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 <[email protected]>
32 */
33
34 #include "pipe/p_state.h"
35 #include "util/format/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,bool 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 bool do_branch)
57 {
58 struct lp_build_context bld;
59
60 lp_build_context_init(&bld, gallivm, type);
61
62 /*
63 * Alpha testing needs to be done in the color buffer precision.
64 *
65 * TODO: Ideally, instead of duplicating the color conversion code, we
66 * would do alpha testing after converting the output colors, but that's
67 * not very convenient, because it needs to be done before depth testing.
68 * Hopefully LLVM will detect and remove the duplicate expression.
69 *
70 * FIXME: This should be generalized to formats other than rgba8 variants.
71 */
72 if (type.floating &&
73 util_format_is_rgba8_variant(cbuf_format_desc)) {
74 const unsigned dst_width = 8;
75
76 alpha = lp_build_clamp(&bld, alpha, bld.zero, bld.one);
77 ref = lp_build_clamp(&bld, ref, bld.zero, bld.one);
78
79 alpha = lp_build_clamped_float_to_unsigned_norm(gallivm, type, dst_width, alpha);
80 ref = lp_build_clamped_float_to_unsigned_norm(gallivm, type, dst_width, ref);
81
82 type.floating = 0;
83 lp_build_context_init(&bld, gallivm, type);
84 }
85
86 LLVMValueRef test = lp_build_cmp(&bld, func, alpha, ref);
87
88 lp_build_name(test, "alpha_mask");
89
90 lp_build_mask_update(mask, test);
91
92 if (do_branch)
93 lp_build_mask_check(mask);
94 }
95