am e5315c67: Merge "fix an issue were hwc wouldn\'t clear some areas of the screen." into ics-mr1

* commit 'e5315c678872c64f0f3064d54ea2f006540917ed':
  fix an issue were hwc wouldn't clear some areas of the screen.

3 files changed, 27 insertions, 1 deletions

diff --git a/libhwcomposer/Android.mk b/libhwcomposer/Android.mk
index eb57887..f484dfd 100644
--- a/libhwcomposer/Android.mk
+++ b/libhwcomposer/Android.mk
@@ -21,7 +21,7 @@ LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 LOCAL_PRELINK_MODULE := false
 LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw
-LOCAL_SHARED_LIBRARIES := liblog libcutils libEGL libhardware
+LOCAL_SHARED_LIBRARIES := liblog libcutils libEGL libGLESv1_CM libhardware
 LOCAL_CFLAGS += -DLOG_TAG=\"hwcomposer\"
 
 LOCAL_C_INCLUDES := \
diff --git a/libhwcomposer/SecHWC.cpp b/libhwcomposer/SecHWC.cpp
index 6488a48..63173a4 100644
--- a/libhwcomposer/SecHWC.cpp
+++ b/libhwcomposer/SecHWC.cpp
@@ -26,6 +26,7 @@
 #include <cutils/log.h>
 #include <cutils/atomic.h>
 #include <EGL/egl.h>
+#include <GLES/gl.h>
 #include "SecHWCUtils.h"
 
 static IMG_gralloc_module_public_t *gpsGrallocModule;
@@ -291,6 +292,30 @@ static int hwc_set(hwc_composer_device_t *dev,
     struct sec_rect src_rect;
     struct sec_rect dst_rect;
 
+
+    /*
+     * H/W composer documentation states:
+     * There is an implicit layer containing opaque black
+     * pixels behind all the layers in the list.
+     * It is the responsibility of the hwcomposer module to make
+     * sure black pixels are output (or blended from).
+     *
+     * Since we're using a blitter, we need to erase the frame-buffer when
+     * switching to all-overlay mode.
+     *
+     */
+    if (ctx->num_of_hwc_layer &&
+        ctx->num_of_fb_layer==0 && ctx->num_of_fb_layer_prev) {
+        /* we're clearing the screen using GLES here, this is very
+         * hack-ish, ideal we would use the fimc (if it can do it) */
+        glDisable(GL_SCISSOR_TEST);
+        glClearColor(0, 0, 0, 0);
+        glClear(GL_COLOR_BUFFER_BIT);
+        glEnable(GL_SCISSOR_TEST);
+    }
+
+    ctx->num_of_fb_layer_prev = ctx->num_of_fb_layer;
+
     EGLBoolean sucess = eglSwapBuffers((EGLDisplay)dpy, (EGLSurface)sur);
     if (!sucess) {
         return HWC_EGL_ERROR;
diff --git a/libhwcomposer/SecHWCUtils.h b/libhwcomposer/SecHWCUtils.h
index 7715cb4..880e073 100644
--- a/libhwcomposer/SecHWCUtils.h
+++ b/libhwcomposer/SecHWCUtils.h
@@ -117,6 +117,7 @@ struct hwc_context_t {
     s5p_fimc_t                fimc;
     unsigned int              num_of_fb_layer;
     unsigned int              num_of_hwc_layer;
+    unsigned int              num_of_fb_layer_prev;
 };
 
 int window_open(struct hwc_win_info_t *win, int id);