Move scissor state to RenderState

Change-Id: I1227a3886fb24e4d9fad79fca469794f06cfb15e
diff --git a/libs/hwui/renderstate/Scissor.cpp b/libs/hwui/renderstate/Scissor.cpp
new file mode 100644
index 0000000..ede57be
--- /dev/null
+++ b/libs/hwui/renderstate/Scissor.cpp
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+#include "Scissor.h"
+
+namespace android {
+namespace uirenderer {
+
+Scissor::Scissor()
+    : mEnabled(false)
+    , mScissorX(0)
+    , mScissorY(0)
+    , mScissorWidth(0)
+    , mScissorHeight(0) {
+}
+
+bool Scissor::setEnabled(bool enabled) {
+    if (mEnabled != enabled) {
+        if (enabled) {
+            glEnable(GL_SCISSOR_TEST);
+        } else {
+            glDisable(GL_SCISSOR_TEST);
+        }
+        mEnabled = enabled;
+        return true;
+    }
+    return false;
+}
+
+bool Scissor::set(GLint x, GLint y, GLint width, GLint height) {
+    if (mEnabled && (x != mScissorX || y != mScissorY
+            || width != mScissorWidth || height != mScissorHeight)) {
+
+        if (x < 0) {
+            width += x;
+            x = 0;
+        }
+        if (y < 0) {
+            height += y;
+            y = 0;
+        }
+        if (width < 0) {
+            width = 0;
+        }
+        if (height < 0) {
+            height = 0;
+        }
+        glScissor(x, y, width, height);
+
+        mScissorX = x;
+        mScissorY = y;
+        mScissorWidth = width;
+        mScissorHeight = height;
+
+        return true;
+    }
+    return false;
+}
+
+void Scissor::reset() {
+    mScissorX = mScissorY = mScissorWidth = mScissorHeight = 0;
+}
+
+void Scissor::invalidate() {
+    mEnabled = glIsEnabled(GL_SCISSOR_TEST);
+    setEnabled(true);
+    reset();
+}
+
+} /* namespace uirenderer */
+} /* namespace android */
+