1 files changed, 68 insertions, 0 deletions
diff --git a/test-app/src/main/java/com/google/android/renderscript_test/ReferenceConvolve.kt b/test-app/src/main/java/com/google/android/renderscript_test/ReferenceConvolve.kt
new file mode 100644
index 0000000..4c87099
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+++ b/test-app/src/main/java/com/google/android/renderscript_test/ReferenceConvolve.kt
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.renderscript_test
+
+import com.google.android.renderscript.Range2d
+
+/**
+ * Reference implementation of a Convolve operation.
+ */
+@ExperimentalUnsignedTypes
+fun referenceConvolve(
+    inputArray: ByteArray,
+    vectorSize: Int,
+    sizeX: Int,
+    sizeY: Int,
+    coefficients: FloatArray,
+    restriction: Range2d?
+): ByteArray {
+    val input = Vector2dArray(inputArray.asUByteArray(), vectorSize, sizeX, sizeY)
+    val radius = when (coefficients.size) {
+        9 -> 1
+        25 -> 2
+        else -> {
+            throw IllegalArgumentException("RenderScriptToolkit Convolve. Only 3x3 and 5x5 convolutions are supported. ${coefficients.size} coefficients provided.")
+        }
+    }
+
+    input.clipReadToRange = true
+    val output = input.createSameSized()
+    input.forEach(restriction) { x, y ->
+        output[x, y] = convolveOne(input, x, y, coefficients, radius)
+    }
+    return output.values.asByteArray()
+}
+
+@ExperimentalUnsignedTypes
+private fun convolveOne(
+    inputAlloc: Vector2dArray,
+    x: Int,
+    y: Int,
+    coefficients: FloatArray,
+    radius: Int
+): UByteArray {
+    var sum = FloatArray(paddedSize(inputAlloc.vectorSize))
+    var coefficientIndex = 0
+    for (deltaY in -radius..radius) {
+        for (deltaX in -radius..radius) {
+            val inputVector = inputAlloc[x + deltaX, y + deltaY]
+            sum += inputVector.toFloatArray() * coefficients[coefficientIndex]
+            coefficientIndex++
+        }
+    }
+    return sum.clampToUByte()
+}