diff options
| -rw-r--r-- | src/glsl/link_varyings.cpp | 20 | ||||
| -rw-r--r-- | src/glsl/lower_packed_varyings.cpp | 95 |
2 files changed, 101 insertions, 14 deletions
diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp index b9c3f5d434d..5c27f231e72 100644 --- a/src/glsl/link_varyings.cpp +++ b/src/glsl/link_varyings.cpp @@ -777,17 +777,25 @@ varying_matches::store_locations(unsigned producer_base, unsigned varying_matches::compute_packing_class(ir_variable *var) { - /* In this initial implementation we conservatively assume that variables - * can only be packed if their base type (float/int/uint/bool) matches and - * their interpolation and centroid qualifiers match. + /* Without help from the back-end, there is no way to pack together + * variables with different interpolation types, because + * lower_packed_varyings must choose exactly one interpolation type for + * each packed varying it creates. * - * TODO: relax these restrictions when the driver back-end permits. + * However, we can safely pack together floats, ints, and uints, because: + * + * - varyings of base type "int" and "uint" must use the "flat" + * interpolation type, which can only occur in GLSL 1.30 and above. + * + * - On platforms that support GLSL 1.30 and above, lower_packed_varyings + * can store flat floats as ints without losing any information (using + * the ir_unop_bitcast_* opcodes). + * + * Therefore, the packing class depends only on the interpolation type. */ unsigned packing_class = var->centroid ? 1 : 0; packing_class *= 4; packing_class += var->interpolation; - packing_class *= GLSL_TYPE_ERROR; - packing_class += var->type->get_scalar_type()->base_type; return packing_class; } diff --git a/src/glsl/lower_packed_varyings.cpp b/src/glsl/lower_packed_varyings.cpp index 09c551c4e63..9e7f274b7d1 100644 --- a/src/glsl/lower_packed_varyings.cpp +++ b/src/glsl/lower_packed_varyings.cpp @@ -66,6 +66,10 @@ * performance. However, hopefully in most cases the performance loss will * either be absorbed by a later optimization pass, or it will be offset by * memory bandwidth savings (because fewer varyings are used). + * + * This lowering pass also packs flat floats, ints, and uints together, by + * using ivec4 as the base type of flat "varyings", and using appropriate + * casts to convert floats and uints into ints. */ #include "glsl_symbol_table.h" @@ -90,6 +94,8 @@ public: void run(exec_list *instructions); private: + ir_assignment *bitwise_assign_pack(ir_rvalue *lhs, ir_rvalue *rhs); + ir_assignment *bitwise_assign_unpack(ir_rvalue *lhs, ir_rvalue *rhs); unsigned lower_rvalue(ir_rvalue *rvalue, unsigned fine_location, ir_variable *unpacked_var, const char *name); unsigned lower_arraylike(ir_rvalue *rvalue, unsigned array_size, @@ -181,6 +187,75 @@ lower_packed_varyings_visitor::run(exec_list *instructions) } } + +/** + * Make an ir_assignment from \c rhs to \c lhs, performing appropriate + * bitcasts if necessary to match up types. + * + * This function is called when packing varyings. + */ +ir_assignment * +lower_packed_varyings_visitor::bitwise_assign_pack(ir_rvalue *lhs, + ir_rvalue *rhs) +{ + if (lhs->type->base_type != rhs->type->base_type) { + /* Since we only mix types in flat varyings, and we always store flat + * varyings as type ivec4, we need only produce conversions from (uint + * or float) to int. + */ + assert(lhs->type->base_type == GLSL_TYPE_INT); + switch (rhs->type->base_type) { + case GLSL_TYPE_UINT: + rhs = new(this->mem_ctx) + ir_expression(ir_unop_u2i, lhs->type, rhs); + break; + case GLSL_TYPE_FLOAT: + rhs = new(this->mem_ctx) + ir_expression(ir_unop_bitcast_f2i, lhs->type, rhs); + break; + default: + assert(!"Unexpected type conversion while lowering varyings"); + break; + } + } + return new(this->mem_ctx) ir_assignment(lhs, rhs); +} + + +/** + * Make an ir_assignment from \c rhs to \c lhs, performing appropriate + * bitcasts if necessary to match up types. + * + * This function is called when unpacking varyings. + */ +ir_assignment * +lower_packed_varyings_visitor::bitwise_assign_unpack(ir_rvalue *lhs, + ir_rvalue *rhs) +{ + if (lhs->type->base_type != rhs->type->base_type) { + /* Since we only mix types in flat varyings, and we always store flat + * varyings as type ivec4, we need only produce conversions from int to + * (uint or float). + */ + assert(rhs->type->base_type == GLSL_TYPE_INT); + switch (lhs->type->base_type) { + case GLSL_TYPE_UINT: + rhs = new(this->mem_ctx) + ir_expression(ir_unop_i2u, lhs->type, rhs); + break; + case GLSL_TYPE_FLOAT: + rhs = new(this->mem_ctx) + ir_expression(ir_unop_bitcast_i2f, lhs->type, rhs); + break; + default: + assert(!"Unexpected type conversion while lowering varyings"); + break; + } + } + return new(this->mem_ctx) ir_assignment(lhs, rhs); +} + + /** * Recursively pack or unpack the given varying (or portion of a varying) by * traversing all of its constituent vectors. @@ -262,12 +337,12 @@ lower_packed_varyings_visitor::lower_rvalue(ir_rvalue *rvalue, ir_swizzle *swizzle = new(this->mem_ctx) ir_swizzle(packed_deref, swizzle_values, components); if (this->mode == ir_var_out) { - ir_assignment *assignment = new(this->mem_ctx) - ir_assignment(swizzle, rvalue); + ir_assignment *assignment + = this->bitwise_assign_pack(swizzle, rvalue); this->main_instructions->push_tail(assignment); } else { - ir_assignment *assignment = new(this->mem_ctx) - ir_assignment(rvalue, swizzle); + ir_assignment *assignment + = this->bitwise_assign_unpack(rvalue, swizzle); this->main_instructions->push_head(assignment); } return fine_location + components; @@ -306,8 +381,9 @@ lower_packed_varyings_visitor::lower_arraylike(ir_rvalue *rvalue, * If no packed varying has been created for the given varying location yet, * create it and add it to the shader before returning it. * - * The newly created varying inherits its base type (float, uint, or int) and - * interpolation parameters from \c unpacked_var. + * The newly created varying inherits its interpolation parameters from \c + * unpacked_var. Its base type is ivec4 if we are lowering a flat varying, + * vec4 otherwise. */ ir_variable * lower_packed_varyings_visitor::get_packed_varying(unsigned location, @@ -318,8 +394,11 @@ lower_packed_varyings_visitor::get_packed_varying(unsigned location, assert(slot < locations_used); if (this->packed_varyings[slot] == NULL) { char *packed_name = ralloc_asprintf(this->mem_ctx, "packed:%s", name); - const glsl_type *packed_type = glsl_type::get_instance( - unpacked_var->type->get_scalar_type()->base_type, 4, 1); + const glsl_type *packed_type; + if (unpacked_var->interpolation == INTERP_QUALIFIER_FLAT) + packed_type = glsl_type::ivec4_type; + else + packed_type = glsl_type::vec4_type; ir_variable *packed_var = new(this->mem_ctx) ir_variable(packed_type, packed_name, this->mode); packed_var->centroid = unpacked_var->centroid; |