src/gallium/auxiliary/draw/draw_pipe_wide_point.c

   1 /**************************************************************************
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   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
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  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_vs.h"
  61 #include "draw_pipe.h"
  62
  63
  64 struct widepoint_stage {
  65    struct draw_stage stage;
  66
  67    float half_point_size;
  68
  69    float xbias;
  70    float ybias;
  71
  72    uint texcoord_slot[PIPE_MAX_SHADER_OUTPUTS];
  73    uint texcoord_enable[PIPE_MAX_SHADER_OUTPUTS];
  74    uint num_texcoords;
  75    uint texcoord_mode;
  76
  77    int psize_slot;
  78
  79    int point_coord_fs_input;  /**< input for pointcoord */
  80 };
  81
  82
  83
  84 static INLINE struct widepoint_stage *
  85 widepoint_stage( struct draw_stage *stage )
  86 {
  87    return (struct widepoint_stage *)stage;
  88 }
  89
  90
  91 /**
  92  * Set the vertex texcoords for sprite mode.
  93  * Coords may be left untouched or set to a right-side-up or upside-down
  94  * orientation.
  95  */
  96 static void set_texcoords(const struct widepoint_stage *wide,
  97                           struct vertex_header *v, const float tc[4])
  98 {
  99    uint i;
 100    for (i = 0; i < wide->num_texcoords; i++) {
 101       if (wide->texcoord_enable[i]) {
 102          uint j = wide->texcoord_slot[i];
 103          v->data[j][0] = tc[0];
 104          if (wide->texcoord_mode == PIPE_SPRITE_COORD_LOWER_LEFT)
 105             v->data[j][1] = 1.0f - tc[1];
 106          else
 107             v->data[j][1] = tc[1];
 108          v->data[j][2] = tc[2];
 109          v->data[j][3] = tc[3];
 110       }
 111    }
 112
 113    if (wide->point_coord_fs_input >= 0) {
 114       /* put gl_PointCoord into the extra vertex slot */
 115       uint slot = wide->stage.draw->extra_shader_outputs.slot;
 116       v->data[slot][0] = tc[0];
 117       v->data[slot][1] = tc[1];
 118       v->data[slot][2] = 0.0F;
 119       v->data[slot][3] = 1.0F;
 120    }
 121 }
 122
 123
 124 /* If there are lots of sprite points (and why wouldn't there be?) it
 125  * would probably be more sensible to change hardware setup to
 126  * optimize this rather than doing the whole thing in software like
 127  * this.
 128  */
 129 static void widepoint_point( struct draw_stage *stage,
 130                              struct prim_header *header )
 131 {
 132    /* XXX should take point_quad_rasterization into account? */
 133    const struct widepoint_stage *wide = widepoint_stage(stage);
 134    const unsigned pos = draw_current_shader_position_output(stage->draw);
 135    const boolean sprite = (boolean) stage->draw->rasterizer->sprite_coord_enable;
 136    float half_size;
 137    float left_adj, right_adj, bot_adj, top_adj;
 138
 139    struct prim_header tri;
 140
 141    /* four dups of original vertex */
 142    struct vertex_header *v0 = dup_vert(stage, header->v[0], 0);
 143    struct vertex_header *v1 = dup_vert(stage, header->v[0], 1);
 144    struct vertex_header *v2 = dup_vert(stage, header->v[0], 2);
 145    struct vertex_header *v3 = dup_vert(stage, header->v[0], 3);
 146
 147    float *pos0 = v0->data[pos];
 148    float *pos1 = v1->data[pos];
 149    float *pos2 = v2->data[pos];
 150    float *pos3 = v3->data[pos];
 151
 152    /* point size is either per-vertex or fixed size */
 153    if (wide->psize_slot >= 0) {
 154       half_size = header->v[0]->data[wide->psize_slot][0];
 155       half_size *= 0.5f;
 156    }
 157    else {
 158       half_size = wide->half_point_size;
 159    }
 160
 161    left_adj = -half_size + wide->xbias;
 162    right_adj = half_size + wide->xbias;
 163    bot_adj = half_size + wide->ybias;
 164    top_adj = -half_size + wide->ybias;
 165
 166    pos0[0] += left_adj;
 167    pos0[1] += top_adj;
 168
 169    pos1[0] += left_adj;
 170    pos1[1] += bot_adj;
 171
 172    pos2[0] += right_adj;
 173    pos2[1] += top_adj;
 174
 175    pos3[0] += right_adj;
 176    pos3[1] += bot_adj;
 177
 178    if (sprite) {
 179       static const float tex00[4] = { 0, 0, 0, 1 };
 180       static const float tex01[4] = { 0, 1, 0, 1 };
 181       static const float tex11[4] = { 1, 1, 0, 1 };
 182       static const float tex10[4] = { 1, 0, 0, 1 };
 183       set_texcoords( wide, v0, tex00 );
 184       set_texcoords( wide, v1, tex01 );
 185       set_texcoords( wide, v2, tex10 );
 186       set_texcoords( wide, v3, tex11 );
 187    }
 188
 189    tri.det = header->det;  /* only the sign matters */
 190    tri.v[0] = v0;
 191    tri.v[1] = v2;
 192    tri.v[2] = v3;
 193    stage->next->tri( stage->next, &tri );
 194
 195    tri.v[0] = v0;
 196    tri.v[1] = v3;
 197    tri.v[2] = v1;
 198    stage->next->tri( stage->next, &tri );
 199 }
 200
 201
 202 static int
 203 find_pntc_input_attrib(struct draw_context *draw)
 204 {
 205    /* Scan the fragment program's input decls to find the pointcoord
 206     * attribute.  The xy components will store the point coord.
 207     */
 208    return 0; /* XXX fix this */
 209 }
 210
 211
 212 static void widepoint_first_point( struct draw_stage *stage,
 213                               struct prim_header *header )
 214 {
 215    struct widepoint_stage *wide = widepoint_stage(stage);
 216    struct draw_context *draw = stage->draw;
 217    struct pipe_context *pipe = draw->pipe;
 218    const struct pipe_rasterizer_state *rast = draw->rasterizer;
 219    void *r;
 220
 221    wide->half_point_size = 0.5f * draw->rasterizer->point_size;
 222    wide->xbias = 0.0;
 223    wide->ybias = 0.0;
 224
 225    if (draw->rasterizer->gl_rasterization_rules) {
 226       wide->xbias = 0.125;
 227    }
 228
 229    /* Disable triangle culling, stippling, unfilled mode etc. */
 230    r = draw_get_rasterizer_no_cull(draw, rast->scissor, rast->flatshade);
 231    draw->suspend_flushing = TRUE;
 232    pipe->bind_rasterizer_state(pipe, r);
 233    draw->suspend_flushing = FALSE;
 234
 235    /* XXX we won't know the real size if it's computed by the vertex shader! */
 236    if ((draw->rasterizer->point_size > draw->pipeline.wide_point_threshold) ||
 237        (draw->rasterizer->sprite_coord_enable && draw->pipeline.point_sprite)) {
 238       stage->point = widepoint_point;
 239    }
 240    else {
 241       stage->point = draw_pipe_passthrough_point;
 242    }
 243
 244    if (draw->rasterizer->sprite_coord_enable) {
 245       /* find vertex shader texcoord outputs */
 246       const struct draw_vertex_shader *vs = draw->vs.vertex_shader;
 247       uint i, j = 0;
 248       wide->texcoord_mode = draw->rasterizer->sprite_coord_mode;
 249       for (i = 0; i < vs->info.num_outputs; i++) {
 250          if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_GENERIC) {
 251             wide->texcoord_slot[j] = i;
 252             wide->texcoord_enable[j] = (draw->rasterizer->sprite_coord_enable >> j) & 1;
 253             j++;
 254          }
 255       }
 256       wide->num_texcoords = j;
 257
 258       /* find fragment shader PointCoord input */
 259       wide->point_coord_fs_input = find_pntc_input_attrib(draw);
 260
 261       /* setup extra vp output (point coord implemented as a texcoord) */
 262       draw->extra_shader_outputs.semantic_name = TGSI_SEMANTIC_GENERIC;
 263       draw->extra_shader_outputs.semantic_index = 0;
 264       draw->extra_shader_outputs.slot = draw_current_shader_outputs(draw);
 265    }
 266    else {
 267       wide->point_coord_fs_input = -1;
 268       draw->extra_shader_outputs.slot = 0;
 269    }
 270
 271    wide->psize_slot = -1;
 272    if (draw->rasterizer->point_size_per_vertex) {
 273       /* find PSIZ vertex output */
 274       const struct draw_vertex_shader *vs = draw->vs.vertex_shader;
 275       uint i;
 276       for (i = 0; i < vs->info.num_outputs; i++) {
 277          if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_PSIZE) {
 278             wide->psize_slot = i;
 279             break;
 280          }
 281       }
 282    }
 283
 284    stage->point( stage, header );
 285 }
 286
 287
 288 static void widepoint_flush( struct draw_stage *stage, unsigned flags )
 289 {
 290    struct draw_context *draw = stage->draw;
 291    struct pipe_context *pipe = draw->pipe;
 292
 293    stage->point = widepoint_first_point;
 294    stage->next->flush( stage->next, flags );
 295    stage->draw->extra_shader_outputs.slot = 0;
 296
 297    /* restore original rasterizer state */
 298    if (draw->rast_handle) {
 299       draw->suspend_flushing = TRUE;
 300       pipe->bind_rasterizer_state(pipe, draw->rast_handle);
 301       draw->suspend_flushing = FALSE;
 302    }
 303 }
 304
 305
 306 static void widepoint_reset_stipple_counter( struct draw_stage *stage )
 307 {
 308    stage->next->reset_stipple_counter( stage->next );
 309 }
 310
 311
 312 static void widepoint_destroy( struct draw_stage *stage )
 313 {
 314    draw_free_temp_verts( stage );
 315    FREE( stage );
 316 }
 317
 318
 319 struct draw_stage *draw_wide_point_stage( struct draw_context *draw )
 320 {
 321    struct widepoint_stage *wide = CALLOC_STRUCT(widepoint_stage);
 322    if (wide == NULL)
 323       goto fail;
 324
 325    if (!draw_alloc_temp_verts( &wide->stage, 4 ))
 326       goto fail;
 327
 328    wide->stage.draw = draw;
 329    wide->stage.name = "wide-point";
 330    wide->stage.next = NULL;
 331    wide->stage.point = widepoint_first_point;
 332    wide->stage.line = draw_pipe_passthrough_line;
 333    wide->stage.tri = draw_pipe_passthrough_tri;
 334    wide->stage.flush = widepoint_flush;
 335    wide->stage.reset_stipple_counter = widepoint_reset_stipple_counter;
 336    wide->stage.destroy = widepoint_destroy;
 337
 338    return &wide->stage;
 339
 340  fail:
 341    if (wide)
 342       wide->stage.destroy( &wide->stage );
 343
 344    return NULL;
 345 }