source/blender/draw/engines/eevee_next/shaders/eevee_shadow_page_tile_frag.glsl

@@ -58,9 +58,12 @@ void main()
   /* Write result to atlas. */
 #  ifdef GPU_METAL
   /* NOTE: Use the fastest possible write function without any parameter wrapping or conversion.*/
-  shadow_atlas_img.texture->write(u_depth, ushort2(out_texel_xy), out_page_z);
+  shadow_atlas_img.texture->write(
+      u_depth, ushort2(interp_noperspective.out_texel_xy), interp_flat.out_page_z);
 #  else
-  imageStore(shadow_atlas_img, ivec3(out_texel_xy, out_page_z), uvec4(u_depth));
+  imageStore(shadow_atlas_img,
+             ivec3(interp_noperspective.out_texel_xy, interp_flat.out_page_z),
+             uvec4(u_depth));
 #  endif
 }
 

source/blender/draw/engines/eevee_next/shaders/eevee_shadow_page_tile_vert.glsl

@@ -23,8 +23,8 @@ void main()
   /* Load where fragment should write the tile data. */
   uvec3 dst_page_co = shadow_page_unpack(dst_coord_buf[tile_id]);
   /* Interpolate output texel  */
-  out_texel_xy = (vec2(dst_page_co.xy) + tile_corner) * vec2(SHADOW_PAGE_RES);
-  out_page_z = dst_page_co.z;
+  interp_noperspective.out_texel_xy = (vec2(dst_page_co.xy) + tile_corner) * vec2(SHADOW_PAGE_RES);
+  interp_flat.out_page_z = dst_page_co.z;
 #endif
 
   /* Load where the quad should be positioned. */

source/blender/draw/engines/eevee_next/shaders/infos/eevee_shadow_info.hh

@@ -227,8 +227,9 @@ GPU_SHADER_CREATE_INFO(eevee_shadow_page_tile_clear)
 #endif
 
 /* Interface for passing precalculated values in accumulation vertex to frag. */
-GPU_SHADER_INTERFACE_INFO(eevee_shadow_page_tile_store_iface, "")
-    .no_perspective(Type::VEC2, "out_texel_xy")
+GPU_SHADER_INTERFACE_INFO(eevee_shadow_page_tile_store_noperspective_iface, "interp_noperspective")
+    .no_perspective(Type::VEC2, "out_texel_xy");
+GPU_SHADER_INTERFACE_INFO(eevee_shadow_page_tile_store_flat_iface, "interp_flat")
     .flat(PAGE_Z_TYPE, "out_page_z");
 
 #undef PAGE_Z_TYPE
@@ -247,7 +248,8 @@ GPU_SHADER_CREATE_INFO(eevee_shadow_page_tile_store)
            Qualifier::READ_WRITE,
            ImageType::UINT_2D_ARRAY,
            "shadow_atlas_img")
-    .vertex_out(eevee_shadow_page_tile_store_iface)
+    .vertex_out(eevee_shadow_page_tile_store_noperspective_iface)
+    .vertex_out(eevee_shadow_page_tile_store_flat_iface)
     .vertex_source("eevee_shadow_page_tile_vert.glsl")
     .fragment_source("eevee_shadow_page_tile_frag.glsl");
 

source/blender/gpu/intern/gpu_shader_create_info.cc

@@ -243,7 +243,37 @@ std::string ShaderCreateInfo::check_error() const
     }
   }
 
-#ifdef DEBUG
+  if (!this->geometry_source_.is_empty()) {
+    if (bool(this->builtins_ & BuiltinBits::BARYCENTRIC_COORD)) {
+      error += "Shader " + this->name_ +
+               " has geometry stage and uses barycentric coordinates. This is not allowed as "
+               "fallback injects a geometry stage.\n";
+    }
+    if (bool(this->builtins_ & BuiltinBits::VIEWPORT_INDEX)) {
+      error += "Shader " + this->name_ +
+               " has geometry stage and uses multi-viewport. This is not allowed as "
+               "fallback injects a geometry stage.\n";
+    }
+    if (bool(this->builtins_ & BuiltinBits::LAYER)) {
+      error += "Shader " + this->name_ +
+               " has geometry stage and uses layer output. This is not allowed as "
+               "fallback injects a geometry stage.\n";
+    }
+  }
+
+#ifndef NDEBUG
+  if (bool(this->builtins_ &
+           (BuiltinBits::BARYCENTRIC_COORD | BuiltinBits::VIEWPORT_INDEX | BuiltinBits::LAYER)))
+  {
+    for (const StageInterfaceInfo *interface : this->vertex_out_interfaces_) {
+      if (interface->instance_name.is_empty()) {
+        error += "Shader " + this->name_ + " uses interface " + interface->name +
+                 " that doesn't contain an instance name, but is required for the fallback "
+                 "geometry shader.\n";
+      }
+    }
+  }
+
   if (!this->is_vulkan_compatible()) {
     error += this->name_ +
              " contains a stage interface using an instance name and mixed interpolation modes. "