src/gallium/auxiliary/draw/draw_pipe_wide_point.c

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  27
  28 /* Authors:  Keith Whitwell <keithw@vmware.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_screen.h"
  56 #include "pipe/p_context.h"
  57 #include "util/u_math.h"
  58 #include "util/u_memory.h"
  59 #include "pipe/p_defines.h"
  60 #include "pipe/p_shader_tokens.h"
  61 #include "draw_fs.h"
  62 #include "draw_vs.h"
  63 #include "draw_pipe.h"
  64
  65
  66 struct widepoint_stage {
  67    struct draw_stage stage;  /**< base class */
  68
  69    float half_point_size;
  70
  71    float xbias;
  72    float ybias;
  73
  74    /** for automatic texcoord generation/replacement */
  75    uint num_texcoord_gen;
  76    uint texcoord_gen_slot[PIPE_MAX_SHADER_OUTPUTS];
  77
  78    /* TGSI_SEMANTIC to which sprite_coord_enable applies */
  79    unsigned sprite_coord_semantic;
  80
  81    int psize_slot;
  82 };
  83
  84
  85
  86 static inline struct widepoint_stage *
  87 widepoint_stage( struct draw_stage *stage )
  88 {
  89    return (struct widepoint_stage *)stage;
  90 }
  91
  92
  93 /**
  94  * Set the vertex texcoords for sprite mode.
  95  * Coords may be left untouched or set to a right-side-up or upside-down
  96  * orientation.
  97  */
  98 static void set_texcoords(const struct widepoint_stage *wide,
  99                           struct vertex_header *v, const float tc[4])
 100 {
 101    const struct draw_context *draw = wide->stage.draw;
 102    const struct pipe_rasterizer_state *rast = draw->rasterizer;
 103    const uint texcoord_mode = rast->sprite_coord_mode;
 104    uint i;
 105
 106    for (i = 0; i < wide->num_texcoord_gen; i++) {
 107       const uint slot = wide->texcoord_gen_slot[i];
 108       v->data[slot][0] = tc[0];
 109       if (texcoord_mode == PIPE_SPRITE_COORD_LOWER_LEFT)
 110          v->data[slot][1] = 1.0f - tc[1];
 111       else
 112          v->data[slot][1] = tc[1];
 113       v->data[slot][2] = tc[2];
 114       v->data[slot][3] = tc[3];
 115    }
 116 }
 117
 118
 119 /* If there are lots of sprite points (and why wouldn't there be?) it
 120  * would probably be more sensible to change hardware setup to
 121  * optimize this rather than doing the whole thing in software like
 122  * this.
 123  */
 124 static void widepoint_point( struct draw_stage *stage,
 125                              struct prim_header *header )
 126 {
 127    const struct widepoint_stage *wide = widepoint_stage(stage);
 128    const unsigned pos = draw_current_shader_position_output(stage->draw);
 129    const boolean sprite = (boolean) stage->draw->rasterizer->point_quad_rasterization;
 130    float half_size;
 131    float left_adj, right_adj, bot_adj, top_adj;
 132
 133    struct prim_header tri;
 134
 135    /* four dups of original vertex */
 136    struct vertex_header *v0 = dup_vert(stage, header->v[0], 0);
 137    struct vertex_header *v1 = dup_vert(stage, header->v[0], 1);
 138    struct vertex_header *v2 = dup_vert(stage, header->v[0], 2);
 139    struct vertex_header *v3 = dup_vert(stage, header->v[0], 3);
 140
 141    float *pos0 = v0->data[pos];
 142    float *pos1 = v1->data[pos];
 143    float *pos2 = v2->data[pos];
 144    float *pos3 = v3->data[pos];
 145
 146    /* point size is either per-vertex or fixed size */
 147    if (wide->psize_slot >= 0) {
 148       half_size = header->v[0]->data[wide->psize_slot][0];
 149       half_size *= 0.5f;
 150    }
 151    else {
 152       half_size = wide->half_point_size;
 153    }
 154
 155    left_adj = -half_size + wide->xbias;
 156    right_adj = half_size + wide->xbias;
 157    bot_adj = half_size + wide->ybias;
 158    top_adj = -half_size + wide->ybias;
 159
 160    pos0[0] += left_adj;
 161    pos0[1] += top_adj;
 162
 163    pos1[0] += left_adj;
 164    pos1[1] += bot_adj;
 165
 166    pos2[0] += right_adj;
 167    pos2[1] += top_adj;
 168
 169    pos3[0] += right_adj;
 170    pos3[1] += bot_adj;
 171
 172    if (sprite) {
 173       static const float tex00[4] = { 0, 0, 0, 1 };
 174       static const float tex01[4] = { 0, 1, 0, 1 };
 175       static const float tex11[4] = { 1, 1, 0, 1 };
 176       static const float tex10[4] = { 1, 0, 0, 1 };
 177       set_texcoords( wide, v0, tex00 );
 178       set_texcoords( wide, v1, tex01 );
 179       set_texcoords( wide, v2, tex10 );
 180       set_texcoords( wide, v3, tex11 );
 181    }
 182
 183    tri.det = header->det;  /* only the sign matters */
 184    tri.v[0] = v0;
 185    tri.v[1] = v2;
 186    tri.v[2] = v3;
 187    stage->next->tri( stage->next, &tri );
 188
 189    tri.v[0] = v0;
 190    tri.v[1] = v3;
 191    tri.v[2] = v1;
 192    stage->next->tri( stage->next, &tri );
 193 }
 194
 195
 196 static void
 197 widepoint_first_point(struct draw_stage *stage,
 198                       struct prim_header *header)
 199 {
 200    struct widepoint_stage *wide = widepoint_stage(stage);
 201    struct draw_context *draw = stage->draw;
 202    struct pipe_context *pipe = draw->pipe;
 203    const struct pipe_rasterizer_state *rast = draw->rasterizer;
 204    void *r;
 205
 206    wide->half_point_size = 0.5f * rast->point_size;
 207    wide->xbias = 0.0;
 208    wide->ybias = 0.0;
 209
 210    if (rast->half_pixel_center) {
 211       wide->xbias = 0.125;
 212       wide->ybias = -0.125;
 213    }
 214
 215    /* Disable triangle culling, stippling, unfilled mode etc. */
 216    r = draw_get_rasterizer_no_cull(draw, rast->scissor, rast->flatshade);
 217    draw->suspend_flushing = TRUE;
 218    pipe->bind_rasterizer_state(pipe, r);
 219    draw->suspend_flushing = FALSE;
 220
 221    /* XXX we won't know the real size if it's computed by the vertex shader! */
 222    if ((rast->point_size > draw->pipeline.wide_point_threshold) ||
 223        (rast->point_quad_rasterization && draw->pipeline.point_sprite)) {
 224       stage->point = widepoint_point;
 225    }
 226    else {
 227       stage->point = draw_pipe_passthrough_point;
 228    }
 229
 230    draw_remove_extra_vertex_attribs(draw);
 231
 232    if (rast->point_quad_rasterization) {
 233       const struct draw_fragment_shader *fs = draw->fs.fragment_shader;
 234       uint i;
 235
 236       assert(fs);
 237
 238       wide->num_texcoord_gen = 0;
 239
 240       /* Loop over fragment shader inputs looking for the PCOORD input or inputs
 241        * for which bit 'k' in sprite_coord_enable is set.
 242        */
 243       for (i = 0; i < fs->info.num_inputs; i++) {
 244          int slot;
 245          const unsigned sn = fs->info.input_semantic_name[i];
 246          const unsigned si = fs->info.input_semantic_index[i];
 247
 248          if (sn == wide->sprite_coord_semantic) {
 249             /* Note that sprite_coord_enable is a bitfield of 32 bits. */
 250             if (si >= 32 || !(rast->sprite_coord_enable & (1 << si)))
 251                continue;
 252          } else if (sn != TGSI_SEMANTIC_PCOORD) {
 253             continue;
 254          }
 255
 256          /* OK, this generic attribute needs to be replaced with a
 257           * sprite coord (see above).
 258           */
 259          slot = draw_alloc_extra_vertex_attrib(draw, sn, si);
 260
 261          /* add this slot to the texcoord-gen list */
 262          wide->texcoord_gen_slot[wide->num_texcoord_gen++] = slot;
 263       }
 264    }
 265
 266    wide->psize_slot = -1;
 267    if (rast->point_size_per_vertex) {
 268       /* find PSIZ vertex output */
 269       const struct draw_vertex_shader *vs = draw->vs.vertex_shader;
 270       uint i;
 271       for (i = 0; i < vs->info.num_outputs; i++) {
 272          if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_PSIZE) {
 273             wide->psize_slot = i;
 274             break;
 275          }
 276       }
 277    }
 278
 279    stage->point( stage, header );
 280 }
 281
 282
 283 static void widepoint_flush( struct draw_stage *stage, unsigned flags )
 284 {
 285    struct draw_context *draw = stage->draw;
 286    struct pipe_context *pipe = draw->pipe;
 287
 288    stage->point = widepoint_first_point;
 289    stage->next->flush( stage->next, flags );
 290
 291    draw_remove_extra_vertex_attribs(draw);
 292
 293    /* restore original rasterizer state */
 294    if (draw->rast_handle) {
 295       draw->suspend_flushing = TRUE;
 296       pipe->bind_rasterizer_state(pipe, draw->rast_handle);
 297       draw->suspend_flushing = FALSE;
 298    }
 299 }
 300
 301
 302 static void widepoint_reset_stipple_counter( struct draw_stage *stage )
 303 {
 304    stage->next->reset_stipple_counter( stage->next );
 305 }
 306
 307
 308 static void widepoint_destroy( struct draw_stage *stage )
 309 {
 310    draw_free_temp_verts( stage );
 311    FREE( stage );
 312 }
 313
 314
 315 struct draw_stage *draw_wide_point_stage( struct draw_context *draw )
 316 {
 317    struct widepoint_stage *wide = CALLOC_STRUCT(widepoint_stage);
 318    if (!wide)
 319       goto fail;
 320
 321    wide->stage.draw = draw;
 322    wide->stage.name = "wide-point";
 323    wide->stage.next = NULL;
 324    wide->stage.point = widepoint_first_point;
 325    wide->stage.line = draw_pipe_passthrough_line;
 326    wide->stage.tri = draw_pipe_passthrough_tri;
 327    wide->stage.flush = widepoint_flush;
 328    wide->stage.reset_stipple_counter = widepoint_reset_stipple_counter;
 329    wide->stage.destroy = widepoint_destroy;
 330
 331    if (!draw_alloc_temp_verts( &wide->stage, 4 ))
 332       goto fail;
 333
 334    wide->sprite_coord_semantic =
 335       draw->pipe->screen->get_param(draw->pipe->screen, PIPE_CAP_TGSI_TEXCOORD)
 336       ?
 337       TGSI_SEMANTIC_TEXCOORD : TGSI_SEMANTIC_GENERIC;
 338
 339    return &wide->stage;
 340
 341  fail:
 342    if (wide)
 343       wide->stage.destroy( &wide->stage );
 344
 345    return NULL;
 346 }