[Mesa-dev] [PATCH v2] glsl: apply shader storage block member rules when adding program resources

[Samuel Iglesias Gonsalvez]

>From ARB_program_interface_query:

"For an active shader storage block member declared as an array, an
 entry will be generated only for the first array element, regardless
 of its type. For arrays of aggregate types, the enumeration rules are
 applied recursively for the single enumerated array element."

v2:
- Simplify 'if' conditions and return true if it is not a buffer
  variable, because these rules only apply to buffer variables (Timothy).

Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
---
 src/glsl/linker.cpp | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 87c7d4b..dbf300a 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -3134,6 +3134,60 @@ check_explicit_uniform_locations(struct gl_context *ctx,
 }
 
 static bool
+should_add_buffer_variable(struct gl_shader_program *shProg,
+                           GLenum type, const char *name)
+{
+   bool found_interface = false;
+   const char *block_name = NULL;
+
+   /* These rules only apply to buffer variables. So we return
+    * true for the rest of types.
+    */
+   if (type != GL_BUFFER_VARIABLE)
+      return true;
+
+   for (unsigned i = 0; i < shProg->NumBufferInterfaceBlocks; i++) {
+      block_name = shProg->UniformBlocks[i].Name;
+      if (strncmp(block_name, name, strlen(block_name)) == 0) {
+         found_interface = true;
+         break;
+      }
+   }
+
+   /* We remove the interface name from the buffer variable name,
+    * including the dot that follows it.
+    */
+   if (found_interface)
+      name = name + strlen(block_name) + 1;
+
+   /* From: ARB_program_interface_query extension:
+    *
+    *  "For an active shader storage block member declared as an array, an
+    *   entry will be generated only for the first array element, regardless
+    *   of its type.  For arrays of aggregate types, the enumeration rules are
+    *   applied recursively for the single enumerated array element.
+    */
+   const char *first_dot = strchr(name, '.');
+   const char *first_square_bracket = strchr(name, '[');
+
+   /* The buffer variable is on top level and it is not an array */
+   if (!first_square_bracket) {
+      return true;
+   /* The shader storage block member is a struct, then generate the entry */
+   } else if (first_dot && first_dot < first_square_bracket) {
+      return true;
+   } else {
+      /* Shader storage block member is an array, only generate an entry for the
+       * first array element.
+       */
+      if (strncmp(first_square_bracket, "[0]", 3) == 0)
+         return true;
+   }
+
+   return false;
+}
+
+static bool
 add_program_resource(struct gl_shader_program *prog, GLenum type,
                      const void *data, uint8_t stages)
 {
@@ -3412,6 +3466,10 @@ build_program_resource_list(struct gl_shader_program *shProg)
 
       bool is_shader_storage =  shProg->UniformStorage[i].is_shader_storage;
       GLenum type = is_shader_storage ? GL_BUFFER_VARIABLE : GL_UNIFORM;
+      if (!should_add_buffer_variable(shProg, type,
+                                      shProg->UniformStorage[i].name))
+         continue;
+
       if (!add_program_resource(shProg, type,
                                 &shProg->UniformStorage[i], stageref))
          return;
-- 
2.1.4