topography_triangle_vertices_indices.java

int image_width = 4;
int image_height = 5;

for (int y = 0; y < image_height - 1; y++) {
  for (int x = 0; x < image_width - 1; x++) {
  
    System.out.println("(" + ((y * image_width) + x) + "," + ((y * image_width) + x + 1) + "," + (x + ((y+1) * image_width)) + ")"); //top triangle indices
    System.out.println("(" + ((y * image_width) + x + 1) + "," + (x + 1 + ((y+1) * image_width)) + "," + (x + ((y+1) * image_width)) + ")"); //bottom triangle indices

  }
}