Add GM to test ETC1

I don't think ETC1 currently gets tested any other way.

Change-Id: I125d6cb52603c87fc91b47d02743dc4efe0409b7
Reviewed-on: https://skia-review.googlesource.com/8316
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/gm/etc1.cpp b/gm/etc1.cpp
new file mode 100644
index 0000000..8111860
--- /dev/null
+++ b/gm/etc1.cpp
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkRandom.h"
+
+#if SK_SUPPORT_GPU
+#include "etc1.h"
+
+#include "GrContext.h"
+#include "GrRenderTargetContext.h"
+#include "GrRenderTargetContextPriv.h"
+#include "GrTextureProxy.h"
+#include "effects/GrSimpleTextureEffect.h"
+#include "ops/GrRectOpFactory.h"
+
+// Basic test of Ganesh's ETC1 support
+class ETC1GM : public skiagm::GM {
+public:
+    ETC1GM() {
+        this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
+    }
+
+protected:
+    SkString onShortName() override {
+        return SkString("etc1");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kTexWidth + 2*kPad, kTexHeight + 2*kPad);
+    }
+
+    // TODO: we should be creating an ETC1 SkData blob here and going through SkImageCacherator.
+    // That will require an ETC1 Codec though - so for later.
+    void onOnceBeforeDraw() override {
+        SkBitmap bm;
+        SkImageInfo ii = SkImageInfo::Make(kTexWidth, kTexHeight, kRGB_565_SkColorType,
+                                           kOpaque_SkAlphaType);
+        bm.allocPixels(ii);
+
+        bm.erase(SK_ColorBLUE, SkIRect::MakeWH(kTexWidth, kTexHeight));
+
+        for (int y = 0; y < kTexHeight; y += 4) {
+            for (int x = 0; x < kTexWidth; x += 4) {
+                bm.erase((x+y) % 8 ? SK_ColorRED : SK_ColorGREEN, SkIRect::MakeXYWH(x, y, 4, 4));
+            }
+        }
+
+        int size = etc1_get_encoded_data_size(bm.width(), bm.height());
+        fETC1Data.reset(size);
+
+        unsigned char* pixels = (unsigned char*) fETC1Data.get();
+
+        if (etc1_encode_image((unsigned char*) bm.getAddr16(0, 0),
+                              bm.width(), bm.height(), 2, bm.rowBytes(), pixels)) {
+            fETC1Data.reset();
+        }
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        GrRenderTargetContext* renderTargetContext =
+            canvas->internal_private_accessTopLayerRenderTargetContext();
+        if (!renderTargetContext) {
+            skiagm::GM::DrawGpuOnlyMessage(canvas);
+            return;
+        }
+
+        GrContext* context = canvas->getGrContext();
+        if (!context) {
+            return;
+        }
+
+        GrSurfaceDesc desc;
+        desc.fConfig = kETC1_GrPixelConfig;
+        desc.fWidth = kTexWidth;
+        desc.fHeight = kTexHeight;
+
+        sk_sp<GrSurfaceProxy> proxy = GrTextureProxy::MakeDeferred(*context->caps(),
+                                                                   context->textureProvider(),
+                                                                   desc, SkBudgeted::kYes,
+                                                                   fETC1Data.get(), 0);
+        if (!proxy || !proxy->asTextureProxy()) {
+            return;
+        }
+
+        const SkMatrix trans = SkMatrix::MakeTrans(-kPad, -kPad);
+
+        sk_sp<GrFragmentProcessor> fp = GrSimpleTextureEffect::Make(
+                                                                context,
+                                                                sk_ref_sp(proxy->asTextureProxy()),
+                                                                nullptr, trans);
+
+        GrPaint grPaint;
+        grPaint.setXPFactory(GrPorterDuffXPFactory::Get(SkBlendMode::kSrc));
+        grPaint.addColorFragmentProcessor(std::move(fp));
+
+        SkRect rect = SkRect::MakeXYWH(kPad, kPad, kTexWidth, kTexHeight);
+
+        std::unique_ptr<GrDrawOp> op(GrRectOpFactory::MakeNonAAFill(
+                GrColor_WHITE, SkMatrix::I(), rect, nullptr, nullptr));
+        renderTargetContext->priv().testingOnly_addDrawOp(
+                std::move(grPaint), GrAAType::kNone, std::move(op));
+    }
+
+private:
+    static const int kPad = 8;
+    static const int kTexWidth = 16;
+    static const int kTexHeight = 20;
+
+    SkAutoTMalloc<char> fETC1Data;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM(return new ETC1GM;)
+
+#endif
diff --git a/gn/gm.gni b/gn/gm.gni
index b1d3c4a..09a7963 100644
--- a/gn/gm.gni
+++ b/gn/gm.gni
@@ -114,6 +114,7 @@
   "$_gm/encode.cpp",
   "$_gm/encode-platform.cpp",
   "$_gm/encode-srgb.cpp",
+  "$_gm/etc1.cpp",
   "$_gm/extractbitmap.cpp",
   "$_gm/fadefilter.cpp",
   "$_gm/fatpathfill.cpp",