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1 /**************************************************************************
2  *
3  * Copyright 2012 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
22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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 #include "pipe/p_state.h"
29 #include "util/u_debug.h"
30 
31 #include "gallivm/lp_bld_type.h"
32 #include "gallivm/lp_bld_arit.h"
33 #include "gallivm/lp_bld_const.h"
34 #include "gallivm/lp_bld_logic.h"
35 #include "gallivm/lp_bld_swizzle.h"
36 #include "gallivm/lp_bld_flow.h"
37 #include "gallivm/lp_bld_debug.h"
38 #include "gallivm/lp_bld_pack.h"
39 
40 #include "lp_bld_blend.h"
41 
42 /**
43  * Is (a OP b) == (b OP a)?
44  */
45 boolean
lp_build_blend_func_commutative(unsigned func)46 lp_build_blend_func_commutative(unsigned func)
47 {
48    switch (func) {
49    case PIPE_BLEND_ADD:
50    case PIPE_BLEND_MIN:
51    case PIPE_BLEND_MAX:
52       return TRUE;
53    case PIPE_BLEND_SUBTRACT:
54    case PIPE_BLEND_REVERSE_SUBTRACT:
55       return FALSE;
56    default:
57       assert(0);
58       return TRUE;
59    }
60 }
61 
62 
63 /**
64  * Whether the blending functions are the reverse of each other.
65  */
66 boolean
lp_build_blend_func_reverse(unsigned rgb_func,unsigned alpha_func)67 lp_build_blend_func_reverse(unsigned rgb_func, unsigned alpha_func)
68 {
69    if (rgb_func == alpha_func)
70       return FALSE;
71    if (rgb_func == PIPE_BLEND_SUBTRACT && alpha_func == PIPE_BLEND_REVERSE_SUBTRACT)
72       return TRUE;
73    if (rgb_func == PIPE_BLEND_REVERSE_SUBTRACT && alpha_func == PIPE_BLEND_SUBTRACT)
74       return TRUE;
75    return FALSE;
76 }
77 
78 
79 /**
80  * Whether the blending factors are complementary of each other.
81  */
82 static inline boolean
lp_build_blend_factor_complementary(unsigned src_factor,unsigned dst_factor)83 lp_build_blend_factor_complementary(unsigned src_factor, unsigned dst_factor)
84 {
85    STATIC_ASSERT((PIPE_BLENDFACTOR_ZERO ^ 0x10) == PIPE_BLENDFACTOR_ONE);
86    STATIC_ASSERT((PIPE_BLENDFACTOR_CONST_COLOR ^ 0x10) ==
87                  PIPE_BLENDFACTOR_INV_CONST_COLOR);
88    return dst_factor == (src_factor ^ 0x10);
89 }
90 
91 
92 /**
93  * Whether this is a inverse blend factor
94  */
95 static inline boolean
is_inverse_factor(unsigned factor)96 is_inverse_factor(unsigned factor)
97 {
98    STATIC_ASSERT(PIPE_BLENDFACTOR_ZERO == 0x11);
99    return factor > 0x11;
100 }
101 
102 
103 /**
104  * Calculates the (expanded to wider type) multiplication
105  * of 2 normalized numbers.
106  */
107 static void
lp_build_mul_norm_expand(struct lp_build_context * bld,LLVMValueRef a,LLVMValueRef b,LLVMValueRef * resl,LLVMValueRef * resh,boolean signedness_differs)108 lp_build_mul_norm_expand(struct lp_build_context *bld,
109                          LLVMValueRef a, LLVMValueRef b,
110                          LLVMValueRef *resl, LLVMValueRef *resh,
111                          boolean signedness_differs)
112 {
113    const struct lp_type type = bld->type;
114    struct lp_type wide_type = lp_wider_type(type);
115    struct lp_type wide_type2 = wide_type;
116    struct lp_type type2 = type;
117    LLVMValueRef al, ah, bl, bh;
118 
119    assert(lp_check_value(type, a));
120    assert(lp_check_value(type, b));
121    assert(!type.floating && !type.fixed && type.norm);
122 
123    if (a == bld->zero || b == bld->zero) {
124       LLVMValueRef zero = LLVMConstNull(lp_build_vec_type(bld->gallivm, wide_type));
125       *resl = zero;
126       *resh = zero;
127       return;
128    }
129 
130    if (signedness_differs) {
131       type2.sign = !type.sign;
132       wide_type2.sign = !wide_type2.sign;
133    }
134 
135    lp_build_unpack2_native(bld->gallivm, type, wide_type, a, &al, &ah);
136    lp_build_unpack2_native(bld->gallivm, type2, wide_type2, b, &bl, &bh);
137 
138    *resl = lp_build_mul_norm(bld->gallivm, wide_type, al, bl);
139    *resh = lp_build_mul_norm(bld->gallivm, wide_type, ah, bh);
140 }
141 
142 
143 /**
144  * @sa http://www.opengl.org/sdk/docs/man/xhtml/glBlendEquationSeparate.xml
145  */
146 LLVMValueRef
lp_build_blend_func(struct lp_build_context * bld,unsigned func,LLVMValueRef term1,LLVMValueRef term2)147 lp_build_blend_func(struct lp_build_context *bld,
148                     unsigned func,
149                     LLVMValueRef term1,
150                     LLVMValueRef term2)
151 {
152    switch (func) {
153    case PIPE_BLEND_ADD:
154       return lp_build_add(bld, term1, term2);
155    case PIPE_BLEND_SUBTRACT:
156       return lp_build_sub(bld, term1, term2);
157    case PIPE_BLEND_REVERSE_SUBTRACT:
158       return lp_build_sub(bld, term2, term1);
159    case PIPE_BLEND_MIN:
160       return lp_build_min(bld, term1, term2);
161    case PIPE_BLEND_MAX:
162       return lp_build_max(bld, term1, term2);
163    default:
164       assert(0);
165       return bld->zero;
166    }
167 }
168 
169 
170 /**
171  * Performs optimisations and blending independent of SoA/AoS
172  *
173  * @param func                   the blend function
174  * @param factor_src             PIPE_BLENDFACTOR_xxx
175  * @param factor_dst             PIPE_BLENDFACTOR_xxx
176  * @param src                    source rgba
177  * @param dst                    dest rgba
178  * @param src_factor             src factor computed value
179  * @param dst_factor             dst factor computed value
180  * @param not_alpha_dependent    same factors accross all channels of src/dst
181  *
182  * not_alpha_dependent should be:
183  *  SoA: always true as it is only one channel at a time
184  *  AoS: rgb_src_factor == alpha_src_factor && rgb_dst_factor == alpha_dst_factor
185  *
186  * Note that pretty much every possible optimisation can only be done on non-unorm targets
187  * due to unorm values not going above 1.0 meaning factorisation can change results.
188  * e.g. (0.9 * 0.9) + (0.9 * 0.9) != 0.9 * (0.9 + 0.9) as result of + is always <= 1.
189  */
190 LLVMValueRef
lp_build_blend(struct lp_build_context * bld,unsigned func,unsigned factor_src,unsigned factor_dst,LLVMValueRef src,LLVMValueRef dst,LLVMValueRef src_factor,LLVMValueRef dst_factor,boolean not_alpha_dependent,boolean optimise_only)191 lp_build_blend(struct lp_build_context *bld,
192                unsigned func,
193                unsigned factor_src,
194                unsigned factor_dst,
195                LLVMValueRef src,
196                LLVMValueRef dst,
197                LLVMValueRef src_factor,
198                LLVMValueRef dst_factor,
199                boolean not_alpha_dependent,
200                boolean optimise_only)
201 {
202    LLVMValueRef result, src_term, dst_term;
203 
204    /* If we are not alpha dependent we can mess with the src/dst factors */
205    if (not_alpha_dependent) {
206       if (lp_build_blend_factor_complementary(factor_src, factor_dst)) {
207          if (func == PIPE_BLEND_ADD) {
208             if (factor_src < factor_dst) {
209                return lp_build_lerp(bld, src_factor, dst, src, 0);
210             } else {
211                return lp_build_lerp(bld, dst_factor, src, dst, 0);
212             }
213          } else if (bld->type.floating && func == PIPE_BLEND_SUBTRACT) {
214             result = lp_build_add(bld, src, dst);
215 
216             if (factor_src < factor_dst) {
217                result = lp_build_mul(bld, result, src_factor);
218                return lp_build_sub(bld, result, dst);
219             } else {
220                result = lp_build_mul(bld, result, dst_factor);
221                return lp_build_sub(bld, src, result);
222             }
223          } else if (bld->type.floating && func == PIPE_BLEND_REVERSE_SUBTRACT) {
224             result = lp_build_add(bld, src, dst);
225 
226             if (factor_src < factor_dst) {
227                result = lp_build_mul(bld, result, src_factor);
228                return lp_build_sub(bld, dst, result);
229             } else {
230                result = lp_build_mul(bld, result, dst_factor);
231                return lp_build_sub(bld, result, src);
232             }
233          }
234       }
235 
236       if (bld->type.floating && factor_src == factor_dst) {
237          if (func == PIPE_BLEND_ADD ||
238              func == PIPE_BLEND_SUBTRACT ||
239              func == PIPE_BLEND_REVERSE_SUBTRACT) {
240             LLVMValueRef result;
241             result = lp_build_blend_func(bld, func, src, dst);
242             return lp_build_mul(bld, result, src_factor);
243          }
244       }
245    }
246 
247    if (optimise_only)
248       return NULL;
249 
250    if ((bld->type.norm && bld->type.sign) &&
251        (is_inverse_factor(factor_src) || is_inverse_factor(factor_dst))) {
252       /*
253        * With snorm blending, the inverse blend factors range from [0,2]
254        * instead of [-1,1], so the ordinary signed normalized arithmetic
255        * doesn't quite work. Unpack must be unsigned, and the add/sub
256        * must be done with wider type.
257        * (Note that it's not quite obvious what the blend equation wrt to
258        * clamping should actually be based on GL spec in this case, but
259        * really the incoming src values are clamped to [-1,1] (the dst is
260        * always clamped already), and then NO further clamping occurs until
261        * the end.)
262        */
263       struct lp_build_context bldw;
264       struct lp_type wide_type = lp_wider_type(bld->type);
265       LLVMValueRef src_terml, src_termh, dst_terml, dst_termh;
266       LLVMValueRef resl, resh;
267 
268       /*
269        * We don't need saturate math for the sub/add, since we have
270        * x+1 bit numbers in x*2 wide type (result is x+2 bits).
271        * (Doesn't really matter on x86 sse2 though as we use saturated
272        * intrinsics.)
273        */
274       wide_type.norm = 0;
275       lp_build_context_init(&bldw, bld->gallivm, wide_type);
276 
277       /*
278        * XXX This is a bit hackish. Note that -128 really should
279        * be -1.0, the same as -127. However, we did not actually clamp
280        * things anywhere (relying on pack intrinsics instead) therefore
281        * we will get -128, and the inverted factor then 255. But the mul
282        * can overflow in this case (rather the rounding fixups for the mul,
283        * -128*255 will be positive).
284        * So we clamp the src and dst up here but only when necessary (we
285        * should do this before calculating blend factors but it's enough
286        * for avoiding overflow).
287        */
288       if (is_inverse_factor(factor_src)) {
289          src = lp_build_max(bld, src,
290                             lp_build_const_vec(bld->gallivm, bld->type, -1.0));
291       }
292       if (is_inverse_factor(factor_dst)) {
293          dst = lp_build_max(bld, dst,
294                             lp_build_const_vec(bld->gallivm, bld->type, -1.0));
295       }
296 
297       lp_build_mul_norm_expand(bld, src, src_factor, &src_terml, &src_termh,
298                                is_inverse_factor(factor_src) ? TRUE : FALSE);
299       lp_build_mul_norm_expand(bld, dst, dst_factor, &dst_terml, &dst_termh,
300                                is_inverse_factor(factor_dst) ? TRUE : FALSE);
301       resl = lp_build_blend_func(&bldw, func, src_terml, dst_terml);
302       resh = lp_build_blend_func(&bldw, func, src_termh, dst_termh);
303 
304       /*
305        * XXX pack2_native is not ok because the values have to be in dst
306        * range. We need native pack though for the correct order on avx2.
307        * Will break on everything not implementing clamping pack intrinsics
308        * (i.e. everything but sse2 and altivec).
309        */
310       return lp_build_pack2_native(bld->gallivm, wide_type, bld->type, resl, resh);
311    } else {
312       src_term = lp_build_mul(bld, src, src_factor);
313       dst_term = lp_build_mul(bld, dst, dst_factor);
314       return lp_build_blend_func(bld, func, src_term, dst_term);
315    }
316 }
317 
318 void
lp_build_alpha_to_coverage(struct gallivm_state * gallivm,struct lp_type type,struct lp_build_mask_context * mask,LLVMValueRef alpha,boolean do_branch)319 lp_build_alpha_to_coverage(struct gallivm_state *gallivm,
320                            struct lp_type type,
321                            struct lp_build_mask_context *mask,
322                            LLVMValueRef alpha,
323                            boolean do_branch)
324 {
325    struct lp_build_context bld;
326    LLVMValueRef test;
327    LLVMValueRef alpha_ref_value;
328 
329    lp_build_context_init(&bld, gallivm, type);
330 
331    alpha_ref_value = lp_build_const_vec(gallivm, type, 0.5);
332 
333    test = lp_build_cmp(&bld, PIPE_FUNC_GREATER, alpha, alpha_ref_value);
334 
335    lp_build_name(test, "alpha_to_coverage");
336 
337    lp_build_mask_update(mask, test);
338 
339    if (do_branch)
340       lp_build_mask_check(mask);
341 }
342