[Mesa-dev] [PATCH 3/5] glsl/ir_builder: Add a new swizzle_for_size() function.
Kenneth Graunke
kenneth at whitecape.org
Tue Jul 10 11:14:43 PDT 2012
This swizzles away unwanted components, while preserving the order of
the ones that remain.
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
src/glsl/ir_builder.cpp | 15 +++++++++++++++
src/glsl/ir_builder.h | 5 +++++
2 files changed, 20 insertions(+)
diff --git a/src/glsl/ir_builder.cpp b/src/glsl/ir_builder.cpp
index fc6ee96..d96e25c 100644
--- a/src/glsl/ir_builder.cpp
+++ b/src/glsl/ir_builder.cpp
@@ -77,6 +77,21 @@ swizzle(operand a, int swizzle, int components)
}
ir_swizzle *
+swizzle_for_size(operand a, int components)
+{
+ void *mem_ctx = ralloc_parent(a.val);
+
+ if (a.val->type->vector_elements < components)
+ components = a.val->type->vector_elements;
+
+ unsigned s[4] = { 0, 1, 2, 3 };
+ for (int i = components; i < 4; i++)
+ s[i] = components - 1;
+
+ return new(mem_ctx) ir_swizzle(a.val, s, components);
+}
+
+ir_swizzle *
swizzle_xxxx(operand a)
{
return swizzle(a, SWIZZLE_XXXX, 4);
diff --git a/src/glsl/ir_builder.h b/src/glsl/ir_builder.h
index 410b08c..7a0a196 100644
--- a/src/glsl/ir_builder.h
+++ b/src/glsl/ir_builder.h
@@ -91,6 +91,11 @@ ir_expression *mul(operand a, operand b);
ir_expression *dot(operand a, operand b);
ir_expression *saturate(operand a);
+/**
+ * Swizzle away later components, but preserve the ordering.
+ */
+ir_swizzle *swizzle_for_size(operand a, int components);
+
ir_swizzle *swizzle_xxxx(operand a);
ir_swizzle *swizzle_yyyy(operand a);
ir_swizzle *swizzle_zzzz(operand a);
--
1.7.10.4
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