Opengl 3d紋理的可見邊緣

Question

我從體積數據的體積渲染中遇到了立方體的可見邊緣，這種情況發生在在立方體邊緣進行查看時。

僅供參考，工件如下：

渲染工件2

渲染工件2

僅供參考，片段着色器代碼片段如下（OpenGL開發手冊）：

    void main()
{ 
    //get the 3D texture coordinates for lookup into the volume dataset
    vec3 dataPos = vUV;

    vec3 geomDir = normalize((vec3(0.556,0.614,0.201)*vUV-vec3(0.278,0.307,0.1005)) - camPos); 

    vec3 dirStep = geomDir * step_size;     

    //flag to indicate if the raymarch loop should terminate
    bool stop = false; 

    //for all samples along the ray
    for (int i = 0; i < MAX_SAMPLES; i++) {
        // advance ray by dirstep
        dataPos = dataPos + dirStep;

        stop = dot(sign(dataPos-texMin),sign(texMax-dataPos)) < 3.0f;

        //if the stopping condition is true we brek out of the ray marching loop
        if (stop) 
            break;

        // data fetching from the red channel of volume texture
        float sample = texture(volume, dataPos).r;  


        float prev_alpha = sample - (sample * vFragColor.a);
        vFragColor.rgb = (prev_alpha) * vec3(sample) + vFragColor.rgb; 
        vFragColor.a += prev_alpha; 


        if( vFragColor.a>0.99)
            break;
    }

僅供參考，使用glTexImage3D加載紋理，其格式為GL_RED，尺寸為556x614x201

Answer 1

僅供參考，通過將mipmapping的插值參數從GL_LINEAR_MIPMAP_LINEAR更改為GL_LINEAR可以解決此問題。

glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);