src/gallium/auxiliary/draw/draw_pipe_wide_point.c

   1 /**************************************************************************
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   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
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  11  * permit persons to whom the Software is furnished to do so, subject to
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  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
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  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
  65 struct 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
  82 static INLINE struct widepoint_stage *
  83 widepoint_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  */
  94 static 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  */
 120 static 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
 192 static void
 193 widepoint_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
 278 static 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
 297 static void widepoint_reset_stipple_counter( struct draw_stage *stage )
 298 {
 299    stage->next->reset_stipple_counter( stage->next );
 300 }
 301
 302
 303 static void widepoint_destroy( struct draw_stage *stage )
 304 {
 305    draw_free_temp_verts( stage );
 306    FREE( stage );
 307 }
 308
 309
 310 struct 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 }