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最近我尝试在 Linux 下使用 MSAA（多采样抗锯齿）。结果令人惊讶：使用 Nvidia 专有驱动程序一切正常，但使用 nouveau 驱动程序就不行了。奇怪的是，glxingo 说 GLX_ARB_multisample 是受支持的，我能够获得适当的 FBConfig，其中 GLX_SAMPLE_BUFFERS 设置为 1，GLX_SAMPLES 设置为 4（或 8）。但是在渲染方面，图片没有应用抗锯齿。我的项目和 freeglut 都存在这个问题，所以我将提供一个基于 glut 的小型程序来证明这个问题：

/*
 * Test multisampling and polygon smoothing.
 *
 * Brian Paul
 * 4 November 2002
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>


static GLfloat Zrot = 0;
static GLboolean Anim = GL_TRUE;
static GLboolean HaveMultisample = GL_TRUE;
static GLboolean DoMultisample = GL_TRUE;


static void
PrintString(const char *s)
{
   while (*s) {
      glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
      s++;
   }
}


static void
Polygon( GLint verts, GLfloat radius, GLfloat z )
{
   int i;
   for (i = 0; i < verts; i++) {
      float a = (i * 2.0 * 3.14159) / verts;
      float x = radius * cos(a);
      float y = radius * sin(a);
      glVertex3f(x, y, z);
   }
}


static void
DrawObject( void )
{
   glLineWidth(3.0);
   glColor3f(1, 1, 1);
   glBegin(GL_LINE_LOOP);
   Polygon(12, 1.2, 0);
   glEnd();

   glLineWidth(1.0);
   glColor3f(1, 1, 1);
   glBegin(GL_LINE_LOOP);
   Polygon(12, 1.1, 0);
   glEnd();

   glColor3f(1, 0, 0);
   glBegin(GL_POLYGON);
   Polygon(12, 0.4, 0.3);
   glEnd();

   glColor3f(0, 1, 0);
   glBegin(GL_POLYGON);
   Polygon(12, 0.6, 0.2);
   glEnd();

   glColor3f(0, 0, 1);
   glBegin(GL_POLYGON);
   Polygon(12, 0.8, 0.1);
   glEnd();

   glColor3f(1, 1, 1);
   glBegin(GL_POLYGON);
   Polygon(12, 1.0, 0);
   glEnd();
}


static void
Display( void )
{
   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

   glColor3f(1, 1, 1);
   if (HaveMultisample) {
      glRasterPos2f(-3.1, -1.6);
      if (DoMultisample)
         PrintString("MULTISAMPLE");
      else
         PrintString("MULTISAMPLE (off)");
   }
   glRasterPos2f(-0.8, -1.6);
   PrintString("No antialiasing");
   glRasterPos2f(1.6, -1.6);
   PrintString("GL_POLYGON_SMOOTH");

   /* multisample */
   if (HaveMultisample) {
      glEnable(GL_DEPTH_TEST);
      if (DoMultisample)
         glEnable(GL_MULTISAMPLE_ARB);
      glPushMatrix();
      glTranslatef(-2.5, 0, 0);
      glPushMatrix();
      glRotatef(Zrot, 0, 0, 1);
      DrawObject();
      glPopMatrix();
      glPopMatrix();
      glDisable(GL_MULTISAMPLE_ARB);
      glDisable(GL_DEPTH_TEST);
   }

   /* non-aa */
   glEnable(GL_DEPTH_TEST);
   glPushMatrix();
   glTranslatef(0, 0, 0);
   glPushMatrix();
   glRotatef(Zrot, 0, 0, 1);
   DrawObject();
   glPopMatrix();
   glPopMatrix();
   glDisable(GL_DEPTH_TEST);

   /* polygon smooth */
   glEnable(GL_POLYGON_SMOOTH);
   glEnable(GL_LINE_SMOOTH);
   glEnable(GL_BLEND);
   glPushMatrix();
   glTranslatef(2.5, 0, 0);
   glPushMatrix();
   glRotatef(Zrot, 0, 0, 1);
   DrawObject();
   glPopMatrix();
   glPopMatrix();
   glDisable(GL_LINE_SMOOTH);
   glDisable(GL_POLYGON_SMOOTH);
   glDisable(GL_BLEND);

   glutSwapBuffers();
}


static void
Reshape( int width, int height )
{
   GLfloat ar = (float) width / (float) height;
   glViewport( 0, 0, width, height );
   glMatrixMode( GL_PROJECTION );
   glLoadIdentity();
   glOrtho(-2.0*ar, 2.0*ar, -2.0, 2.0, -1.0, 1.0);
   glMatrixMode( GL_MODELVIEW );
   glLoadIdentity();
}


static void
Idle( void )
{
   Zrot = 0.01 * glutGet(GLUT_ELAPSED_TIME);
   glutPostRedisplay();
}


static void
Key( unsigned char key, int x, int y )
{
   const GLfloat step = 1.0;
   (void) x;
   (void) y;
   switch (key) {
      case 'a':
         Anim = !Anim;
         if (Anim)
            glutIdleFunc(Idle);
         else
            glutIdleFunc(NULL);
         break;
      case 'm':
         DoMultisample = !DoMultisample;
         break;
      case 'z':
         Zrot = (int) (Zrot - step);
         break;
      case 'Z':
         Zrot = (int) (Zrot + step);
         break;
      case 27:
         exit(0);
         break;
   }
   glutPostRedisplay();
}


static void
Init( void )
{
   /* GLUT imposes the four samples/pixel requirement */
   int s;
   glGetIntegerv(GL_SAMPLES_ARB, &s);
   if (!glutExtensionSupported("GL_ARB_multisample") || s < 1) {
      printf("Warning: multisample antialiasing not supported.\n");
      HaveMultisample = GL_FALSE;
   }
   printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
   printf("GL_SAMPLES_ARB = %d\n", s);

   glBlendFunc(GL_SRC_ALPHA, GL_ONE);
   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
   glBlendFunc(GL_SRC_ALPHA_SATURATE, GL_ONE);

   glGetIntegerv(GL_MULTISAMPLE_ARB, &s);
   printf("GL_MULTISAMPLE_ARB = %d\n", s);
}


int
main( int argc, char *argv[] )
{
   glutInit( &argc, argv );
   glutInitWindowPosition( 0, 0 );
   glutInitWindowSize( 600, 300 );
   glutInitDisplayMode( GLUT_RGB | GLUT_ALPHA | GLUT_DOUBLE |
                        GLUT_DEPTH | GLUT_MULTISAMPLE );
   glutCreateWindow(argv[0]);
   glutReshapeFunc( Reshape );
   glutKeyboardFunc( Key );
   glutDisplayFunc( Display );
   if (Anim)
      glutIdleFunc( Idle );
   Init();
   glutMainLoop();
   return 0;
}

这是 glxinfo 输出（不包括视觉信息）：

name of display: :0.0
display: :0  screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.4
server glx extensions:
    GLX_ARB_multisample, GLX_EXT_import_context, GLX_EXT_texture_from_pixmap, 
    GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_copy_sub_buffer, 
    GLX_OML_swap_method, GLX_SGI_swap_control, GLX_SGIS_multisample, 
    GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group, 
    GLX_INTEL_swap_event
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_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context, 
    GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_EXT_framebuffer_sRGB, 
    GLX_EXT_create_context_es2_profile, GLX_MESA_copy_sub_buffer, 
    GLX_MESA_multithread_makecurrent, GLX_MESA_swap_control, 
    GLX_OML_swap_method, GLX_OML_sync_control, GLX_SGI_make_current_read, 
    GLX_SGI_swap_control, GLX_SGI_video_sync, GLX_SGIS_multisample, 
    GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group, 
    GLX_EXT_texture_from_pixmap, GLX_INTEL_swap_event
GLX version: 1.4
GLX extensions:
    GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context, 
    GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_copy_sub_buffer, 
    GLX_MESA_multithread_makecurrent, GLX_MESA_swap_control, 
    GLX_OML_swap_method, GLX_OML_sync_control, GLX_SGI_make_current_read, 
    GLX_SGI_swap_control, GLX_SGI_video_sync, GLX_SGIS_multisample, 
    GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group, 
    GLX_EXT_texture_from_pixmap
OpenGL vendor string: nouveau
OpenGL renderer string: Gallium 0.4 on NVC1
OpenGL version string: 2.1 Mesa 8.0.4
OpenGL shading language version string: 1.30
OpenGL extensions:
    GL_ARB_multisample, GL_EXT_abgr, GL_EXT_bgra, GL_EXT_blend_color, 
    GL_EXT_blend_minmax, GL_EXT_blend_subtract, GL_EXT_copy_texture, 
    GL_EXT_polygon_offset, GL_EXT_subtexture, GL_EXT_texture_object, 
    GL_EXT_vertex_array, GL_EXT_compiled_vertex_array, GL_EXT_texture, 
    GL_EXT_texture3D, GL_IBM_rasterpos_clip, GL_ARB_point_parameters, 
    GL_EXT_draw_range_elements, GL_EXT_packed_pixels, GL_EXT_point_parameters, 
    GL_EXT_rescale_normal, GL_EXT_separate_specular_color, 
    GL_EXT_texture_edge_clamp, GL_SGIS_generate_mipmap, 
    GL_SGIS_texture_border_clamp, GL_SGIS_texture_edge_clamp, 
    GL_SGIS_texture_lod, GL_ARB_framebuffer_sRGB, GL_ARB_multitexture, 
    GL_EXT_framebuffer_sRGB, GL_IBM_multimode_draw_arrays, 
    GL_IBM_texture_mirrored_repeat, GL_ARB_texture_cube_map, 
    GL_ARB_texture_env_add, GL_ARB_transpose_matrix, 
    GL_EXT_blend_func_separate, GL_EXT_fog_coord, GL_EXT_multi_draw_arrays, 
    GL_EXT_secondary_color, GL_EXT_texture_env_add, 
    GL_EXT_texture_filter_anisotropic, GL_EXT_texture_lod_bias, 
    GL_INGR_blend_func_separate, GL_NV_blend_square, GL_NV_light_max_exponent, 
    GL_NV_texgen_reflection, GL_NV_texture_env_combine4, 
    GL_SUN_multi_draw_arrays, GL_ARB_texture_border_clamp, 
    GL_ARB_texture_compression, GL_EXT_framebuffer_object, 
    GL_EXT_texture_env_combine, GL_EXT_texture_env_dot3, GL_MESA_window_pos, 
    GL_NV_packed_depth_stencil, GL_NV_texture_rectangle, GL_ARB_depth_texture, 
    GL_ARB_occlusion_query, GL_ARB_shadow, GL_ARB_texture_env_combine, 
    GL_ARB_texture_env_crossbar, GL_ARB_texture_env_dot3, 
    GL_ARB_texture_mirrored_repeat, GL_ARB_window_pos, 
    GL_EXT_stencil_two_side, GL_EXT_texture_cube_map, GL_NV_depth_clamp, 
    GL_NV_fog_distance, GL_APPLE_packed_pixels, GL_APPLE_vertex_array_object, 
    GL_ARB_draw_buffers, GL_ARB_fragment_program, GL_ARB_fragment_shader, 
    GL_ARB_shader_objects, GL_ARB_vertex_program, GL_ARB_vertex_shader, 
    GL_ATI_draw_buffers, GL_ATI_texture_env_combine3, GL_EXT_shadow_funcs, 
    GL_EXT_stencil_wrap, GL_MESA_pack_invert, GL_NV_primitive_restart, 
    GL_ARB_depth_clamp, GL_ARB_fragment_program_shadow, 
    GL_ARB_half_float_pixel, GL_ARB_occlusion_query2, GL_ARB_point_sprite, 
    GL_ARB_shading_language_100, GL_ARB_sync, GL_ARB_texture_non_power_of_two, 
    GL_ARB_vertex_buffer_object, GL_ATI_blend_equation_separate, 
    GL_EXT_blend_equation_separate, GL_OES_read_format, 
    GL_ARB_color_buffer_float, GL_ARB_pixel_buffer_object, 
    GL_ARB_texture_compression_rgtc, GL_ARB_texture_rectangle, 
    GL_ATI_texture_compression_3dc, GL_EXT_packed_float, 
    GL_EXT_pixel_buffer_object, GL_EXT_texture_compression_rgtc, 
    GL_EXT_texture_mirror_clamp, GL_EXT_texture_rectangle, 
    GL_EXT_texture_sRGB, GL_EXT_texture_shared_exponent, 
    GL_ARB_framebuffer_object, GL_EXT_framebuffer_blit, 
    GL_EXT_framebuffer_multisample, GL_EXT_packed_depth_stencil, 
    GL_ARB_vertex_array_object, GL_ATI_separate_stencil, 
    GL_ATI_texture_mirror_once, GL_EXT_draw_buffers2, GL_EXT_draw_instanced, 
    GL_EXT_gpu_program_parameters, GL_EXT_texture_array, 
    GL_EXT_texture_compression_latc, GL_EXT_texture_integer, 
    GL_EXT_texture_sRGB_decode, GL_EXT_timer_query, GL_OES_EGL_image, 
    GL_MESA_texture_array, GL_ARB_copy_buffer, GL_ARB_depth_buffer_float, 
    GL_ARB_draw_instanced, GL_ARB_half_float_vertex, GL_ARB_instanced_arrays, 
    GL_ARB_map_buffer_range, GL_ARB_texture_rg, GL_ARB_texture_swizzle, 
    GL_ARB_vertex_array_bgra, GL_EXT_separate_shader_objects, 
    GL_EXT_texture_swizzle, GL_EXT_vertex_array_bgra, 
    GL_NV_conditional_render, GL_AMD_conservative_depth, 
    GL_AMD_draw_buffers_blend, GL_ARB_ES2_compatibility, 
    GL_ARB_draw_buffers_blend, GL_ARB_draw_elements_base_vertex, 
    GL_ARB_explicit_attrib_location, GL_ARB_fragment_coord_conventions, 
    GL_ARB_provoking_vertex, GL_ARB_sampler_objects, GL_ARB_seamless_cube_map, 
    GL_ARB_shader_texture_lod, GL_EXT_provoking_vertex, GL_EXT_texture_snorm, 
    GL_MESA_texture_signed_rgba, GL_NV_texture_barrier, GL_ARB_robustness, 
    GL_ARB_transform_feedback2, GL_ARB_conservative_depth, 
    GL_ARB_texture_storage, GL_EXT_transform_feedback

glewIsSupported 表示扩展可用，glGetIntegerv 表示样本数为 4，在获取 FBConfig 时指定。我不知道发生了什么。

Edit: Here is the output of glXQueryExtensionsString: GLX_ARB_get_proc_address GLX_ARB_multisample GLX_EXT_import_context GLX_EXT_visual_info GLX_EXT_visual_rating GLX_MESA_copy_sub_buffer GLX_MESA_multithread_makecurrent GLX_MESA_swap_control GLX_OML_swap_method GLX_OML_sync_control GLX_SGI_make_current_read GLX_SGI_swap_control GLX_SGI_video_sync GLX_SGIS_multisample GLX_SGIX_fbconfig GLX_SGIX_pbuffer GLX_SGIX_visual_select_group GLX_EXT_texture_from_pixmap

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1 回答 1

1

忘记 MSAA。在 nouveau 上，除非你有非常新鲜的 MESA + kernel + X.org。

MSAA 是 OpenGL 3.0 及更高版本的要求。因此，直到最近，它在优先级列表中的位置并不高。为此，您需要 Mesa 9.0。

（如果您想获得有关如何获取所需软件的提示，请发布您的硬件和软件 - 发行版、内核、台面、xorg - 版本）。

于 2012-11-14T20:10:05.743 回答