1 files changed, 84 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/image_util/loadimage_astc.cpp b/gfx/angle/checkout/src/image_util/loadimage_astc.cpp
new file mode 100644
index 0000000000..34fd164322
--- /dev/null
+++ b/gfx/angle/checkout/src/image_util/loadimage_astc.cpp
@@ -0,0 +1,84 @@
+//
+// Copyright 2022 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+// loadimage_astc.cpp: Decodes ASTC encoded textures.
+
+#ifdef ANGLE_HAS_ASTCENC
+#    include <astcenc.h>
+#endif
+
+#include "image_util/loadimage.h"
+
+namespace angle
+{
+
+void LoadASTCToRGBA8Inner(size_t width,
+                          size_t height,
+                          size_t depth,
+                          uint32_t blockWidth,
+                          uint32_t blockHeight,
+                          const uint8_t *input,
+                          size_t inputRowPitch,
+                          size_t inputDepthPitch,
+                          uint8_t *output,
+                          size_t outputRowPitch,
+                          size_t outputDepthPitch)
+{
+#ifdef ANGLE_HAS_ASTCENC
+    astcenc_config config;
+
+    constexpr unsigned int kBlockZ = 1;
+
+    const float kQuality               = ASTCENC_PRE_MEDIUM;
+    constexpr astcenc_profile kProfile = ASTCENC_PRF_LDR;
+
+    astcenc_error status;
+    status = astcenc_config_init(kProfile, blockWidth, blockHeight, kBlockZ, kQuality,
+                                 ASTCENC_FLG_DECOMPRESS_ONLY, &config);
+    if (status != ASTCENC_SUCCESS)
+    {
+        WARN() << "astcenc config init failed: " << astcenc_get_error_string(status);
+        return;
+    }
+
+    constexpr unsigned int kThreadCount = 1;
+
+    astcenc_context *context;
+    status = astcenc_context_alloc(&config, kThreadCount, &context);
+    if (status != ASTCENC_SUCCESS)
+    {
+        WARN() << "Could not allocate astcenc context: " << astcenc_get_error_string(status);
+        return;
+    }
+
+    // Compute the number of ASTC blocks in each dimension
+    uint32_t blockCountX = (static_cast<uint32_t>(width) + config.block_x - 1) / config.block_x;
+    uint32_t blockCountY = (static_cast<uint32_t>(height) + config.block_y - 1) / config.block_y;
+
+    // Space needed for 16 bytes of output per compressed block
+    size_t blockSize = blockCountX * blockCountY * 16;
+
+    astcenc_image image;
+    image.dim_x     = static_cast<uint32_t>(width);
+    image.dim_y     = static_cast<uint32_t>(height);
+    image.dim_z     = 1;
+    image.data_type = ASTCENC_TYPE_U8;
+    image.data      = reinterpret_cast<void **>(&output);
+
+    constexpr astcenc_swizzle swizzle{ASTCENC_SWZ_R, ASTCENC_SWZ_G, ASTCENC_SWZ_B, ASTCENC_SWZ_A};
+
+    status = astcenc_decompress_image(context, input, blockSize, &image, &swizzle, 0);
+    if (status != ASTCENC_SUCCESS)
+    {
+        WARN() << "astcenc decompress failed: " << astcenc_get_error_string(status);
+    }
+
+    astcenc_context_free(context);
+#else
+    ERR() << "Trying to decode ASTC without having ASTC support built.";
+#endif
+}
+}  // namespace angle