Testing OpenGL instancing for emscripten / WebGL1

webgl_instancing_test.c

#include <stdio.h>
#include <stdlib.h>
#include <emscripten/emscripten.h>
#include <emscripten/html5.h>
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>

int main()
{
  EmscriptenWebGLContextAttributes attr;
  emscripten_webgl_init_context_attributes(&attr);

  attr.enableExtensionsByDefault = 1;

  EMSCRIPTEN_WEBGL_CONTEXT_HANDLE ctx = emscripten_webgl_create_context("#canvas", &attr);
  emscripten_webgl_make_context_current(ctx);

  glClearColor(0.3f,0.3f,0.3f,1);
  glClear(GL_COLOR_BUFFER_BIT);

  /*
   * Not drawing anything, just testing if it compiles and links
   */
  glDrawArraysInstanced(GL_TRIANGLES, 0, 0, 0);
  glDrawArraysInstancedARB(GL_TRIANGLES, 0, 0, 0);
  glDrawArraysInstancedANGLE(GL_TRIANGLES, 0, 0, 0);

  return 0;
}

More context here