Fix T73931: Stereo Viewport Color Management

Stereoscopic viewport didn't support Color Manangement due recent
changes in the color management pipeline. In order to solve the issue we
will migrate the strereo rendering into the GPUViewport. This will share
some textures and reduce required GPU memory.

Reviewed By: fclem, dfelinto

Differential Revision: https://developer.blender.org/D6922

6 files changed, 35 insertions, 140 deletions

diff --git a/source/blender/windowmanager/WM_api.h b/source/blender/windowmanager/WM_api.h
index 1be7a8679c4..7426d64c769 100644
--- a/source/blender/windowmanager/WM_api.h
+++ b/source/blender/windowmanager/WM_api.h
@@ -778,7 +778,7 @@ void WM_draw_region_viewport_unbind(struct ARegion *region);
 
 /* Region drawing */
 void WM_draw_region_free(struct ARegion *region);
-struct GPUViewport *WM_draw_region_get_viewport(struct ARegion *region, int view);
+struct GPUViewport *WM_draw_region_get_viewport(struct ARegion *region);
 struct GPUViewport *WM_draw_region_get_bound_viewport(struct ARegion *region);
 
 void WM_main_playanim(int argc, const char **argv);
diff --git a/source/blender/windowmanager/intern/wm_draw.c b/source/blender/windowmanager/intern/wm_draw.c
index 5289b747f05..38cd667c422 100644
--- a/source/blender/windowmanager/intern/wm_draw.c
+++ b/source/blender/windowmanager/intern/wm_draw.c
@@ -235,7 +235,7 @@ static void wm_region_test_render_do_draw(const Scene *scene,
   if (sa->spacetype == SPACE_VIEW3D && region->regiontype == RGN_TYPE_WINDOW) {
     RegionView3D *rv3d = region->regiondata;
     RenderEngine *engine = rv3d->render_engine;
-    GPUViewport *viewport = WM_draw_region_get_viewport(region, 0);
+    GPUViewport *viewport = WM_draw_region_get_viewport(region);
 
     if (engine && (engine->flag & RE_ENGINE_DO_DRAW)) {
       View3D *v3d = sa->spacedata.first;
@@ -332,10 +332,8 @@ static void wm_draw_callbacks(wmWindow *win)
 static void wm_draw_region_buffer_free(ARegion *region)
 {
   if (region->draw_buffer) {
-    for (int view = 0; view < 2; view++) {
-      if (region->draw_buffer->viewport[view]) {
-        GPU_viewport_free(region->draw_buffer->viewport[view]);
-      }
+    if (region->draw_buffer->viewport) {
+      GPU_viewport_free(region->draw_buffer->viewport);
     }
     if (region->draw_buffer->offscreen) {
       GPU_offscreen_free(region->draw_buffer->offscreen);
@@ -361,7 +359,6 @@ static void wm_draw_offscreen_texture_parameters(GPUOffScreen *offscreen)
   /* GL_TEXTURE_BASE_LEVEL = 0 by default */
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-
   glBindTexture(GL_TEXTURE_2D, 0);
 }
 
@@ -387,8 +384,8 @@ static void wm_draw_region_buffer_create(ARegion *region, bool stereo, bool use_
       /* Allocate viewport which includes an offscreen buffer with depth
        * multisample, etc. */
       region->draw_buffer = MEM_callocN(sizeof(wmDrawBuffer), "wmDrawBuffer");
-      region->draw_buffer->viewport[0] = GPU_viewport_create();
-      region->draw_buffer->viewport[1] = (stereo) ? GPU_viewport_create() : NULL;
+      region->draw_buffer->viewport = stereo ? GPU_viewport_stereo_create() :
+                                               GPU_viewport_create();
     }
     else {
       /* Allocate offscreen buffer if it does not exist. This one has no
@@ -417,8 +414,8 @@ static void wm_draw_region_bind(ARegion *region, int view)
     return;
   }
 
-  if (region->draw_buffer->viewport[view]) {
-    GPU_viewport_bind(region->draw_buffer->viewport[view], &region->winrct);
+  if (region->draw_buffer->viewport) {
+    GPU_viewport_bind(region->draw_buffer->viewport, view, &region->winrct);
   }
   else {
     GPU_offscreen_bind(region->draw_buffer->offscreen, false);
@@ -432,7 +429,7 @@ static void wm_draw_region_bind(ARegion *region, int view)
   region->draw_buffer->bound_view = view;
 }
 
-static void wm_draw_region_unbind(ARegion *region, int view)
+static void wm_draw_region_unbind(ARegion *region)
 {
   if (!region->draw_buffer) {
     return;
@@ -440,8 +437,8 @@ static void wm_draw_region_unbind(ARegion *region, int view)
 
   region->draw_buffer->bound_view = -1;
 
-  if (region->draw_buffer->viewport[view]) {
-    GPU_viewport_unbind(region->draw_buffer->viewport[view]);
+  if (region->draw_buffer->viewport) {
+    GPU_viewport_unbind(region->draw_buffer->viewport);
   }
   else {
     glDisable(GL_SCISSOR_TEST);
@@ -460,14 +457,14 @@ static void wm_draw_region_blit(ARegion *region, int view)
     view = 0;
   }
   else if (view > 0) {
-    if (region->draw_buffer->viewport[view] == NULL) {
+    if (region->draw_buffer->viewport == NULL) {
       /* Region does not need stereo or failed to allocate stereo buffers. */
       view = 0;
     }
   }
 
-  if (region->draw_buffer->viewport[view]) {
-    GPU_viewport_draw_to_screen(region->draw_buffer->viewport[view], &region->winrct);
+  if (region->draw_buffer->viewport) {
+    GPU_viewport_draw_to_screen(region->draw_buffer->viewport, view, &region->winrct);
   }
   else {
     GPU_offscreen_draw_to_screen(
@@ -481,8 +478,9 @@ GPUTexture *wm_draw_region_texture(ARegion *region, int view)
     return NULL;
   }
 
-  if (region->draw_buffer->viewport[view]) {
-    return GPU_viewport_color_texture(region->draw_buffer->viewport[view]);
+  GPUViewport *viewport = region->draw_buffer->viewport;
+  if (viewport) {
+    return GPU_viewport_color_texture(viewport, view);
   }
   else {
     return GPU_offscreen_color_texture(region->draw_buffer->offscreen);
@@ -573,13 +571,14 @@ void wm_draw_region_blend(ARegion *region, int view, bool blend)
   }
 }
 
-GPUViewport *WM_draw_region_get_viewport(ARegion *region, int view)
+GPUViewport *WM_draw_region_get_viewport(ARegion *region)
 {
   if (!region->draw_buffer) {
     return NULL;
   }
 
-  return region->draw_buffer->viewport[view];
+  GPUViewport *viewport = region->draw_buffer->viewport;
+  return viewport;
 }
 
 GPUViewport *WM_draw_region_get_bound_viewport(ARegion *region)
@@ -588,8 +587,8 @@ GPUViewport *WM_draw_region_get_bound_viewport(ARegion *region)
     return NULL;
   }
 
-  int view = region->draw_buffer->bound_view;
-  return region->draw_buffer->viewport[view];
+  GPUViewport *viewport = region->draw_buffer->viewport;
+  return viewport;
 }
 
 static void wm_draw_window_offscreen(bContext *C, wmWindow *win, bool stereo)
@@ -650,14 +649,18 @@ static void wm_draw_window_offscreen(bContext *C, wmWindow *win, bool stereo)
 
             wm_draw_region_bind(region, view);
             ED_region_do_draw(C, region);
-            wm_draw_region_unbind(region, view);
+            wm_draw_region_unbind(region);
+          }
+          if (use_viewport) {
+            GPUViewport *viewport = region->draw_buffer->viewport;
+            GPU_viewport_stereo_composite(viewport, win->stereo3d_format);
           }
         }
         else {
           wm_draw_region_buffer_create(region, false, use_viewport);
           wm_draw_region_bind(region, 0);
           ED_region_do_draw(C, region);
-          wm_draw_region_unbind(region, 0);
+          wm_draw_region_unbind(region);
         }
 
         region->do_draw = false;
@@ -686,7 +689,7 @@ static void wm_draw_window_offscreen(bContext *C, wmWindow *win, bool stereo)
       glClearColor(0, 0, 0, 0);
       glClear(GL_COLOR_BUFFER_BIT);
       ED_region_do_draw(C, region);
-      wm_draw_region_unbind(region, 0);
+      wm_draw_region_unbind(region);
 
       region->do_draw = false;
       CTX_wm_menu_set(C, NULL);
@@ -715,19 +718,8 @@ static void wm_draw_window_onscreen(bContext *C, wmWindow *win, int view)
   {
     for (ARegion *region = sa->regionbase.first; region; region = region->next) {
       if (region->visible && region->overlap == false) {
-        if (view == -1 && region->draw_buffer && region->draw_buffer->stereo) {
-          /* Stereo drawing from textures. */
-          if (win->stereo3d_format->display_mode == S3D_DISPLAY_ANAGLYPH) {
-            wm_stereo3d_draw_anaglyph(win, region);
-          }
-          else {
-            wm_stereo3d_draw_interlace(win, region);
-          }
-        }
-        else {
-          /* Blit from offscreen buffer. */
-          wm_draw_region_blit(region, view);
-        }
+        /* Blit from offscreen buffer. */
+        wm_draw_region_blit(region, view);
       }
     }
   }
@@ -789,7 +781,6 @@ static void wm_draw_window(bContext *C, wmWindow *win)
 {
   bScreen *screen = WM_window_get_active_screen(win);
   bool stereo = WM_stereo3d_enabled(win, false);
-
   /* Draw area regions into their own framebuffer. This way we can redraw
    * the areas that need it, and blit the rest from existing framebuffers. */
   wm_draw_window_offscreen(C, win, stereo);
@@ -1028,7 +1019,7 @@ void wm_draw_region_test(bContext *C, ScrArea *sa, ARegion *region)
   wm_draw_region_buffer_create(region, false, use_viewport);
   wm_draw_region_bind(region, 0);
   ED_region_do_draw(C, region);
-  wm_draw_region_unbind(region, 0);
+  wm_draw_region_unbind(region);
   region->do_draw = false;
 }
 
@@ -1068,7 +1059,7 @@ void WM_draw_region_viewport_bind(ARegion *region)
 
 void WM_draw_region_viewport_unbind(ARegion *region)
 {
-  wm_draw_region_unbind(region, 0);
+  wm_draw_region_unbind(region);
 }
 
 /** \} */
diff --git a/source/blender/windowmanager/intern/wm_stereo.c b/source/blender/windowmanager/intern/wm_stereo.c
index c5f8fb71b60..8ae343d5eb5 100644
--- a/source/blender/windowmanager/intern/wm_stereo.c
+++ b/source/blender/windowmanager/intern/wm_stereo.c
@@ -53,100 +53,6 @@
 #include "UI_interface.h"
 #include "UI_resources.h"
 
-static eGPUInterlaceShader interlace_gpu_id_from_type(eStereo3dInterlaceType interlace_type)
-{
-  switch (interlace_type) {
-    case S3D_INTERLACE_ROW:
-      return GPU_SHADER_INTERLACE_ROW;
-    case S3D_INTERLACE_COLUMN:
-      return GPU_SHADER_INTERLACE_COLUMN;
-    case S3D_INTERLACE_CHECKERBOARD:
-    default:
-      return GPU_SHADER_INTERLACE_CHECKER;
-  }
-}
-
-void wm_stereo3d_draw_interlace(wmWindow *win, ARegion *region)
-{
-  bool swap = (win->stereo3d_format->flag & S3D_INTERLACE_SWAP) != 0;
-  enum eStereo3dInterlaceType interlace_type = win->stereo3d_format->interlace_type;
-
-  /* wmOrtho for the screen has this same offset */
-  float halfx = GLA_PIXEL_OFS / region->winx;
-  float halfy = GLA_PIXEL_OFS / region->winy;
-
-  GPUVertFormat *format = immVertexFormat();
-  uint texcoord = GPU_vertformat_attr_add(format, "texCoord", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
-  uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
-
-  /* leave GL_TEXTURE0 as the latest active texture */
-  for (int view = 1; view >= 0; view--) {
-    GPUTexture *texture = wm_draw_region_texture(region, view);
-    glActiveTexture(GL_TEXTURE0 + view);
-    glBindTexture(GL_TEXTURE_2D, GPU_texture_opengl_bindcode(texture));
-  }
-
-  immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_INTERLACE);
-  immUniform1i("image_a", (swap) ? 1 : 0);
-  immUniform1i("image_b", (swap) ? 0 : 1);
-
-  immUniform1i("interlace_id", interlace_gpu_id_from_type(interlace_type));
-
-  immBegin(GPU_PRIM_TRI_FAN, 4);
-
-  immAttr2f(texcoord, halfx, halfy);
-  immVertex2f(pos, region->winrct.xmin, region->winrct.ymin);
-
-  immAttr2f(texcoord, 1.0f + halfx, halfy);
-  immVertex2f(pos, region->winrct.xmax + 1, region->winrct.ymin);
-
-  immAttr2f(texcoord, 1.0f + halfx, 1.0f + halfy);
-  immVertex2f(pos, region->winrct.xmax + 1, region->winrct.ymax + 1);
-
-  immAttr2f(texcoord, halfx, 1.0f + halfy);
-  immVertex2f(pos, region->winrct.xmin, region->winrct.ymax + 1);
-
-  immEnd();
-  immUnbindProgram();
-
-  for (int view = 1; view >= 0; view--) {
-    glActiveTexture(GL_TEXTURE0 + view);
-    glBindTexture(GL_TEXTURE_2D, 0);
-  }
-}
-
-void wm_stereo3d_draw_anaglyph(wmWindow *win, ARegion *region)
-{
-  for (int view = 0; view < 2; view++) {
-    int bit = view + 1;
-
-    switch (win->stereo3d_format->anaglyph_type) {
-      case S3D_ANAGLYPH_REDCYAN:
-        glColorMask((1 & bit) ? GL_TRUE : GL_FALSE,
-                    (2 & bit) ? GL_TRUE : GL_FALSE,
-                    (2 & bit) ? GL_TRUE : GL_FALSE,
-                    GL_FALSE);
-        break;
-      case S3D_ANAGLYPH_GREENMAGENTA:
-        glColorMask((2 & bit) ? GL_TRUE : GL_FALSE,
-                    (1 & bit) ? GL_TRUE : GL_FALSE,
-                    (2 & bit) ? GL_TRUE : GL_FALSE,
-                    GL_FALSE);
-        break;
-      case S3D_ANAGLYPH_YELLOWBLUE:
-        glColorMask((1 & bit) ? GL_TRUE : GL_FALSE,
-                    (1 & bit) ? GL_TRUE : GL_FALSE,
-                    (2 & bit) ? GL_TRUE : GL_FALSE,
-                    GL_FALSE);
-        break;
-    }
-
-    wm_draw_region_blend(region, view, false);
-  }
-
-  glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
-}
-
 void wm_stereo3d_draw_sidebyside(wmWindow *win, int view)
 {
   bool cross_eyed = (win->stereo3d_format->flag & S3D_SIDEBYSIDE_CROSSEYED) != 0;
diff --git a/source/blender/windowmanager/intern/wm_xr.c b/source/blender/windowmanager/intern/wm_xr.c
index 4c770834f14..ef6fa6d28f2 100644
--- a/source/blender/windowmanager/intern/wm_xr.c
+++ b/source/blender/windowmanager/intern/wm_xr.c
@@ -685,7 +685,7 @@ static void wm_xr_draw_viewport_buffers_to_active_framebuffer(
   if (is_upside_down) {
     SWAP(int, rect.ymin, rect.ymax);
   }
-  GPU_viewport_draw_to_screen_ex(surface_data->viewport, &rect, draw_view->expects_srgb_buffer);
+  GPU_viewport_draw_to_screen_ex(surface_data->viewport, 0, &rect, draw_view->expects_srgb_buffer);
 }
 
 /**
diff --git a/source/blender/windowmanager/wm.h b/source/blender/windowmanager/wm.h
index 22c01df5d3b..97403a0315a 100644
--- a/source/blender/windowmanager/wm.h
+++ b/source/blender/windowmanager/wm.h
@@ -82,8 +82,6 @@ void wm_autosave_location(char *filepath);
 void WM_OT_splash(wmOperatorType *ot);
 
 /* wm_stereo.c */
-void wm_stereo3d_draw_interlace(wmWindow *win, struct ARegion *region);
-void wm_stereo3d_draw_anaglyph(wmWindow *win, struct ARegion *region);
 void wm_stereo3d_draw_sidebyside(wmWindow *win, int view);
 void wm_stereo3d_draw_topbottom(wmWindow *win, int view);
 
diff --git a/source/blender/windowmanager/wm_draw.h b/source/blender/windowmanager/wm_draw.h
index 4ebf2c820cd..b19fdf97569 100644
--- a/source/blender/windowmanager/wm_draw.h
+++ b/source/blender/windowmanager/wm_draw.h
@@ -32,7 +32,7 @@ struct GPUViewport;
 
 typedef struct wmDrawBuffer {
   struct GPUOffScreen *offscreen;
-  struct GPUViewport *viewport[2];
+  struct GPUViewport *viewport;
   bool stereo;
   int bound_view;
 } wmDrawBuffer;