1 /**************************************************************************
2 *
3 * Copyright 2009 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
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23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28 /**
29 * Alpha testing to LLVM IR translation.
30 *
31 * @author Jose Fonseca <jfonseca@vmware.com>
32 */
33
34 #include "pipe/p_state.h"
35 #include "util/u_format.h"
36
37 #include "gallivm/lp_bld_type.h"
38 #include "gallivm/lp_bld_const.h"
39 #include "gallivm/lp_bld_arit.h"
40 #include "gallivm/lp_bld_conv.h"
41 #include "gallivm/lp_bld_logic.h"
42 #include "gallivm/lp_bld_flow.h"
43 #include "gallivm/lp_bld_debug.h"
44
45 #include "lp_bld_alpha.h"
46
47
48 void
lp_build_alpha_test(struct gallivm_state * gallivm,unsigned func,struct lp_type type,const struct util_format_description * cbuf_format_desc,struct lp_build_mask_context * mask,LLVMValueRef alpha,LLVMValueRef ref,boolean do_branch)49 lp_build_alpha_test(struct gallivm_state *gallivm,
50 unsigned func,
51 struct lp_type type,
52 const struct util_format_description *cbuf_format_desc,
53 struct lp_build_mask_context *mask,
54 LLVMValueRef alpha,
55 LLVMValueRef ref,
56 boolean do_branch)
57 {
58 struct lp_build_context bld;
59 LLVMValueRef test;
60
61 lp_build_context_init(&bld, gallivm, type);
62
63 /*
64 * Alpha testing needs to be done in the color buffer precision.
65 *
66 * TODO: Ideally, instead of duplicating the color conversion code, we would do
67 * alpha testing after converting the output colors, but that's not very
68 * convenient, because it needs to be done before depth testing. Hopefully
69 * LLVM will detect and remove the duplicate expression.
70 *
71 * FIXME: This should be generalized to formats other than rgba8 variants.
72 */
73 if (type.floating &&
74 util_format_is_rgba8_variant(cbuf_format_desc)) {
75 const unsigned dst_width = 8;
76
77 alpha = lp_build_clamp(&bld, alpha, bld.zero, bld.one);
78 ref = lp_build_clamp(&bld, ref, bld.zero, bld.one);
79
80 alpha = lp_build_clamped_float_to_unsigned_norm(gallivm, type, dst_width, alpha);
81 ref = lp_build_clamped_float_to_unsigned_norm(gallivm, type, dst_width, ref);
82
83 type.floating = 0;
84 lp_build_context_init(&bld, gallivm, type);
85 }
86
87 test = lp_build_cmp(&bld, func, alpha, ref);
88
89 lp_build_name(test, "alpha_mask");
90
91 lp_build_mask_update(mask, test);
92
93 if (do_branch)
94 lp_build_mask_check(mask);
95 }
96