Emscripten minimal test-case for showcasing issue with anisotropic filtering

anisotropy.cpp

#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>

#include <stdio.h>
#include <emscripten.h>
#include <emscripten/html5.h>

int main()
{
  emscripten_set_canvas_size(256, 256);

  EmscriptenWebGLContextAttributes attrs;
  emscripten_webgl_init_context_attributes(&attrs);

  attrs.enableExtensionsByDefault = 1;
  attrs.majorVersion = 1;
  attrs.minorVersion = 0;

  EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = emscripten_webgl_create_context(0, &attrs);
  emscripten_webgl_make_context_current(context);

  EM_BOOL enabled = emscripten_webgl_enable_extension(context, "EXT_texture_filter_anisotropic");
  printf("anisotropy enabled: %d\n", enabled);

  // GLint maxAnisotropy;
  // glGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &maxAnisotropy);
  // printf("max anisotropy: %d\n", maxAnisotropy);

  GLfloat maxAnisotropy;
  glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &maxAnisotropy);
  printf("max anisotropy: %f", maxAnisotropy);

  GLuint texture;
  glGenTextures(1, &texture);
  glBindTexture(GL_TEXTURE_2D, texture);

  // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 4);
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 4);

  return 0;
}