From 35476c2bae5d59adf5fcfce8c83958ed076264e5 Mon Sep 17 00:00:00 2001 From: Samuel Iglesias Gonsalvez Date: Mon, 31 Aug 2015 07:44:47 +0200 Subject: [PATCH] glsl: Add std430 related member functions to glsl_type class MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit They are used to calculate size, base alignment and array stride values for a glsl_type following std430 rules. v2: - Paste OpenGL 4.3 spec wording as it mentions stride of array. (Jordan) Signed-off-by: Samuel Iglesias Gonsalvez Reviewed-by: Jordan Justen Reviewed-by: Kristian Høgsberg --- src/glsl/glsl_types.cpp | 207 ++++++++++++++++++++++++++++++++++++++++ src/glsl/glsl_types.h | 19 ++++ 2 files changed, 226 insertions(+) diff --git a/src/glsl/glsl_types.cpp b/src/glsl/glsl_types.cpp index 07d72489057..93034a67f01 100644 --- a/src/glsl/glsl_types.cpp +++ b/src/glsl/glsl_types.cpp @@ -1388,6 +1388,213 @@ glsl_type::std140_size(bool row_major) const return -1; } +unsigned +glsl_type::std430_base_alignment(bool row_major) const +{ + + unsigned N = is_double() ? 8 : 4; + + /* (1) If the member is a scalar consuming basic machine units, the + * base alignment is . + * + * (2) If the member is a two- or four-component vector with components + * consuming basic machine units, the base alignment is 2 or + * 4, respectively. + * + * (3) If the member is a three-component vector with components consuming + * basic machine units, the base alignment is 4. + */ + if (this->is_scalar() || this->is_vector()) { + switch (this->vector_elements) { + case 1: + return N; + case 2: + return 2 * N; + case 3: + case 4: + return 4 * N; + } + } + + /* OpenGL 4.30 spec, section 7.6.2.2 "Standard Uniform Block Layout": + * + * "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. + */ + + /* (1) If the member is a scalar consuming basic machine units, the + * base alignment is . + * + * (2) If the member is a two- or four-component vector with components + * consuming basic machine units, the base alignment is 2 or + * 4, respectively. + * + * (3) If the member is a three-component vector with components consuming + * basic machine units, the base alignment is 4. + */ + if (this->is_array()) + return this->fields.array->std430_base_alignment(row_major); + + /* (5) If the member is a column-major matrix with columns and + * rows, the matrix is stored identically to an array of + * column vectors with components each, according to + * rule (4). + * + * (7) If the member is a row-major matrix with columns and + * rows, the matrix is stored identically to an array of + * row vectors with components each, according to rule (4). + */ + if (this->is_matrix()) { + const struct glsl_type *vec_type, *array_type; + int c = this->matrix_columns; + int r = this->vector_elements; + + if (row_major) { + vec_type = get_instance(base_type, c, 1); + array_type = glsl_type::get_array_instance(vec_type, r); + } else { + vec_type = get_instance(base_type, r, 1); + array_type = glsl_type::get_array_instance(vec_type, c); + } + + return array_type->std430_base_alignment(false); + } + + /* (9) If the member is a structure, the base alignment of the + * structure is , where is the largest base alignment + * value of any of its members, and rounded up to the base + * alignment of a vec4. The individual members of this + * sub-structure are then assigned offsets by applying this set + * of rules recursively, where the base offset of the first + * member of the sub-structure is equal to the aligned offset + * of the structure. The structure may have padding at the end; + * the base offset of the member following the sub-structure is + * rounded up to the next multiple of the base alignment of the + * structure. + */ + if (this->is_record()) { + unsigned base_alignment = 0; + for (unsigned i = 0; i < this->length; i++) { + bool field_row_major = row_major; + const enum glsl_matrix_layout matrix_layout = + glsl_matrix_layout(this->fields.structure[i].matrix_layout); + if (matrix_layout == GLSL_MATRIX_LAYOUT_ROW_MAJOR) { + field_row_major = true; + } else if (matrix_layout == GLSL_MATRIX_LAYOUT_COLUMN_MAJOR) { + field_row_major = false; + } + + const struct glsl_type *field_type = this->fields.structure[i].type; + base_alignment = MAX2(base_alignment, + field_type->std430_base_alignment(field_row_major)); + } + return base_alignment; + } + assert(!"not reached"); + return -1; +} + +unsigned +glsl_type::std430_array_stride(bool row_major) const +{ + unsigned N = is_double() ? 8 : 4; + + /* Notice that the array stride of a vec3 is not 3 * N but 4 * N. + * See OpenGL 4.30 spec, section 7.6.2.2 "Standard Uniform Block Layout" + * + * (3) If the member is a three-component vector with components consuming + * basic machine units, the base alignment is 4. + */ + if (this->is_vector() && this->vector_elements == 3) + return 4 * N; + + /* By default use std430_size(row_major) */ + return this->std430_size(row_major); +} + +unsigned +glsl_type::std430_size(bool row_major) const +{ + unsigned N = is_double() ? 8 : 4; + + /* OpenGL 4.30 spec, section 7.6.2.2 "Standard Uniform Block Layout": + * + * "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. + */ + if (this->is_scalar() || this->is_vector()) + return this->vector_elements * N; + + if (this->without_array()->is_matrix()) { + const struct glsl_type *element_type; + const struct glsl_type *vec_type; + unsigned int array_len; + + if (this->is_array()) { + element_type = this->fields.array; + array_len = this->length; + } else { + element_type = this; + array_len = 1; + } + + if (row_major) { + vec_type = get_instance(element_type->base_type, + element_type->matrix_columns, 1); + + array_len *= element_type->vector_elements; + } else { + vec_type = get_instance(element_type->base_type, + element_type->vector_elements, 1); + array_len *= element_type->matrix_columns; + } + const glsl_type *array_type = glsl_type::get_array_instance(vec_type, + array_len); + + return array_type->std430_size(false); + } + + if (this->is_array()) { + if (this->fields.array->is_record()) + return this->length * this->fields.array->std430_size(row_major); + else + return this->length * this->fields.array->std430_base_alignment(row_major); + } + + if (this->is_record() || this->is_interface()) { + unsigned size = 0; + unsigned max_align = 0; + + for (unsigned i = 0; i < this->length; i++) { + bool field_row_major = row_major; + const enum glsl_matrix_layout matrix_layout = + glsl_matrix_layout(this->fields.structure[i].matrix_layout); + if (matrix_layout == GLSL_MATRIX_LAYOUT_ROW_MAJOR) { + field_row_major = true; + } else if (matrix_layout == GLSL_MATRIX_LAYOUT_COLUMN_MAJOR) { + field_row_major = false; + } + + const struct glsl_type *field_type = this->fields.structure[i].type; + unsigned align = field_type->std430_base_alignment(field_row_major); + size = glsl_align(size, align); + size += field_type->std430_size(field_row_major); + + max_align = MAX2(align, max_align); + } + size = glsl_align(size, max_align); + return size; + } + + assert(!"not reached"); + return -1; +} unsigned glsl_type::count_attribute_slots() const diff --git a/src/glsl/glsl_types.h b/src/glsl/glsl_types.h index 860276a2b17..785f5aa74bf 100644 --- a/src/glsl/glsl_types.h +++ b/src/glsl/glsl_types.h @@ -333,6 +333,25 @@ struct glsl_type { */ unsigned std140_size(bool row_major) const; + /** + * Alignment in bytes of the start of this type in a std430 shader + * storage block. + */ + unsigned std430_base_alignment(bool row_major) const; + + /** + * Calculate array stride in bytes of this type in a std430 shader storage + * block. + */ + unsigned std430_array_stride(bool row_major) const; + + /** + * Size in bytes of this type in a std430 shader storage block. + * + * Note that this is not GL_BUFFER_SIZE + */ + unsigned std430_size(bool row_major) const; + /** * \brief Can this type be implicitly converted to another? * -- 2.30.2