1 // Copyright 2017 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // Utilities for processing transparent channel, NEON version. 11 // 12 // Author: Skal (pascal.massimino (at) gmail.com) 13 14 #include "./dsp.h" 15 16 #if defined(WEBP_USE_NEON) 17 18 #include "./neon.h" 19 20 //------------------------------------------------------------------------------ 21 22 #define MULTIPLIER(a) ((a) * 0x8081) 23 #define PREMULTIPLY(x, m) (((x) * (m)) >> 23) 24 25 #define MULTIPLY_BY_ALPHA(V, ALPHA, OTHER) do { \ 26 const uint8x8_t alpha = (V).val[(ALPHA)]; \ 27 const uint16x8_t r1 = vmull_u8((V).val[1], alpha); \ 28 const uint16x8_t g1 = vmull_u8((V).val[2], alpha); \ 29 const uint16x8_t b1 = vmull_u8((V).val[(OTHER)], alpha); \ 30 /* we use: v / 255 = (v + 1 + (v >> 8)) >> 8 */ \ 31 const uint16x8_t r2 = vsraq_n_u16(r1, r1, 8); \ 32 const uint16x8_t g2 = vsraq_n_u16(g1, g1, 8); \ 33 const uint16x8_t b2 = vsraq_n_u16(b1, b1, 8); \ 34 const uint16x8_t r3 = vaddq_u16(r2, kOne); \ 35 const uint16x8_t g3 = vaddq_u16(g2, kOne); \ 36 const uint16x8_t b3 = vaddq_u16(b2, kOne); \ 37 (V).val[1] = vshrn_n_u16(r3, 8); \ 38 (V).val[2] = vshrn_n_u16(g3, 8); \ 39 (V).val[(OTHER)] = vshrn_n_u16(b3, 8); \ 40 } while (0) 41 42 static void ApplyAlphaMultiply_NEON(uint8_t* rgba, int alpha_first, 43 int w, int h, int stride) { 44 const uint16x8_t kOne = vdupq_n_u16(1u); 45 while (h-- > 0) { 46 uint32_t* const rgbx = (uint32_t*)rgba; 47 int i = 0; 48 if (alpha_first) { 49 for (; i + 8 <= w; i += 8) { 50 // load aaaa...|rrrr...|gggg...|bbbb... 51 uint8x8x4_t RGBX = vld4_u8((const uint8_t*)(rgbx + i)); 52 MULTIPLY_BY_ALPHA(RGBX, 0, 3); 53 vst4_u8((uint8_t*)(rgbx + i), RGBX); 54 } 55 } else { 56 for (; i + 8 <= w; i += 8) { 57 uint8x8x4_t RGBX = vld4_u8((const uint8_t*)(rgbx + i)); 58 MULTIPLY_BY_ALPHA(RGBX, 3, 0); 59 vst4_u8((uint8_t*)(rgbx + i), RGBX); 60 } 61 } 62 // Finish with left-overs. 63 for (; i < w; ++i) { 64 uint8_t* const rgb = rgba + (alpha_first ? 1 : 0); 65 const uint8_t* const alpha = rgba + (alpha_first ? 0 : 3); 66 const uint32_t a = alpha[4 * i]; 67 if (a != 0xff) { 68 const uint32_t mult = MULTIPLIER(a); 69 rgb[4 * i + 0] = PREMULTIPLY(rgb[4 * i + 0], mult); 70 rgb[4 * i + 1] = PREMULTIPLY(rgb[4 * i + 1], mult); 71 rgb[4 * i + 2] = PREMULTIPLY(rgb[4 * i + 2], mult); 72 } 73 } 74 rgba += stride; 75 } 76 } 77 #undef MULTIPLY_BY_ALPHA 78 #undef MULTIPLIER 79 #undef PREMULTIPLY 80 81 //------------------------------------------------------------------------------ 82 83 static int DispatchAlpha_NEON(const uint8_t* alpha, int alpha_stride, 84 int width, int height, 85 uint8_t* dst, int dst_stride) { 86 uint32_t alpha_mask = 0xffffffffu; 87 uint8x8_t mask8 = vdup_n_u8(0xff); 88 uint32_t tmp[2]; 89 int i, j; 90 for (j = 0; j < height; ++j) { 91 // We don't know if alpha is first or last in dst[] (depending on rgbA/Argb 92 // mode). So we must be sure dst[4*i + 8 - 1] is writable for the store. 93 // Hence the test with 'width - 1' instead of just 'width'. 94 for (i = 0; i + 8 <= width - 1; i += 8) { 95 uint8x8x4_t rgbX = vld4_u8((const uint8_t*)(dst + 4 * i)); 96 const uint8x8_t alphas = vld1_u8(alpha + i); 97 rgbX.val[0] = alphas; 98 vst4_u8((uint8_t*)(dst + 4 * i), rgbX); 99 mask8 = vand_u8(mask8, alphas); 100 } 101 for (; i < width; ++i) { 102 const uint32_t alpha_value = alpha[i]; 103 dst[4 * i] = alpha_value; 104 alpha_mask &= alpha_value; 105 } 106 alpha += alpha_stride; 107 dst += dst_stride; 108 } 109 vst1_u8((uint8_t*)tmp, mask8); 110 alpha_mask &= tmp[0]; 111 alpha_mask &= tmp[1]; 112 return (alpha_mask != 0xffffffffu); 113 } 114 115 static void DispatchAlphaToGreen_NEON(const uint8_t* alpha, int alpha_stride, 116 int width, int height, 117 uint32_t* dst, int dst_stride) { 118 int i, j; 119 uint8x8x4_t greens; // leave A/R/B channels zero'd. 120 greens.val[0] = vdup_n_u8(0); 121 greens.val[2] = vdup_n_u8(0); 122 greens.val[3] = vdup_n_u8(0); 123 for (j = 0; j < height; ++j) { 124 for (i = 0; i + 8 <= width; i += 8) { 125 greens.val[1] = vld1_u8(alpha + i); 126 vst4_u8((uint8_t*)(dst + i), greens); 127 } 128 for (; i < width; ++i) dst[i] = alpha[i] << 8; 129 alpha += alpha_stride; 130 dst += dst_stride; 131 } 132 } 133 134 static int ExtractAlpha_NEON(const uint8_t* argb, int argb_stride, 135 int width, int height, 136 uint8_t* alpha, int alpha_stride) { 137 uint32_t alpha_mask = 0xffffffffu; 138 uint8x8_t mask8 = vdup_n_u8(0xff); 139 uint32_t tmp[2]; 140 int i, j; 141 for (j = 0; j < height; ++j) { 142 // We don't know if alpha is first or last in dst[] (depending on rgbA/Argb 143 // mode). So we must be sure dst[4*i + 8 - 1] is writable for the store. 144 // Hence the test with 'width - 1' instead of just 'width'. 145 for (i = 0; i + 8 <= width - 1; i += 8) { 146 const uint8x8x4_t rgbX = vld4_u8((const uint8_t*)(argb + 4 * i)); 147 const uint8x8_t alphas = rgbX.val[0]; 148 vst1_u8((uint8_t*)(alpha + i), alphas); 149 mask8 = vand_u8(mask8, alphas); 150 } 151 for (; i < width; ++i) { 152 alpha[i] = argb[4 * i]; 153 alpha_mask &= alpha[i]; 154 } 155 argb += argb_stride; 156 alpha += alpha_stride; 157 } 158 vst1_u8((uint8_t*)tmp, mask8); 159 alpha_mask &= tmp[0]; 160 alpha_mask &= tmp[1]; 161 return (alpha_mask == 0xffffffffu); 162 } 163 164 static void ExtractGreen_NEON(const uint32_t* argb, 165 uint8_t* alpha, int size) { 166 int i; 167 for (i = 0; i + 16 <= size; i += 16) { 168 const uint8x16x4_t rgbX = vld4q_u8((const uint8_t*)(argb + i)); 169 const uint8x16_t greens = rgbX.val[1]; 170 vst1q_u8(alpha + i, greens); 171 } 172 for (; i < size; ++i) alpha[i] = (argb[i] >> 8) & 0xff; 173 } 174 175 //------------------------------------------------------------------------------ 176 177 extern void WebPInitAlphaProcessingNEON(void); 178 179 WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingNEON(void) { 180 WebPApplyAlphaMultiply = ApplyAlphaMultiply_NEON; 181 WebPDispatchAlpha = DispatchAlpha_NEON; 182 WebPDispatchAlphaToGreen = DispatchAlphaToGreen_NEON; 183 WebPExtractAlpha = ExtractAlpha_NEON; 184 WebPExtractGreen = ExtractGreen_NEON; 185 } 186 187 #else // !WEBP_USE_NEON 188 189 WEBP_DSP_INIT_STUB(WebPInitAlphaProcessingNEON) 190 191 #endif // WEBP_USE_NEON 192
