Question

我正在尝试使用顶点和片段着色器在OpenGL ES 2.0（Android 4.0.4，Galaxy Nexus）中显示简单的纹理作为全屏背景。最终结果应该是在那里显示摄像机图像，但首先，文件中的简单纹理就足够了。我测试了许多东西，并且在一段时间内它使用了OpenGL ES 1.x但是因为我打算使用着色器进行YUV-> RGB转换，所以我必须使用2.0。

我有以下顶点着色器：

attribute vec4 position;
attribute vec4 inputTextureCoordinate;

varying vec2 textureCoordinate;

void main() {
    gl_Position = position;
    textureCoordinate = inputTextureCoordinate.xy
}

和这个片段着色器：

varying highp vec2 textureCoordinate;

uniform sampler2D videoFrame;

void main() {
    gl_FragColor = texture2D(videoFrame, textureCoordinate);
}

这样的着色器创建应该没问题，因为当我写gl_FragColor=vec4(1,0,0,0)时，它的效果非常好，并向我显示红色背景。

OnSurfaceCreated我执行以下操作：

 a = makeFloatBuffer(squareVertices);
 b = makeFloatBuffer(textureVertices);

squareVertices和textureVertices如下：

static float squareVertices[] = { -1.0f, -1.0f, 1.0f, -1.0f, -1.0f, 1.0f,
        1.0f, 1.0f, };

static float textureVertices[] = { 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f,
        0.0f, 0.0f, };

OnSurfaceChanged我执行以下操作：

GLES20.glViewport(0, 0, width, height);
Bitmap bitmap = BitmapFactory.decodeResource(mContext.getResources(), R.raw.htc);
GLES20.glGenTextures(1, textures, 0);
GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);

R.raw.htc是128x128像素png。

OnDrawFrame：

    GLES20.glUseProgram(program);

    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textures[0]);

    GLES20.glUniform1i(GLES20.glGetUniformLocation(program, "videoFrame"),0);

    GLES20.glClearColor(0.0f, 0.0f, 1.0f, 0.0f);
    GLES20.glClearDepthf(1.0f);
    GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);

    int x = GLES20.glGetAttribLocation(program, "position");
    int y = GLES20.glGetAttribLocation(program, "inputTextureCoordinate");

    GLES20.glEnableVertexAttribArray(x);        
    GLES20.glVertexAttribPointer(x, 2, GLES20.GL_FLOAT, false, 0, a);
    GLES20.glEnableVertexAttribArray(y);
    GLES20.glVertexAttribPointer(y, 4, GLES20.GL_FLOAT, false, 0, b);

    GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);

我唯一看到的是一个完全黑屏，我不明白为什么。我在这里看到了其他一些类似问题的帖子，但是没有一个提议的解决方案帮助我，或者根本没有解决方案。

Answer 1

如上所述，我们可以找到问题的解决方案，虽然我们不知道它现在正在工作的原因而不是之前（我们改变了一些事情并且突然之间有效）。尽管如此，我想分享我们的工作版本：

现在已完成着色器以进行YUV-> RGB转换：顶点着色器：

attribute vec4 position;
attribute vec4 inputTextureCoordinate;

varying vec2 textureCoordinate;

 void main() {
      gl_Position = position;
      textureCoordinate = inputTextureCoordinate.xy;
 };

片段着色器：

varying highp vec2 textureCoordinate;
uniform sampler2D videoFrame;
uniform sampler2D videoFrame2;

void main(void) {
    highp float nx,ny,r,g,b,y,u,v;
    highp vec2 uv;
    highp vec4 txl,ux,vx;"
    nx=(textureCoordinate.x)/1024.0*720.0;
    ny=(textureCoordinate.y)/1024.0*480.0;
    y=texture2D(videoFrame,vec2(nx,ny)).r;
    uv=texture2D(videoFrame2,vec2(nx,ny)).ag;
    y=1.1643*(y-0.0625);
    u=uv[0]-0.5;
    v=uv[1]-0.5;
    r=y+1.5958*v;
    g=y-0.39173*u-0.81290*v;
    b=y+2.017*u;

    gl_FragColor=vec4(r,g,b,1);
};

OnSurfaceCreated仍然相同，但顶点的定义有所改变：

static float squareVertices[] = { -1.0f, -1.0f, 1.0f, -1.0f, -1.0f, 1.0f,
        1.0f, 1.0f, };

private float textureVertices[] = { 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
        1.0f, 0.0f, };

OnSurfaceChanged：

    buffer = new int[2];
    GLES20.glGenTextures(2, buffer, 0);
    for (int i = 0; i < 2; i++) {
        int texture = buffer[i];
        Log.v("Texture", "Texture is at " + texture);
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, texture);
        GLES20.glPixelStorei(GLES20.GL_UNPACK_ALIGNMENT, GLES20.GL_TRUE);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);
    }

    buf = new byte[1024 * 1024];
    for (int i = 0; i < 1024 * 1024; i++) {
        buf[i] = 0;
    }
    buf2 = new byte[1024 * 1024];
    for (int i = 0; i < 1024 * 1024; i++) {
        buf2[i] = -128;
    }

    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, buffer[0]);

    GLES20.glTexImage2D(GL10.GL_TEXTURE_2D, 0, GL10.GL_LUMINANCE, 1024,
            1024, 0, GL10.GL_LUMINANCE, GL10.GL_UNSIGNED_BYTE,
            ByteBuffer.wrap(buf));

    GLES20.glActiveTexture(GLES20.GL_TEXTURE1);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, buffer[1]);

    GLES20.glTexImage2D(GL10.GL_TEXTURE_2D, 0, GL10.GL_LUMINANCE_ALPHA,
            512, 512, 0, GL10.GL_LUMINANCE_ALPHA, GL10.GL_UNSIGNED_BYTE,
            ByteBuffer.wrap(buf2));

OnDrawFrame：

    GLES20.glViewport(0, 0, mWidth, mHeight);

    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, buffer[0]);

    GLES20.glTexSubImage2D(GL10.GL_TEXTURE_2D, 0, 0, 0, Util.CAMWIDTH,
            Util.CAMHEIGHT, GL10.GL_LUMINANCE, GL10.GL_UNSIGNED_BYTE,
            ByteBuffer.wrap(mBuffer, 0, Util.CAMWIDTH * Util.CAMHEIGHT));

    GLES20.glActiveTexture(GLES20.GL_TEXTURE1);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, buffer[1]);

    GLES20.glTexSubImage2D(
            GL10.GL_TEXTURE_2D,
            0,
            0,
            0,
            Util.CAMWIDTH / 2,
            Util.CAMHEIGHT / 2,
            GL10.GL_LUMINANCE_ALPHA,
            GL10.GL_UNSIGNED_BYTE,
            ByteBuffer.wrap(mBuffer, Util.CAMWIDTH * Util.CAMHEIGHT,
                    Util.CAMWIDTH / 2 * Util.CAMHEIGHT).slice());

    GLES20.glClearColor(1.0f, .0f, .0f, .0f);

    GLES20.glUseProgram(program);

    GLES20.glUniform1i(GLES20.glGetUniformLocation(program, "videoFrame"),
            0);
    GLES20.glUniform1i(GLES20.glGetUniformLocation(program, "videoFrame2"),
            1);

    GLES20.glClearDepthf(1.0f);
    GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);

    int x = GLES20.glGetAttribLocation(program, "position");
    int y = GLES20.glGetAttribLocation(program, "inputTextureCoordinate");

    GLES20.glEnableVertexAttribArray(x);
    GLES20.glVertexAttribPointer(x, 2, GLES20.GL_FLOAT, false, 0, a);
    GLES20.glEnableVertexAttribArray(y);
    GLES20.glVertexAttribPointer(y, 2, GLES20.GL_FLOAT, false, 0, b);

    GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);

Answer 2

您将纹理坐标声明为4个组件，而不是看起来应该是2.代码看起来不错。

Answer 3

GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);

这两行代码为我做了诀窍

GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);

我还需要这两个才能显示PNG文件

Android：OpenGL ES 2.0 - 纹理总是黑色

3 个答案: