GPUTexture: Add Cube view as 2D array

This is useful to read/write to the textures directly using compute
shaders and imageLoad/Store.

4 files changed, 22 insertions, 11 deletions

diff --git a/source/blender/draw/intern/DRW_gpu_wrapper.hh b/source/blender/draw/intern/DRW_gpu_wrapper.hh
index 46d4b651330..bb9d24f5045 100644
--- a/source/blender/draw/intern/DRW_gpu_wrapper.hh
+++ b/source/blender/draw/intern/DRW_gpu_wrapper.hh
@@ -514,7 +514,7 @@ class Texture : NonCopyable {
    * Ensure the availability of mipmap views.
    * Mip view covers all layers of array textures.
    */
-  bool ensure_mip_views()
+  bool ensure_mip_views(bool cube_as_array = false)
   {
     int mip_len = GPU_texture_mip_count(tx_);
     if (mip_views_.size() != mip_len) {
@@ -523,7 +523,8 @@ class Texture : NonCopyable {
       }
       eGPUTextureFormat format = GPU_texture_format(tx_);
       for (auto i : IndexRange(mip_len)) {
-        mip_views_.append(GPU_texture_create_view(name_, tx_, format, i, 1, 0, 9999));
+        mip_views_.append(
+            GPU_texture_create_view(name_, tx_, format, i, 1, 0, 9999, cube_as_array));
       }
       return true;
     }
@@ -539,7 +540,7 @@ class Texture : NonCopyable {
    * Ensure the availability of mipmap views.
    * Layer views covers all layers of array textures.
    */
-  bool ensure_layer_views()
+  bool ensure_layer_views(bool cube_as_array = false)
   {
     int layer_len = GPU_texture_layer_count(tx_);
     if (layer_views_.size() != layer_len) {
@@ -548,7 +549,8 @@ class Texture : NonCopyable {
       }
       eGPUTextureFormat format = GPU_texture_format(tx_);
       for (auto i : IndexRange(layer_len)) {
-        layer_views_.append(GPU_texture_create_view(name_, tx_, format, 0, 9999, i, 1));
+        layer_views_.append(
+            GPU_texture_create_view(name_, tx_, format, 0, 9999, i, 1, cube_as_array));
       }
       return true;
     }
@@ -560,11 +562,11 @@ class Texture : NonCopyable {
     return layer_views_[layer];
   }
 
-  GPUTexture *stencil_view()
+  GPUTexture *stencil_view(bool cube_as_array = false)
   {
     if (stencil_view_ == nullptr) {
       eGPUTextureFormat format = GPU_texture_format(tx_);
-      stencil_view_ = GPU_texture_create_view(name_, tx_, format, 0, 9999, 0, 9999);
+      stencil_view_ = GPU_texture_create_view(name_, tx_, format, 0, 9999, 0, 9999, cube_as_array);
       GPU_texture_stencil_texture_mode_set(stencil_view_, true);
     }
     return stencil_view_;
diff --git a/source/blender/gpu/GPU_texture.h b/source/blender/gpu/GPU_texture.h
index 4dbcd84672c..37edc2abeb2 100644
--- a/source/blender/gpu/GPU_texture.h
+++ b/source/blender/gpu/GPU_texture.h
@@ -230,6 +230,7 @@ GPUTexture *GPU_texture_create_error(int dimension, bool array);
  * Create an alias of the source texture data.
  * If \a src is freed, the texture view will continue to be valid.
  * If \a mip_start or \a mip_len is bigger than available mips they will be clamped.
+ * If \a cube_as_array is true, then the texture cube (array) becomes a 2D array texture.
  * TODO(@fclem): Target conversion is not implemented yet.
  */
 GPUTexture *GPU_texture_create_view(const char *name,
@@ -238,7 +239,8 @@ GPUTexture *GPU_texture_create_view(const char *name,
                                     int mip_start,
                                     int mip_len,
                                     int layer_start,
-                                    int layer_len);
+                                    int layer_len,
+                                    bool cube_as_array);
 
 void GPU_texture_update_mipmap(GPUTexture *tex,
                                int miplvl,
diff --git a/source/blender/gpu/intern/gpu_texture.cc b/source/blender/gpu/intern/gpu_texture.cc
index 0d2ec43533f..b41193f12fa 100644
--- a/source/blender/gpu/intern/gpu_texture.cc
+++ b/source/blender/gpu/intern/gpu_texture.cc
@@ -136,7 +136,8 @@ bool Texture::init_view(const GPUTexture *src_,
                         int mip_start,
                         int mip_len,
                         int layer_start,
-                        int layer_len)
+                        int layer_len,
+                        bool cube_as_array)
 {
   const Texture *src = unwrap(src_);
   w_ = src->w_;
@@ -165,6 +166,10 @@ bool Texture::init_view(const GPUTexture *src_,
   format_flag_ = to_format_flag(format);
   /* For now always copy the target. Target aliasing could be exposed later. */
   type_ = src->type_;
+  if (cube_as_array) {
+    BLI_assert(type_ & GPU_TEXTURE_CUBE);
+    type_ = (type_ & ~GPU_TEXTURE_CUBE) | GPU_TEXTURE_2D_ARRAY;
+  }
   sampler_state = src->sampler_state;
   return this->init_internal(src_, mip_start, layer_start);
 }
@@ -387,12 +392,13 @@ GPUTexture *GPU_texture_create_view(const char *name,
                                     int mip_start,
                                     int mip_len,
                                     int layer_start,
-                                    int layer_len)
+                                    int layer_len,
+                                    bool cube_as_array)
 {
   BLI_assert(mip_len > 0);
   BLI_assert(layer_len > 0);
   Texture *view = GPUBackend::get()->texture_alloc(name);
-  view->init_view(src, format, mip_start, mip_len, layer_start, layer_len);
+  view->init_view(src, format, mip_start, mip_len, layer_start, layer_len, cube_as_array);
   return wrap(view);
 }
 
diff --git a/source/blender/gpu/intern/gpu_texture_private.hh b/source/blender/gpu/intern/gpu_texture_private.hh
index 1e81980e95f..109e60e19a6 100644
--- a/source/blender/gpu/intern/gpu_texture_private.hh
+++ b/source/blender/gpu/intern/gpu_texture_private.hh
@@ -111,7 +111,8 @@ class Texture {
                  int mip_start,
                  int mip_len,
                  int layer_start,
-                 int layer_len);
+                 int layer_len,
+                 bool cube_as_array);
 
   virtual void generate_mipmap() = 0;
   virtual void copy_to(Texture *tex) = 0;