webp: Make it a module and unbundle libwebp thirdparty files

Note that there are two Godot-specific changes made to libwebp
for the javascript/HTML5 platform. They are documented in the
README.md.

1 files changed, 143 insertions, 0 deletions

diff --git a/thirdparty/libwebp/dsp/lossless_enc_neon.c b/thirdparty/libwebp/dsp/lossless_enc_neon.c
new file mode 100644
index 0000000000..4c56f2594b
--- /dev/null
+++ b/thirdparty/libwebp/dsp/lossless_enc_neon.c
@@ -0,0 +1,143 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// NEON variant of methods for lossless encoder
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "./dsp.h"
+
+#if defined(WEBP_USE_NEON)
+
+#include <arm_neon.h>
+
+#include "./lossless.h"
+#include "./neon.h"
+
+//------------------------------------------------------------------------------
+// Subtract-Green Transform
+
+// vtbl?_u8 are marked unavailable for iOS arm64 with Xcode < 6.3, use
+// non-standard versions there.
+#if defined(__APPLE__) && defined(__aarch64__) && \
+    defined(__apple_build_version__) && (__apple_build_version__< 6020037)
+#define USE_VTBLQ
+#endif
+
+#ifdef USE_VTBLQ
+// 255 = byte will be zeroed
+static const uint8_t kGreenShuffle[16] = {
+  1, 255, 1, 255, 5, 255, 5, 255, 9, 255, 9, 255, 13, 255, 13, 255
+};
+
+static WEBP_INLINE uint8x16_t DoGreenShuffle(const uint8x16_t argb,
+                                             const uint8x16_t shuffle) {
+  return vcombine_u8(vtbl1q_u8(argb, vget_low_u8(shuffle)),
+                     vtbl1q_u8(argb, vget_high_u8(shuffle)));
+}
+#else  // !USE_VTBLQ
+// 255 = byte will be zeroed
+static const uint8_t kGreenShuffle[8] = { 1, 255, 1, 255, 5, 255, 5, 255  };
+
+static WEBP_INLINE uint8x16_t DoGreenShuffle(const uint8x16_t argb,
+                                             const uint8x8_t shuffle) {
+  return vcombine_u8(vtbl1_u8(vget_low_u8(argb), shuffle),
+                     vtbl1_u8(vget_high_u8(argb), shuffle));
+}
+#endif  // USE_VTBLQ
+
+static void SubtractGreenFromBlueAndRed(uint32_t* argb_data, int num_pixels) {
+  const uint32_t* const end = argb_data + (num_pixels & ~3);
+#ifdef USE_VTBLQ
+  const uint8x16_t shuffle = vld1q_u8(kGreenShuffle);
+#else
+  const uint8x8_t shuffle = vld1_u8(kGreenShuffle);
+#endif
+  for (; argb_data < end; argb_data += 4) {
+    const uint8x16_t argb = vld1q_u8((uint8_t*)argb_data);
+    const uint8x16_t greens = DoGreenShuffle(argb, shuffle);
+    vst1q_u8((uint8_t*)argb_data, vsubq_u8(argb, greens));
+  }
+  // fallthrough and finish off with plain-C
+  VP8LSubtractGreenFromBlueAndRed_C(argb_data, num_pixels & 3);
+}
+
+//------------------------------------------------------------------------------
+// Color Transform
+
+static void TransformColor(const VP8LMultipliers* const m,
+                           uint32_t* argb_data, int num_pixels) {
+  // sign-extended multiplying constants, pre-shifted by 6.
+#define CST(X)  (((int16_t)(m->X << 8)) >> 6)
+  const int16_t rb[8] = {
+    CST(green_to_blue_), CST(green_to_red_),
+    CST(green_to_blue_), CST(green_to_red_),
+    CST(green_to_blue_), CST(green_to_red_),
+    CST(green_to_blue_), CST(green_to_red_)
+  };
+  const int16x8_t mults_rb = vld1q_s16(rb);
+  const int16_t b2[8] = {
+    0, CST(red_to_blue_), 0, CST(red_to_blue_),
+    0, CST(red_to_blue_), 0, CST(red_to_blue_),
+  };
+  const int16x8_t mults_b2 = vld1q_s16(b2);
+#undef CST
+#ifdef USE_VTBLQ
+  static const uint8_t kg0g0[16] = {
+    255, 1, 255, 1, 255, 5, 255, 5, 255, 9, 255, 9, 255, 13, 255, 13
+  };
+  const uint8x16_t shuffle = vld1q_u8(kg0g0);
+#else
+  static const uint8_t k0g0g[8] = { 255, 1, 255, 1, 255, 5, 255, 5 };
+  const uint8x8_t shuffle = vld1_u8(k0g0g);
+#endif
+  const uint32x4_t mask_rb = vdupq_n_u32(0x00ff00ffu);  // red-blue masks
+  int i;
+  for (i = 0; i + 4 <= num_pixels; i += 4) {
+    const uint8x16_t in = vld1q_u8((uint8_t*)(argb_data + i));
+    // 0 g 0 g
+    const uint8x16_t greens = DoGreenShuffle(in, shuffle);
+    // x dr  x db1
+    const int16x8_t A = vqdmulhq_s16(vreinterpretq_s16_u8(greens), mults_rb);
+    // r 0   b   0
+    const int16x8_t B = vshlq_n_s16(vreinterpretq_s16_u8(in), 8);
+    // x db2 0   0
+    const int16x8_t C = vqdmulhq_s16(B, mults_b2);
+    // 0 0   x db2
+    const uint32x4_t D = vshrq_n_u32(vreinterpretq_u32_s16(C), 16);
+    // x dr  x  db
+    const int8x16_t E = vaddq_s8(vreinterpretq_s8_u32(D),
+                                 vreinterpretq_s8_s16(A));
+    // 0 dr  0  db
+    const uint32x4_t F = vandq_u32(vreinterpretq_u32_s8(E), mask_rb);
+    const int8x16_t out = vsubq_s8(vreinterpretq_s8_u8(in),
+                                   vreinterpretq_s8_u32(F));
+    vst1q_s8((int8_t*)(argb_data + i), out);
+  }
+  // fallthrough and finish off with plain-C
+  VP8LTransformColor_C(m, argb_data + i, num_pixels - i);
+}
+
+#undef USE_VTBLQ
+
+//------------------------------------------------------------------------------
+// Entry point
+
+extern void VP8LEncDspInitNEON(void);
+
+WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitNEON(void) {
+  VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed;
+  VP8LTransformColor = TransformColor;
+}
+
+#else  // !WEBP_USE_NEON
+
+WEBP_DSP_INIT_STUB(VP8LEncDspInitNEON)
+
+#endif  // WEBP_USE_NEON