1/**************************************************************************
2 *
3 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28/* Authors:  Keith Whitwell <keith@tungstengraphics.com>
29 */
30
31/**
32 * Notes on wide points and sprite mode:
33 *
34 * In wide point/sprite mode we effectively need to convert each incoming
35 * vertex into four outgoing vertices specifying the corners of a quad.
36 * Since we don't (yet) have geometry shaders, we have to handle this here
37 * in the draw module.
38 *
39 * For sprites, it also means that this is where we have to handle texcoords
40 * for the vertices of the quad.  OpenGL's GL_COORD_REPLACE state specifies
41 * if/how enabled texcoords are automatically generated for sprites.  We pass
42 * that info through gallium in the pipe_rasterizer_state::sprite_coord_mode
43 * array.
44 *
45 * Additionally, GLSL's gl_PointCoord fragment attribute has to be handled
46 * here as well.  This is basically an additional texture/generic attribute
47 * that varies .x from 0 to 1 horizontally across the point and varies .y
48 * vertically from 0 to 1 down the sprite.
49 *
50 * With geometry shaders, the state tracker could create a GS to do
51 * most/all of this.
52 */
53
54
55#include "pipe/p_context.h"
56#include "util/u_math.h"
57#include "util/u_memory.h"
58#include "pipe/p_defines.h"
59#include "pipe/p_shader_tokens.h"
60#include "draw_fs.h"
61#include "draw_vs.h"
62#include "draw_pipe.h"
63
64
65struct widepoint_stage {
66   struct draw_stage stage;  /**< base class */
67
68   float half_point_size;
69
70   float xbias;
71   float ybias;
72
73   /** for automatic texcoord generation/replacement */
74   uint num_texcoord_gen;
75   uint texcoord_gen_slot[PIPE_MAX_SHADER_OUTPUTS];
76
77   int psize_slot;
78};
79
80
81
82static INLINE struct widepoint_stage *
83widepoint_stage( struct draw_stage *stage )
84{
85   return (struct widepoint_stage *)stage;
86}
87
88
89/**
90 * Set the vertex texcoords for sprite mode.
91 * Coords may be left untouched or set to a right-side-up or upside-down
92 * orientation.
93 */
94static void set_texcoords(const struct widepoint_stage *wide,
95                          struct vertex_header *v, const float tc[4])
96{
97   const struct draw_context *draw = wide->stage.draw;
98   const struct pipe_rasterizer_state *rast = draw->rasterizer;
99   const uint texcoord_mode = rast->sprite_coord_mode;
100   uint i;
101
102   for (i = 0; i < wide->num_texcoord_gen; i++) {
103      const uint slot = wide->texcoord_gen_slot[i];
104      v->data[slot][0] = tc[0];
105      if (texcoord_mode == PIPE_SPRITE_COORD_LOWER_LEFT)
106         v->data[slot][1] = 1.0f - tc[1];
107      else
108         v->data[slot][1] = tc[1];
109      v->data[slot][2] = tc[2];
110      v->data[slot][3] = tc[3];
111   }
112}
113
114
115/* If there are lots of sprite points (and why wouldn't there be?) it
116 * would probably be more sensible to change hardware setup to
117 * optimize this rather than doing the whole thing in software like
118 * this.
119 */
120static void widepoint_point( struct draw_stage *stage,
121                             struct prim_header *header )
122{
123   const struct widepoint_stage *wide = widepoint_stage(stage);
124   const unsigned pos = draw_current_shader_position_output(stage->draw);
125   const boolean sprite = (boolean) stage->draw->rasterizer->point_quad_rasterization;
126   float half_size;
127   float left_adj, right_adj, bot_adj, top_adj;
128
129   struct prim_header tri;
130
131   /* four dups of original vertex */
132   struct vertex_header *v0 = dup_vert(stage, header->v[0], 0);
133   struct vertex_header *v1 = dup_vert(stage, header->v[0], 1);
134   struct vertex_header *v2 = dup_vert(stage, header->v[0], 2);
135   struct vertex_header *v3 = dup_vert(stage, header->v[0], 3);
136
137   float *pos0 = v0->data[pos];
138   float *pos1 = v1->data[pos];
139   float *pos2 = v2->data[pos];
140   float *pos3 = v3->data[pos];
141
142   /* point size is either per-vertex or fixed size */
143   if (wide->psize_slot >= 0) {
144      half_size = header->v[0]->data[wide->psize_slot][0];
145      half_size *= 0.5f;
146   }
147   else {
148      half_size = wide->half_point_size;
149   }
150
151   left_adj = -half_size + wide->xbias;
152   right_adj = half_size + wide->xbias;
153   bot_adj = half_size + wide->ybias;
154   top_adj = -half_size + wide->ybias;
155
156   pos0[0] += left_adj;
157   pos0[1] += top_adj;
158
159   pos1[0] += left_adj;
160   pos1[1] += bot_adj;
161
162   pos2[0] += right_adj;
163   pos2[1] += top_adj;
164
165   pos3[0] += right_adj;
166   pos3[1] += bot_adj;
167
168   if (sprite) {
169      static const float tex00[4] = { 0, 0, 0, 1 };
170      static const float tex01[4] = { 0, 1, 0, 1 };
171      static const float tex11[4] = { 1, 1, 0, 1 };
172      static const float tex10[4] = { 1, 0, 0, 1 };
173      set_texcoords( wide, v0, tex00 );
174      set_texcoords( wide, v1, tex01 );
175      set_texcoords( wide, v2, tex10 );
176      set_texcoords( wide, v3, tex11 );
177   }
178
179   tri.det = header->det;  /* only the sign matters */
180   tri.v[0] = v0;
181   tri.v[1] = v2;
182   tri.v[2] = v3;
183   stage->next->tri( stage->next, &tri );
184
185   tri.v[0] = v0;
186   tri.v[1] = v3;
187   tri.v[2] = v1;
188   stage->next->tri( stage->next, &tri );
189}
190
191
192static void
193widepoint_first_point(struct draw_stage *stage,
194                      struct prim_header *header)
195{
196   struct widepoint_stage *wide = widepoint_stage(stage);
197   struct draw_context *draw = stage->draw;
198   struct pipe_context *pipe = draw->pipe;
199   const struct pipe_rasterizer_state *rast = draw->rasterizer;
200   void *r;
201
202   wide->half_point_size = 0.5f * rast->point_size;
203   wide->xbias = 0.0;
204   wide->ybias = 0.0;
205
206   if (rast->gl_rasterization_rules) {
207      wide->xbias = 0.125;
208      wide->ybias = -0.125;
209   }
210
211   /* Disable triangle culling, stippling, unfilled mode etc. */
212   r = draw_get_rasterizer_no_cull(draw, rast->scissor, rast->flatshade);
213   draw->suspend_flushing = TRUE;
214   pipe->bind_rasterizer_state(pipe, r);
215   draw->suspend_flushing = FALSE;
216
217   /* XXX we won't know the real size if it's computed by the vertex shader! */
218   if ((rast->point_size > draw->pipeline.wide_point_threshold) ||
219       (rast->point_quad_rasterization && draw->pipeline.point_sprite)) {
220      stage->point = widepoint_point;
221   }
222   else {
223      stage->point = draw_pipe_passthrough_point;
224   }
225
226   draw_remove_extra_vertex_attribs(draw);
227
228   if (rast->point_quad_rasterization) {
229      const struct draw_fragment_shader *fs = draw->fs.fragment_shader;
230      uint i;
231
232      assert(fs);
233
234      wide->num_texcoord_gen = 0;
235
236      /* Loop over fragment shader inputs looking for generic inputs
237       * for which bit 'k' in sprite_coord_enable is set.
238       */
239      for (i = 0; i < fs->info.num_inputs; i++) {
240         if (fs->info.input_semantic_name[i] == TGSI_SEMANTIC_GENERIC) {
241            const int generic_index = fs->info.input_semantic_index[i];
242            /* Note that sprite_coord enable is a bitfield of
243             * PIPE_MAX_SHADER_OUTPUTS bits.
244             */
245            if (generic_index < PIPE_MAX_SHADER_OUTPUTS &&
246                (rast->sprite_coord_enable & (1 << generic_index))) {
247               /* OK, this generic attribute needs to be replaced with a
248                * texcoord (see above).
249                */
250               int slot = draw_alloc_extra_vertex_attrib(draw,
251                                                         TGSI_SEMANTIC_GENERIC,
252                                                         generic_index);
253
254               /* add this slot to the texcoord-gen list */
255               wide->texcoord_gen_slot[wide->num_texcoord_gen++] = slot;
256            }
257         }
258      }
259   }
260
261   wide->psize_slot = -1;
262   if (rast->point_size_per_vertex) {
263      /* find PSIZ vertex output */
264      const struct draw_vertex_shader *vs = draw->vs.vertex_shader;
265      uint i;
266      for (i = 0; i < vs->info.num_outputs; i++) {
267         if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_PSIZE) {
268            wide->psize_slot = i;
269            break;
270         }
271      }
272   }
273
274   stage->point( stage, header );
275}
276
277
278static void widepoint_flush( struct draw_stage *stage, unsigned flags )
279{
280   struct draw_context *draw = stage->draw;
281   struct pipe_context *pipe = draw->pipe;
282
283   stage->point = widepoint_first_point;
284   stage->next->flush( stage->next, flags );
285
286   draw_remove_extra_vertex_attribs(draw);
287
288   /* restore original rasterizer state */
289   if (draw->rast_handle) {
290      draw->suspend_flushing = TRUE;
291      pipe->bind_rasterizer_state(pipe, draw->rast_handle);
292      draw->suspend_flushing = FALSE;
293   }
294}
295
296
297static void widepoint_reset_stipple_counter( struct draw_stage *stage )
298{
299   stage->next->reset_stipple_counter( stage->next );
300}
301
302
303static void widepoint_destroy( struct draw_stage *stage )
304{
305   draw_free_temp_verts( stage );
306   FREE( stage );
307}
308
309
310struct draw_stage *draw_wide_point_stage( struct draw_context *draw )
311{
312   struct widepoint_stage *wide = CALLOC_STRUCT(widepoint_stage);
313   if (wide == NULL)
314      goto fail;
315
316   wide->stage.draw = draw;
317   wide->stage.name = "wide-point";
318   wide->stage.next = NULL;
319   wide->stage.point = widepoint_first_point;
320   wide->stage.line = draw_pipe_passthrough_line;
321   wide->stage.tri = draw_pipe_passthrough_tri;
322   wide->stage.flush = widepoint_flush;
323   wide->stage.reset_stipple_counter = widepoint_reset_stipple_counter;
324   wide->stage.destroy = widepoint_destroy;
325
326   if (!draw_alloc_temp_verts( &wide->stage, 4 ))
327      goto fail;
328
329   return &wide->stage;
330
331 fail:
332   if (wide)
333      wide->stage.destroy( &wide->stage );
334
335   return NULL;
336}
337