How can I get the values ​​(coordinates) generated by opengl's evaluator?

gjpro1981

The value obtained by glEvalCoord2f ((float) j, i) is the coordinates of the vertex. The problem is that it is drawn directly on the screen. I now want to know its x, y, z values. If you can get it with the feedback mode, but after a big bend, is there a way to return directly?

rsq666

should not;
Use gluProject, gluUnproject functions.

rsq666

should not,
Use gluproject, gluUnproject functions.

流浪桃

OpenGL also has a kind of feedback, which is drawing grids and assigning coordinates to each grid, so that querying which grid displays the coordinates of which grid.

gjpro1981

Theoretically there should be, because the evaluation program must first calculate the x, y, z coordinates and then calculate the projection coordinates. What is the problem to return the x, y, z coordinates?

czzhaoshuang

Have the same feelings and are following