correct blending between multiple volumes in opengl

Asked Sep 07 '20 at 09:00

Active Sep 07 '20 at 09:00

Viewed 47 times

I draw multiple 3d shapes in cube volumes with raycasting in fragment shader, like described here: https://github.com/bagobor/opengl33_dev_cookbook_2013/blob/master/Chapter7/GPURaycasting/shaders/raycaster.frag

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

It goes from front to back of the raycast and accumulates the alpha in each step. For alpha blending i use this settings:

glAlphaFunc(GL_GREATER, 0.01);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

I have an blending problem, when i draw multiple volumes. Fully transparent parts of cubes are drawn in front non-transparent parts of others. How can i fix this, discard the transparent parts of the cubes? (Rearranging the array of volumes to its xyz position dont work, because i can turn the camera)

asked Sep 07 '20 at 09:00

Meldryt

fixed it. i had to disable depth test for this. – Meldryt Sep 07 '20 at 10:25
If your answer is solved, then please post an answer or delete it altogether. – Nico Schertler Sep 07 '20 at 15:39
Even with disabled depth test, results will still depend on draw order. – derhass Sep 07 '20 at 18:24
@derhass thats right. do you know a better solution, without changing draw order? – Meldryt Sep 08 '20 at 10:02

correct blending between multiple volumes in opengl

0 Answers0