如何使用 GPUImageLibrary“减去”颜色滤镜？

android java opengl-es gpuimage

2022-09-01 00:13:56

目前，BlendModes（减法，排除等）使用启动器图像作为掩码。我可以将这些混合模式应用于ColorMatrix吗？

colorMatrix[
    0.393, 0.7689999, 0.18899999, 0, 0,
    0.349, 0.6859999, 0.16799999, 0, 0,
    0.272, 0.5339999, 0.13099999, 0, 0,
    0,     0,         0,          1, 0];

减去BlendFilter.java

public class GPUImageSubtractBlendFilter extends GPUImageTwoInputFilter {
    public static final String SUBTRACT_BLEND_FRAGMENT_SHADER = "varying highp vec2 textureCoordinate;\n" +
            " varying highp vec2 textureCoordinate2;\n" +
            "\n" +
            " uniform sampler2D inputImageTexture;\n" +
            " uniform sampler2D inputImageTexture2;\n" +
            " \n" +
            " void main()\n" +
            " {\n" +
            "   lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);\n" +
            "   lowp vec4 textureColor2 = texture2D(inputImageTexture2, textureCoordinate2);\n" +
            "\n" +
            "   gl_FragColor = vec4(textureColor.rgb - textureColor2.rgb, textureColor.a);\n" +
            " }";

    public GPUImageSubtractBlendFilter() {
        super(SUBTRACT_BLEND_FRAGMENT_SHADER);
    }
}

GPUIMageTwoInputFilter.java

public class GPUImageTwoInputFilter extends GPUImageFilter {
    private static final String VERTEX_SHADER = "attribute vec4 position;\n" +
            "attribute vec4 inputTextureCoordinate;\n" +
            "attribute vec4 inputTextureCoordinate2;\n" +
            " \n" +
            "varying vec2 textureCoordinate;\n" +
            "varying vec2 textureCoordinate2;\n" +
            " \n" +
            "void main()\n" +
            "{\n" +
            "    gl_Position = position;\n" +
            "    textureCoordinate = inputTextureCoordinate.xy;\n" +
            "    textureCoordinate2 = inputTextureCoordinate2.xy;\n" +
            "}";

    public int mFilterSecondTextureCoordinateAttribute;
    public int mFilterInputTextureUniform2;
    public int mFilterSourceTexture2 = OpenGlUtils.NO_TEXTURE;
    private ByteBuffer mTexture2CoordinatesBuffer;
    private Bitmap mBitmap;

    public GPUImageTwoInputFilter(String fragmentShader) {
        this(VERTEX_SHADER, fragmentShader);
    }

    public GPUImageTwoInputFilter(String vertexShader, String fragmentShader) {
        super(vertexShader, fragmentShader);
        setRotation(Rotation.NORMAL, false, false);
    }

    @Override
    public void onInit() {
        super.onInit();

        mFilterSecondTextureCoordinateAttribute = GLES20.glGetAttribLocation(getProgram(), "inputTextureCoordinate2");
        mFilterInputTextureUniform2 = GLES20.glGetUniformLocation(getProgram(), "inputImageTexture2"); // This does assume a name of "inputImageTexture2" for second input texture in the fragment shader
        GLES20.glEnableVertexAttribArray(mFilterSecondTextureCoordinateAttribute);

        if (mBitmap != null&&!mBitmap.isRecycled()) {
            setBitmap(mBitmap);
        }
    }

    public void setBitmap(final Bitmap bitmap) {
        if (bitmap != null && bitmap.isRecycled()) {
            return;
        }
        mBitmap = bitmap;
        if (mBitmap == null) {
            return;
        }
        runOnDraw(new Runnable() {
            public void run() {
                if (mFilterSourceTexture2 == OpenGlUtils.NO_TEXTURE) {
                    if (bitmap == null || bitmap.isRecycled()) {
                        return;
                    }
                    GLES20.glActiveTexture(GLES20.GL_TEXTURE3);
                    mFilterSourceTexture2 = OpenGlUtils.loadTexture(bitmap, OpenGlUtils.NO_TEXTURE, false);
                }
            }
        });
    }

    public Bitmap getBitmap() {
        return mBitmap;
    }

    public void recycleBitmap() {
        if (mBitmap != null && !mBitmap.isRecycled()) {
            mBitmap.recycle();
            mBitmap = null;
        }
    }

    public void onDestroy() {
        super.onDestroy();
        GLES20.glDeleteTextures(1, new int[]{
                mFilterSourceTexture2
        }, 0);
        mFilterSourceTexture2 = OpenGlUtils.NO_TEXTURE;
    }

    @Override
    protected void onDrawArraysPre() {
        GLES20.glEnableVertexAttribArray(mFilterSecondTextureCoordinateAttribute);
        GLES20.glActiveTexture(GLES20.GL_TEXTURE3);
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mFilterSourceTexture2);
        GLES20.glUniform1i(mFilterInputTextureUniform2, 3);

        mTexture2CoordinatesBuffer.position(0);
        GLES20.glVertexAttribPointer(mFilterSecondTextureCoordinateAttribute, 2, GLES20.GL_FLOAT, false, 0, mTexture2CoordinatesBuffer);
    }

    public void setRotation(final Rotation rotation, final boolean flipHorizontal, final boolean flipVertical) {
        float[] buffer = TextureRotationUtil.getRotation(rotation, flipHorizontal, flipVertical);

        ByteBuffer bBuffer = ByteBuffer.allocateDirect(32).order(ByteOrder.nativeOrder());
        FloatBuffer fBuffer = bBuffer.asFloatBuffer();
        fBuffer.put(buffer);
        fBuffer.flip();

        mTexture2CoordinatesBuffer = bBuffer;
    }
}

我猜它涉及用 & 改变一些东西。String SUBTRACT_BLEND_GRAGMENT_SHADERString VERTEX_SHADER

答案 1

颜色矩阵是将某些像素的新颜色分量值定义为同一像素的当前颜色分量的线性函数的实体。即，颜色矩阵转换的唯一输入是像素，哪些颜色应该转换。无法让其他像素进行此类转换。无论它们是来自另一个图像的像素，甚至是转换像素的邻居 - 这是不可能的。

答案 2

免責聲明

最初，我回答了同一作者的另一个问题，似乎在同一个问题中被问到。我决定不将这个标记为重复，因为第一个问题没有使用的上下文，这使得事情变得更简单。但是，我不想过度操作，因此，如果您需要任何其他详细信息，请参阅原始答案。在这里，我将仅概述解决方案。GPUImageLibrary

您实际上不需要扩展的或任何后代，因为（正如 Sergio 正确指出的那样）您应该只处理纹理的一个实例。相反，请定义您自己的片段着色器，该着色器将采用颜色滤镜，应用它并从原始像素中减去结果值：GPUImageSubtractBlendFilterGPUImageTwoInputFilter

precision mediump float;
struct ColorFilter {
  mat4 factor;
  vec4 shift;
};
uniform sampler2D inputImageTexture;
uniform ColorFilter uColorFilter;
varying vec2 textureCoordinate;
void main() {
  vec4 originalColor = texture2D(inputImageTexture, textureCoordinate);
  originalColor.rgb *= originalColor.a;
  vec4 filteredColor = (originalColor * uColorFilter.factor) + uColorFilter.shift;
  filteredColor.rgb *= filteredColor.a;
  gl_FragColor = vec4(originalColor.rgb - filteredColor.rgb, originalColor.a);
}

现在只需将颜色滤镜矩阵附加到着色器：

@Override
public void onInitialized() {
    super.onInitialized();
    attachColorFilter(getProgram());
}

// ========================================== //
// Private
// ========================================== //

private void attachColorFilter(int program) {
    final float[] colorFilterFactor = new float[4 * 4];
    final float[] colorFilterShift = new float[4];
    for (int i = 0; i < mColorFilter.length; i++) {
        final float value = mColorFilter[i];
        final int calculateIndex = i + 1;
        if (calculateIndex % 5 == 0) {
            colorFilterShift[calculateIndex / 5 - 1] = value / 255;
        } else {
            colorFilterFactor[i - calculateIndex / 5] = value;
        }
    }
    final int colorFactorLocation = GLES20.glGetUniformLocation(program,
            "uColorFilter.factor");
    setUniformMatrix4f(colorFactorLocation, colorFilterFactor);
    final int colorShiftLocation = GLES20.glGetUniformLocation(program,
            "uColorFilter.shift");
    setFloatVec4(colorShiftLocation, colorFilterShift);
}

可以随意将要点与工作子类一起使用。只需实例化它并传递给：GPUImageView

mBlendedImageView.setFilter(new ColorMatrixSubtractFilter(new float[] {
    0.393f, 0.7689999f, 0.18899999f, 0, 0,
    0.349f, 0.6859999f, 0.16799999f, 0, 0,
    0.272f, 0.5339999f, 0.13099999f, 0, 0,
    0,      0,         0,            1, 0
}));

在右侧，您可以看到应用于左侧图像的减去滤镜的输出：