Attachment 43096 Details for Bug 33934 – Test case showing the performance difference

Test case showing the performance difference

copy-tex-subimage.c (text/x-csrc), 4.78 KB, created by Neil Roberts on 2011-02-08 05:08:06 UTC

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Creator: Neil Roberts

Created: 2011-02-08 05:08:06 UTC

Size: 4.78 KB

patch

obsolete

>#include <GL/glew.h>
>#include <GL/freeglut.h>
>#include <GL/gl.h>
>#include <stdio.h>
>#include <string.h>
>
>typedef struct
>{
>  int x, y;
>  int tx, ty;
>} Vert;
>
>#define TEX_SIZE 1024
>
>enum BlitMode
>  {
>    BLIT_MODE_BLIT_FRAMEBUFFER,
>    BLIT_MODE_COPY_TEX_SUBIMAGE,
>
>    BLIT_MODE_COUNT
>  };
>
>static const char *
>blit_mode_names[BLIT_MODE_COUNT] = {
>  "glBlitFramebuffer",
>  "glCopyTexSubImage2D"
>};
>
>#define N_FRAMES_PER_MODE 2
>#define MODE_FOR_FRAME(frame_num) (((frame_num) - 1) / N_FRAMES_PER_MODE)
>
>static int mode_start_time;
>static int frame_num = 0;
>
>static void
>display_cb (void)
>{
>  GLuint texa, texb;
>  GLuint fboa, fbob;
>  static const Vert verts[] =
>    {
>      { -1,   -1,    0, 0 },
>      { 1,    -1,    1, 0 },
>      { -1,   1,     0, 1 },
>      { 1,    1,     1, 1 }
>    };
>  GLubyte tex_data[TEX_SIZE * TEX_SIZE * 4], *p;
>  GLuint x, y;
>  enum BlitMode blit_mode;
>
>  glClear (GL_COLOR_BUFFER_BIT);
>
>  /* Don't do anything for the first frame in case it affects timing */
>  if (frame_num == 0)
>     {
>       frame_num = 1;
>       glutSwapBuffers ();
>       return;
>     }
>
>   blit_mode = MODE_FOR_FRAME (frame_num);
>
>   if (frame_num == 1 ||
>       MODE_FOR_FRAME (frame_num - 1) != blit_mode)
>     mode_start_time = glutGet (GLUT_ELAPSED_TIME);
>
>   /* Create data for a rainbow texture */
>   for (p = tex_data, y = 0; y < TEX_SIZE; y++)
>     for (x = 0; x < TEX_SIZE; x++)
>       {
>         *(p++) = x * 255 / TEX_SIZE;
>         *(p++) = y * 255 / TEX_SIZE;
>         *(p++) = 0;
>         *(p++) = 255;
>       }
>
>   /* Upload it to a texture */
>   glGenTextures (1, &texa);
>   glBindTexture (GL_TEXTURE_2D, texa);
>   glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
>   glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, TEX_SIZE, TEX_SIZE, 0,
>                 GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
>
>   /* Bind it to a framebuffer */
>   glGenFramebuffers (1, &fboa);
>   glBindFramebuffer (GL_READ_FRAMEBUFFER, fboa);
>   glFramebufferTexture2D (GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
>                           GL_TEXTURE_2D, texa, 0);
>
>   /* Create a second texture at the same size and format with no
>      data */
>   glGenTextures (1, &texb);
>   glBindTexture (GL_TEXTURE_2D, texb);
>   glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
>   glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, TEX_SIZE, TEX_SIZE, 0,
>                 GL_RGBA, GL_UNSIGNED_BYTE, NULL);
>
>   if (blit_mode == BLIT_MODE_BLIT_FRAMEBUFFER)
>     {
>       /* Create a separate fbo for the dest texture */
>       glGenFramebuffers (1, &fbob);
>       glBindFramebuffer (GL_DRAW_FRAMEBUFFER, fbob);
>       glFramebufferTexture2D (GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
>                               GL_TEXTURE_2D, texb, 0);
>
>       /* Fill the texture by blitting one pixel at a time */
>       for (y = 0; y < TEX_SIZE; y++)
>         for (x = 0; x < TEX_SIZE; x++)
>           glBlitFramebuffer (x, y, x + 1, y + 1,
>                              x, y, x + 1, y + 1,
>                              GL_COLOR_BUFFER_BIT,
>                              GL_NEAREST);
>
>       glDeleteFramebuffers (1, &fbob);
>     }
>   else
>     {
>       /* Fill the texture by blitting one pixel at a time */
>       for (y = 0; y < TEX_SIZE; y++)
>         for (x = 0; x < TEX_SIZE; x++)
>           glCopyTexSubImage2D (GL_TEXTURE_2D,
>                                0,
>                                x, y,
>                                x, y,
>                                1, 1);
>     }
>
>   /* Restore the framebuffer binding to the window */
>   glBindFramebuffer (GL_FRAMEBUFFER, 0);
>
>   /* Draw the target texture to verify that it worked */
>   glEnableClientState (GL_VERTEX_ARRAY);
>   glVertexPointer (2, GL_INT, sizeof (Vert), &verts[0].x);
>   glEnableClientState (GL_TEXTURE_COORD_ARRAY);
>   glTexCoordPointer (2, GL_INT, sizeof (Vert), &verts[0].tx);
>   glEnable (GL_TEXTURE_2D);
>
>   glDrawArrays (GL_TRIANGLE_STRIP, 0, 4);
>
>   glDisable (GL_TEXTURE_2D);
>   glDisableClientState (GL_TEXTURE_COORD_ARRAY);
>   glDisableClientState (GL_VERTEX_ARRAY);
>
>   /* Clean up the resources */
>   glDeleteFramebuffers (1, &fboa);
>   glBindTexture (GL_TEXTURE_2D, 0);
>   glDeleteTextures (1, &texa);
>   glDeleteTextures (1, &texb);
>
>   glutSwapBuffers ();
>
>   if (MODE_FOR_FRAME (frame_num + 1) != blit_mode)
>     {
>       printf ("time for %s = %i\n",
>               blit_mode_names[blit_mode],
>               glutGet (GLUT_ELAPSED_TIME) - mode_start_time);
>       if (MODE_FOR_FRAME (frame_num + 1) >= BLIT_MODE_COUNT)
>         exit (0);
>    }
>
>   frame_num++;
>}
>
>void
>idle_cb (void)
>{
>  glutPostRedisplay ();
>}
>
>int
>main (int argc, char **argv)
>{
>  glutInit (&argc, argv);
>  glutInitDisplayMode (GLUT_RGB | GLUT_DOUBLE);
>  glutInitWindowSize (512, 512);
>  glutCreateWindow ("Inter-texture blit test");
>  glutDisplayFunc (display_cb);
>  glutIdleFunc (idle_cb);
>  glewInit ();
>
>  glutMainLoop ();
>
>  return 0;
>}

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Attachments on bug 33934: 42961 | 43096 | 43167

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