add skpdiff tool to compare bitmaps

experimental/skpdiff/SkCLImageDiffer.cpp

Index: experimental/skpdiff/SkCLImageDiffer.cpp
diff --git a/experimental/skpdiff/SkCLImageDiffer.cpp b/experimental/skpdiff/SkCLImageDiffer.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..4bbb18ce83ee009d41696431207c64b6bb7c876f
--- /dev/null
+++ b/experimental/skpdiff/SkCLImageDiffer.cpp
@@ -0,0 +1,210 @@
+
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <cstring>
+
+#include "SkBitmap.h"
+#include "SkStream.h"
+
+#include "SkCLImageDiffer.h"
+#include "skpdiff_util.h"
+
+SkCLImageDiffer::SkCLImageDiffer() {
+    fIsGood = false;
+}
+
+
+bool SkCLImageDiffer::init(cl_device_id device, cl_context context) {
+    fContext = context;
+    fDevice = device;
+
+    cl_int queueErr;
+    fCommandQueue = clCreateCommandQueue(fContext, fDevice, 0, &queueErr);
+    if (CL_SUCCESS != queueErr) {
+        SkDebugf("Command queue creation failed: %s\n", cl_error_to_string(queueErr));
+        fIsGood = false;
+        return false;
+    }
+
+    fIsGood = this->onInit();
+    return fIsGood;
+}
+
+bool SkCLImageDiffer::loadKernelFile(const char file[], const char name[], cl_kernel* kernel) {
+    // Open the kernel source file
+    SkFILEStream sourceStream(file);
+    if (!sourceStream.isValid()) {
+        SkDebugf("Failed to open kernel source file");
+        return false;
+    }
+
+    return loadKernelStream(&sourceStream, name, kernel);
+}
+
+bool SkCLImageDiffer::loadKernelStream(SkStream* stream, const char name[], cl_kernel* kernel) {
+    // Read the kernel source into memory
+    SkString sourceString;
+    sourceString.resize(stream->getLength());
+    size_t bytesRead = stream->read(sourceString.writable_str(), sourceString.size());
+    if (bytesRead != sourceString.size()) {
+        SkDebugf("Failed to read kernel source file");
+        return false;
+    }
+
+    return loadKernelSource(sourceString.c_str(), name, kernel);
+}
+
+bool SkCLImageDiffer::loadKernelSource(const char source[], const char name[], cl_kernel* kernel) {
+    // Build the kernel source
+    size_t sourceLen = strlen(source);
+    cl_program program = clCreateProgramWithSource(fContext, 1, &source, &sourceLen, NULL);
+    cl_int programErr = clBuildProgram(program, 1, &fDevice, "", NULL, NULL);
+    if (CL_SUCCESS != programErr) {
+        SkDebugf("Program creation failed: %s\n", cl_error_to_string(programErr));
+
+        // Attempt to get information about why the build failed
+        char buildLog[4096];
+        clGetProgramBuildInfo(program, fDevice, CL_PROGRAM_BUILD_LOG, sizeof(buildLog), buildLog, NULL);
+        SkDebugf("Build log: %s\n", buildLog);
+
+        return false;
+    }
+
+    cl_int kernelErr;
+    *kernel = clCreateKernel(program, name, &kernelErr);
+    if (CL_SUCCESS != kernelErr) {
+        SkDebugf("Kernel creation failed: %s\n", cl_error_to_string(kernelErr));
+        return false;
+    }
+
+    return true;
+}
+
+bool SkCLImageDiffer::makeImage2D(SkBitmap* bitmap, cl_mem* image) {
+    cl_int imageErr;
+    cl_image_format bitmapFormat;
+    switch (bitmap->config()) {
+        case SkBitmap::kA8_Config:
+            bitmapFormat.image_channel_order = CL_A;
+            bitmapFormat.image_channel_data_type = CL_UNSIGNED_INT8;
+            break;
+        case SkBitmap::kRGB_565_Config:
+            bitmapFormat.image_channel_order = CL_RGB;
+            bitmapFormat.image_channel_data_type = CL_UNORM_SHORT_565;
+            break;
+        case SkBitmap::kARGB_8888_Config:
+            bitmapFormat.image_channel_order = CL_RGBA;
+            bitmapFormat.image_channel_data_type = CL_UNSIGNED_INT8;
+            break;
+        default:
+            SkDebugf("Image format is unsupported\n");
+            return false;
+    }
+
+    // Upload the bitmap data to OpenCL
+    bitmap->lockPixels();
+    *image = clCreateImage2D(fContext, CL_MEM_READ_ONLY | CL_MEM_COPY_HOST_PTR,
+                             &bitmapFormat, bitmap->width(), bitmap->height(),
+                             bitmap->rowBytes(), bitmap->getPixels(),
+                             &imageErr);
+    bitmap->unlockPixels();
+
+    if (CL_SUCCESS != imageErr) {
+        SkDebugf("Input image creation failed: %s\n", cl_error_to_string(imageErr));
+        return false;
+    }
+
+    return true;
+}
+
+
+////////////////////////////////////////////////////////////////
+
+const char* SkDifferentPixelsImageDiffer::getName() {
+    return "Find Different Pixels";
+}
+
+int SkDifferentPixelsImageDiffer::queueDiff(SkBitmap * baseline, SkBitmap * test) {
+    int diffID = fQueuedDiffs.count();
+    double startTime = get_seconds();
+    QueuedDiff* diff = fQueuedDiffs.push();
+
+    // Ensure the images are comparable
+    if (baseline->width() != test->width() || baseline->height() != test->height() ||
+                    baseline->width() <= 0 || baseline->height() <= 0) {
+        diff->finished = true;
+        diff->result = 0.0;
+        return diffID;
+    }
+
+    // Upload images to the CL device
+    if (!this->makeImage2D(baseline, &diff->baseline) || !this->makeImage2D(test, &diff->test)) {
+        diff->finished = true;
+        diff->result = 0.0;
+        fIsGood = false;
+        return -1;
+    }
+
+    // A small hack that makes calculating percentage difference easier later on.
+    diff->result = 1.0 / ((double)baseline->width() * baseline->height());
+
+    // Make a buffer to store results into
+    int numDiffPixels = 0;
+    diff->resultsBuffer = clCreateBuffer(fContext, CL_MEM_READ_WRITE | CL_MEM_COPY_HOST_PTR,
+                                         sizeof(int), &numDiffPixels, NULL);
+
+    // Set all kernel arguments
+    cl_int setArgErr = clSetKernelArg(fKernel, 0, sizeof(cl_mem), &diff->baseline);
+    setArgErr       |= clSetKernelArg(fKernel, 1, sizeof(cl_mem), &diff->test);
+    setArgErr       |= clSetKernelArg(fKernel, 2, sizeof(cl_mem), &diff->resultsBuffer);
+    if (CL_SUCCESS != setArgErr) {
+        SkDebugf("Set arg failed: %s\n", cl_error_to_string(setArgErr));
+        fIsGood = false;
+        return -1;
+    }
+
+    // Queue this diff on the CL device
+    cl_event event;
+    const size_t workSize[] = { baseline->width(), baseline->height() };
+    cl_int enqueueErr;
+    enqueueErr = clEnqueueNDRangeKernel(fCommandQueue, fKernel, 2, NULL, workSize, NULL, 0, NULL, &event);
+    if (CL_SUCCESS != enqueueErr) {
+        SkDebugf("Enqueue failed: %s\n", cl_error_to_string(enqueueErr));
+        fIsGood = false;
+        return -1;
+    }
+
+    // This makes things totally synchronous. Actual queue is not ready yet
+    clWaitForEvents(1, &event);
+    diff->finished = true;
+
+    // Immediate read back the results
+    clEnqueueReadBuffer(fCommandQueue, diff->resultsBuffer, CL_TRUE, 0, sizeof(int), &numDiffPixels, 0, NULL, NULL);
+    diff->result *= (double)numDiffPixels;
+    diff->result = (1.0 - diff->result);
+    SkDebugf("Time: %f\n", (get_seconds() - startTime));
+
+    return diffID;
+}
+
+bool SkDifferentPixelsImageDiffer::isFinished(int id) {
+    return fQueuedDiffs[id].finished;
+}
+
+double SkDifferentPixelsImageDiffer::getResult(int id) {
+    return fQueuedDiffs[id].result;
+}
+
+
+bool SkDifferentPixelsImageDiffer::onInit() {
+    if (!loadKernelFile("experimental/skpdiff/diff_pixels.cl", "diff", &fKernel)) {
+        return false;
+    }
+
+    return true;
+}