Buggy window with very simple code

OpenGL OpenGL: Basic Coding
1

Hello :slight_smile:

I’m using this simple code in Qt Creator :

#define GLEW_STATIC
#include <GL/glew.h>
#include <iostream>
#include <SDL2/SDL.h>

int main()
{
    SDL_Init(SDL_INIT_VIDEO);

    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);

    SDL_Window* window = SDL_CreateWindow("OpenGL", 100, 100, 800, 600, SDL_WINDOW_OPENGL);

    SDL_GLContext context = SDL_GL_CreateContext(window);

    glewExperimental = GL_TRUE;
    glewInit();

    glClearColor(0.0f,0.0f,0.0f,0.0f);

    SDL_Event windowEvent;
    while (true)
    {
        if (SDL_PollEvent(&windowEvent))
        {
            if (windowEvent.type == SDL_QUIT) break;
        }

        glClear(GL_COLOR_BUFFER_BIT);
        SDL_GL_SwapWindow(window);
    }

    SDL_GL_DeleteContext(context);



    SDL_Quit();

    return 0;
}

With this .pro file :

TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt
CONFIG += c++11

SOURCES += main.cpp

win32:CONFIG(release, debug|release): LIBS += -L$$PWD/../../../usr/lib/release/ -lGL
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/../../../usr/lib/debug/ -lGL
else:unix: LIBS += -L$$PWD/../../../usr/lib/ -lGL

INCLUDEPATH += $$PWD/../../../usr/include/GL
DEPENDPATH += $$PWD/../../../usr/include/GL




win32:CONFIG(release, debug|release): LIBS += -L$$PWD/../../../usr/lib/release/ -lSDL2
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/../../../usr/lib/debug/ -lSDL2
else:unix: LIBS += -L$$PWD/../../../usr/lib/ -lSDL2

INCLUDEPATH += $$PWD/../../../usr/include/SDL2
DEPENDPATH += $$PWD/../../../usr/include/SDL2


win32:CONFIG(release, debug|release): LIBS += -L$$PWD/../../../usr/lib/release/ -lGLEW
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/../../../usr/lib/debug/ -lGLEW
else:unix: LIBS += -L$$PWD/../../../usr/lib/ -lGLEW

I get no error, the window is opened, but instead of being black it is “transparent” (I can see my desktop through it and this image of the desktop is moved when I move the window).

Screenshot :

[ATTACH=CONFIG]622[/ATTACH]

A friend of mine could run the code and told me a black window opened normally.

Here are some informations about my laptop :

[ul]
[li] glxinfo : [/li]

Name of display: :0
display: :0  screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.4
server glx extensions:
    GLX_ARB_create_context, GLX_ARB_create_context_profile, 
    GLX_ARB_fbconfig_float, GLX_ARB_framebuffer_sRGB, GLX_ARB_multisample, 
    GLX_EXT_create_context_es2_profile, GLX_EXT_framebuffer_sRGB, 
    GLX_EXT_import_context, GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, 
    GLX_EXT_visual_rating, GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer, 
    GLX_OML_swap_method, GLX_SGIS_multisample, GLX_SGIX_fbconfig, 
    GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group, GLX_SGI_swap_control
client glx vendor string: Mesa Project and SGI
client glx version string: 1.4
client glx extensions:
    GLX_ARB_create_context, GLX_ARB_create_context_profile, 
    GLX_ARB_create_context_robustness, GLX_ARB_fbconfig_float, 
    GLX_ARB_framebuffer_sRGB, GLX_ARB_get_proc_address, GLX_ARB_multisample, 
    GLX_EXT_create_context_es2_profile, GLX_EXT_fbconfig_packed_float, 
    GLX_EXT_framebuffer_sRGB, GLX_EXT_import_context, 
    GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, GLX_EXT_visual_rating, 
    GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer, 
    GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer, 
    GLX_MESA_swap_control, GLX_OML_swap_method, GLX_OML_sync_control, 
    GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, 
    GLX_SGIX_visual_select_group, GLX_SGI_make_current_read, 
    GLX_SGI_swap_control, GLX_SGI_video_sync
GLX version: 1.4
GLX extensions:
    GLX_ARB_create_context, GLX_ARB_create_context_profile, 
    GLX_ARB_fbconfig_float, GLX_ARB_framebuffer_sRGB, 
    GLX_ARB_get_proc_address, GLX_ARB_multisample, 
    GLX_EXT_create_context_es2_profile, GLX_EXT_framebuffer_sRGB, 
    GLX_EXT_import_context, GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, 
    GLX_EXT_visual_rating, GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer, 
    GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer, 
    GLX_MESA_swap_control, GLX_OML_swap_method, GLX_OML_sync_control, 
    GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, 
    GLX_SGIX_visual_select_group, GLX_SGI_make_current_read, 
    GLX_SGI_swap_control, GLX_SGI_video_sync
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) IGD 
OpenGL version string: 2.1 Mesa 10.1.1
OpenGL shading language version string: 1.20
OpenGL extensions:
    GL_3DFX_texture_compression_FXT1, GL_AMD_shader_trinary_minmax, 
    GL_ANGLE_texture_compression_dxt3, GL_ANGLE_texture_compression_dxt5, 
    GL_APPLE_object_purgeable, GL_APPLE_packed_pixels, 
    GL_APPLE_vertex_array_object, GL_ARB_ES2_compatibility, 
    GL_ARB_clear_buffer_object, GL_ARB_copy_buffer, GL_ARB_debug_output, 
    GL_ARB_depth_texture, GL_ARB_draw_buffers, 
    GL_ARB_draw_elements_base_vertex, GL_ARB_explicit_attrib_location, 
    GL_ARB_fragment_program, GL_ARB_fragment_shader, 
    GL_ARB_framebuffer_object, GL_ARB_get_program_binary, 
    GL_ARB_half_float_pixel, GL_ARB_internalformat_query, 
    GL_ARB_invalidate_subdata, GL_ARB_map_buffer_alignment, 
    GL_ARB_map_buffer_range, GL_ARB_multisample, GL_ARB_multitexture, 
    GL_ARB_occlusion_query, GL_ARB_pixel_buffer_object, 
    GL_ARB_point_parameters, GL_ARB_point_sprite, GL_ARB_provoking_vertex, 
    GL_ARB_robustness, GL_ARB_sampler_objects, GL_ARB_shader_objects, 
    GL_ARB_shading_language_100, GL_ARB_shadow, GL_ARB_sync, 
    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_ARB_texture_env_crossbar, 
    GL_ARB_texture_env_dot3, GL_ARB_texture_mirrored_repeat, 
    GL_ARB_texture_non_power_of_two, GL_ARB_texture_rectangle, 
    GL_ARB_texture_storage, GL_ARB_transpose_matrix, 
    GL_ARB_vertex_array_object, GL_ARB_vertex_attrib_binding, 
    GL_ARB_vertex_buffer_object, GL_ARB_vertex_program, GL_ARB_vertex_shader, 
    GL_ARB_window_pos, GL_ATI_blend_equation_separate, GL_ATI_draw_buffers, 
    GL_ATI_separate_stencil, GL_ATI_texture_env_combine3, GL_EXT_abgr, 
    GL_EXT_bgra, GL_EXT_blend_color, GL_EXT_blend_equation_separate, 
    GL_EXT_blend_func_separate, GL_EXT_blend_minmax, GL_EXT_blend_subtract, 
    GL_EXT_compiled_vertex_array, GL_EXT_copy_texture, 
    GL_EXT_draw_range_elements, GL_EXT_fog_coord, GL_EXT_framebuffer_blit, 
    GL_EXT_framebuffer_object, GL_EXT_gpu_program_parameters, 
    GL_EXT_multi_draw_arrays, GL_EXT_packed_depth_stencil, 
    GL_EXT_packed_pixels, GL_EXT_pixel_buffer_object, GL_EXT_point_parameters, 
    GL_EXT_polygon_offset, GL_EXT_provoking_vertex, GL_EXT_rescale_normal, 
    GL_EXT_secondary_color, GL_EXT_separate_shader_objects, 
    GL_EXT_separate_specular_color, GL_EXT_shadow_funcs, 
    GL_EXT_stencil_two_side, GL_EXT_stencil_wrap, GL_EXT_subtexture, 
    GL_EXT_texture, GL_EXT_texture3D, GL_EXT_texture_compression_dxt1, 
    GL_EXT_texture_compression_s3tc, GL_EXT_texture_cube_map, 
    GL_EXT_texture_edge_clamp, GL_EXT_texture_env_add, 
    GL_EXT_texture_env_combine, GL_EXT_texture_env_dot3, 
    GL_EXT_texture_filter_anisotropic, GL_EXT_texture_lod_bias, 
    GL_EXT_texture_object, GL_EXT_texture_rectangle, GL_EXT_texture_sRGB, 
    GL_EXT_texture_sRGB_decode, GL_EXT_vertex_array, 
    GL_IBM_multimode_draw_arrays, GL_IBM_rasterpos_clip, 
    GL_IBM_texture_mirrored_repeat, GL_INGR_blend_func_separate, GL_KHR_debug, 
    GL_MESA_pack_invert, GL_MESA_window_pos, GL_MESA_ycbcr_texture, 
    GL_NV_blend_square, GL_NV_light_max_exponent, GL_NV_packed_depth_stencil, 
    GL_NV_texgen_reflection, GL_NV_texture_env_combine4, 
    GL_NV_texture_rectangle, GL_OES_EGL_image, GL_OES_read_format, 
    GL_S3_s3tc, GL_SGIS_generate_mipmap, GL_SGIS_texture_border_clamp, 
    GL_SGIS_texture_edge_clamp, GL_SGIS_texture_lod, GL_SUN_multi_draw_arrays

12 GLX Visuals
    visual  x   bf lv rg d st  colorbuffer  sr ax dp st accumbuffer  ms  cav
  id dep cl sp  sz l  ci b ro  r  g  b  a F gb bf th cl  r  g  b  a ns b eat
----------------------------------------------------------------------------
0x020 24 tc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x021 24 dc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x074 24 tc  0  32  0 r  y .   8  8  8  8 .  .  0  0  0  0  0  0  0  0 0 None
0x075 24 tc  0  32  0 r  . .   8  8  8  8 .  .  0  0  0  0  0  0  0  0 0 None
0x076 24 tc  0  32  0 r  . .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x077 24 tc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8 16 16 16 16  0 0 Slow
0x078 24 dc  0  32  0 r  y .   8  8  8  8 .  .  0  0  0  0  0  0  0  0 0 None
0x079 24 dc  0  32  0 r  . .   8  8  8  8 .  .  0  0  0  0  0  0  0  0 0 None
0x07a 24 dc  0  32  0 r  . .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x07b 24 dc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x07c 24 dc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8 16 16 16 16  0 0 Slow
0x05b 32 tc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None

24 GLXFBConfigs:
    visual  x   bf lv rg d st  colorbuffer  sr ax dp st accumbuffer  ms  cav
  id dep cl sp  sz l  ci b ro  r  g  b  a F gb bf th cl  r  g  b  a ns b eat
----------------------------------------------------------------------------
0x05c  0 tc  0  16  0 r  y .   5  6  5  0 .  .  0  0  0  0  0  0  0  0 0 None
0x05d  0 tc  0  16  0 r  . .   5  6  5  0 .  .  0  0  0  0  0  0  0  0 0 None
0x05e  0 tc  0  16  0 r  y .   5  6  5  0 .  .  0 16  0  0  0  0  0  0 0 None
0x05f  0 tc  0  16  0 r  . .   5  6  5  0 .  .  0 16  0  0  0  0  0  0 0 None
0x060 24 tc  0  32  0 r  y .   8  8  8  8 .  .  0  0  0  0  0  0  0  0 0 None
0x061 24 tc  0  32  0 r  . .   8  8  8  8 .  .  0  0  0  0  0  0  0  0 0 None
0x062 24 tc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x063 24 tc  0  32  0 r  . .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x064  0 tc  0  16  0 r  y .   5  6  5  0 .  .  0 16  0  0  0  0  0  0 0 None
0x065  0 tc  0  16  0 r  y .   5  6  5  0 .  .  0 16  0 16 16 16  0  0 0 Slow
0x066 32 tc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x067 24 tc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8 16 16 16 16  0 0 Slow
0x068  0 dc  0  16  0 r  y .   5  6  5  0 .  .  0  0  0  0  0  0  0  0 0 None
0x069  0 dc  0  16  0 r  . .   5  6  5  0 .  .  0  0  0  0  0  0  0  0 0 None
0x06a  0 dc  0  16  0 r  y .   5  6  5  0 .  .  0 16  0  0  0  0  0  0 0 None
0x06b  0 dc  0  16  0 r  . .   5  6  5  0 .  .  0 16  0  0  0  0  0  0 0 None
0x06c 24 dc  0  32  0 r  y .   8  8  8  8 .  .  0  0  0  0  0  0  0  0 0 None
0x06d 24 dc  0  32  0 r  . .   8  8  8  8 .  .  0  0  0  0  0  0  0  0 0 None
0x06e 24 dc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x06f 24 dc  0  32  0 r  . .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x070  0 dc  0  16  0 r  y .   5  6  5  0 .  .  0 16  0  0  0  0  0  0 0 None
0x071  0 dc  0  16  0 r  y .   5  6  5  0 .  .  0 16  0 16 16 16  0  0 0 Slow
0x072 24 dc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8  0  0  0  0  0 0 None
0x073 24 dc  0  32  0 r  y .   8  8  8  8 .  .  0 24  8 16 16 16 16  0 0 Slow

[li] lspci : 00:02.0 VGA compatible controller: Intel Corporation Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller[/li][/ul]

Thanks !

2

Is the context single buffered? Try calling glFlush before the buffer swap call.

3

You should probably be requesting double buffering and have some error checking in there too, there’s an SDL example here that has both that might be of some help.

4

Hello, thank you for your answer. Here’s what I get :

SDL Error: Unknown touch device

  • line: 62
    SDL Error: Could not create GL context
  • line: 66

Lines 65 and 66 :

maincontext = SDL_GL_CreateContext(mainwindow);
checkSDLError(LINE);

5

I may be wrong but in your GL_Info says: OpenGL version string: 2.1 Mesa 10.1.1

Does not that mean that your hardware/drive only supports up to opengl 2.1? And you are trying to create a context with 3.2.
Try to open a context with 2.1 and see what happens

6

[QUOTE=alexgg.developer;1259313]I may be wrong but in your GL_Info says: OpenGL version string: 2.1 Mesa 10.1.1

Does not that mean that your hardware/drive only supports up to opengl 2.1? And you are trying to create a context with 3.2.
Try to open a context with 2.1 and see what happens[/QUOTE]

That solved it. I feel stupid now :stuck_out_tongue:

Thank you !