XR: Color Depth Adjustments

This addresses reduced visibility of scenes (as displayed in the VR
headset) that can result from the 8-bit color depth format currently
used for XR swapchain images.

By switching to a swapchain format with higher color depth (RGB10_A2,
RGBA16, RGBA16F) for supported runtimes, visibility in VR should be
noticeably improved.

However, current limitations are lack of support for these higher
color depth formats by some XR runtimes, especially for OpenGL.

Also important to note that GPU_offscreen_create() now explicitly
takes in the texture format (eGPUTextureFormat) instead of a
"high_bitdepth" boolean.

Reviewed By: Julian Eisel, Clément Foucault

Differential Revision: http://developer.blender.org/D9842

9 files changed, 33 insertions, 15 deletions

diff --git a/source/blender/editors/gpencil/gpencil_fill.c b/source/blender/editors/gpencil/gpencil_fill.c
index 67e1bd5294b..0c88d678ef4 100644
--- a/source/blender/editors/gpencil/gpencil_fill.c
+++ b/source/blender/editors/gpencil/gpencil_fill.c
@@ -646,7 +646,8 @@ static bool gpencil_render_offscreen(tGPDfill *tgpf)
   tgpf->sizey = (int)tgpf->region->winy;
 
   char err_out[256] = "unknown";
-  GPUOffScreen *offscreen = GPU_offscreen_create(tgpf->sizex, tgpf->sizey, true, false, err_out);
+  GPUOffScreen *offscreen = GPU_offscreen_create(
+      tgpf->sizex, tgpf->sizey, true, GPU_RGBA8, err_out);
   if (offscreen == NULL) {
     printf("GPencil - Fill - Unable to create fill buffer\n");
     return false;
diff --git a/source/blender/editors/render/render_opengl.c b/source/blender/editors/render/render_opengl.c
index d3307ebf274..749010a5ba3 100644
--- a/source/blender/editors/render/render_opengl.c
+++ b/source/blender/editors/render/render_opengl.c
@@ -768,7 +768,7 @@ static bool screen_opengl_render_init(bContext *C, wmOperator *op)
 
   /* corrects render size with actual size, not every card supports non-power-of-two dimensions */
   DRW_opengl_context_enable(); /* Off-screen creation needs to be done in DRW context. */
-  ofs = GPU_offscreen_create(sizex, sizey, true, true, err_out);
+  ofs = GPU_offscreen_create(sizex, sizey, true, GPU_RGBA16F, err_out);
   DRW_opengl_context_disable();
 
   if (!ofs) {
diff --git a/source/blender/editors/screen/screen_draw.c b/source/blender/editors/screen/screen_draw.c
index dca464bbf22..ab50e327de3 100644
--- a/source/blender/editors/screen/screen_draw.c
+++ b/source/blender/editors/screen/screen_draw.c
@@ -451,7 +451,7 @@ static void screen_preview_draw(const bScreen *screen, int size_x, int size_y)
 void ED_screen_preview_render(const bScreen *screen, int size_x, int size_y, uint *r_rect)
 {
   char err_out[256] = "unknown";
-  GPUOffScreen *offscreen = GPU_offscreen_create(size_x, size_y, true, false, err_out);
+  GPUOffScreen *offscreen = GPU_offscreen_create(size_x, size_y, true, GPU_RGBA8, err_out);
 
   GPU_offscreen_bind(offscreen, true);
   GPU_clear_color(0.0f, 0.0f, 0.0f, 0.0f);
diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index d87c14b9844..ec99affe43b 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -1876,7 +1876,7 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Depsgraph *depsgraph,
 
   if (own_ofs) {
     /* bind */
-    ofs = GPU_offscreen_create(sizex, sizey, true, false, err_out);
+    ofs = GPU_offscreen_create(sizex, sizey, true, GPU_RGBA8, err_out);
     if (ofs == NULL) {
       DRW_opengl_context_disable();
       return NULL;
diff --git a/source/blender/gpu/GPU_framebuffer.h b/source/blender/gpu/GPU_framebuffer.h
index 6482d9a9d3e..bf0ab3dc533 100644
--- a/source/blender/gpu/GPU_framebuffer.h
+++ b/source/blender/gpu/GPU_framebuffer.h
@@ -223,7 +223,7 @@ uint GPU_framebuffer_stack_level_get(void);
  */
 
 GPUOffScreen *GPU_offscreen_create(
-    int width, int height, bool depth, bool high_bitdepth, char err_out[256]);
+    int width, int height, bool depth, eGPUTextureFormat format, char err_out[256]);
 void GPU_offscreen_free(GPUOffScreen *ofs);
 void GPU_offscreen_bind(GPUOffScreen *ofs, bool save);
 void GPU_offscreen_unbind(GPUOffScreen *ofs, bool restore);
diff --git a/source/blender/gpu/intern/gpu_framebuffer.cc b/source/blender/gpu/intern/gpu_framebuffer.cc
index a6f7d43e563..9099a6e4245 100644
--- a/source/blender/gpu/intern/gpu_framebuffer.cc
+++ b/source/blender/gpu/intern/gpu_framebuffer.cc
@@ -591,7 +591,7 @@ static GPUFrameBuffer *gpu_offscreen_fb_get(GPUOffScreen *ofs)
 }
 
 GPUOffScreen *GPU_offscreen_create(
-    int width, int height, bool depth, bool high_bitdepth, char err_out[256])
+    int width, int height, bool depth, eGPUTextureFormat format, char err_out[256])
 {
   GPUOffScreen *ofs = (GPUOffScreen *)MEM_callocN(sizeof(GPUOffScreen), __func__);
 
@@ -600,8 +600,7 @@ GPUOffScreen *GPU_offscreen_create(
   height = max_ii(1, height);
   width = max_ii(1, width);
 
-  ofs->color = GPU_texture_create_2d(
-      "ofs_color", width, height, 1, (high_bitdepth) ? GPU_RGBA16F : GPU_RGBA8, nullptr);
+  ofs->color = GPU_texture_create_2d("ofs_color", width, height, 1, format, nullptr);
 
   if (depth) {
     ofs->depth = GPU_texture_create_2d(
diff --git a/source/blender/python/gpu/gpu_py_offscreen.c b/source/blender/python/gpu/gpu_py_offscreen.c
index 32053df5e97..6f23c2213e2 100644
--- a/source/blender/python/gpu/gpu_py_offscreen.c
+++ b/source/blender/python/gpu/gpu_py_offscreen.c
@@ -227,7 +227,7 @@ static PyObject *pygpu_offscreen__tp_new(PyTypeObject *UNUSED(self),
   }
 
   if (GPU_context_active_get()) {
-    ofs = GPU_offscreen_create(width, height, true, false, err_out);
+    ofs = GPU_offscreen_create(width, height, true, GPU_RGBA8, err_out);
   }
   else {
     STRNCPY(err_out, "No active GPU context found");
diff --git a/source/blender/windowmanager/intern/wm_draw.c b/source/blender/windowmanager/intern/wm_draw.c
index f01e28f8822..dcb918747f3 100644
--- a/source/blender/windowmanager/intern/wm_draw.c
+++ b/source/blender/windowmanager/intern/wm_draw.c
@@ -455,7 +455,7 @@ static void wm_draw_region_buffer_create(ARegion *region, bool stereo, bool use_
        * depth or multisample buffers. 3D view creates own buffers with
        * the data it needs. */
       GPUOffScreen *offscreen = GPU_offscreen_create(
-          region->winx, region->winy, false, false, NULL);
+          region->winx, region->winy, false, GPU_RGBA8, NULL);
       if (!offscreen) {
         WM_report(RPT_ERROR, "Region could not be drawn!");
         return;
@@ -888,7 +888,7 @@ static void wm_draw_window(bContext *C, wmWindow *win)
      * stereo methods, but it's less efficient than drawing directly. */
     const int width = WM_window_pixels_x(win);
     const int height = WM_window_pixels_y(win);
-    GPUOffScreen *offscreen = GPU_offscreen_create(width, height, false, false, NULL);
+    GPUOffScreen *offscreen = GPU_offscreen_create(width, height, false, GPU_RGBA8, NULL);
 
     if (offscreen) {
       GPUTexture *texture = GPU_offscreen_color_texture(offscreen);
diff --git a/source/blender/windowmanager/xr/intern/wm_xr_session.c b/source/blender/windowmanager/xr/intern/wm_xr_session.c
index dd9cac2bb16..ba30b0dd864 100644
--- a/source/blender/windowmanager/xr/intern/wm_xr_session.c
+++ b/source/blender/windowmanager/xr/intern/wm_xr_session.c
@@ -657,9 +657,6 @@ bool wm_xr_session_surface_offscreen_ensure(wmXrSurfaceData *surface_data,
   GPUViewport *viewport = vp->viewport;
   const bool size_changed = offscreen && (GPU_offscreen_width(offscreen) != draw_view->width) &&
                             (GPU_offscreen_height(offscreen) != draw_view->height);
-  char err_out[256] = "unknown";
-  bool failure = false;
-
   if (offscreen) {
     BLI_assert(viewport);
 
@@ -670,8 +667,29 @@ bool wm_xr_session_surface_offscreen_ensure(wmXrSurfaceData *surface_data,
     GPU_offscreen_free(offscreen);
   }
 
+  char err_out[256] = "unknown";
+  bool failure = false;
+  eGPUTextureFormat format =
+      GPU_R8; /* Initialize with some unsupported format to check following switch statement. */
+
+  switch (draw_view->swapchain_format) {
+    case GHOST_kXrSwapchainFormatRGBA8:
+      format = GPU_RGBA8;
+      break;
+    case GHOST_kXrSwapchainFormatRGBA16:
+      format = GPU_RGBA16;
+      break;
+    case GHOST_kXrSwapchainFormatRGBA16F:
+      format = GPU_RGBA16F;
+      break;
+    case GHOST_kXrSwapchainFormatRGB10_A2:
+      format = GPU_RGB10_A2;
+      break;
+  }
+  BLI_assert(format != GPU_R8);
+
   offscreen = vp->offscreen = GPU_offscreen_create(
-      draw_view->width, draw_view->height, true, false, err_out);
+      draw_view->width, draw_view->height, true, format, err_out);
   if (offscreen) {
     viewport = vp->viewport = GPU_viewport_create();
     if (!viewport) {