gallium: WIP: Introduce sampler views.

1 files changed, 97 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/util/u_sampler.c b/src/gallium/auxiliary/util/u_sampler.c
new file mode 100644
index 0000000000..3e45a2fa70
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_sampler.c
@@ -0,0 +1,97 @@
+/**************************************************************************
+ *
+ * Copyright 2010 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 VMWARE 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.
+ *
+ **************************************************************************/
+
+
+#include "u_format.h"
+#include "u_sampler.h"
+
+
+static void
+default_template(struct pipe_sampler_view *view,
+                 const struct pipe_texture *texture,
+                 enum pipe_format format,
+                 unsigned expand_green_blue)
+{
+   /* XXX: Check if format is compatible with texture->format.
+    */
+
+   view->format = format;
+   view->first_level = 0;
+   view->num_levels = texture->last_level + 1;
+   view->swizzle_r = PIPE_SWIZZLE_RED;
+   view->swizzle_g = PIPE_SWIZZLE_GREEN;
+   view->swizzle_b = PIPE_SWIZZLE_BLUE;
+   view->swizzle_a = PIPE_SWIZZLE_ALPHA;
+
+   /* Override default green and blue component expansion to the requested one.
+    *
+    * Gallium expands nonexistent components to (0,0,0,1), DX9 expands to (1,1,1,1).
+    * Since alpha is always expanded to 1, and red is always present, we only really
+    * care about green and blue components.
+    *
+    * To make it look less hackish, one would have to add UTIL_FORMAT_SWIZZLE_EXPAND
+    * to indicate components for expansion and then override without exceptions or
+    * favoring one component over another.
+    */
+   if (format != PIPE_FORMAT_A8_UNORM) {
+      const struct util_format_description *desc = util_format_description(format);
+
+      assert(desc);
+      if (desc) {
+         if (desc->swizzle[1] == UTIL_FORMAT_SWIZZLE_0) {
+            view->swizzle_g = expand_green_blue;
+         }
+         if (desc->swizzle[2] == UTIL_FORMAT_SWIZZLE_0) {
+            view->swizzle_b = expand_green_blue;
+         }
+      }
+   }
+}
+
+void
+u_sampler_view_default_template(struct pipe_sampler_view *view,
+                                const struct pipe_texture *texture,
+                                enum pipe_format format)
+{
+   /* Expand to (0, 0, 0, 1) */
+   default_template(view,
+                    texture,
+                    format,
+                    PIPE_SWIZZLE_ZERO);
+}
+
+void
+u_sampler_view_default_dx9_template(struct pipe_sampler_view *view,
+                                    const struct pipe_texture *texture,
+                                    enum pipe_format format)
+{
+   /* Expand to (1, 1, 1, 1) */
+   default_template(view,
+                    texture,
+                    format,
+                    PIPE_SWIZZLE_ONE);
+}