Add new Query class for debugging

This class can be used to perform occlusion queries. An occlusion query
can be used to test whether an object is entirely hidden or not.

Change-Id: Ida456df81dbe008a64d3ff4cb7879340785c6abf

5 files changed, 159 insertions, 3 deletions

diff --git a/libs/hwui/Caches.cpp b/libs/hwui/Caches.cpp
index 74aeddb..31b0f6a 100644
--- a/libs/hwui/Caches.cpp
+++ b/libs/hwui/Caches.cpp
@@ -145,7 +145,7 @@ void Caches::initStaticProperties() {
     gpuPixelBuffersEnabled = false;
 
     // OpenGL ES 3.0+ specific features
-    if (mExtensions.getMajorGlVersion() >= 3) {
+    if (mExtensions.hasPixelBufferObjects()) {
         char property[PROPERTY_VALUE_MAX];
         if (property_get(PROPERTY_ENABLE_GPU_PIXEL_BUFFERS, property, "true") > 0) {
             gpuPixelBuffersEnabled = !strcmp(property, "true");
diff --git a/libs/hwui/Dither.cpp b/libs/hwui/Dither.cpp
index 649a7bc..77006a4 100644
--- a/libs/hwui/Dither.cpp
+++ b/libs/hwui/Dither.cpp
@@ -29,7 +29,7 @@ Dither::Dither(): mCaches(NULL), mInitialized(false), mDitherTexture(0) {
 
 void Dither::bindDitherTexture() {
     if (!mInitialized) {
-        bool useFloatTexture = Extensions::getInstance().getMajorGlVersion() >= 3;
+        bool useFloatTexture = Extensions::getInstance().hasFloatTextures();
 
         glGenTextures(1, &mDitherTexture);
         mCaches->bindTexture(mDitherTexture);
diff --git a/libs/hwui/Extensions.h b/libs/hwui/Extensions.h
index 3112244..5e574a6 100644
--- a/libs/hwui/Extensions.h
+++ b/libs/hwui/Extensions.h
@@ -42,6 +42,10 @@ public:
     inline bool has4BitStencil() const { return mHas4BitStencil; }
     inline bool hasNvSystemTime() const { return mHasNvSystemTime; }
 
+    inline bool hasPixelBufferObjects() const { return mVersionMajor >= 3; }
+    inline bool hasOcclusionQueries() const { return mVersionMajor >= 3; }
+    inline bool hasFloatTextures() const { return mVersionMajor >= 3; }
+
     inline int getMajorGlVersion() const { return mVersionMajor; }
     inline int getMinorGlVersion() const { return mVersionMinor; }
 
diff --git a/libs/hwui/GradientCache.cpp b/libs/hwui/GradientCache.cpp
index 1815bff..0916942 100644
--- a/libs/hwui/GradientCache.cpp
+++ b/libs/hwui/GradientCache.cpp
@@ -78,7 +78,7 @@ GradientCache::GradientCache():
     mCache.setOnEntryRemovedListener(this);
 
     const Extensions& extensions = Extensions::getInstance();
-    mUseFloatTexture = extensions.getMajorGlVersion() >= 3;
+    mUseFloatTexture = extensions.hasFloatTextures();
     mHasNpot = extensions.hasNPot();
 }
 
diff --git a/libs/hwui/Query.h b/libs/hwui/Query.h
new file mode 100644
index 0000000..e25b16b
--- /dev/null
+++ b/libs/hwui/Query.h
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef ANDROID_HWUI_QUERY_H
+#define ANDROID_HWUI_QUERY_H
+
+#include <GLES3/gl3.h>
+
+#include "Extensions.h"
+
+namespace android {
+namespace uirenderer {
+
+/**
+ * A Query instance can be used to perform occlusion queries. If the device
+ * does not support occlusion queries, the result of a query will always be
+ * 0 and the result will always be marked available.
+ *
+ * To run an occlusion query successfully, you must start end end the query:
+ *
+ * Query query;
+ * query.begin();
+ * // execute OpenGL calls
+ * query.end();
+ * GLuint result = query.getResult();
+ */
+class Query {
+public:
+    /**
+     * Possible query targets.
+     */
+    enum Target {
+        /**
+         * Indicates if any sample passed the depth & stencil tests.
+         */
+        kTargetSamples = GL_ANY_SAMPLES_PASSED,
+        /**
+         * Indicates if any sample passed the depth & stencil tests.
+         * The implementation may choose to use a less precise version
+         * of the test, potentially resulting in false positives.
+         */
+        kTargetConservativeSamples = GL_ANY_SAMPLES_PASSED_CONSERVATIVE,
+    };
+
+    /**
+     * Creates a new query with the specified target. The default
+     * target is kTargetSamples (of GL_ANY_SAMPLES_PASSED in OpenGL.)
+     */
+    Query(Target target = kTargetSamples): mActive(false), mTarget(target),
+            mCanQuery(Extensions::getInstance().hasOcclusionQueries()),
+            mQuery(0) {
+    }
+
+    ~Query() {
+        if (mQuery) {
+            glDeleteQueries(1, &mQuery);
+        }
+    }
+
+    /**
+     * Begins the query. If the query has already begun or if the device
+     * does not support occlusion queries, calling this method as no effect.
+     * After calling this method successfully, the query is marked active.
+     */
+    void begin() {
+        if (!mActive && mCanQuery) {
+            if (!mQuery) {
+                glGenQueries(1, &mQuery);
+            }
+
+            glBeginQuery(mTarget, mQuery);
+            mActive = true;
+        }
+    }
+
+    /**
+     * Ends the query. If the query has already begun or if the device
+     * does not support occlusion queries, calling this method as no effect.
+     * After calling this method successfully, the query is marked inactive.
+     */
+    void end() {
+        if (mQuery && mActive) {
+            glEndQuery(mTarget);
+            mActive = false;
+        }
+    }
+
+    /**
+     * Returns true if the query is active, false otherwise.
+     */
+    bool isActive() {
+        return mActive;
+    }
+
+    /**
+     * Returns true if the result of the query is available,
+     * false otherwise. Calling getResult() before the result
+     * is available may result in the calling thread being blocked.
+     * If the device does not support queries, this method always
+     * returns true.
+     */
+    bool isResultAvailable() {
+        if (!mQuery) return true;
+
+        GLuint result;
+        glGetQueryObjectuiv(mQuery, GL_QUERY_RESULT_AVAILABLE, &result);
+        return result == GL_TRUE;
+    }
+
+    /**
+     * Returns the result of the query. If the device does not
+     * support queries this method will return 0.
+     *
+     * Calling this method implicitely calls end() if the query
+     * is currently active.
+     */
+    GLuint getResult() {
+        if (!mQuery) return 0;
+
+        end();
+
+        GLuint result;
+        glGetQueryObjectuiv(mQuery, GL_QUERY_RESULT, &result);
+        return result;
+    }
+
+
+private:
+    bool mActive;
+    GLenum mTarget;
+    bool mCanQuery;
+    GLuint mQuery;
+
+}; // class Query
+
+}; // namespace uirenderer
+}; // namespace android
+
+#endif // ANDROID_HWUI_QUERY_H