How can I achieve noSmooth() with the P3D renderer? - opengl

Question

I'd like to render basic 3D shapes without any aliasing/smoothing with a PGraphics instance using the P3D renderer, but noSmooth() doesn't seem to work.
In OF I remember calling setTextureMinMagFilter(GL_NEAREST,GL_NEAREST); on a texture.
What would be the equivalent in Processing ?
I tried to use PGL:
PGL.TEXTURE_MIN_FILTER = PGL.NEAREST;
PGL.TEXTURE_MAG_FILTER = PGL.NEAREST;
but I get a black image as the result.
If I comment PGL.TEXTURE_MIN_FILTER = PGL.NEAREST; I can see the render, but it's interpolated, not sharp.
Here'a basic test sketch with a few things I've tried:
PGraphics buffer;
PGraphicsOpenGL pgl;
void setup() {
size(320, 240, P3D);
noSmooth();
//hint(DISABLE_TEXTURE_MIPMAPS);
//((PGraphicsOpenGL)g).textureSampling(0);
//PGL pgl = beginPGL();
//PGL.TEXTURE_MIN_FILTER = PGL.NEAREST;
//PGL.TEXTURE_MAG_FILTER = PGL.NEAREST;
//endPGL();
buffer=createGraphics(width/8, height/8, P3D);
buffer.noSmooth();
buffer.beginDraw();
//buffer.hint(DISABLE_TEXTURE_MIPMAPS);
//((PGraphicsOpenGL)buffer).textureSampling(0);
PGL bpgl = buffer.beginPGL();
//PGL.TEXTURE_MIN_FILTER = PGL.NEAREST;//commenting this back in results in a blank buffer
PGL.TEXTURE_MAG_FILTER = PGL.NEAREST;
buffer.endPGL();
buffer.background(0);
buffer.stroke(255);
buffer.line(0, 0, buffer.width, buffer.height);
buffer.endDraw();
}
void draw() {
image(buffer, 0, 0, width, height);
}
(I've also posted on the Processing Forum, but no luck so far)

Answer 1

You were actually on the right track. You were just passing the wrong value to textureSampling().
Since the documentation on PGraphicsOpenGL::textureSampling()
is a bit scarce to say the least.
I decided to peak into it using a decompiler, which lead me to
Texture::usingMipmaps().
There I was able to see the values and what they reflected (in the decompiled code).
2 = POINT
3 = LINEAR
4 = BILINEAR
5 = TRILINEAR
Where PGraphicsOpenGL's default textureSampling is 5 (TRILINEAR).
I also later found this old comment on an issue equally confirming it.
So to get point/nearest filtering you only need to call noSmooth() on the application itself, and call textureSampling() on your PGraphics.
size(320, 240, P3D);
noSmooth();
buffer = createGraphics(width/8, height/8, P3D);
((PGraphicsOpenGL) buffer).textureSampling(2);
So considering the above, and only including the code you used to draw the line and drawing buffer to the application. Then that gives the following desired result.

Answer 2

I needed to combine both GL_LINEAR and GL_NEAREST with one shader so the ((PGraphicsOpenGL) buffer).textureSampling(2); was no option.
It was some digging, but this works for me:
PGL pgl = beginPGL();
Texture ascii_map_tex = ((PGraphicsOpenGL)g).getTexture(ascii_map);
pgl.bindTexture(PGL.TEXTURE_2D, ascii_map_tex.glName);
pgl.texParameteri(PGL.TEXTURE_2D, PGL.TEXTURE_MIN_FILTER, PGL.NEAREST);
pgl.texParameteri(PGL.TEXTURE_2D, PGL.TEXTURE_MAG_FILTER, PGL.NEAREST);
pgl.bindTexture(PGL.TEXTURE_2D, 0);
endPGL();