Initial version of R8 support

http://codereview.appspot.com/5967067/



git-svn-id: http://skia.googlecode.com/svn/trunk@3622 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/ReadWriteAlphaTest.cpp b/tests/ReadWriteAlphaTest.cpp
new file mode 100644
index 0000000..2d6da96
--- /dev/null
+++ b/tests/ReadWriteAlphaTest.cpp
@@ -0,0 +1,103 @@
+
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+#include "SkGpuDevice.h"
+
+static const int X_SIZE = 12;
+static const int Y_SIZE = 12;
+
+void ReadWriteAlphaTest(skiatest::Reporter* reporter, GrContext* context) {
+
+    unsigned char textureData[X_SIZE][Y_SIZE];
+
+    memset(textureData, 0, X_SIZE * Y_SIZE);
+
+    GrTextureDesc desc;
+
+    // let Skia know we will be using this texture as a render target
+    desc.fFlags     = kRenderTarget_GrTextureFlagBit;
+    // it is a single channel texture
+    desc.fConfig    = kAlpha_8_GrPixelConfig;
+    desc.fWidth     = X_SIZE;
+    desc.fHeight    = Y_SIZE;
+    desc.fSampleCnt = 0;
+
+    // We are initializing the texture with zeros here
+    GrTexture* texture = context->createUncachedTexture(desc, textureData, 0);
+    if (!texture) {
+        return;
+    }
+
+    GrAutoUnref au(texture);
+
+    // create a distinctive texture
+    for (int y = 0; y < Y_SIZE; ++y) {
+        for (int x = 0; x < X_SIZE; ++x) {
+            textureData[x][y] = x*Y_SIZE+y;
+        }
+    }
+
+    // upload the texture
+    texture->writePixels(0, 0, desc.fWidth, desc.fHeight, desc.fConfig,
+                         textureData, 0);
+
+    unsigned char readback[X_SIZE][Y_SIZE];
+
+    // clear readback to something non-zero so we can detect readback failures
+    memset(readback, 0x1, X_SIZE * Y_SIZE);
+
+    // read the texture back
+    texture->readPixels(0, 0, desc.fWidth, desc.fHeight, desc.fConfig, 
+                        readback, 0);
+
+    // make sure the original & read back versions match
+    bool match = true;
+
+    for (int y = 0; y < Y_SIZE; ++y) {
+        for (int x = 0; x < X_SIZE; ++x) {
+            if (textureData[x][y] != readback[x][y]) {
+                match = false;
+            }
+        }
+    }
+
+    REPORTER_ASSERT(reporter, match);
+
+    // Now try writing on the single channel texture
+    SkCanvas canvas;
+
+    canvas.setDevice(new SkGpuDevice(context, texture->asRenderTarget()))->unref();
+
+    SkPaint paint;
+
+    const SkRect rect = SkRect::MakeLTRB(-10, -10, X_SIZE + 10, Y_SIZE + 10);
+
+    paint.setColor(SK_ColorWHITE);
+
+    canvas.drawRect(rect, paint);
+
+    texture->readPixels(0, 0, desc.fWidth, desc.fHeight, desc.fConfig, 
+                        readback, 0);
+
+    match = true;
+    
+    for (int y = 0; y < Y_SIZE; ++y) {
+        for (int x = 0; x < X_SIZE; ++x) {
+            if (0xFF != readback[x][y]) {
+                match = false;
+            }
+        }
+    }
+
+    REPORTER_ASSERT(reporter, match);
+}
+
+#include "TestClassDef.h"
+DEFINE_GPUTESTCLASS("ReadWriteAlpha", ReadWriteAlphaTestClass, ReadWriteAlphaTest)
+