src/gallium/drivers/r300/r300_render_stencilref.c

   1 /*
   2  * Copyright 2010 Marek Olšák <maraeo@gmail.com>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * on the rights to use, copy, modify, merge, publish, distribute, sub
   8  * license, and/or sell copies of the Software, and to permit persons to whom
   9  * the Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  18  * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
  19  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  20  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  21  * USE OR OTHER DEALINGS IN THE SOFTWARE. */
  22
  23 /**
  24  * The two-sided stencil reference value fallback for r3xx-r4xx chips.
  25  * These chips support two-sided stencil functions but they do not support
  26  * a two-sided reference value.
  27  *
  28  * The functions below split every draw call which uses the two-sided
  29  * reference value into two draw calls -- the first one renders front faces
  30  * and the second renders back faces with the other reference value.
  31  */
  32
  33 #include "r300_context.h"
  34 #include "r300_reg.h"
  35
  36 struct r300_stencilref_context {
  37     void (*draw_vbo)(struct pipe_context *pipe,
  38                      const struct pipe_draw_info *info);
  39
  40     uint32_t rs_cull_mode;
  41     uint32_t zb_stencilrefmask;
  42     ubyte ref_value_front;
  43 };
  44
  45 static boolean r300_stencilref_needed(struct r300_context *r300)
  46 {
  47     struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
  48
  49     return dsa->two_sided_stencil_ref ||
  50            (dsa->two_sided &&
  51             r300->stencil_ref.ref_value[0] != r300->stencil_ref.ref_value[1]);
  52 }
  53
  54 /* Set drawing for front faces. */
  55 static void r300_stencilref_begin(struct r300_context *r300)
  56 {
  57     struct r300_stencilref_context *sr = r300->stencilref_fallback;
  58     struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
  59     struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
  60
  61     /* Save state. */
  62     sr->rs_cull_mode = rs->cb_main[rs->cull_mode_index];
  63     sr->zb_stencilrefmask = dsa->stencil_ref_mask;
  64     sr->ref_value_front = r300->stencil_ref.ref_value[0];
  65
  66     /* We *cull* pixels, therefore no need to mask out the bits. */
  67     rs->cb_main[rs->cull_mode_index] |= R300_CULL_BACK;
  68
  69     r300_mark_atom_dirty(r300, &r300->rs_state);
  70 }
  71
  72 /* Set drawing for back faces. */
  73 static void r300_stencilref_switch_side(struct r300_context *r300)
  74 {
  75     struct r300_stencilref_context *sr = r300->stencilref_fallback;
  76     struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
  77     struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
  78
  79     rs->cb_main[rs->cull_mode_index] = sr->rs_cull_mode | R300_CULL_FRONT;
  80     dsa->stencil_ref_mask = dsa->stencil_ref_bf;
  81     r300->stencil_ref.ref_value[0] = r300->stencil_ref.ref_value[1];
  82
  83     r300_mark_atom_dirty(r300, &r300->rs_state);
  84     r300_mark_atom_dirty(r300, &r300->dsa_state);
  85 }
  86
  87 /* Restore the original state. */
  88 static void r300_stencilref_end(struct r300_context *r300)
  89 {
  90     struct r300_stencilref_context *sr = r300->stencilref_fallback;
  91     struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
  92     struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
  93
  94     /* Restore state. */
  95     rs->cb_main[rs->cull_mode_index] = sr->rs_cull_mode;
  96     dsa->stencil_ref_mask = sr->zb_stencilrefmask;
  97     r300->stencil_ref.ref_value[0] = sr->ref_value_front;
  98
  99     r300_mark_atom_dirty(r300, &r300->rs_state);
 100     r300_mark_atom_dirty(r300, &r300->dsa_state);
 101 }
 102
 103 static void r300_stencilref_draw_vbo(struct pipe_context *pipe,
 104                                      const struct pipe_draw_info *info)
 105 {
 106     struct r300_context *r300 = r300_context(pipe);
 107     struct r300_stencilref_context *sr = r300->stencilref_fallback;
 108
 109     if (!r300_stencilref_needed(r300)) {
 110         sr->draw_vbo(pipe, info);
 111     } else {
 112         r300_stencilref_begin(r300);
 113         sr->draw_vbo(pipe, info);
 114         r300_stencilref_switch_side(r300);
 115         sr->draw_vbo(pipe, info);
 116         r300_stencilref_end(r300);
 117     }
 118 }
 119
 120 void r300_plug_in_stencil_ref_fallback(struct r300_context *r300)
 121 {
 122     r300->stencilref_fallback = CALLOC_STRUCT(r300_stencilref_context);
 123
 124     /* Save original draw function. */
 125     r300->stencilref_fallback->draw_vbo = r300->context.draw_vbo;
 126
 127     /* Override the draw function. */
 128     r300->context.draw_vbo = r300_stencilref_draw_vbo;
 129 }