tests/webgl2_backwards_compatibility_emulation.cpp

#include <GLES3/gl3.h>
#include <GLES2/gl2ext.h>

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

EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context;

int main()
{
  EmscriptenWebGLContextAttributes attrs;
  emscripten_webgl_init_context_attributes(&attrs);
  attrs.majorVersion = 2;
  attrs.minorVersion = 0;

  int result = 0;

  EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = emscripten_webgl_create_context(0, &attrs);
  assert(context);
  EMSCRIPTEN_RESULT res = emscripten_webgl_make_context_current(context);
  assert(res == EMSCRIPTEN_RESULT_SUCCESS);
  assert(emscripten_webgl_get_current_context() == context);
  GLuint tex;
  glGenTextures(1, &tex);
  glBindTexture(GL_TEXTURE_2D, tex);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 16, 16, 0, GL_RGBA, GL_HALF_FLOAT_OES, 0);
  assert(glGetError() == 0);
  emscripten_webgl_destroy_context(context);

#ifdef REPORT_RESULT
  REPORT_RESULT(result);
#endif
  return 0;
}