- * Data structure tracking information about a transform feedback declaration
- * during linking.
- */
-class tfeedback_decl
-{
-public:
- bool init(struct gl_shader_program *prog, const void *mem_ctx,
- const char *input);
- static bool is_same(const tfeedback_decl &x, const tfeedback_decl &y);
- bool assign_location(struct gl_context *ctx, struct gl_shader_program *prog,
- ir_variable *output_var);
- bool store(struct gl_shader_program *prog,
- struct gl_transform_feedback_info *info, unsigned buffer) const;
-
-
- /**
- * True if assign_location() has been called for this object.
- */
- bool is_assigned() const
- {
- return this->location != -1;
- }
-
- /**
- * Determine whether this object refers to the variable var.
- */
- bool matches_var(ir_variable *var) const
- {
- return strcmp(var->name, this->var_name) == 0;
- }
-
- /**
- * The total number of varying components taken up by this variable. Only
- * valid if is_assigned() is true.
- */
- unsigned num_components() const
- {
- return this->vector_elements * this->matrix_columns;
- }
-
-private:
- /**
- * The name that was supplied to glTransformFeedbackVaryings. Used for
- * error reporting.
- */
- const char *orig_name;
-
- /**
- * The name of the variable, parsed from orig_name.
- */
- char *var_name;
-
- /**
- * True if the declaration in orig_name represents an array.
- */
- bool is_array;
-
- /**
- * If is_array is true, the array index that was specified in orig_name.
- */
- unsigned array_index;
-
- /**
- * The vertex shader output location that the linker assigned for this
- * variable. -1 if a location hasn't been assigned yet.
- */
- int location;
-
- /**
- * If location != -1, the number of vector elements in this variable, or 1
- * if this variable is a scalar.
- */
- unsigned vector_elements;
-
- /**
- * If location != -1, the number of matrix columns in this variable, or 1
- * if this variable is not a matrix.
- */
- unsigned matrix_columns;
-};
-
-
-/**
- * Initialize this object based on a string that was passed to
- * glTransformFeedbackVaryings. If there is a parse error, the error is
- * reported using linker_error(), and false is returned.
- */
-bool
-tfeedback_decl::init(struct gl_shader_program *prog, const void *mem_ctx,
- const char *input)
-{
- /* We don't have to be pedantic about what is a valid GLSL variable name,
- * because any variable with an invalid name can't exist in the IR anyway.
- */
-
- this->location = -1;
- this->orig_name = input;
-
- const char *bracket = strrchr(input, '[');
-
- if (bracket) {
- this->var_name = ralloc_strndup(mem_ctx, input, bracket - input);
- if (sscanf(bracket, "[%u]", &this->array_index) == 1) {
- this->is_array = true;
- return true;
- }
- } else {
- this->var_name = ralloc_strdup(mem_ctx, input);
- this->is_array = false;
- return true;
- }
-
- linker_error(prog, "Cannot parse transform feedback varying %s", input);
- return false;
-}
-
-
-/**
- * Determine whether two tfeedback_decl objects refer to the same variable and
- * array index (if applicable).
- */
-bool
-tfeedback_decl::is_same(const tfeedback_decl &x, const tfeedback_decl &y)
-{
- if (strcmp(x.var_name, y.var_name) != 0)
- return false;
- if (x.is_array != y.is_array)
- return false;
- if (x.is_array && x.array_index != y.array_index)
- return false;
- return true;
-}
-
-
-/**
- * Assign a location for this tfeedback_decl object based on the location
- * assignment in output_var.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-bool
-tfeedback_decl::assign_location(struct gl_context *ctx,
- struct gl_shader_program *prog,
- ir_variable *output_var)
-{
- if (output_var->type->is_array()) {
- /* Array variable */
- if (!this->is_array) {
- linker_error(prog, "Transform feedback varying %s found, "
- "but it's not an array ([] not expected).",
- this->orig_name);
- return false;
- }
- /* Check array bounds. */
- if (this->array_index >=
- (unsigned) output_var->type->array_size()) {
- linker_error(prog, "Transform feedback varying %s has index "
- "%i, but the array size is %i.",
- this->orig_name, this->array_index,
- output_var->type->array_size());
- return false;
- }
- const unsigned matrix_cols =
- output_var->type->fields.array->matrix_columns;
- this->location = output_var->location + this->array_index * matrix_cols;
- this->vector_elements = output_var->type->fields.array->vector_elements;
- this->matrix_columns = matrix_cols;
- } else {
- /* Regular variable (scalar, vector, or matrix) */
- if (this->is_array) {
- linker_error(prog, "Transform feedback varying %s found, "
- "but it's an array ([] expected).",
- this->orig_name);
- return false;
- }
- this->location = output_var->location;
- this->vector_elements = output_var->type->vector_elements;
- this->matrix_columns = output_var->type->matrix_columns;
- }
- /* From GL_EXT_transform_feedback:
- * A program will fail to link if:
- *
- * * the total number of components to capture in any varying
- * variable in <varyings> is greater than the constant
- * MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS_EXT and the
- * buffer mode is SEPARATE_ATTRIBS_EXT;
- */
- if (prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS &&
- this->num_components() >
- ctx->Const.MaxTransformFeedbackSeparateComponents) {
- linker_error(prog, "Transform feedback varying %s exceeds "
- "MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS.",
- this->orig_name);
- return false;
- }
-
- return true;
-}
-
-
-/**
- * Update gl_transform_feedback_info to reflect this tfeedback_decl.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-bool
-tfeedback_decl::store(struct gl_shader_program *prog,
- struct gl_transform_feedback_info *info,
- unsigned buffer) const
-{
- if (!this->is_assigned()) {
- /* From GL_EXT_transform_feedback:
- * A program will fail to link if:
- *
- * * any variable name specified in the <varyings> array is not
- * declared as an output in the geometry shader (if present) or
- * the vertex shader (if no geometry shader is present);
- */
- linker_error(prog, "Transform feedback varying %s undeclared.",
- this->orig_name);
- return false;
- }
- for (unsigned v = 0; v < this->matrix_columns; ++v) {
- info->Outputs[info->NumOutputs].OutputRegister = this->location + v;
- info->Outputs[info->NumOutputs].NumComponents = this->vector_elements;
- info->Outputs[info->NumOutputs].OutputBuffer = buffer;
- ++info->NumOutputs;
- }
- return true;
-}
-
-
-/**
- * Parse all the transform feedback declarations that were passed to
- * glTransformFeedbackVaryings() and store them in tfeedback_decl objects.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-static bool
-parse_tfeedback_decls(struct gl_shader_program *prog, const void *mem_ctx,
- unsigned num_names, char **varying_names,
- tfeedback_decl *decls)
-{
- for (unsigned i = 0; i < num_names; ++i) {
- if (!decls[i].init(prog, mem_ctx, varying_names[i]))
- return false;
- /* From GL_EXT_transform_feedback:
- * A program will fail to link if:
- *
- * * any two entries in the <varyings> array specify the same varying
- * variable;
- *
- * We interpret this to mean "any two entries in the <varyings> array
- * specify the same varying variable and array index", since transform
- * feedback of arrays would be useless otherwise.
- */
- for (unsigned j = 0; j < i; ++j) {
- if (tfeedback_decl::is_same(decls[i], decls[j])) {
- linker_error(prog, "Transform feedback varying %s specified "
- "more than once.", varying_names[i]);
- return false;
- }
- }
- }
- return true;
-}
-
-
-/**
- * Assign a location for a variable that is produced in one pipeline stage
- * (the "producer") and consumed in the next stage (the "consumer").
- *
- * \param input_var is the input variable declaration in the consumer.
- *
- * \param output_var is the output variable declaration in the producer.
- *
- * \param input_index is the counter that keeps track of assigned input
- * locations in the consumer.
- *
- * \param output_index is the counter that keeps track of assigned output
- * locations in the producer.
- *
- * It is permissible for \c input_var to be NULL (this happens if a variable
- * is output by the producer and consumed by transform feedback, but not
- * consumed by the consumer).
- *
- * If the variable has already been assigned a location, this function has no
- * effect.