Question

我在Android上使用open gl es来显示用透明色替换的黑色视频。但是当我使用我的特定着色器GL_INVALID_OPERATION错误代码时。

这是我的着色器：

protected final String mFragmentShader =
                "#extension GL_OES_EGL_image_external : require\n" +
                        "uniform samplerExternalOES sTexture;\n" +
                        "varying vec2 vTextureCoord;\n" +
                        "vec4 color;\n" +
                        "\n" +
                        "void main(){\n" +
                        "    color =  texture2D(sTexture, vTextureCoord);\n" +
                        "    if(color.r < 0.1 && color.g < 0.1 && color.b < 0.1){\n" +
                        "        gl_FragColor = vec4(0.0,0.0,0.0,0.0);\n" +
                        "    } else{\n" +
                        "        gl_FragColor = color;\n" +
                        "    }\n" +
                        "}";

当我使用下一个着色器时 - 一切都显示良好（当然透明度除外）

 protected final String mFragmentShader =
                "#extension GL_OES_EGL_image_external : require\n" +
                        "precision mediump float;\n" +
                        "varying vec2 vTextureCoord;\n" +
                        "uniform samplerExternalOES sTexture;\n" +
                        "void main() {\n" +
                        "  gl_FragColor = texture2D(sTexture, vTextureCoord);\n" +
                        "}\n";

这是我的onDrawFrame代码：

 public void onDrawFrame(GL10 glUnused) {
            if(!mMediaPlayer.isPlaying())
                return;
            synchronized (this) {
                if (updateSurface) {
                    mSurface.updateTexImage();
                    mSurface.getTransformMatrix(mSTMatrix);
                    updateSurface = false;
                }
            }

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

            GLES20.glUseProgram(mProgram);
            checkGlError("glUseProgram");

            GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
            GLES20.glBindTexture(GL_TEXTURE_EXTERNAL_OES, mTextureID);

            mTriangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET);
            GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false,
                    TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
            checkGlError("glVertexAttribPointer maPosition");
            GLES20.glEnableVertexAttribArray(maPositionHandle);
            checkGlError("glEnableVertexAttribArray maPositionHandle");

            mTriangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET);
            GLES20.glVertexAttribPointer(maTextureHandle, 3, GLES20.GL_FLOAT, false,
                    TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
            checkGlError("glVertexAttribPointer maTextureHandle");
            GLES20.glEnableVertexAttribArray(maTextureHandle);
            checkGlError("glEnableVertexAttribArray maTextureHandle");

            Matrix.setIdentityM(mMVPMatrix, 0);
            GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
            GLES20.glUniformMatrix4fv(muSTMatrixHandle, 1, false, mSTMatrix, 0);

            GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
            checkGlError("glDrawArrays");
            GLES20.glFinish();

        }

可能是什么问题？

Answer 1

问题在于浮动精度。当我在第一个着色器中设置precision mediump float时，一切都运行良好

Answer 2

在您的第一个着色器中，当您使用color.r时，您正在使用color.x，依此类推。 vec4对象是成员x,y,z,w

的对象

glDrawArrays为特定着色器抛出GL_INVALID_OPERATION异常

2 个答案: