1; |
| } |
| |
| stage->next->line( stage->next, &newprim ); |
| } |
| |
| |
| static void |
| clip_point( struct draw_stage *stage, |
| struct prim_header *header ) |
| { |
| if (header->v[0]->clipmask == 0) |
| stage->next->point( stage->next, header ); |
| } |
| |
| |
| static void |
| clip_line( struct draw_stage *stage, |
| struct prim_header *header ) |
| { |
| unsigned clipmask = (header->v[0]->clipmask | |
| header->v[1]->clipmask); |
| |
| if (clipmask == 0) { |
| /* no clipping needed */ |
| stage->next->line( stage->next, header ); |
| } |
| else if ((header->v[0]->clipmask & |
| header->v[1]->clipmask) == 0) { |
| do_clip_line(stage, header, clipmask); |
| } |
| /* else, totally clipped */ |
| } |
| |
| |
| static void |
| clip_tri( struct draw_stage *stage, |
| struct prim_header *header ) |
| { |
| unsigned clipmask = (header->v[0]->clipmask | |
| header->v[1]->clipmask | |
| header->v[2]->clipmask); |
| |
| if (clipmask == 0) { |
| /* no clipping needed */ |
| stage->next->tri( stage->next, header ); |
| } |
| else if ((header->v[0]->clipmask & |
| header->v[1]->clipmask & |
| header->v[2]->clipmask) == 0) { |
| do_clip_tri(stage, header, clipmask); |
| } |
| } |
| |
| |
| /* Update state. Could further delay this until we hit the first |
| * primitive that really requires clipping. |
| */ |
| static void |
| clip_init_state( struct draw_stage *stage ) |
| { |
| struct clip_stage *clipper = clip_stage( stage ); |
| const struct draw_vertex_shader *vs = stage->draw->vs.vertex_shader; |
| const struct draw_fragment_shader *fs = stage->draw->fs.fragment_shader; |
| uint i; |
| |
| /* We need to know for each attribute what kind of interpolation is |
| * done on it (flat, smooth or noperspective). But the information |
| * is not directly accessible for outputs, only for inputs. So we |
| * have to match semantic name and index between the VS (or GS/ES) |
| * outputs and the FS inputs to get to the interpolation mode. |
| * |
| * The only hitch is with gl_FrontColor/gl_BackColor which map to |
| * gl_Color, and their Secondary versions. First there are (up to) |
| * two outputs for one input, so we tuck the information in a |
| * specific array. Second if they don't have qualifiers, the |
| * default value has to be picked from the global shade mode. |
| * |
| * Of course, if we don't have a fragment shader in the first |
| * place, defaults should be used. |
| */ |
| |
| /* First pick up the interpolation mode for |
| * gl_Color/gl_SecondaryColor, with the correct default. |
| */ |
| int indexed_interp[2]; |
| indexed_interp[0] = indexed_interp[1] = stage->draw->rasterizer->flatshade ? |
| TGSI_INTERPOLATE_CONSTANT : TGSI_INTERPOLATE_PERSPECTIVE; |
| |
| if (fs) { |
| for (i = 0; i < fs->info.num_inputs; i++) { |
| if (fs->info.input_semantic_name[i] == TGSI_SEMANTIC_COLOR) { |
| if (fs->info.input_interpolate[i] != TGSI_INTERPOLATE_COLOR) |
| indexed_interp[fs->info.input_semantic_index[i]] = fs->info.input_interpolate[i]; |
| } |
| } |
| } |
| |
| /* Then resolve the interpolation mode for every output attribute. |
| * |
| * Given how the rest of the code, the most efficient way is to |
| * have a vector of flat-mode attributes, and a mask for |
| * noperspective attributes. |
| */ |
| |
| clipper->num_flat_attribs = 0; |
| memset(clipper->noperspective_attribs, 0, sizeof(clipper->noperspective_attribs)); |
| for (i = 0; i < vs->info.num_outputs; i++) { |
| /* Find the interpolation mode for a specific attribute |
| */ |
| int interp; |
| |
| /* If it's gl_{Front,Back}{,Secondary}Color, pick up the mode |
| * from the array we've filled before. */ |
| if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_COLOR || |
| vs->info.output_semantic_name[i] == TGSI_SEMANTIC_BCOLOR) { |
| interp = indexed_interp[vs->info.output_semantic_index[i]]; |
| } else { |
| /* Otherwise, search in the FS inputs, with a decent default |
| * if we don't find it. |
| */ |
| uint j; |
| interp = TGSI_INTERPOLATE_PERSPECTIVE; |
| if (fs) { |
| for (j = 0; j < fs->info.num_inputs; j++) { |
| if (vs->info.output_semantic_name[i] == fs->info.input_semantic_name[j] && |
| vs->info.output_semantic_index[i] == fs->info.input_semantic_index[j]) { |
| interp = fs->info.input_interpolate[j]; |
| break; |
| } |
| } |
| } |
| } |
| |
| /* If it's flat, add it to the flat vector. Otherwise update |
| * the noperspective mask. |
| */ |
| if (interp == TGSI_INTERPOLATE_CONSTANT) { |
| clipper->flat_attribs[clipper->num_flat_attribs] = i; |
| clipper->num_flat_attribs++; |
| } else |
| clipper->noperspective_attribs[i] = interp == TGSI_INTERPOLATE_LINEAR; |
| } |
| |
| stage->tri = clip_tri; |
| stage->line = clip_line; |
| } |
| |
| |
| |
| static void clip_first_tri( struct draw_stage *stage, |
| struct prim_header *header ) |
| { |
| clip_init_state( stage ); |
| stage->tri( stage, header ); |
| } |
| |
| static void clip_first_line( struct draw_stage *stage, |
| struct prim_header *header ) |
| { |
| clip_init_state( stage ); |
| stage->line( stage, header ); |
| } |
| |
| |
| static void clip_flush( struct draw_stage *stage, |
| unsigned flags ) |
| { |
| stage->tri = clip_first_tri; |
| stage->line = clip_first_line; |
| stage->next->flush( stage->next, flags ); |
| } |
| |
| |
| static void clip_reset_stipple_counter( struct draw_stage *stage ) |
| { |
| stage->next->reset_stipple_counter( stage->next ); |
| } |
| |
| |
| static void clip_destroy( struct draw_stage *stage ) |
| { |
| draw_free_temp_verts( stage ); |
| FREE( stage ); |
| } |
| |
| |
| /** |
| * Allocate a new clipper stage. |
| * \return pointer to new stage object |
| */ |
| struct draw_stage *draw_clip_stage( struct draw_context *draw ) |
| { |
| struct clip_stage *clipper = CALLOC_STRUCT(clip_stage); |
| if (clipper == NULL) |
| goto fail; |
| |
| clipper->stage.draw = draw; |
| clipper->stage.name = "clipper"; |
| clipper->stage.point = clip_point; |
| clipper->stage.line = clip_first_line; |
| clipper->stage.tri = clip_first_tri; |
| clipper->stage.flush = clip_flush; |
| clipper->stage.reset_stipple_counter = clip_reset_stipple_counter; |
| clipper->stage.destroy = clip_destroy; |
| |
| clipper->plane = draw->plane; |
| |
| if (!draw_alloc_temp_verts( &clipper->stage, MAX_CLIPPED_VERTICES+1 )) |
| goto fail; |
| |
| return &clipper->stage; |
| |
| fail: |
| if (clipper) |
| clipper->stage.destroy( &clipper->stage ); |
| |
| return NULL; |
| } |
