tgsi: adds tgsi utility to transform a shader to support point sprite

This adds a tgsi utility tgsi_add_point_sprite to transform a geometry
shader to emulate wide points by drawing quads. This utility adds an
extra output for the original point position if the point position is
to be written to a stream output buffer. It also assumes the driver will
add a constant for inverse viewport scale after the user defined constants.

Reviewed-by: Brian Paul <[email protected]>

1 files changed, 38 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/tgsi/tgsi_point_sprite.h b/src/gallium/auxiliary/tgsi/tgsi_point_sprite.h
new file mode 100644
index 00000000000..d1958914bc3
--- /dev/null
+++ b/src/gallium/auxiliary/tgsi/tgsi_point_sprite.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2014 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * 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, sub license, 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 NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS 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.
+ */
+
+#ifndef TGSI_POINT_SPRITE_H
+#define TGSI_POINT_SPRITE_H
+
+struct tgsi_token;
+
+struct tgsi_token *
+tgsi_add_point_sprite(const struct tgsi_token *tokens_in,
+                      const unsigned point_coord_enable,
+                      const bool sprite_origin_lower_left,
+                      const bool stream_out_point_pos,
+                      int *aa_point_coord_index);
+
+#endif /* TGSI_POINT_SPRITE_H */