OpenGL rendering can be used only once per Lisp process run under Ubuntu in VirtualBox.

[TeMPOraL]

This also happens with cl-sdl example using OpenGL.

Relevant log excerpts:

First run:

<INFO> [18:41:27] p2d main.lisp (log-engine-startup-message) -
 Parenscript 2D Engine, version 0.0.3 (stepping stones)
<WARN> [18:41:27] p2d main.lisp (run) -
 No game registered; will use engine default scene.
<INFO> [18:41:27] p2d main.lisp (preinit default-game) - Default game pre-init.
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) -
 Running on fidelis - LINUX X64 SBCL 1.3.2 sbcl-1.3.2-linux-x64.
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - Using SDL version 2.0.4
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:CPU-COUNT): 1 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:CPU-CACHE-LINE-SIZE): 64 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:ALTI-VEC-P): NIL 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:MMX-P): T 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:RDTSC-P): T 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:SSE-P): T 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:SSE2-P): T 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:SSE3-P): T 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:SSE41-P): T 
<INFO> [18:41:27] p2d main.lisp (log-sysinfo) - (SDL2:SSE42-P): T 
<INFO> [18:41:28] p2d renderer.lisp (init-main-window) -
 Opening new 800x600 window "Parendeck 2D - no game loaded".
<INFO> [18:41:28] p2d renderer.lisp (init-main-window) - Acquiing GL context.
<INFO> [18:41:28] p2d renderer.lisp (log-opengl-info) -
 GL version: 2.1 Chromium 1.9.
<INFO> [18:41:28] p2d renderer.lisp (log-opengl-info) - GL vendor: Humper.
<INFO> [18:41:28] p2d renderer.lisp (log-opengl-info) - GL renderer: Chromium.
<INFO> [18:41:28] p2d renderer.lisp (log-opengl-info) -
 GLSL version: 4.20 - Build 10.18.10.4061.
<INFO> [18:41:28] p2d renderer.lisp (log-opengl-info) -
 GL extensions: GL_EXT_texture_compression_s3tc GL_EXT_draw_range_elements GL_EXT_framebuffer_object GL_EXT_compiled_vertex_array GL_ARB_depth_texture GL_ARB_fragment_program GL_ARB_multisample GL_ARB_multitexture GL_ARB_occlusion_query GL_ARB_point_parameters GL_ARB_point_sprite GL_ARB_shadow GL_ARB_texture_border_clamp GL_ARB_texture_compression GL_ARB_texture_cube_map GL_ARB_texture_env_add GL_ARB_texture_env_combine GL_EXT_texture_env_combine GL_ARB_texture_env_crossbar GL_ARB_texture_env_dot3 GL_IBM_texture_mirrored_repeat GL_ARB_texture_non_power_of_two GL_ARB_transpose_matrix GL_ARB_vertex_buffer_object GL_ARB_pixel_buffer_object GL_ARB_vertex_program GL_ARB_window_pos GL_EXT_blend_color GL_EXT_blend_minmax GL_EXT_blend_func_separate GL_EXT_clip_volume_hint GL_EXT_blend_subtract GL_EXT_texture_env_add GL_EXT_fog_coord GL_EXT_multi_draw_arrays GL_EXT_secondary_color GL_EXT_shadow_funcs GL_EXT_stencil_wrap GL_EXT_texture_edge_clamp GL_EXT_texture_filter_anisotropic GL_EXT_texture_lod_bias GL_EXT_texture3D GL_NV_texgen_reflection GL_EXT_texture_rectangle GL_ARB_texture_rectangle GL_SGIS_generate_mipmap GL_SGIS_texture_edge_clamp GL_ARB_shading_language_100 GL_ARB_shader_objects GL_ARB_vertex_shader GL_ARB_fragment_shader GL_EXT_texture_sRGB GL_EXT_framebuffer_blit GL_EXT_blend_equation_separate GL_EXT_stencil_two_side GL_CR_state_parameter GL_CR_cursor_position GL_CR_bounding_box GL_CR_print_string GL_CR_tilesort_info GL_CR_synchronization GL_CR_head_spu_name GL_CR_performance_info GL_CR_window_size GL_CR_tile_info GL_CR_saveframe GL_CR_readback_barrier_size GL_CR_server_id_sharing GL_CR_server_matrix  GL_EXT_stencil_two_side.
<INFO> [18:41:28] p2d main.lisp (initialize default-game) - Default game init.
<INFO> [18:41:28] p2d main.lisp (run-main-loop) - Entering main loop.

Second run:

<INFO> [18:42:08] p2d main.lisp (log-engine-startup-message) -
 Parenscript 2D Engine, version 0.0.3 (stepping stones)
<WARN> [18:42:08] p2d main.lisp (run) -
 No game registered; will use engine default scene.
<INFO> [18:42:08] p2d main.lisp (preinit default-game) - Default game pre-init.
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) -
 Running on fidelis - LINUX X64 SBCL 1.3.2 sbcl-1.3.2-linux-x64.
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - Using SDL version 2.0.4
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:CPU-COUNT): 1 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:CPU-CACHE-LINE-SIZE): 64 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:ALTI-VEC-P): NIL 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:MMX-P): T 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:RDTSC-P): T 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:SSE-P): T 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:SSE2-P): T 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:SSE3-P): T 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:SSE41-P): T 
<INFO> [18:42:08] p2d main.lisp (log-sysinfo) - (SDL2:SSE42-P): T 
<INFO> [18:42:08] p2d renderer.lisp (init-main-window) -
 Opening new 800x600 window "Parendeck 2D - no game loaded".
<INFO> [18:42:08] p2d renderer.lisp (init-main-window) - Acquiing GL context.
<INFO> [18:42:08] p2d renderer.lisp (log-opengl-info) - GL version: NIL.
<INFO> [18:42:08] p2d renderer.lisp (log-opengl-info) - GL vendor: NIL.
<INFO> [18:42:08] p2d renderer.lisp (log-opengl-info) - GL renderer: NIL.
<INFO> [18:42:08] p2d renderer.lisp (log-opengl-info) - GLSL version: NIL.
<INFO> [18:42:08] p2d renderer.lisp (log-opengl-info) - GL extensions: NIL.
<INFO> [18:42:08] p2d main.lisp (initialize default-game) - Default game init.
<INFO> [18:42:08] p2d main.lisp (run-main-loop) - Entering main loop.

[TeMPOraL]

It fixed itself...? Or I fixed it somehow. I don't know how.