1 /*
2 * Copyright © 2010 Intel Corporation
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 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * 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 NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24 /**
25 * \file lower_texture_projection.cpp
26 *
27 * IR lower pass to perform the division of texture coordinates by the texture
28 * projector if present.
29 *
30 * Many GPUs have a texture sampling opcode that takes the projector
31 * and does the divide internally, thus the presence of the projector
32 * in the IR. For GPUs that don't, this saves the driver needing the
33 * logic for handling the divide.
34 *
35 * \author Eric Anholt <eric@anholt.net>
36 */
37
38 #include "ir.h"
39
40 namespace {
41
42 class lower_texture_projection_visitor : public ir_hierarchical_visitor {
43 public:
lower_texture_projection_visitor()44 lower_texture_projection_visitor()
45 {
46 progress = false;
47 }
48
49 ir_visitor_status visit_leave(ir_texture *ir);
50
51 bool progress;
52 };
53
54 } /* anonymous namespace */
55
56 ir_visitor_status
visit_leave(ir_texture * ir)57 lower_texture_projection_visitor::visit_leave(ir_texture *ir)
58 {
59 if (!ir->projector)
60 return visit_continue;
61
62 void *mem_ctx = ralloc_parent(ir);
63
64 ir_variable *var = new(mem_ctx) ir_variable(ir->projector->type,
65 "projector", ir_var_temporary);
66 base_ir->insert_before(var);
67 ir_dereference *deref = new(mem_ctx) ir_dereference_variable(var);
68 ir_expression *expr = new(mem_ctx) ir_expression(ir_unop_rcp,
69 ir->projector->type,
70 ir->projector,
71 NULL);
72 ir_assignment *assign = new(mem_ctx) ir_assignment(deref, expr, NULL);
73 base_ir->insert_before(assign);
74
75 deref = new(mem_ctx) ir_dereference_variable(var);
76 ir->coordinate = new(mem_ctx) ir_expression(ir_binop_mul,
77 ir->coordinate->type,
78 ir->coordinate,
79 deref);
80
81 if (ir->shadow_comparator) {
82 deref = new(mem_ctx) ir_dereference_variable(var);
83 ir->shadow_comparator = new(mem_ctx) ir_expression(ir_binop_mul,
84 ir->shadow_comparator->type,
85 ir->shadow_comparator,
86 deref);
87 }
88
89 ir->projector = NULL;
90
91 progress = true;
92 return visit_continue;
93 }
94
95 bool
do_lower_texture_projection(exec_list * instructions)96 do_lower_texture_projection(exec_list *instructions)
97 {
98 lower_texture_projection_visitor v;
99
100 visit_list_elements(&v, instructions);
101
102 return v.progress;
103 }
104