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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 class lower_texture_projection_visitor : public ir_hierarchical_visitor {
41 public:
lower_texture_projection_visitor()42    lower_texture_projection_visitor()
43    {
44       progress = false;
45    }
46 
47    ir_visitor_status visit_leave(ir_texture *ir);
48 
49    bool progress;
50 };
51 
52 ir_visitor_status
visit_leave(ir_texture * ir)53 lower_texture_projection_visitor::visit_leave(ir_texture *ir)
54 {
55    if (!ir->projector)
56       return visit_continue;
57 
58    void *mem_ctx = hieralloc_parent(ir);
59 
60    ir_variable *var = new(mem_ctx) ir_variable(ir->projector->type,
61 					       "projector", ir_var_auto);
62    base_ir->insert_before(var);
63    ir_dereference *deref = new(mem_ctx) ir_dereference_variable(var);
64    ir_expression *expr = new(mem_ctx) ir_expression(ir_unop_rcp,
65 						    ir->projector->type,
66 						    ir->projector,
67 						    NULL);
68    ir_assignment *assign = new(mem_ctx) ir_assignment(deref, expr, NULL);
69    base_ir->insert_before(assign);
70 
71    deref = new(mem_ctx) ir_dereference_variable(var);
72    ir->coordinate = new(mem_ctx) ir_expression(ir_binop_mul,
73 					       ir->coordinate->type,
74 					       ir->coordinate,
75 					       deref);
76 
77    if (ir->shadow_comparitor) {
78       deref = new(mem_ctx) ir_dereference_variable(var);
79       ir->shadow_comparitor = new(mem_ctx) ir_expression(ir_binop_mul,
80 						  ir->shadow_comparitor->type,
81 						  ir->shadow_comparitor,
82 						  deref);
83    }
84 
85    ir->projector = NULL;
86 
87    progress = true;
88    return visit_continue;
89 }
90 
91 bool
do_lower_texture_projection(exec_list * instructions)92 do_lower_texture_projection(exec_list *instructions)
93 {
94    lower_texture_projection_visitor v;
95 
96    visit_list_elements(&v, instructions);
97 
98    return v.progress;
99 }
100