make OpenCL optional for skpdiff

experimental/skpdiff/main.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
+#if SK_SUPPORT_OPENCL
 #define __NO_STD_VECTOR // Uses cl::vectpr instead of std::vectpr
 #define __NO_STD_STRING // Uses cl::STRING_CLASS instead of std::string
 #include <CL/cl.hpp>
+#endif
 
 #include "SkCommandLineFlags.h"
 #include "SkGraphics.h"
 #include "SkStream.h"
 #include "SkTDArray.h"
 
-#include "SkCLImageDiffer.h"
+#include "SkDifferentPixelsMetric.h"
 #include "SkDiffContext.h"
 #include "SkImageDiffer.h"
 #include "SkPMetric.h"
 #include "skpdiff_util.h"
 
 #include "SkForceLinking.h"
 __SK_FORCE_IMAGE_DECODER_LINKING;
 
 // Command line argument definitions go here
 DEFINE_bool2(list, l, false, "List out available differs");
 DEFINE_string2(differs, d, "", "The names of the differs to use or all of them by default");
 DEFINE_string2(folders, f, "", "Compare two folders with identical subfile names: <baseline folder> <test folder>");
 DEFINE_string2(patterns, p, "", "Use two patterns to compare images: <baseline> <test>");
 DEFINE_string2(output, o, "skpdiff_output.json", "Writes the output of these diffs to output: <output>");
 DEFINE_bool(jsonp, true, "Output JSON with padding");
 
+#if SK_SUPPORT_OPENCL
 /// A callback for any OpenCL errors
 CL_CALLBACK void error_notify(const char* errorInfo, const void* privateInfoSize, ::size_t cb, void* userData) {
     SkDebugf("OpenCL error notify: %s\n", errorInfo);
     exit(1);
 }
 
 /// Creates a device and context with OpenCL
 static bool init_device_and_context(cl::Device* device, cl::Context* context) {
     // Query for a platform
     cl::vector<cl::Platform> platformList;
@@ skipping 21 matching lines @@
     cl_int contextErr = CL_SUCCESS;
     *context = cl::Context(deviceList, NULL, error_notify, NULL, &contextErr);
     if (contextErr != CL_SUCCESS) {
         SkDebugf("Context creation failed: %s\n", cl_error_to_string(contextErr));
         return false;
     }
 
     return true;
 }
 
-
-
 static bool init_cl_diff(SkImageDiffer* differ) {
     // Setup OpenCL
     cl::Device device;
     cl::Context context;
     if (!init_device_and_context(&device, &context)) {
         return false;
     }
 
     // Setup our differ of choice
     SkCLImageDiffer* clDiffer = (SkCLImageDiffer*)differ;
     return clDiffer->init(device(), context());
 }
-
-static bool init_dummy(SkImageDiffer* differ) {
-    return true;
-}
-
+#endif
 
 // TODO Find a better home for the diff registry. One possibility is to have the differs self
 // register.
 
 // List here every differ
-SkDifferentPixelsImageDiffer gDiffPixel;
+SkDifferentPixelsMetric gDiffPixel;
 SkPMetric gPDiff;
 
 // A null terminated array of pointer to every differ declared above
 SkImageDiffer* gDiffers[] = { &gDiffPixel, &gPDiff, NULL };
 
-// A parallel array of functions to initialize the above differs. The reason we don't initialize
-// everything immediately is that certain differs may require special initialization, but we still
-// want to construct all of them globally so they can be queried for things like their name and
-// description.
-bool (*gDiffInits[])(SkImageDiffer*) = { init_cl_diff, init_dummy, NULL };
-
-
 int main(int argc, char** argv) {
     // Setup command line parsing
     SkCommandLineFlags::SetUsage("Compare images using various metrics.");
     SkCommandLineFlags::Parse(argc, argv);
 
     // Needed by various Skia components
     SkAutoGraphics ag;
 
     if (FLAGS_list) {
         SkDebugf("Available Metrics:\n");
     }
 
     // Figure which differs the user chose, and optionally print them if the user requests it
     SkTDArray<SkImageDiffer*> chosenDiffers;
     for (int differIndex = 0; NULL != gDiffers[differIndex]; differIndex++) {
         SkImageDiffer* differ = gDiffers[differIndex];
         if (FLAGS_list) {
             SkDebugf("    %s", differ->getName());
             SkDebugf("\n");
         }
 
         // Check if this differ was chosen by any of the flags. Initialize them if they were chosen.
         if (FLAGS_differs.isEmpty()) {
             // If no differs were chosen, they all get added
-            chosenDiffers.push(differ);
-            gDiffInits[differIndex](differ);
+            if (differ->requiresOpenCL()) {
+#if SK_SUPPORT_OPENCL
+                init_cl_diff(differ);
+                chosenDiffers.push(differ);
+#endif
+            } else {
+                chosenDiffers.push(differ);
+            }
         } else {
             for (int flagIndex = 0; flagIndex < FLAGS_differs.count(); flagIndex++) {
                 if (SkString(FLAGS_differs[flagIndex]).equals(differ->getName())) {
-                    chosenDiffers.push(differ);
-                    gDiffInits[differIndex](differ);
+                    // Initialize OpenCL for the differ if it needs it and support was compiled in.
+                    if (differ->requiresOpenCL()) {
+#if SK_SUPPORT_OPENCL
+                        init_cl_diff(differ);
+                        chosenDiffers.push(differ);
+#endif
+                    } else {
+                        chosenDiffers.push(differ);
+                    }
                     break;
                 }
             }
         }
     }
 
     // Don't attempt to initialize the differ if we aren't going to use it
     if (FLAGS_folders.isEmpty() && FLAGS_patterns.isEmpty()) {
         return 0;
     }
@@ skipping 27 matching lines @@
     }
 
     // Output to the file specified
     if (!FLAGS_output.isEmpty()) {
         SkFILEWStream outputStream(FLAGS_output[0]);
         ctx.outputRecords(outputStream, FLAGS_jsonp);
     }
 
     return 0;
 }