It does not distinguish triangles from the .obj model (eagle), which got

[gibson]

It does not distinguish triangles from the .obj model (eagle), which got into the inside of the frustum

Here near is the front rectangle, far back planeA, planeB ... planeF- plane, prevx, prevy-initial coordinates when selecting,curx, cury- final coordinates when selecting.

///
{
  Vector3f[] near = new Vector3f[4];
  near[0]=new Vector3f(Rectangle.getPrevX(),Rectangle.getPrevY(),1);
  near[1]=new Vector3f(Rectangle.getPrevX(),Rectangle.getCurY(),1);
  near[2]=new Vector3f(Rectangle.getCurX(),Rectangle.getCurY(),1);
  near[3]=new Vector3f(Rectangle.getCurX(),Rectangle.getPrevY(),1);
  Vector3f[] far = new Vector3f[4];
  far[0]=new Vector3f(Rectangle.getPrevX(),Rectangle.getPrevY(),-100);
  far[1]=new Vector3f(Rectangle.getPrevX(),Rectangle.getCurY(),-100);
  far[2]=new Vector3f(Rectangle.getCurX(),Rectangle.getCurY(),-100);
  far[3]=new Vector3f(Rectangle.getCurX(),Rectangle.getPrevY(),-100);
  Vector3f center = getCenter(near,far);// I get the center
  Vector4f planeA = Util.getABCD(new Vector3f(Rectangle.getPrevX(), Rectangle.getCurY(), 1),
  new Vector3f(Rectangle.getPrevX(), Rectangle.getPrevY(), 1),
  new Vector3f(Rectangle.getCurX(), Rectangle.getCurY(), 1),center);
  Vector4f planeE = Util.getABCD(new Vector3f(Rectangle.getPrevX(), Rectangle.getCurY(), 1),
  new Vector3f(Rectangle.getPrevX(), Rectangle.getPrevY(), 1),
  new Vector3f(Rectangle.getPrevX(), Rectangle.getPrevY(), -100),center);
  Vector4f planeB = Util.getABCD(new Vector3f(Rectangle.getCurX(), Rectangle.getPrevY(), 1),
  new Vector3f(Rectangle.getCurX(), Rectangle.getCurY(), 1),
  new Vector3f(Rectangle.getCurX(), Rectangle.getCurY(), -100),center);
  Vector4f planeD = Util.getABCD(new Vector3f(Rectangle.getPrevX(), Rectangle.getPrevY(), 1),
  new Vector3f(Rectangle.getPrevX(), Rectangle.getPrevY(), -100),
  new Vector3f(Rectangle.getCurX(), Rectangle.getPrevY(), -100),center);
  Vector4f planeC = Util.getABCD(new Vector3f(Rectangle.getPrevX(), Rectangle.getCurY(), 1),
  new Vector3f(Rectangle.getPrevX(), Rectangle.getCurY(), -100),
  new Vector3f(Rectangle.getCurX(), Rectangle.getCurY(), -100),center);
  Vector4f planeF = Util.getABCD(new Vector3f(Rectangle.getPrevX(), Rectangle.getPrevY(), -100),
  new Vector3f(Rectangle.getPrevX(), Rectangle.getCurY(), -100),
  new Vector3f(Rectangle.getCurX(), Rectangle.getCurY(), -100),center);
  FloatBuffer fbuf= BufferUtils.createFloatBuffer(3 * 8 * Float.BYTES).put(new float[]{
      planeA.x,planeA.y,planeA.z,planeA.w,
      planeB.x,planeB.y,planeB.z,planeB.w,
      planeC.x,planeC.y,planeC.z,planeC.w,
      planeD.x,planeD.y,planeD.z,planeD.w,
      planeE.x,planeE.y,planeE.z,planeE.w,
      planeF.x,planeF.y,planeF.z,planeF.w
     }).rewind();
  glUniform4fv(glGetUniformLocation(shaderProgram, "planes"), fbuf);
}
for (ArrayIdTriangle aVbao : sceneManyTexture.getVbao()) {
Map<String, Material> materials = sceneManyTexture.getMaterials();
String nameTexture = aVbao.getObjTexture().getNameTexture();
Optional<Texture> texture = Optional.ofNullable(materials.get(nameTexture).getTexture());
if (texture.isPresent()) {
   glActiveTexture(GL_TEXTURE0);
   glBindTexture(GL_TEXTURE_2D, texture.get().getId());
}
glBindVertexArray(aVbao.getId());
glEnableVertexAttribArray(vertexLocation);
glEnableVertexAttribArray(textureLocation);
glEnableVertexAttribArray(normalLocation);
glDrawElements(GL_TRIANGLES, aVbao.getSize(), GL_UNSIGNED_INT, 0);   

Here I get the components a, b, c, d from the equation of the plane:

public static Vector4f getABCD(Vector3f p0, Vector3f p1, Vector3f p2,Vector3f center) {
  Vector3f n = (p1.sub(p0)).cross(p2.sub(p1));
  float d=-n.dot(p0);
  if(n.dot(center)+d<0.0f){
    n=n.mul(-1);
    d=-d;
  }
  return new Vector4f(n,d);
}

Vertex Shader:

#version 330

layout(location = 0) in vec3 vertexPos;
layout(location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoord;

out float[6] dis;
out vec3 normal_modelspace;
out vec3 vertex_modelspace;
out vec2 TexCoord;
out vec4 vertexColor;
uniform mat4 P;
uniform mat4 V;
uniform mat4 M;

uniform vec4[6] planes;


void main() {
    TexCoord = texCoord;
    vertex_modelspace = (M * vec4(vertexPos.xyz, 1.0)).xyz;
    vertexColor = vec4(0.5f, 0.0f, 0.0f, 1.0f);
    gl_Position = P * V * vec4(vertex_modelspace.xyz, 1.0);
    normal_modelspace = (M * vec4(normal.xyz, 1.0)).xyz;
    vec3 EyeDirection_cameraspace = vec3(0,0,0) - (V * M * vec4(vertexPos,1)).xyz;
    for(int i = 0;i<6;i++){
      float denom = sqrt(planes[0].x * planes[0].x + planes[0].y * planes[0].y + planes[0].z * planes[0].z);
      dis[i] = float((planes[0].x * vertex_modelspace.x + planes[0].y * vertex_modelspace.y + planes[0].z * vertex_modelspace.z + planes[0].w) / denom);
    }
}

Fragment shader:

#version 330 core

in vec3 normal_modelspace;
in vec3 vertex_modelspace;
in vec2 TexCoord;
in vec4 vertexColor;
in float[6] dis;
out vec4 color;

uniform vec3 light_worldspace;

uniform sampler2D ourTexture;

void main() {
  vec3 n = normalize(normal_modelspace);
  vec3 l = normalize(light_worldspace - vertex_modelspace);
  float cosTheta = clamp( dot( n, l), 0,1 );
  float ambient = 0.05;
    int i=0;
    while(i<6 && dis[i]<=0){
      i++;
    }
    if(i==6){
      color = texture(ourTexture, TexCoord);
    }
    else
      color = vertexColor;
}

Link to video:
https://youtu.be/OgZzKX9Qwzg

[darkyellow]

Is there a question here? People aren't here to debug your code unless there is a very specific error taking place