volume rendering - Visible edges from Opengl 3d texture -

volume rendering - Visible edges from Opengl 3d texture -

i have encountered visible edges of cube volume rendering of volume data, happens when viewing done @ edges of cube.

fyi, artifacts below:

rendering artifacts 2

rendering artifacts 2

fyi, fragment shader snippet below(opengl development cookbook):

void main() { //get 3d texture coordinates lookup 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 indicate if raymarch loop should terminate bool stop = false; //for samples along ray (int = 0; < max_samples; i++) { // advance ray dirstep datapos = datapos + dirstep; stop = dot(sign(datapos-texmin),sign(texmax-datapos)) < 3.0f; //if stopping status true brek out of ray marching loop if (stop) break; // info fetching reddish 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; }

fyi, texture loaded using glteximage3d format of gl_red , dimension of 556x614x201

fyi, problem solved changing interpolation parameter of mipmapping gl_linear gl_linear_mipmap_linear.

gltexparameteri(gl_texture_3d, gl_texture_min_filter, gl_linear);

opengl volume-rendering 3d-texture