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Commit d99c088f authored by Jamie Gennis's avatar Jamie Gennis
Browse files

SurfaceTexture: fix transform matrix computation. 

This change fixes the transform matrix computation in SurfaceTexture
when a crop rectangle is specified by the image producer.  It also adds
a test for this case as well as a basic test for the uncropped case.

Bug: 4070775
Change-Id: I1481c9ce9d08fe7f2bff86d3afdeab7d4002b157
parent 181f1c33

libs/gui/SurfaceTexture.cpp

+37 −6
Original line number Diff line number Diff line
@@ -283,11 +283,42 @@ void SurfaceTexture::getTransformMatrix(float mtx[16]) { 
    sp<GraphicBuffer>& buf(mSlots[mCurrentTexture].mGraphicBuffer);

    float tx, ty, sx, sy;

    if (!mCurrentCrop.isEmpty()) {

        tx = float(mCurrentCrop.left) / float(buf->getWidth());

        ty = float(buf->getHeight() - mCurrentCrop.bottom) /

        // In order to prevent bilinear sampling at the of the crop rectangle we

        // may need to shrink it by 2 texels in each direction.  Normally this

        // would just need to take 1/2 a texel off each end, but because the

        // chroma channels will likely be subsampled we need to chop off a whole

        // texel.  This will cause artifacts if someone does nearest sampling

        // with 1:1 pixel:texel ratio, but it's impossible to simultaneously

        // accomodate the bilinear and nearest sampling uses.

        //

        // If nearest sampling turns out to be a desirable usage of these

        // textures then we could add the ability to switch a SurfaceTexture to

        // nearest-mode.  Preferably, however, the image producers (video

        // decoder, camera, etc.) would simply not use a crop rectangle (or at

        // least not tell the framework about it) so that the GPU can do the

        // correct edge behavior.

        int xshrink = 0, yshrink = 0;

        if (mCurrentCrop.left > 0) {

            tx = float(mCurrentCrop.left + 1) / float(buf->getWidth());

            xshrink++;

        } else {

            tx = 0.0f;

        }

        if (mCurrentCrop.right < buf->getWidth()) {

            xshrink++;

        }

        if (mCurrentCrop.bottom < buf->getHeight()) {

            ty = (float(buf->getHeight() - mCurrentCrop.bottom) + 1.0f) /

                    float(buf->getHeight());

        sx = float(mCurrentCrop.width()) / float(buf->getWidth());

        sy = float(mCurrentCrop.height()) / float(buf->getHeight());

            yshrink++;

        } else {

            ty = 0.0f;

        }

        if (mCurrentCrop.top > 0) {

            yshrink++;

        }

        sx = float(mCurrentCrop.width() - xshrink) / float(buf->getWidth());

        sy = float(mCurrentCrop.height() - yshrink) / float(buf->getHeight());

    } else {

        tx = 0.0f;

        ty = 0.0f;
@@ -298,7 +329,7 @@ void SurfaceTexture::getTransformMatrix(float mtx[16]) { 
        sx, 0, 0, 0,

        0, sy, 0, 0,

        0, 0, 1, 0,

        sx*tx, sy*ty, 0, 1,

        tx, ty, 0, 1,

    };



    float mtxBeforeFlipV[16];

libs/gui/tests/Android.mk

+17 −19
Original line number Diff line number Diff line
@@ -4,39 +4,37 @@ include $(CLEAR_VARS) 


ifneq ($(TARGET_SIMULATOR),true)



# Build the unit tests.

test_src_files := \

LOCAL_MODULE := SurfaceTexture_test



LOCAL_MODULE_TAGS := tests



LOCAL_SRC_FILES := \

    SurfaceTextureClient_test.cpp \

    SurfaceTexture_test.cpp \



shared_libraries := \

	libcutils \

	libutils \

LOCAL_SHARED_LIBRARIES := \

	libEGL \

	libGLESv2 \

	libandroid \

	libbinder \

	libcutils \

	libgui \

	libstlport \

	libsurfaceflinger_client \

	libui \

	libutils \



static_libraries := \

LOCAL_STATIC_LIBRARIES := \

	libgtest \

	libgtest_main \



c_includes := \

LOCAL_C_INCLUDES := \

    bionic \

    bionic/libstdc++/include \

    external/gtest/include \

    external/stlport/stlport \



module_tags := tests



$(foreach file,$(test_src_files), \

    $(eval include $(CLEAR_VARS)) \

    $(eval LOCAL_SHARED_LIBRARIES := $(shared_libraries)) \

    $(eval LOCAL_STATIC_LIBRARIES := $(static_libraries)) \

    $(eval LOCAL_C_INCLUDES := $(c_includes)) \

    $(eval LOCAL_SRC_FILES := $(file)) \

    $(eval LOCAL_MODULE := $(notdir $(file:%.cpp=%))) \

    $(eval LOCAL_MODULE_TAGS := $(module_tags)) \

    $(eval include $(BUILD_EXECUTABLE)) \

)

include $(BUILD_EXECUTABLE)



# Build the manual test programs.

include $(call all-subdir-makefiles)