Viewport: MSAA support during ViewportRendering

When rendering viewport to an offscreen buffer the buffer was
constructed for non anti aliasing (0 samples). This made the objects
that are drawn by the `object_mode` including `wireframe` draw type
non-anti-aliased.

The offscreen buffers will be constructed based on the user setting for
viewport multisampling (`U.ogl_multisamples`). The same setting will
also be used when previewing scene strips in the sequencer. For now
this only improves wireframe drawing in the scene strips. To improve the
Anti aliasing in the scene strips we need to get finer control in the
draw manager. This will be part of a different patch I am preparing.

Please note that this patch also cleansup some unused code in the offscreen rendering (FSAA code was still existing, but never called)

Reviewed By: brecht

Maniphest Tasks: T64849

Differential Revision: https://developer.blender.org/D4907

1 files changed, 22 insertions, 117 deletions

diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index 54955c83ad9..2ce67bfbe4c 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -1595,7 +1595,6 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Depsgraph *depsgraph,
                                       int sizex,
                                       int sizey,
                                       uint flag,
-                                      uint draw_flags,
                                       int alpha_mode,
                                       int samples,
                                       const char *viewname,
@@ -1605,7 +1604,6 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Depsgraph *depsgraph,
 {
   RegionView3D *rv3d = ar->regiondata;
   const bool draw_sky = (alpha_mode == R_ADDSKY);
-  const bool use_full_sample = (draw_flags & V3D_OFSDRAW_USE_FULL_SAMPLE);
 
   /* view state */
   bool is_ortho = false;
@@ -1627,7 +1625,7 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Depsgraph *depsgraph,
 
   if (own_ofs) {
     /* bind */
-    ofs = GPU_offscreen_create(sizex, sizey, use_full_sample ? 0 : samples, true, false, err_out);
+    ofs = GPU_offscreen_create(sizex, sizey, samples, true, false, err_out);
     if (ofs == NULL) {
       DRW_opengl_context_disable();
       return NULL;
@@ -1683,120 +1681,28 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Depsgraph *depsgraph,
     }
   }
 
-  if ((samples && use_full_sample) == 0) {
-    const bool do_color_management = (ibuf->rect_float == NULL);
-    /* Single-pass render, common case */
-    ED_view3d_draw_offscreen(depsgraph,
-                             scene,
-                             drawtype,
-                             v3d,
-                             ar,
-                             sizex,
-                             sizey,
-                             NULL,
-                             winmat,
-                             draw_sky,
-                             !is_ortho,
-                             viewname,
-                             do_color_management,
-                             ofs,
-                             NULL);
-
-    if (ibuf->rect_float) {
-      GPU_offscreen_read_pixels(ofs, GL_FLOAT, ibuf->rect_float);
-    }
-    else if (ibuf->rect) {
-      GPU_offscreen_read_pixels(ofs, GL_UNSIGNED_BYTE, ibuf->rect);
-    }
-  }
-  else {
-    /* Multi-pass render, use accumulation buffer & jitter for 'full' oversampling.
-     * Use because OpenGL may use a lower quality MSAA, and only over-sample edges. */
-    static float jit_ofs[32][2];
-    float winmat_jitter[4][4];
-    float *rect_temp = (ibuf->rect_float) ?
-                           ibuf->rect_float :
-                           MEM_mallocN(sizex * sizey * sizeof(float[4]), "rect_temp");
-    float *accum_buffer = MEM_mallocN(sizex * sizey * sizeof(float[4]), "accum_buffer");
-    GPUViewport *viewport = GPU_viewport_create_from_offscreen(ofs);
-
-    BLI_jitter_init(jit_ofs, samples);
-
-    /* first sample buffer, also initializes 'rv3d->persmat' */
-    ED_view3d_draw_offscreen(depsgraph,
-                             scene,
-                             drawtype,
-                             v3d,
-                             ar,
-                             sizex,
-                             sizey,
-                             NULL,
-                             winmat,
-                             draw_sky,
-                             !is_ortho,
-                             viewname,
-                             false,
-                             ofs,
-                             viewport);
-    GPU_offscreen_read_pixels(ofs, GL_FLOAT, accum_buffer);
-
-    /* skip the first sample */
-    for (int j = 1; j < samples; j++) {
-      copy_m4_m4(winmat_jitter, winmat);
-      window_translate_m4(winmat_jitter,
-                          rv3d->persmat,
-                          (jit_ofs[j][0] * 2.0f) / sizex,
-                          (jit_ofs[j][1] * 2.0f) / sizey);
-
-      ED_view3d_draw_offscreen(depsgraph,
-                               scene,
-                               drawtype,
-                               v3d,
-                               ar,
-                               sizex,
-                               sizey,
-                               NULL,
-                               winmat_jitter,
-                               draw_sky,
-                               !is_ortho,
-                               viewname,
-                               false,
-                               ofs,
-                               viewport);
-      GPU_offscreen_read_pixels(ofs, GL_FLOAT, rect_temp);
-
-      uint i = sizex * sizey * 4;
-      while (i--) {
-        accum_buffer[i] += rect_temp[i];
-      }
-    }
-
-    {
-      /* don't free data owned by 'ofs' */
-      GPU_viewport_clear_from_offscreen(viewport);
-      GPU_viewport_free(viewport);
-    }
+  const bool do_color_management = (ibuf->rect_float == NULL);
+  ED_view3d_draw_offscreen(depsgraph,
+                           scene,
+                           drawtype,
+                           v3d,
+                           ar,
+                           sizex,
+                           sizey,
+                           NULL,
+                           winmat,
+                           draw_sky,
+                           !is_ortho,
+                           viewname,
+                           do_color_management,
+                           ofs,
+                           NULL);
 
-    if (ibuf->rect_float == NULL) {
-      MEM_freeN(rect_temp);
-    }
-
-    if (ibuf->rect_float) {
-      float *rect_float = ibuf->rect_float;
-      uint i = sizex * sizey * 4;
-      while (i--) {
-        rect_float[i] = accum_buffer[i] / samples;
-      }
-    }
-    else {
-      uchar *rect_ub = (uchar *)ibuf->rect;
-      uint i = sizex * sizey * 4;
-      while (i--) {
-        rect_ub[i] = (uchar)(255.0f * accum_buffer[i] / samples);
-      }
-    }
-
-    MEM_freeN(accum_buffer);
+  if (ibuf->rect_float) {
+    GPU_offscreen_read_pixels(ofs, GL_FLOAT, ibuf->rect_float);
+  }
+  else if (ibuf->rect) {
+    GPU_offscreen_read_pixels(ofs, GL_UNSIGNED_BYTE, ibuf->rect);
   }
 
   /* unbind */
@@ -1905,7 +1811,6 @@ ImBuf *ED_view3d_draw_offscreen_imbuf_simple(Depsgraph *depsgraph,
                                         width,
                                         height,
                                         flag,
-                                        draw_flags,
                                         alpha_mode,
                                         samples,
                                         viewname,