--- /dev/null
+/*
+ * Copyright © 2012 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file brw_lower_texture_gradients.cpp
+ */
+
+#include "glsl/ir.h"
+#include "glsl/ir_builder.h"
+
+using namespace ir_builder;
+
+class lower_texture_grad_visitor : public ir_hierarchical_visitor {
+public:
+ lower_texture_grad_visitor()
+ {
+ progress = false;
+ }
+
+ ir_visitor_status visit_leave(ir_texture *ir);
+
+
+ bool progress;
+
+private:
+ void emit(ir_variable *, ir_rvalue *);
+};
+
+/**
+ * Emit a variable declaration and an assignment to initialize it.
+ */
+void
+lower_texture_grad_visitor::emit(ir_variable *var, ir_rvalue *value)
+{
+ base_ir->insert_before(var);
+ base_ir->insert_before(assign(var, value));
+}
+
+static const glsl_type *
+txs_type(const glsl_type *type)
+{
+ unsigned dims;
+ switch (type->sampler_dimensionality) {
+ case GLSL_SAMPLER_DIM_1D:
+ dims = 1;
+ break;
+ case GLSL_SAMPLER_DIM_2D:
+ case GLSL_SAMPLER_DIM_RECT:
+ case GLSL_SAMPLER_DIM_CUBE:
+ dims = 2;
+ break;
+ case GLSL_SAMPLER_DIM_3D:
+ dims = 3;
+ break;
+ default:
+ assert(!"Should not get here: invalid sampler dimensionality");
+ }
+
+ if (type->sampler_array)
+ dims++;
+
+ return glsl_type::get_instance(GLSL_TYPE_INT, dims, 1);
+}
+
+ir_visitor_status
+lower_texture_grad_visitor::visit_leave(ir_texture *ir)
+{
+ /* Only lower textureGrad with shadow samplers */
+ if (ir->op != ir_txd || !ir->shadow_comparitor)
+ return visit_continue;
+
+ /* Cubes are broken. Avoid assertion failures when swizzling. */
+ if (ir->sampler->type->sampler_dimensionality == GLSL_SAMPLER_DIM_CUBE)
+ return visit_continue;
+
+ void *mem_ctx = ralloc_parent(ir);
+
+ const glsl_type *grad_type = ir->lod_info.grad.dPdx->type;
+
+ /* Use textureSize() to get the width and height of LOD 0; swizzle away
+ * the depth/number of array slices.
+ */
+ ir_texture *txs = new(mem_ctx) ir_texture(ir_txs);
+ txs->set_sampler(ir->sampler->clone(mem_ctx, NULL),
+ txs_type(ir->sampler->type));
+ txs->lod_info.lod = new(mem_ctx) ir_constant(0);
+ ir_variable *size =
+ new(mem_ctx) ir_variable(grad_type, "size", ir_var_temporary);
+ emit(size, expr(ir_unop_i2f,
+ swizzle_for_size(txs, grad_type->vector_elements)));
+
+ /* Scale the gradients by width and height. Effectively, the incoming
+ * gradients are s'(x,y), t'(x,y), and r'(x,y) from equation 3.19 in the
+ * GL 3.0 spec; we want u'(x,y), which is w_t * s'(x,y).
+ */
+ ir_variable *dPdx =
+ new(mem_ctx) ir_variable(grad_type, "dPdx", ir_var_temporary);
+ emit(dPdx, mul(size, ir->lod_info.grad.dPdx));
+
+ ir_variable *dPdy =
+ new(mem_ctx) ir_variable(grad_type, "dPdy", ir_var_temporary);
+ emit(dPdy, mul(size, ir->lod_info.grad.dPdy));
+
+ /* Calculate rho from equation 3.20 of the GL 3.0 specification. */
+ ir_rvalue *rho;
+ if (dPdx->type->is_scalar()) {
+ rho = expr(ir_binop_max, expr(ir_unop_abs, dPdx),
+ expr(ir_unop_abs, dPdy));
+ } else {
+ rho = expr(ir_binop_max, expr(ir_unop_sqrt, dot(dPdx, dPdx)),
+ expr(ir_unop_sqrt, dot(dPdy, dPdy)));
+ }
+
+ /* lambda_base = log2(rho). We're ignoring GL state biases for now. */
+ ir->op = ir_txl;
+ ir->lod_info.lod = expr(ir_unop_log2, rho);
+
+ progress = true;
+ return visit_continue;
+}
+
+extern "C" {
+
+bool
+brw_lower_texture_gradients(struct exec_list *instructions)
+{
+ lower_texture_grad_visitor v;
+
+ visit_list_elements(&v, instructions);
+
+ return v.progress;
+}
+
+}
projects / mesa.git / commitdiff