rework screenshot API and implementation

- SurfaceFlinger now supports to take a screenshot
  directly into an IGraphicBufferProducer

- reimplement the IMemoryHeap screenshot on top
  of the above

- reimplement LayerScreenshot such that its
  BufferQueue is directly used as the destination
  of the screenshot. LayerScreenshot is now a thin
  wrapper around Layer

Bug: 6940974

Change-Id: I69a2096b44b91acbb99eba16f83a9c78d94e0d10
diff --git a/services/surfaceflinger/LayerScreenshot.cpp b/services/surfaceflinger/LayerScreenshot.cpp
index f8009b3..3470d67 100644
--- a/services/surfaceflinger/LayerScreenshot.cpp
+++ b/services/surfaceflinger/LayerScreenshot.cpp
@@ -18,152 +18,28 @@
 #include <stdint.h>
 #include <sys/types.h>
 
-#include <GLES/gl.h>
-#include <GLES/glext.h>
-
-#include <utils/Errors.h>
-#include <utils/Log.h>
-
-#include <ui/GraphicBuffer.h>
-
 #include "LayerScreenshot.h"
 #include "SurfaceFlinger.h"
 #include "DisplayDevice.h"
 
-
 namespace android {
 // ---------------------------------------------------------------------------
 
 LayerScreenshot::LayerScreenshot(SurfaceFlinger* flinger,
         const sp<Client>& client)
-    : LayerBaseClient(flinger, client),
-      mTextureName(0), mFlinger(flinger), mIsSecure(false)
+    : Layer(flinger, client)
 {
 }
 
-LayerScreenshot::~LayerScreenshot()
+void LayerScreenshot::onFirstRef()
 {
-    if (mTextureName) {
-        mFlinger->deleteTextureAsync(mTextureName);
-    }
-}
+    Layer::onFirstRef();
 
-status_t LayerScreenshot::captureLocked(int32_t layerStack) {
-    GLfloat u, v;
-    status_t result = mFlinger->renderScreenToTextureLocked(layerStack,
-            &mTextureName, &u, &v);
-    if (result != NO_ERROR) {
-        return result;
-    }
-    initTexture(u, v);
-
-    // Currently screenshot always comes from the default display
-    mIsSecure = mFlinger->getDefaultDisplayDevice()->getSecureLayerVisible();
-
-    return NO_ERROR;
-}
-
-status_t LayerScreenshot::capture() {
-    GLfloat u, v;
-    status_t result = mFlinger->renderScreenToTexture(0, &mTextureName, &u, &v);
-    if (result != NO_ERROR) {
-        return result;
-    }
-    initTexture(u, v);
-
-    // Currently screenshot always comes from the default display
-    mIsSecure = mFlinger->getDefaultDisplayDevice()->getSecureLayerVisible();
-    
-    return NO_ERROR;
-}
-
-void LayerScreenshot::initTexture(GLfloat u, GLfloat v) {
-    glBindTexture(GL_TEXTURE_2D, mTextureName);
-    glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-    glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-    mTexCoords[0] = 0;         mTexCoords[1] = v;
-    mTexCoords[2] = 0;         mTexCoords[3] = 0;
-    mTexCoords[4] = u;         mTexCoords[5] = 0;
-    mTexCoords[6] = u;         mTexCoords[7] = v;
-}
-
-void LayerScreenshot::initStates(uint32_t w, uint32_t h, uint32_t flags) {
-    LayerBaseClient::initStates(w, h, flags);
-    if (!(flags & ISurfaceComposerClient::eHidden)) {
-        capture();
-    }
-    if (flags & ISurfaceComposerClient::eSecure) {
-        ALOGW("ignoring surface flag eSecure - LayerScreenshot is considered "
-                "secure iff it captures the contents of a secure surface.");
-    }
-}
-
-uint32_t LayerScreenshot::doTransaction(uint32_t flags)
-{
-    const LayerBase::State& draw(drawingState());
-    const LayerBase::State& curr(currentState());
-
-    if (draw.flags & layer_state_t::eLayerHidden) {
-        if (!(curr.flags & layer_state_t::eLayerHidden)) {
-            // we're going from hidden to visible
-            status_t err = captureLocked(curr.layerStack);
-            if (err != NO_ERROR) {
-                ALOGW("createScreenshotSurface failed (%s)", strerror(-err));
-            }
-        }
-    } else if (curr.flags & layer_state_t::eLayerHidden) {
-        // we're going from visible to hidden
-        if (mTextureName) {
-            glDeleteTextures(1, &mTextureName);
-            mTextureName = 0;
-        }
-    }
-    return LayerBaseClient::doTransaction(flags);
-}
-
-void LayerScreenshot::onDraw(const sp<const DisplayDevice>& hw, const Region& clip) const
-{
-    const State& s(drawingState());
-    if (s.alpha>0) {
-        const GLfloat alpha = s.alpha/255.0f;
-        const uint32_t fbHeight = hw->getHeight();
-
-        if (s.alpha == 0xFF) {
-            glDisable(GL_BLEND);
-            glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
-        } else {
-            glEnable(GL_BLEND);
-            glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
-            glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
-        }
-
-        GLuint texName = mTextureName;
-        if (isSecure() && !hw->isSecure()) {
-            texName = mFlinger->getProtectedTexName();
-        }
-
-        LayerMesh mesh;
-        computeGeometry(hw, &mesh);
-
-        glColor4f(alpha, alpha, alpha, alpha);
-
-        glDisable(GL_TEXTURE_EXTERNAL_OES);
-        glEnable(GL_TEXTURE_2D);
-
-        glBindTexture(GL_TEXTURE_2D, texName);
-        glMatrixMode(GL_TEXTURE);
-        glLoadIdentity();
-        glMatrixMode(GL_MODELVIEW);
-
-        glEnableClientState(GL_TEXTURE_COORD_ARRAY);
-        glTexCoordPointer(2, GL_FLOAT, 0, mTexCoords);
-        glVertexPointer(2, GL_FLOAT, 0, mesh.getVertices());
-        glDrawArrays(GL_TRIANGLE_FAN, 0, mesh.getVertexCount());
-
-        glDisable(GL_BLEND);
-        glDisable(GL_TEXTURE_2D);
-        glDisableClientState(GL_TEXTURE_COORD_ARRAY);
-    }
+    // FIXME: we currently hardcode the default display
+    // it's unclear what should we do instead.
+    sp<const DisplayDevice> hw(mFlinger->getDefaultDisplayDevice());
+    mFlinger->captureScreenImplLocked(hw, getConsumer()->getBufferQueue(),
+            0, 0, 0, 0x7FFFFFFF);
 }
 
 // ---------------------------------------------------------------------------