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-rw-r--r--src/gallium/auxiliary/indices/u_indices.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/indices/u_indices.c b/src/gallium/auxiliary/indices/u_indices.c
index 30b54b9fb6a..1b33f413fc4 100644
--- a/src/gallium/auxiliary/indices/u_indices.c
+++ b/src/gallium/auxiliary/indices/u_indices.c
@@ -42,6 +42,27 @@ static void translate_memcpy_uint( const void *in,
}
+/**
+ * Translate indexes when a driver can't support certain types
+ * of drawing. Example include:
+ * - Translate 1-byte indexes into 2-byte indexes
+ * - Translate PIPE_PRIM_QUADS into PIPE_PRIM_TRIANGLES when the hardware
+ * doesn't support the former.
+ * - Translate from first provoking vertex to last provoking vertex and
+ * vice versa.
+ *
+ * \param hw_mask mask of (1 << PIPE_PRIM_x) flags indicating which types
+ * of primitives are supported by the hardware.
+ * \param prim incoming PIPE_PRIM_x
+ * \param in_index_size bytes per index value (1, 2 or 4)
+ * \param nr number of incoming vertices
+ * \param in_pv incoming provoking vertex convention (PV_FIRST or PV_LAST)
+ * \param out_pv desired provoking vertex convention (PV_FIRST or PV_LAST)
+ * \param out_prim returns new PIPE_PRIM_x we'll translate to
+ * \param out_index_size returns bytes per new index value (2 or 4)
+ * \param out_nr returns number of new vertices
+ * \param out_translate returns the translation function to use by the caller
+ */
int u_index_translator( unsigned hw_mask,
unsigned prim,
unsigned in_index_size,
@@ -57,6 +78,10 @@ int u_index_translator( unsigned hw_mask,
unsigned out_idx;
int ret = U_TRANSLATE_NORMAL;
+ assert(in_index_size == 1 ||
+ in_index_size == 2 ||
+ in_index_size == 4);
+
u_index_init();
in_idx = in_size_idx(in_index_size);
@@ -67,6 +92,7 @@ int u_index_translator( unsigned hw_mask,
in_index_size == *out_index_size &&
in_pv == out_pv)
{
+ /* Index translation not really needed */
if (in_index_size == 4)
*out_translate = translate_memcpy_uint;
else