GL_ARB_uniform_buffer_object spec defines standard layout rules to define how
data
are packed in a uniform buffer object, using offset and stride. A single
ir_variable::location is not enough to hold every possible case and thus we
defined a
new type whose structure mirror the one of associated glsl_type of stored
variable.
---
src/glsl/linker.cpp | 23 +++++++++++++++++++++++
src/mesa/main/mtypes.h | 25 +++++++++++++++++++++++++
2 files changed, 48 insertions(+), 0 deletions(-)
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 289a398..5ae928d 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1173,6 +1173,29 @@ update_array_sizes(struct gl_shader_program *prog)
}
}
+#if FEATURE_ARB_uniform_buffer_object
+/**
+ * Create gl_variable_storage tree that mirror type.
+ */
+static union gl_variable_storage *
+create_storage_type(const struct glsl_type *const type, void *ctx=NULL)
+{
+ union gl_variable_storage *storage_tree = (union gl_variable_storage *)
ralloc_size(ctx,sizeof(union gl_variable_storage));
+ if ( type->is_record() ) {
+ storage_tree->AsRecord.Fields = (union gl_variable_storage **)
ralloc_array_size(storage_tree, sizeof(union gl_variable_storage *),
type->length);
+ for (unsigned i = 0; i < type->length; i++) {
+ storage_tree->AsRecord.Fields[i] =
create_storage_type(type->fields.structure[i].type, storage_tree);
+ }
+ }
+ if (type->is_array()) {
+ storage_tree->AsArray.FirstElement =
create_storage_type(type->fields.array, storage_tree);
+ }
+ return storage_tree;
+}
+
+#endif
+
+
/**
* Find a contiguous set of available bits in a bitmask.
*
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index c4b5e28..865b6dc 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2128,6 +2128,29 @@ struct gl_sl_pragmas
};
/**
+ * Holds storage information (offset and stride) about complex data type
+ */
+union gl_variable_storage
+{
+ struct {
+ GLuint Offset; /** Offset in bytes from start of buffer */
+ } AsLeaf; /** Associated type is scalar or vector not in an array */
+ struct {
+ GLuint Offset; /** Offset in bytes from start of buffer */
+ GLuint RowStride; /** Stride to access next element in a row */
+ GLuint ColumnStride; /** Stride to access next element in a column */
+ } AsMatrix; /** Associated type is a matrix */
+ struct {
+ union gl_variable_storage **Fields; /** Ralloced array of
gl_variable_storage* associated to each fields */
+ } AsRecord; /** Associated type is record */
+ struct {
+ GLuint Stride; /** Stride in bytes between elements */
+ union gl_variable_storage *FirstElement; /** Ralloced
gl_variable_storage that holds storage info for
+ the first element of the array ; info about others element are deducable
using this and Stride */
+ } AsArray;
+};
+
+/**
* Uniform Buffer Object variable informations.
* This come in 2 flavors :
* As layout informations (Size,Offset,...) are defined per program and not
per shader,
@@ -2140,6 +2163,8 @@ struct gl_shader_ubo_variable
{
char* Name;
const struct glsl_type* Type;
+ const union gl_variable_storage *Storage;
+};
};
--
1.7.7
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