glsl: Refactor matrix stride calculation into a utility function
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Thomas Helland <thomashelland90@gmail.com>
diff --git a/src/compiler/glsl/link_uniforms.cpp b/src/compiler/glsl/link_uniforms.cpp
index 4aa29f4..46c746b 100644
--- a/src/compiler/glsl/link_uniforms.cpp
+++ b/src/compiler/glsl/link_uniforms.cpp
@@ -398,6 +398,48 @@
} /* anonymous namespace */
+unsigned
+link_calculate_matrix_stride(const glsl_type *matrix, bool row_major,
+ enum glsl_interface_packing packing)
+{
+ const unsigned N = matrix->is_double() ? 8 : 4;
+ const unsigned items =
+ row_major ? matrix->matrix_columns : matrix->vector_elements;
+
+ assert(items <= 4);
+
+ /* Matrix stride for std430 mat2xY matrices are not rounded up to
+ * vec4 size.
+ *
+ * Section 7.6.2.2 "Standard Uniform Block Layout" of the OpenGL 4.3 spec
+ * says:
+ *
+ * 2. If the member is a two- or four-component vector with components
+ * consuming N basic machine units, the base alignment is 2N or 4N,
+ * respectively.
+ * ...
+ * 4. If the member is an array of scalars or vectors, the base
+ * alignment and array stride are set to match the base alignment of
+ * a single array element, according to rules (1), (2), and (3), and
+ * rounded up to the base alignment of a vec4.
+ * ...
+ * 7. If the member is a row-major matrix with C columns and R rows, the
+ * matrix is stored identically to an array of R row vectors with C
+ * components each, according to rule (4).
+ * ...
+ *
+ * When using the std430 storage layout, shader storage blocks will be
+ * laid out in buffer storage identically to uniform and shader storage
+ * blocks using the std140 layout, except that the base alignment and
+ * stride of arrays of scalars and vectors in rule 4 and of structures
+ * in rule 9 are not rounded up a multiple of the base alignment of a
+ * vec4.
+ */
+ return packing == GLSL_INTERFACE_PACKING_STD430
+ ? (items < 3 ? items * N : glsl_align(items * N, 16))
+ : glsl_align(items * N, 16);
+}
+
/**
* Class to help parcel out pieces of backing storage to uniforms
*
@@ -856,17 +898,10 @@
}
if (type->without_array()->is_matrix()) {
- const glsl_type *matrix = type->without_array();
- const unsigned N = matrix->is_double() ? 8 : 4;
- const unsigned items =
- row_major ? matrix->matrix_columns : matrix->vector_elements;
-
- assert(items <= 4);
- if (packing == GLSL_INTERFACE_PACKING_STD430)
- this->uniforms[id].matrix_stride = items < 3 ? items * N :
- glsl_align(items * N, 16);
- else
- this->uniforms[id].matrix_stride = glsl_align(items * N, 16);
+ this->uniforms[id].matrix_stride =
+ link_calculate_matrix_stride(type->without_array(),
+ row_major,
+ packing);
this->uniforms[id].row_major = row_major;
} else {
this->uniforms[id].matrix_stride = 0;
diff --git a/src/compiler/glsl/linker.h b/src/compiler/glsl/linker.h
index 03ed9d5..12a48e0 100644
--- a/src/compiler/glsl/linker.h
+++ b/src/compiler/glsl/linker.h
@@ -92,6 +92,10 @@
unsigned num_shaders,
bool allow_missing_main);
+extern unsigned
+link_calculate_matrix_stride(const glsl_type *matrix, bool row_major,
+ enum glsl_interface_packing packing);
+
/**
* Class for processing all of the leaf fields of a variable that corresponds
* to a program resource.