fdo-mirrors/mesa
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/mesa/mesa.git synced 2026-05-07 20:08:06 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 4

glsl/gs: handle gl_ClipDistance geometry input in lower_clip_distance.

Browse source 
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 <stereotype441@gmail.com>): 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 <jordan.l.justen@intel.com>

v3 (Paul Berry <stereotype441@gmail.com>): Add comments and assertions
to clarify that the 2D version of clip distance is only used for
geometry shader inputs.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
This commit is contained in:
Bryan Cain 2013-02-15 09:30:51 -06:00 • committed by Paul Berry
parent c09adcb21b
commit 8f758b0b92
1 changed files with 193 additions and 60 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

253
src/glsl/lower_clip_distance.cpp
View file

@ -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_var);
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);
/* 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;
}