From 8f758b0b92f6105c9615740096fa1206befe343b Mon Sep 17 00:00:00 2001 From: Bryan Cain Date: Fri, 15 Feb 2013 09:30:51 -0600 Subject: [PATCH] glsl/gs: handle gl_ClipDistance geometry input in lower_clip_distance. This corresponds to the lowering of gl_ClipDistance to gl_ClipDistanceMESA for vertex and geometry shader outputs. Since this lowering pass occurs after lower_named_interface blocks, it deals with 2D arrays (gl_ClipDistance[vertex][clip_plane]) rather than 1D arrays in an interface block (gl_in[vertex].gl_ClipDistance[clip_plane]). v2 (Paul Berry ): Fix indexing order for gl_ClipDistance input lowering. Properly lower bulk assignment of gl_ClipDistance inputs. Rework for GLSL 1.50 style geometry shaders. Reviewed-by: Jordan Justen v3 (Paul Berry ): Add comments and assertions to clarify that the 2D version of clip distance is only used for geometry shader inputs. Reviewed-by: Ian Romanick --- src/glsl/lower_clip_distance.cpp | 253 +++++++++++++++++++++++-------- 1 file changed, 193 insertions(+), 60 deletions(-) diff --git a/src/glsl/lower_clip_distance.cpp b/src/glsl/lower_clip_distance.cpp index 9ddd64603e6..682c8fdcd3e 100644 --- a/src/glsl/lower_clip_distance.cpp +++ b/src/glsl/lower_clip_distance.cpp @@ -54,14 +54,17 @@ namespace { class lower_clip_distance_visitor : public ir_rvalue_visitor { public: - lower_clip_distance_visitor() - : progress(false), old_clip_distance_var(NULL), - new_clip_distance_var(NULL) + explicit lower_clip_distance_visitor(GLenum shader_type) + : progress(false), old_clip_distance_1d_var(NULL), + old_clip_distance_2d_var(NULL), new_clip_distance_1d_var(NULL), + new_clip_distance_2d_var(NULL), shader_type(shader_type) { } virtual ir_visitor_status visit(ir_variable *); void create_indices(ir_rvalue*, ir_rvalue *&, ir_rvalue *&); + bool is_clip_distance_vec8(ir_rvalue *ir); + ir_rvalue *lower_clip_distance_vec8(ir_rvalue *ir); virtual ir_visitor_status visit_leave(ir_assignment *); void visit_new_assignment(ir_assignment *ir); virtual ir_visitor_status visit_leave(ir_call *); @@ -74,13 +77,28 @@ public: /** * Pointer to the declaration of gl_ClipDistance, if found. + * + * Note: + * + * - the 2d_var is for geometry shader input only. + * + * - since gl_ClipDistance is available in geometry shaders as both an + * input and an output, it's possible for both old_clip_distance_1d_var + * and old_clip_distance_2d_var to be non-null. */ - ir_variable *old_clip_distance_var; + ir_variable *old_clip_distance_1d_var; + ir_variable *old_clip_distance_2d_var; /** * Pointer to the newly-created gl_ClipDistanceMESA variable. */ - ir_variable *new_clip_distance_var; + ir_variable *new_clip_distance_1d_var; + ir_variable *new_clip_distance_2d_var; + + /** + * Type of shader we are compiling (e.g. GL_VERTEX_SHADER) + */ + const GLenum shader_type; }; } /* anonymous namespace */ @@ -92,30 +110,61 @@ public: ir_visitor_status lower_clip_distance_visitor::visit(ir_variable *ir) { - /* No point in looking for the declaration of gl_ClipDistance if - * we've already found it. - */ - if (this->old_clip_distance_var) + if (!ir->name || strcmp(ir->name, "gl_ClipDistance") != 0) return visit_continue; + assert (ir->type->is_array()); + + if (!ir->type->element_type()->is_array()) { + /* 1D gl_ClipDistance (used for vertex and geometry output, and fragment + * input). + */ + if (this->old_clip_distance_1d_var) + return visit_continue; - if (ir->name && strcmp(ir->name, "gl_ClipDistance") == 0) { this->progress = true; - this->old_clip_distance_var = ir; - assert (ir->type->is_array()); + this->old_clip_distance_1d_var = ir; assert (ir->type->element_type() == glsl_type::float_type); unsigned new_size = (ir->type->array_size() + 3) / 4; /* Clone the old var so that we inherit all of its properties */ - this->new_clip_distance_var = ir->clone(ralloc_parent(ir), NULL); + this->new_clip_distance_1d_var = ir->clone(ralloc_parent(ir), NULL); /* And change the properties that we need to change */ - this->new_clip_distance_var->name - = ralloc_strdup(this->new_clip_distance_var, "gl_ClipDistanceMESA"); - this->new_clip_distance_var->type + this->new_clip_distance_1d_var->name + = ralloc_strdup(this->new_clip_distance_1d_var, + "gl_ClipDistanceMESA"); + this->new_clip_distance_1d_var->type = glsl_type::get_array_instance(glsl_type::vec4_type, new_size); - this->new_clip_distance_var->max_array_access = ir->max_array_access / 4; + this->new_clip_distance_1d_var->max_array_access + = ir->max_array_access / 4; + + ir->replace_with(this->new_clip_distance_1d_var); + } else { + /* 2D gl_ClipDistance (used for geometry input). */ + assert(ir->mode == ir_var_shader_in && + this->shader_type == GL_GEOMETRY_SHADER_ARB); + if (this->old_clip_distance_2d_var) + return visit_continue; + + this->progress = true; + this->old_clip_distance_2d_var = ir; + assert (ir->type->element_type()->element_type() == glsl_type::float_type); + unsigned new_size = (ir->type->element_type()->array_size() + 3) / 4; + + /* Clone the old var so that we inherit all of its properties */ + this->new_clip_distance_2d_var = ir->clone(ralloc_parent(ir), NULL); - ir->replace_with(this->new_clip_distance_var); + /* And change the properties that we need to change */ + this->new_clip_distance_2d_var->name + = ralloc_strdup(this->new_clip_distance_2d_var, "gl_ClipDistanceMESA"); + this->new_clip_distance_2d_var->type = glsl_type::get_array_instance( + glsl_type::get_array_instance(glsl_type::vec4_type, + new_size), + ir->type->array_size()); + this->new_clip_distance_2d_var->max_array_access + = ir->max_array_access / 4; + + ir->replace_with(this->new_clip_distance_2d_var); } return visit_continue; } @@ -180,39 +229,111 @@ lower_clip_distance_visitor::create_indices(ir_rvalue *old_index, } +/** + * Determine whether the given rvalue describes an array of 8 floats that + * needs to be lowered to an array of 2 vec4's; that is, determine whether it + * matches one of the following patterns: + * + * - gl_ClipDistance (if gl_ClipDistance is 1D) + * - gl_ClipDistance[i] (if gl_ClipDistance is 2D) + */ +bool +lower_clip_distance_visitor::is_clip_distance_vec8(ir_rvalue *ir) +{ + /* Note that geometry shaders contain gl_ClipDistance both as an input + * (which is a 2D array) and an output (which is a 1D array), so it's + * possible for both this->old_clip_distance_1d_var and + * this->old_clip_distance_2d_var to be non-NULL in the same shader. + */ + + if (this->old_clip_distance_1d_var) { + ir_dereference_variable *var_ref = ir->as_dereference_variable(); + if (var_ref && var_ref->var == this->old_clip_distance_1d_var) + return true; + } + if (this->old_clip_distance_2d_var) { + /* 2D clip distance is only possible as a geometry input */ + assert(this->shader_type == GL_GEOMETRY_SHADER_ARB); + + ir_dereference_array *array_ref = ir->as_dereference_array(); + if (array_ref) { + ir_dereference_variable *var_ref = + array_ref->array->as_dereference_variable(); + if (var_ref && var_ref->var == this->old_clip_distance_2d_var) + return true; + } + } + return false; +} + + +/** + * If the given ir satisfies is_clip_distance_vec8(), return new ir + * representing its lowered equivalent. That is, map: + * + * - gl_ClipDistance => gl_ClipDistanceMESA (if gl_ClipDistance is 1D) + * - gl_ClipDistance[i] => gl_ClipDistanceMESA[i] (if gl_ClipDistance is 2D) + * + * Otherwise return NULL. + */ +ir_rvalue * +lower_clip_distance_visitor::lower_clip_distance_vec8(ir_rvalue *ir) +{ + if (this->old_clip_distance_1d_var) { + ir_dereference_variable *var_ref = ir->as_dereference_variable(); + if (var_ref && var_ref->var == this->old_clip_distance_1d_var) { + return new(ralloc_parent(ir)) + ir_dereference_variable(this->new_clip_distance_1d_var); + } + } + if (this->old_clip_distance_2d_var) { + /* 2D clip distance is only possible as a geometry input */ + assert(this->shader_type == GL_GEOMETRY_SHADER_ARB); + + ir_dereference_array *array_ref = ir->as_dereference_array(); + if (array_ref) { + ir_dereference_variable *var_ref = + array_ref->array->as_dereference_variable(); + if (var_ref && var_ref->var == this->old_clip_distance_2d_var) { + return new(ralloc_parent(ir)) + ir_dereference_array(this->new_clip_distance_2d_var, + array_ref->array_index); + } + } + } + return NULL; +} + + void lower_clip_distance_visitor::handle_rvalue(ir_rvalue **rv) { - /* If the gl_ClipDistance var hasn't been declared yet, then - * there's no way this deref can refer to it. - */ - if (!this->old_clip_distance_var || *rv == NULL) + if (*rv == NULL) return; ir_dereference_array *const array_deref = (*rv)->as_dereference_array(); if (array_deref == NULL) return; - /* Replace any expression that indexes into the gl_ClipDistance array + /* Replace any expression that indexes one of the floats in gl_ClipDistance * with an expression that indexes into one of the vec4's in * gl_ClipDistanceMESA and accesses the appropriate component. */ - ir_dereference_variable *old_var_ref = - array_deref->array->as_dereference_variable(); - if (old_var_ref && old_var_ref->var == this->old_clip_distance_var) { + ir_rvalue *lowered_vec8 = + this->lower_clip_distance_vec8(array_deref->array); + if (lowered_vec8 != NULL) { this->progress = true; ir_rvalue *array_index; ir_rvalue *swizzle_index; this->create_indices(array_deref->array_index, array_index, swizzle_index); void *mem_ctx = ralloc_parent(array_deref); - ir_dereference_array *const ClipDistanceMESA_deref = - new(mem_ctx) ir_dereference_array(this->new_clip_distance_var, - array_index); + ir_dereference_array *const new_array_deref = + new(mem_ctx) ir_dereference_array(lowered_vec8, array_index); ir_expression *const expr = new(mem_ctx) ir_expression(ir_binop_vector_extract, - ClipDistanceMESA_deref, + new_array_deref, swizzle_index); *rv = expr; @@ -246,30 +367,34 @@ lower_clip_distance_visitor::fix_lhs(ir_assignment *ir) } /** - * Replace any assignment having gl_ClipDistance (undereferenced) as its LHS - * or RHS with a sequence of assignments, one for each component of the array. - * Each of these assignments is lowered to refer to gl_ClipDistanceMESA as - * appropriate. + * Replace any assignment having the 1D gl_ClipDistance (undereferenced) as + * its LHS or RHS with a sequence of assignments, one for each component of + * the array. Each of these assignments is lowered to refer to + * gl_ClipDistanceMESA as appropriate. + * + * We need to do a similar replacement for 2D gl_ClipDistance, however since + * it's an input, the only case we need to address is where a 1D slice of it + * is the entire RHS of an assignment, e.g.: + * + * foo = gl_in[i].gl_ClipDistance */ ir_visitor_status lower_clip_distance_visitor::visit_leave(ir_assignment *ir) { - ir_dereference_variable *lhs_var = ir->lhs->as_dereference_variable(); - ir_dereference_variable *rhs_var = ir->rhs->as_dereference_variable(); - if ((lhs_var && lhs_var->var == this->old_clip_distance_var) - || (rhs_var && rhs_var->var == this->old_clip_distance_var)) { - /* LHS or RHS of the assignment is the entire gl_ClipDistance array. - * Since we are reshaping gl_ClipDistance from an array of floats to an - * array of vec4's, this isn't going to work as a bulk assignment - * anymore, so unroll it to element-by-element assignments and lower - * each of them. + if (this->is_clip_distance_vec8(ir->lhs) || + this->is_clip_distance_vec8(ir->rhs)) { + /* LHS or RHS of the assignment is the entire 1D gl_ClipDistance array + * (or a 1D slice of a 2D gl_ClipDistance input array). Since we are + * reshaping gl_ClipDistance from an array of floats to an array of + * vec4's, this isn't going to work as a bulk assignment anymore, so + * unroll it to element-by-element assignments and lower each of them. * * Note: to unroll into element-by-element assignments, we need to make * clones of the LHS and RHS. This is safe because expressions and * l-values are side-effect free. */ void *ctx = ralloc_parent(ir); - int array_size = this->old_clip_distance_var->type->array_size(); + int array_size = ir->lhs->type->array_size(); for (int i = 0; i < array_size; ++i) { ir_dereference_array *new_lhs = new(ctx) ir_dereference_array( ir->lhs->clone(ctx, NULL), new(ctx) ir_constant(i)); @@ -329,11 +454,17 @@ lower_clip_distance_visitor::visit_new_assignment(ir_assignment *ir) /** - * If gl_ClipDistance appears as an argument in an ir_call expression, replace - * it with a temporary variable, and make sure the ir_call is preceded and/or - * followed by assignments that copy the contents of the temporary variable to - * and/or from gl_ClipDistance. Each of these assignments is then lowered to - * refer to gl_ClipDistanceMESA. + * If a 1D gl_ClipDistance variable appears as an argument in an ir_call + * expression, replace it with a temporary variable, and make sure the ir_call + * is preceded and/or followed by assignments that copy the contents of the + * temporary variable to and/or from gl_ClipDistance. Each of these + * assignments is then lowered to refer to gl_ClipDistanceMESA. + * + * We need to do a similar replacement for 2D gl_ClipDistance, however since + * it's an input, the only case we need to address is where a 1D slice of it + * is passed as an "in" parameter to an ir_call, e.g.: + * + * foo(gl_in[i].gl_ClipDistance) */ ir_visitor_status lower_clip_distance_visitor::visit_leave(ir_call *ir) @@ -352,12 +483,12 @@ lower_clip_distance_visitor::visit_leave(ir_call *ir) formal_param_node = formal_param_node->next; actual_param_node = actual_param_node->next; - ir_dereference_variable *deref = actual_param->as_dereference_variable(); - if (deref && deref->var == this->old_clip_distance_var) { - /* User is trying to pass the whole gl_ClipDistance array to a - * function call. Since we are reshaping gl_ClipDistance from an - * array of floats to an array of vec4's, this isn't going to work - * anymore, so use a temporary array instead. + if (this->is_clip_distance_vec8(actual_param)) { + /* User is trying to pass the whole 1D gl_ClipDistance array (or a 1D + * slice of a 2D gl_ClipDistance array) to a function call. Since we + * are reshaping gl_ClipDistance from an array of floats to an array + * of vec4's, this isn't going to work anymore, so use a temporary + * array instead. */ ir_variable *temp_clip_distance = new(ctx) ir_variable( actual_param->type, "temp_clip_distance", ir_var_temporary); @@ -373,7 +504,7 @@ lower_clip_distance_visitor::visit_leave(ir_call *ir) */ ir_assignment *new_assignment = new(ctx) ir_assignment( new(ctx) ir_dereference_variable(temp_clip_distance), - new(ctx) ir_dereference_variable(old_clip_distance_var)); + actual_param->clone(ctx, NULL)); this->base_ir->insert_before(new_assignment); this->visit_new_assignment(new_assignment); } @@ -385,7 +516,7 @@ lower_clip_distance_visitor::visit_leave(ir_call *ir) * afterwards to make sure it gets lowered. */ ir_assignment *new_assignment = new(ctx) ir_assignment( - new(ctx) ir_dereference_variable(old_clip_distance_var), + actual_param->clone(ctx, NULL), new(ctx) ir_dereference_variable(temp_clip_distance)); this->base_ir->insert_after(new_assignment); this->visit_new_assignment(new_assignment); @@ -400,12 +531,14 @@ lower_clip_distance_visitor::visit_leave(ir_call *ir) bool lower_clip_distance(gl_shader *shader) { - lower_clip_distance_visitor v; + lower_clip_distance_visitor v(shader->Type); visit_list_elements(&v, shader->ir); - if (v.new_clip_distance_var) - shader->symbols->add_variable(v.new_clip_distance_var); + if (v.new_clip_distance_1d_var) + shader->symbols->add_variable(v.new_clip_distance_1d_var); + if (v.new_clip_distance_2d_var) + shader->symbols->add_variable(v.new_clip_distance_2d_var); return v.progress; } -- 2.30.2