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_arrays)(struct pipe_context *pipe,
  38                         unsigned mode, unsigned start, unsigned count);
  39
  40     void (*draw_range_elements)(
  41         struct pipe_context *pipe, struct pipe_resource *indexBuffer,
  42         unsigned indexSize, int indexBias, unsigned minIndex, unsigned maxIndex,
  43         unsigned mode, unsigned start, unsigned count);
  44
  45     uint32_t rs_cull_mode;
  46     uint32_t zb_stencilrefmask;
  47     ubyte ref_value_front;
  48 };
  49
  50 static boolean r300_stencilref_needed(struct r300_context *r300)
  51 {
  52     struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
  53
  54     return dsa->two_sided_stencil_ref ||
  55            (dsa->two_sided &&
  56             r300->stencil_ref.ref_value[0] != r300->stencil_ref.ref_value[1]);
  57 }
  58
  59 /* Set drawing for front faces. */
  60 static void r300_stencilref_begin(struct r300_context *r300)
  61 {
  62     struct r300_stencilref_context *sr = r300->stencilref_fallback;
  63     struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
  64     struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
  65
  66     /* Save state. */
  67     sr->rs_cull_mode = rs->cull_mode;
  68     sr->zb_stencilrefmask = dsa->stencil_ref_mask;
  69     sr->ref_value_front = r300->stencil_ref.ref_value[0];
  70
  71     /* We *cull* pixels, therefore no need to mask out the bits. */
  72     rs->cull_mode |= R300_CULL_BACK;
  73
  74     r300->rs_state.dirty = TRUE;
  75 }
  76
  77 /* Set drawing for back faces. */
  78 static void r300_stencilref_switch_side(struct r300_context *r300)
  79 {
  80     struct r300_stencilref_context *sr = r300->stencilref_fallback;
  81     struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
  82     struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
  83
  84     rs->cull_mode = sr->rs_cull_mode | R300_CULL_FRONT;
  85     dsa->stencil_ref_mask = dsa->stencil_ref_bf;
  86     r300->stencil_ref.ref_value[0] = r300->stencil_ref.ref_value[1];
  87
  88     r300->rs_state.dirty = TRUE;
  89     r300->dsa_state.dirty = TRUE;
  90 }
  91
  92 /* Restore the original state. */
  93 static void r300_stencilref_end(struct r300_context *r300)
  94 {
  95     struct r300_stencilref_context *sr = r300->stencilref_fallback;
  96     struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
  97     struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
  98
  99     /* Restore state. */
 100     rs->cull_mode = sr->rs_cull_mode;
 101     dsa->stencil_ref_mask = sr->zb_stencilrefmask;
 102     r300->stencil_ref.ref_value[0] = sr->ref_value_front;
 103
 104     r300->rs_state.dirty = TRUE;
 105     r300->dsa_state.dirty = TRUE;
 106 }
 107
 108 static void r300_stencilref_draw_arrays(struct pipe_context *pipe, unsigned mode,
 109                                         unsigned start, unsigned count)
 110 {
 111     struct r300_context *r300 = r300_context(pipe);
 112     struct r300_stencilref_context *sr = r300->stencilref_fallback;
 113
 114     if (!r300_stencilref_needed(r300)) {
 115         sr->draw_arrays(pipe, mode, start, count);
 116     } else {
 117         r300_stencilref_begin(r300);
 118         sr->draw_arrays(pipe, mode, start, count);
 119         r300_stencilref_switch_side(r300);
 120         sr->draw_arrays(pipe, mode, start, count);
 121         r300_stencilref_end(r300);
 122     }
 123 }
 124
 125 static void r300_stencilref_draw_range_elements(
 126     struct pipe_context *pipe, struct pipe_resource *indexBuffer,
 127     unsigned indexSize, int indexBias, unsigned minIndex, unsigned maxIndex,
 128     unsigned mode, unsigned start, unsigned count)
 129 {
 130     struct r300_context *r300 = r300_context(pipe);
 131     struct r300_stencilref_context *sr = r300->stencilref_fallback;
 132
 133     if (!r300_stencilref_needed(r300)) {
 134         sr->draw_range_elements(pipe, indexBuffer, indexSize, indexBias,
 135                                 minIndex, maxIndex, mode, start, count);
 136     } else {
 137         r300_stencilref_begin(r300);
 138         sr->draw_range_elements(pipe, indexBuffer, indexSize, indexBias,
 139                                 minIndex, maxIndex, mode, start, count);
 140         r300_stencilref_switch_side(r300);
 141         sr->draw_range_elements(pipe, indexBuffer, indexSize, indexBias,
 142                                 minIndex, maxIndex, mode, start, count);
 143         r300_stencilref_end(r300);
 144     }
 145 }
 146
 147 void r300_plug_in_stencil_ref_fallback(struct r300_context *r300)
 148 {
 149     r300->stencilref_fallback = CALLOC_STRUCT(r300_stencilref_context);
 150
 151     /* Save original draw functions. */
 152     r300->stencilref_fallback->draw_arrays = r300->context.draw_arrays;
 153     r300->stencilref_fallback->draw_range_elements = r300->context.draw_range_elements;
 154
 155     /* Override the draw functions. */
 156     r300->context.draw_arrays = r300_stencilref_draw_arrays;
 157     r300->context.draw_range_elements = r300_stencilref_draw_range_elements;
 158 }