st/mesa: move all sampler view code into new st_sampler_view.[ch] files

Previously, the sampler view code was scattered across several different
files.

Note, the previous REALLOC(), FREE() for st_texture_object::sampler_views
are replaced by realloc(), free() to avoid conflicting macros in Mesa vs.
Gallium.

Reviewed-by: Edward O'Callaghan <[email protected]>
Acked-by: Nicolai Hähnle <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>

12 files changed, 587 insertions, 493 deletions

diff --git a/src/mesa/state_tracker/st_atom_pixeltransfer.c b/src/mesa/state_tracker/st_atom_pixeltransfer.c
index 26d8adec3a2..a2951a1d6be 100644
--- a/src/mesa/state_tracker/st_atom_pixeltransfer.c
+++ b/src/mesa/state_tracker/st_atom_pixeltransfer.c
@@ -30,6 +30,7 @@
  */
 
 #include "st_context.h"
+#include "st_sampler_view.h"
 #include "st_texture.h"
 
 #include "util/u_inlines.h"
diff --git a/src/mesa/state_tracker/st_atom_texture.c b/src/mesa/state_tracker/st_atom_texture.c
index 45f1f6b02f1..c8ae62c2a7b 100644
--- a/src/mesa/state_tracker/st_atom_texture.c
+++ b/src/mesa/state_tracker/st_atom_texture.c
@@ -42,6 +42,7 @@
 
 #include "st_context.h"
 #include "st_atom.h"
+#include "st_sampler_view.h"
 #include "st_texture.h"
 #include "st_format.h"
 #include "st_cb_texture.h"
@@ -51,372 +52,6 @@
 #include "cso_cache/cso_context.h"
 
 
-/**
- * Return swizzle1(swizzle2)
- */
-static unsigned
-swizzle_swizzle(unsigned swizzle1, unsigned swizzle2)
-{
-   unsigned i, swz[4];
-
-   if (swizzle1 == SWIZZLE_XYZW) {
-      /* identity swizzle, no change to swizzle2 */
-      return swizzle2;
-   }
-
-   for (i = 0; i < 4; i++) {
-      unsigned s = GET_SWZ(swizzle1, i);
-      switch (s) {
-      case SWIZZLE_X:
-      case SWIZZLE_Y:
-      case SWIZZLE_Z:
-      case SWIZZLE_W:
-         swz[i] = GET_SWZ(swizzle2, s);
-         break;
-      case SWIZZLE_ZERO:
-         swz[i] = SWIZZLE_ZERO;
-         break;
-      case SWIZZLE_ONE:
-         swz[i] = SWIZZLE_ONE;
-         break;
-      default:
-         assert(!"Bad swizzle term");
-         swz[i] = SWIZZLE_X;
-      }
-   }
-
-   return MAKE_SWIZZLE4(swz[0], swz[1], swz[2], swz[3]);
-}
-
-
-/**
- * Given a user-specified texture base format, the actual gallium texture
- * format and the current GL_DEPTH_MODE, return a texture swizzle.
- *
- * Consider the case where the user requests a GL_RGB internal texture
- * format the driver actually uses an RGBA format.  The A component should
- * be ignored and sampling from the texture should always return (r,g,b,1).
- * But if we rendered to the texture we might have written A values != 1.
- * By sampling the texture with a ".xyz1" swizzle we'll get the expected A=1.
- * This function computes the texture swizzle needed to get the expected
- * values.
- *
- * In the case of depth textures, the GL_DEPTH_MODE state determines the
- * texture swizzle.
- *
- * This result must be composed with the user-specified swizzle to get
- * the final swizzle.
- */
-static unsigned
-compute_texture_format_swizzle(GLenum baseFormat, GLenum depthMode,
-                               enum pipe_format actualFormat,
-                               unsigned glsl_version)
-{
-   switch (baseFormat) {
-   case GL_RGBA:
-      return SWIZZLE_XYZW;
-   case GL_RGB:
-      if (util_format_has_alpha(actualFormat))
-         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_ONE);
-      else
-         return SWIZZLE_XYZW;
-   case GL_RG:
-      if (util_format_get_nr_components(actualFormat) > 2)
-         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_ZERO, SWIZZLE_ONE);
-      else
-         return SWIZZLE_XYZW;
-   case GL_RED:
-      if (util_format_get_nr_components(actualFormat) > 1)
-         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_ZERO,
-                              SWIZZLE_ZERO, SWIZZLE_ONE);
-      else
-         return SWIZZLE_XYZW;
-   case GL_ALPHA:
-      if (util_format_get_nr_components(actualFormat) > 1)
-         return MAKE_SWIZZLE4(SWIZZLE_ZERO, SWIZZLE_ZERO,
-                              SWIZZLE_ZERO, SWIZZLE_W);
-      else
-         return SWIZZLE_XYZW;
-   case GL_LUMINANCE:
-      if (util_format_get_nr_components(actualFormat) > 1)
-         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_ONE);
-      else
-         return SWIZZLE_XYZW;
-   case GL_LUMINANCE_ALPHA:
-      if (util_format_get_nr_components(actualFormat) > 2)
-         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_W);
-      else
-         return SWIZZLE_XYZW;
-   case GL_INTENSITY:
-      if (util_format_get_nr_components(actualFormat) > 1)
-         return SWIZZLE_XXXX;
-      else
-         return SWIZZLE_XYZW;
-   case GL_STENCIL_INDEX:
-   case GL_DEPTH_STENCIL:
-   case GL_DEPTH_COMPONENT:
-      /* Now examine the depth mode */
-      switch (depthMode) {
-      case GL_LUMINANCE:
-         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_ONE);
-      case GL_INTENSITY:
-         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_X);
-      case GL_ALPHA:
-         /* The texture(sampler*Shadow) functions from GLSL 1.30 ignore
-          * the depth mode and return float, while older shadow* functions
-          * and ARB_fp instructions return vec4 according to the depth mode.
-          *
-          * The problem with the GLSL 1.30 functions is that GL_ALPHA forces
-          * them to return 0, breaking them completely.
-          *
-          * A proper fix would increase code complexity and that's not worth
-          * it for a rarely used feature such as the GL_ALPHA depth mode
-          * in GL3. Therefore, change GL_ALPHA to GL_INTENSITY for all
-          * shaders that use GLSL 1.30 or later.
-          *
-          * BTW, it's required that sampler views are updated when
-          * shaders change (check_sampler_swizzle takes care of that).
-          */
-         if (glsl_version && glsl_version >= 130)
-            return SWIZZLE_XXXX;
-         else
-            return MAKE_SWIZZLE4(SWIZZLE_ZERO, SWIZZLE_ZERO,
-                                 SWIZZLE_ZERO, SWIZZLE_X);
-      case GL_RED:
-         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_ZERO,
-                              SWIZZLE_ZERO, SWIZZLE_ONE);
-      default:
-         assert(!"Unexpected depthMode");
-         return SWIZZLE_XYZW;
-      }
-   default:
-      assert(!"Unexpected baseFormat");
-      return SWIZZLE_XYZW;
-   }
-}
-
-
-static unsigned
-get_texture_format_swizzle(const struct st_context *st,
-                           const struct st_texture_object *stObj,
-                           unsigned glsl_version)
-{
-   GLenum baseFormat = _mesa_texture_base_format(&stObj->base);
-   unsigned tex_swizzle;
-
-   if (baseFormat != GL_NONE) {
-      GLenum depth_mode = stObj->base.DepthMode;
-      /* In ES 3.0, DEPTH_TEXTURE_MODE is expected to be GL_RED for textures
-       * with depth component data specified with a sized internal format.
-       */
-      if (_mesa_is_gles3(st->ctx) &&
-          util_format_is_depth_or_stencil(stObj->pt->format)) {
-         const struct gl_texture_image *firstImage =
-            _mesa_base_tex_image(&stObj->base);
-         if (firstImage->InternalFormat != GL_DEPTH_COMPONENT &&
-             firstImage->InternalFormat != GL_DEPTH_STENCIL &&
-             firstImage->InternalFormat != GL_STENCIL_INDEX)
-            depth_mode = GL_RED;
-      }
-      tex_swizzle = compute_texture_format_swizzle(baseFormat,
-                                                   depth_mode,
-                                                   stObj->pt->format,
-                                                   glsl_version);
-   }
-   else {
-      tex_swizzle = SWIZZLE_XYZW;
-   }
-
-   /* Combine the texture format swizzle with user's swizzle */
-   return swizzle_swizzle(stObj->base._Swizzle, tex_swizzle);
-}
-
-
-/**
- * Return TRUE if the texture's sampler view swizzle is not equal to
- * the texture's swizzle.
- *
- * \param stObj  the st texture object,
- */
-static boolean
-check_sampler_swizzle(const struct st_context *st,
-                      const struct st_texture_object *stObj,
-		      const struct pipe_sampler_view *sv, unsigned glsl_version)
-{
-   unsigned swizzle = get_texture_format_swizzle(st, stObj, glsl_version);
-
-   return ((sv->swizzle_r != GET_SWZ(swizzle, 0)) ||
-           (sv->swizzle_g != GET_SWZ(swizzle, 1)) ||
-           (sv->swizzle_b != GET_SWZ(swizzle, 2)) ||
-           (sv->swizzle_a != GET_SWZ(swizzle, 3)));
-}
-
-
-static unsigned
-last_level(const struct st_texture_object *stObj)
-{
-   unsigned ret = MIN2(stObj->base.MinLevel + stObj->base._MaxLevel,
-                       stObj->pt->last_level);
-   if (stObj->base.Immutable)
-      ret = MIN2(ret, stObj->base.MinLevel + stObj->base.NumLevels - 1);
-   return ret;
-}
-
-static unsigned
-last_layer(const struct st_texture_object *stObj)
-{
-   if (stObj->base.Immutable && stObj->pt->array_size > 1)
-      return MIN2(stObj->base.MinLayer + stObj->base.NumLayers - 1,
-                  stObj->pt->array_size - 1);
-   return stObj->pt->array_size - 1;
-}
-
-
-/**
- * Determine the format for the texture sampler view.
- */
-static enum pipe_format
-get_sampler_view_format(struct st_context *st,
-                        const struct st_texture_object *stObj,
-                        const struct gl_sampler_object *samp)
-{
-   enum pipe_format format;
-
-   if (stObj->base.Target == GL_TEXTURE_BUFFER) {
-      format =
-         st_mesa_format_to_pipe_format(st, stObj->base._BufferObjectFormat);
-   }
-   else {
-      format =
-         stObj->surface_based ? stObj->surface_format : stObj->pt->format;
-
-      if (util_format_is_depth_and_stencil(format)) {
-         if (stObj->base.StencilSampling) {
-            format = util_format_stencil_only(format);
-         }
-         else {
-            GLenum baseFormat = _mesa_texture_base_format(&stObj->base);
-            if (baseFormat == GL_STENCIL_INDEX) {
-               format = util_format_stencil_only(format);
-            }
-         }
-      }
-      else {
-         /* If sRGB decoding is off, use the linear format */
-         if (samp->sRGBDecode == GL_SKIP_DECODE_EXT) {
-            format = util_format_linear(format);
-         }
-
-         /* Use R8_UNORM for video formats */
-         switch (format) {
-         case PIPE_FORMAT_NV12:
-         case PIPE_FORMAT_IYUV:
-            format = PIPE_FORMAT_R8_UNORM;
-            break;
-         default:
-            break;
-         }
-      }
-   }
-
-   return format;
-}
-
-
-static struct pipe_sampler_view *
-st_create_texture_sampler_view_from_stobj(struct st_context *st,
-					  struct st_texture_object *stObj,
-					  enum pipe_format format,
-                                          unsigned glsl_version)
-{
-   struct pipe_sampler_view templ;
-   unsigned swizzle = get_texture_format_swizzle(st, stObj, glsl_version);
-
-   u_sampler_view_default_template(&templ,
-                                   stObj->pt,
-                                   format);
-
-   if (stObj->pt->target == PIPE_BUFFER) {
-      unsigned base, size;
-
-      base = stObj->base.BufferOffset;
-      if (base >= stObj->pt->width0)
-         return NULL;
-      size = MIN2(stObj->pt->width0 - base, (unsigned)stObj->base.BufferSize);
-      if (!size)
-         return NULL;
-
-      templ.u.buf.offset = base;
-      templ.u.buf.size = size;
-   } else {
-      templ.u.tex.first_level = stObj->base.MinLevel + stObj->base.BaseLevel;
-      templ.u.tex.last_level = last_level(stObj);
-      assert(templ.u.tex.first_level <= templ.u.tex.last_level);
-      templ.u.tex.first_layer = stObj->base.MinLayer;
-      templ.u.tex.last_layer = last_layer(stObj);
-      assert(templ.u.tex.first_layer <= templ.u.tex.last_layer);
-      templ.target = gl_target_to_pipe(stObj->base.Target);
-   }
-
-   templ.swizzle_r = GET_SWZ(swizzle, 0);
-   templ.swizzle_g = GET_SWZ(swizzle, 1);
-   templ.swizzle_b = GET_SWZ(swizzle, 2);
-   templ.swizzle_a = GET_SWZ(swizzle, 3);
-
-   return st->pipe->create_sampler_view(st->pipe, stObj->pt, &templ);
-}
-
-
-static struct pipe_sampler_view *
-st_get_texture_sampler_view_from_stobj(struct st_context *st,
-                                       struct st_texture_object *stObj,
-                                       const struct gl_sampler_object *samp,
-                                       unsigned glsl_version)
-{
-   struct pipe_sampler_view **sv;
-
-   if (!stObj || !stObj->pt) {
-      return NULL;
-   }
-
-   sv = st_texture_get_sampler_view(st, stObj);
-
-   if (*sv) {
-      /* Debug check: make sure that the sampler view's parameters are
-       * what they're supposed to be.
-       */
-      struct pipe_sampler_view *view = *sv;
-      assert(!check_sampler_swizzle(st, stObj, view, glsl_version));
-      assert(get_sampler_view_format(st, stObj, samp) == view->format);
-      assert(gl_target_to_pipe(stObj->base.Target) == view->target);
-      if (stObj->base.Target == GL_TEXTURE_BUFFER) {
-         unsigned base = stObj->base.BufferOffset;
-         unsigned size = MIN2(stObj->pt->width0 - base,
-                              (unsigned) stObj->base.BufferSize);
-         assert(view->u.buf.offset == base);
-         assert(view->u.buf.size == size);
-      }
-      else {
-         assert(stObj->base.MinLevel + stObj->base.BaseLevel ==
-                view->u.tex.first_level);
-         assert(last_level(stObj) == view->u.tex.last_level);
-         assert(stObj->base.MinLayer == view->u.tex.first_layer);
-         assert(last_layer(stObj) == view->u.tex.last_layer);
-      }
-   }
-   else {
-      /* create new sampler view */
-      enum pipe_format format = get_sampler_view_format(st, stObj, samp);
-
-      *sv = st_create_texture_sampler_view_from_stobj(st, stObj,
-                                                      format, glsl_version);
-
-   }
-
-   return *sv;
-}
-
-
 static GLboolean
 update_single_texture(struct st_context *st,
                       struct pipe_sampler_view **sampler_view,
diff --git a/src/mesa/state_tracker/st_cb_bitmap.c b/src/mesa/state_tracker/st_cb_bitmap.c
index a7d269b82e6..1e4becd10bd 100644
--- a/src/mesa/state_tracker/st_cb_bitmap.c
+++ b/src/mesa/state_tracker/st_cb_bitmap.c
@@ -45,6 +45,7 @@
 #include "st_draw.h"
 #include "st_program.h"
 #include "st_cb_bitmap.h"
+#include "st_sampler_view.h"
 #include "st_texture.h"
 
 #include "pipe/p_context.h"
diff --git a/src/mesa/state_tracker/st_cb_drawpixels.c b/src/mesa/state_tracker/st_cb_drawpixels.c
index b5f4227f6dd..7f92e02dc5e 100644
--- a/src/mesa/state_tracker/st_cb_drawpixels.c
+++ b/src/mesa/state_tracker/st_cb_drawpixels.c
@@ -60,6 +60,7 @@
 #include "st_draw.h"
 #include "st_format.h"
 #include "st_program.h"
+#include "st_sampler_view.h"
 #include "st_scissor.h"
 #include "st_texture.h"
 
diff --git a/src/mesa/state_tracker/st_cb_eglimage.c b/src/mesa/state_tracker/st_cb_eglimage.c
index 7bea5653e46..c425154ba91 100644
--- a/src/mesa/state_tracker/st_cb_eglimage.c
+++ b/src/mesa/state_tracker/st_cb_eglimage.c
@@ -35,6 +35,8 @@
 #include "st_texture.h"
 #include "st_format.h"
 #include "st_manager.h"
+#include "st_sampler_view.h"
+
 
 /**
  * Return the base format just like _mesa_base_fbo_format does.
diff --git a/src/mesa/state_tracker/st_cb_texture.c b/src/mesa/state_tracker/st_cb_texture.c
index 392b2a4b512..b448e56738f 100644
--- a/src/mesa/state_tracker/st_cb_texture.c
+++ b/src/mesa/state_tracker/st_cb_texture.c
@@ -58,6 +58,7 @@
 #include "state_tracker/st_texture.h"
 #include "state_tracker/st_gen_mipmap.h"
 #include "state_tracker/st_atom.h"
+#include "state_tracker/st_sampler_view.h"
 
 #include "pipe/p_context.h"
 #include "pipe/p_defines.h"
diff --git a/src/mesa/state_tracker/st_context.c b/src/mesa/state_tracker/st_context.c
index b9dc0c67da3..174503f80ff 100644
--- a/src/mesa/state_tracker/st_context.c
+++ b/src/mesa/state_tracker/st_context.c
@@ -70,6 +70,7 @@
 #include "st_gen_mipmap.h"
 #include "st_pbo.h"
 #include "st_program.h"
+#include "st_sampler_view.h"
 #include "st_vdpau.h"
 #include "st_texture.h"
 #include "pipe/p_context.h"
diff --git a/src/mesa/state_tracker/st_sampler_view.c b/src/mesa/state_tracker/st_sampler_view.c
new file mode 100644
index 00000000000..9fe0bfe87d3
--- /dev/null
+++ b/src/mesa/state_tracker/st_sampler_view.c
@@ -0,0 +1,495 @@
+/*
+ * Copyright 2016 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 "pipe/p_context.h"
+#include "util/u_format.h"
+#include "util/u_inlines.h"
+
+#include "main/context.h"
+#include "main/macros.h"
+#include "main/mtypes.h"
+#include "main/teximage.h"
+#include "main/texobj.h"
+#include "program/prog_instruction.h"
+
+#include "st_context.h"
+#include "st_sampler_view.h"
+#include "st_texture.h"
+#include "st_format.h"
+#include "st_cb_texture.h"
+
+
+/**
+ * Try to find a matching sampler view for the given context.
+ * If none is found an empty slot is initialized with a
+ * template and returned instead.
+ */
+struct pipe_sampler_view **
+st_texture_get_sampler_view(struct st_context *st,
+                            struct st_texture_object *stObj)
+{
+   struct pipe_sampler_view **free = NULL;
+   GLuint i;
+
+   for (i = 0; i < stObj->num_sampler_views; ++i) {
+      struct pipe_sampler_view **sv = &stObj->sampler_views[i];
+      /* Is the array entry used ? */
+      if (*sv) {
+         /* check if the context matches */
+         if ((*sv)->context == st->pipe) {
+            return sv;
+         }
+      } else {
+         /* Found a free slot, remember that */
+         free = sv;
+      }
+   }
+
+   /* Couldn't find a slot for our context, create a new one */
+
+   if (!free) {
+      /* Haven't even found a free one, resize the array */
+      unsigned new_size = (stObj->num_sampler_views + 1) *
+         sizeof(struct pipe_sampler_view *);
+      stObj->sampler_views = realloc(stObj->sampler_views, new_size);
+      free = &stObj->sampler_views[stObj->num_sampler_views++];
+      *free = NULL;
+   }
+
+   assert(*free == NULL);
+
+   return free;
+}
+
+
+/**
+ * For the given texture object, release any sampler views which belong
+ * to the calling context.
+ */
+void
+st_texture_release_sampler_view(struct st_context *st,
+                                struct st_texture_object *stObj)
+{
+   GLuint i;
+
+   for (i = 0; i < stObj->num_sampler_views; ++i) {
+      struct pipe_sampler_view **sv = &stObj->sampler_views[i];
+
+      if (*sv && (*sv)->context == st->pipe) {
+         pipe_sampler_view_reference(sv, NULL);
+         break;
+      }
+   }
+}
+
+
+/**
+ * Release all sampler views attached to the given texture object, regardless
+ * of the context.
+ */
+void
+st_texture_release_all_sampler_views(struct st_context *st,
+                                     struct st_texture_object *stObj)
+{
+   GLuint i;
+
+   /* XXX This should use sampler_views[i]->pipe, not st->pipe */
+   for (i = 0; i < stObj->num_sampler_views; ++i)
+      pipe_sampler_view_release(st->pipe, &stObj->sampler_views[i]);
+}
+
+
+void
+st_texture_free_sampler_views(struct st_texture_object *stObj)
+{
+   free(stObj->sampler_views);
+   stObj->sampler_views = NULL;
+   stObj->num_sampler_views = 0;
+}
+
+
+/**
+ * Return swizzle1(swizzle2)
+ */
+static unsigned
+swizzle_swizzle(unsigned swizzle1, unsigned swizzle2)
+{
+   unsigned i, swz[4];
+
+   if (swizzle1 == SWIZZLE_XYZW) {
+      /* identity swizzle, no change to swizzle2 */
+      return swizzle2;
+   }
+
+   for (i = 0; i < 4; i++) {
+      unsigned s = GET_SWZ(swizzle1, i);
+      switch (s) {
+      case SWIZZLE_X:
+      case SWIZZLE_Y:
+      case SWIZZLE_Z:
+      case SWIZZLE_W:
+         swz[i] = GET_SWZ(swizzle2, s);
+         break;
+      case SWIZZLE_ZERO:
+         swz[i] = SWIZZLE_ZERO;
+         break;
+      case SWIZZLE_ONE:
+         swz[i] = SWIZZLE_ONE;
+         break;
+      default:
+         assert(!"Bad swizzle term");
+         swz[i] = SWIZZLE_X;
+      }
+   }
+
+   return MAKE_SWIZZLE4(swz[0], swz[1], swz[2], swz[3]);
+}
+
+
+/**
+ * Given a user-specified texture base format, the actual gallium texture
+ * format and the current GL_DEPTH_MODE, return a texture swizzle.
+ *
+ * Consider the case where the user requests a GL_RGB internal texture
+ * format the driver actually uses an RGBA format.  The A component should
+ * be ignored and sampling from the texture should always return (r,g,b,1).
+ * But if we rendered to the texture we might have written A values != 1.
+ * By sampling the texture with a ".xyz1" swizzle we'll get the expected A=1.
+ * This function computes the texture swizzle needed to get the expected
+ * values.
+ *
+ * In the case of depth textures, the GL_DEPTH_MODE state determines the
+ * texture swizzle.
+ *
+ * This result must be composed with the user-specified swizzle to get
+ * the final swizzle.
+ */
+static unsigned
+compute_texture_format_swizzle(GLenum baseFormat, GLenum depthMode,
+                               enum pipe_format actualFormat,
+                               unsigned glsl_version)
+{
+   switch (baseFormat) {
+   case GL_RGBA:
+      return SWIZZLE_XYZW;
+   case GL_RGB:
+      if (util_format_has_alpha(actualFormat))
+         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_ONE);
+      else
+         return SWIZZLE_XYZW;
+   case GL_RG:
+      if (util_format_get_nr_components(actualFormat) > 2)
+         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_ZERO, SWIZZLE_ONE);
+      else
+         return SWIZZLE_XYZW;
+   case GL_RED:
+      if (util_format_get_nr_components(actualFormat) > 1)
+         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_ZERO,
+                              SWIZZLE_ZERO, SWIZZLE_ONE);
+      else
+         return SWIZZLE_XYZW;
+   case GL_ALPHA:
+      if (util_format_get_nr_components(actualFormat) > 1)
+         return MAKE_SWIZZLE4(SWIZZLE_ZERO, SWIZZLE_ZERO,
+                              SWIZZLE_ZERO, SWIZZLE_W);
+      else
+         return SWIZZLE_XYZW;
+   case GL_LUMINANCE:
+      if (util_format_get_nr_components(actualFormat) > 1)
+         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_ONE);
+      else
+         return SWIZZLE_XYZW;
+   case GL_LUMINANCE_ALPHA:
+      if (util_format_get_nr_components(actualFormat) > 2)
+         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_W);
+      else
+         return SWIZZLE_XYZW;
+   case GL_INTENSITY:
+      if (util_format_get_nr_components(actualFormat) > 1)
+         return SWIZZLE_XXXX;
+      else
+         return SWIZZLE_XYZW;
+   case GL_STENCIL_INDEX:
+   case GL_DEPTH_STENCIL:
+   case GL_DEPTH_COMPONENT:
+      /* Now examine the depth mode */
+      switch (depthMode) {
+      case GL_LUMINANCE:
+         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_ONE);
+      case GL_INTENSITY:
+         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_X);
+      case GL_ALPHA:
+         /* The texture(sampler*Shadow) functions from GLSL 1.30 ignore
+          * the depth mode and return float, while older shadow* functions
+          * and ARB_fp instructions return vec4 according to the depth mode.
+          *
+          * The problem with the GLSL 1.30 functions is that GL_ALPHA forces
+          * them to return 0, breaking them completely.
+          *
+          * A proper fix would increase code complexity and that's not worth
+          * it for a rarely used feature such as the GL_ALPHA depth mode
+          * in GL3. Therefore, change GL_ALPHA to GL_INTENSITY for all
+          * shaders that use GLSL 1.30 or later.
+          *
+          * BTW, it's required that sampler views are updated when
+          * shaders change (check_sampler_swizzle takes care of that).
+          */
+         if (glsl_version && glsl_version >= 130)
+            return SWIZZLE_XXXX;
+         else
+            return MAKE_SWIZZLE4(SWIZZLE_ZERO, SWIZZLE_ZERO,
+                                 SWIZZLE_ZERO, SWIZZLE_X);
+      case GL_RED:
+         return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_ZERO,
+                              SWIZZLE_ZERO, SWIZZLE_ONE);
+      default:
+         assert(!"Unexpected depthMode");
+         return SWIZZLE_XYZW;
+      }
+   default:
+      assert(!"Unexpected baseFormat");
+      return SWIZZLE_XYZW;
+   }
+}
+
+
+static unsigned
+get_texture_format_swizzle(const struct st_context *st,
+                           const struct st_texture_object *stObj,
+                           unsigned glsl_version)
+{
+   GLenum baseFormat = _mesa_texture_base_format(&stObj->base);
+   unsigned tex_swizzle;
+
+   if (baseFormat != GL_NONE) {
+      GLenum depth_mode = stObj->base.DepthMode;
+      /* In ES 3.0, DEPTH_TEXTURE_MODE is expected to be GL_RED for textures
+       * with depth component data specified with a sized internal format.
+       */
+      if (_mesa_is_gles3(st->ctx) &&
+          util_format_is_depth_or_stencil(stObj->pt->format)) {
+         const struct gl_texture_image *firstImage =
+            _mesa_base_tex_image(&stObj->base);
+         if (firstImage->InternalFormat != GL_DEPTH_COMPONENT &&
+             firstImage->InternalFormat != GL_DEPTH_STENCIL &&
+             firstImage->InternalFormat != GL_STENCIL_INDEX)
+            depth_mode = GL_RED;
+      }
+      tex_swizzle = compute_texture_format_swizzle(baseFormat,
+                                                   depth_mode,
+                                                   stObj->pt->format,
+                                                   glsl_version);
+   }
+   else {
+      tex_swizzle = SWIZZLE_XYZW;
+   }
+
+   /* Combine the texture format swizzle with user's swizzle */
+   return swizzle_swizzle(stObj->base._Swizzle, tex_swizzle);
+}
+
+
+/**
+ * Return TRUE if the texture's sampler view swizzle is not equal to
+ * the texture's swizzle.
+ *
+ * \param stObj  the st texture object,
+ */
+static boolean
+check_sampler_swizzle(const struct st_context *st,
+                      const struct st_texture_object *stObj,
+		      const struct pipe_sampler_view *sv, unsigned glsl_version)
+{
+   unsigned swizzle = get_texture_format_swizzle(st, stObj, glsl_version);
+
+   return ((sv->swizzle_r != GET_SWZ(swizzle, 0)) ||
+           (sv->swizzle_g != GET_SWZ(swizzle, 1)) ||
+           (sv->swizzle_b != GET_SWZ(swizzle, 2)) ||
+           (sv->swizzle_a != GET_SWZ(swizzle, 3)));
+}
+
+
+static unsigned
+last_level(const struct st_texture_object *stObj)
+{
+   unsigned ret = MIN2(stObj->base.MinLevel + stObj->base._MaxLevel,
+                       stObj->pt->last_level);
+   if (stObj->base.Immutable)
+      ret = MIN2(ret, stObj->base.MinLevel + stObj->base.NumLevels - 1);
+   return ret;
+}
+
+
+static unsigned
+last_layer(const struct st_texture_object *stObj)
+{
+   if (stObj->base.Immutable && stObj->pt->array_size > 1)
+      return MIN2(stObj->base.MinLayer + stObj->base.NumLayers - 1,
+                  stObj->pt->array_size - 1);
+   return stObj->pt->array_size - 1;
+}
+
+
+/**
+ * Determine the format for the texture sampler view.
+ */
+static enum pipe_format
+get_sampler_view_format(struct st_context *st,
+                        const struct st_texture_object *stObj,
+                        const struct gl_sampler_object *samp)
+{
+   enum pipe_format format;
+
+   if (stObj->base.Target == GL_TEXTURE_BUFFER) {
+      format =
+         st_mesa_format_to_pipe_format(st, stObj->base._BufferObjectFormat);
+   }
+   else {
+      format =
+         stObj->surface_based ? stObj->surface_format : stObj->pt->format;
+
+      if (util_format_is_depth_and_stencil(format)) {
+         if (stObj->base.StencilSampling) {
+            format = util_format_stencil_only(format);
+         }
+         else {
+            GLenum baseFormat = _mesa_texture_base_format(&stObj->base);
+            if (baseFormat == GL_STENCIL_INDEX) {
+               format = util_format_stencil_only(format);
+            }
+         }
+      }
+      else {
+         /* If sRGB decoding is off, use the linear format */
+         if (samp->sRGBDecode == GL_SKIP_DECODE_EXT) {
+            format = util_format_linear(format);
+         }
+
+         /* Use R8_UNORM for video formats */
+         switch (format) {
+         case PIPE_FORMAT_NV12:
+         case PIPE_FORMAT_IYUV:
+            format = PIPE_FORMAT_R8_UNORM;
+            break;
+         default:
+            break;
+         }
+      }
+   }
+
+   return format;
+}
+
+
+static struct pipe_sampler_view *
+st_create_texture_sampler_view_from_stobj(struct st_context *st,
+					  struct st_texture_object *stObj,
+					  enum pipe_format format,
+                                          unsigned glsl_version)
+{
+   struct pipe_sampler_view templ;
+   unsigned swizzle = get_texture_format_swizzle(st, stObj, glsl_version);
+
+   u_sampler_view_default_template(&templ, stObj->pt, format);
+
+   if (stObj->pt->target == PIPE_BUFFER) {
+      unsigned base, size;
+
+      base = stObj->base.BufferOffset;
+      if (base >= stObj->pt->width0)
+         return NULL;
+      size = MIN2(stObj->pt->width0 - base, (unsigned)stObj->base.BufferSize);
+      if (!size)
+         return NULL;
+
+      templ.u.buf.offset = base;
+      templ.u.buf.size = size;
+   } else {
+      templ.u.tex.first_level = stObj->base.MinLevel + stObj->base.BaseLevel;
+      templ.u.tex.last_level = last_level(stObj);
+      assert(templ.u.tex.first_level <= templ.u.tex.last_level);
+      templ.u.tex.first_layer = stObj->base.MinLayer;
+      templ.u.tex.last_layer = last_layer(stObj);
+      assert(templ.u.tex.first_layer <= templ.u.tex.last_layer);
+      templ.target = gl_target_to_pipe(stObj->base.Target);
+   }
+
+   templ.swizzle_r = GET_SWZ(swizzle, 0);
+   templ.swizzle_g = GET_SWZ(swizzle, 1);
+   templ.swizzle_b = GET_SWZ(swizzle, 2);
+   templ.swizzle_a = GET_SWZ(swizzle, 3);
+
+   return st->pipe->create_sampler_view(st->pipe, stObj->pt, &templ);
+}
+
+
+struct pipe_sampler_view *
+st_get_texture_sampler_view_from_stobj(struct st_context *st,
+                                       struct st_texture_object *stObj,
+                                       const struct gl_sampler_object *samp,
+                                       unsigned glsl_version)
+{
+   struct pipe_sampler_view **sv;
+
+   if (!stObj || !stObj->pt) {
+      return NULL;
+   }
+
+   sv = st_texture_get_sampler_view(st, stObj);
+
+   if (*sv) {
+      /* Debug check: make sure that the sampler view's parameters are
+       * what they're supposed to be.
+       */
+      MAYBE_UNUSED struct pipe_sampler_view *view = *sv;
+      assert(!check_sampler_swizzle(st, stObj, view, glsl_version));
+      assert(get_sampler_view_format(st, stObj, samp) == view->format);
+      assert(gl_target_to_pipe(stObj->base.Target) == view->target);
+      if (stObj->base.Target == GL_TEXTURE_BUFFER) {
+         unsigned base = stObj->base.BufferOffset;
+         unsigned size = MIN2(stObj->pt->width0 - base,
+                              (unsigned) stObj->base.BufferSize);
+         assert(view->u.buf.offset == base);
+         assert(view->u.buf.size == size);
+      }
+      else {
+         assert(stObj->base.MinLevel + stObj->base.BaseLevel ==
+                view->u.tex.first_level);
+         assert(last_level(stObj) == view->u.tex.last_level);
+         assert(stObj->base.MinLayer == view->u.tex.first_layer);
+         assert(last_layer(stObj) == view->u.tex.last_layer);
+      }
+   }
+   else {
+      /* create new sampler view */
+      enum pipe_format format = get_sampler_view_format(st, stObj, samp);
+
+      *sv = st_create_texture_sampler_view_from_stobj(st, stObj,
+                                                      format, glsl_version);
+
+   }
+
+   return *sv;
+}
diff --git a/src/mesa/state_tracker/st_sampler_view.h b/src/mesa/state_tracker/st_sampler_view.h
new file mode 100644
index 00000000000..d4c38bccdce
--- /dev/null
+++ b/src/mesa/state_tracker/st_sampler_view.h
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2016 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.
+ */
+
+
+#ifndef ST_SAMPLER_VIEW_H
+#define ST_SAMPLER_VIEW_H
+
+#include "pipe/p_compiler.h"
+#include "pipe/p_context.h"
+#include "pipe/p_state.h"
+#include "util/u_sampler.h"
+
+struct st_texture_object;
+
+
+static inline struct pipe_sampler_view *
+st_create_texture_sampler_view_format(struct pipe_context *pipe,
+                                      struct pipe_resource *texture,
+                                      enum pipe_format format)
+{
+   struct pipe_sampler_view templ;
+
+   u_sampler_view_default_template(&templ, texture, format);
+
+   return pipe->create_sampler_view(pipe, texture, &templ);
+}
+
+
+static inline struct pipe_sampler_view *
+st_create_texture_sampler_view(struct pipe_context *pipe,
+                               struct pipe_resource *texture)
+{
+   return st_create_texture_sampler_view_format(pipe, texture,
+                                                texture->format);
+}
+
+
+extern struct pipe_sampler_view **
+st_texture_get_sampler_view(struct st_context *st,
+                            struct st_texture_object *stObj);
+
+extern void
+st_texture_release_sampler_view(struct st_context *st,
+                                struct st_texture_object *stObj);
+
+extern void
+st_texture_release_all_sampler_views(struct st_context *st,
+                                     struct st_texture_object *stObj);
+
+void
+st_texture_free_sampler_views(struct st_texture_object *stObj);
+
+
+struct pipe_sampler_view *
+st_get_texture_sampler_view_from_stobj(struct st_context *st,
+                                       struct st_texture_object *stObj,
+                                       const struct gl_sampler_object *samp,
+                                       unsigned glsl_version);
+
+
+#endif /* ST_SAMPLER_VIEW_H */
diff --git a/src/mesa/state_tracker/st_texture.c b/src/mesa/state_tracker/st_texture.c
index 32e5b84a5af..a2c36ace461 100644
--- a/src/mesa/state_tracker/st_texture.c
+++ b/src/mesa/state_tracker/st_texture.c
@@ -418,96 +418,3 @@ st_create_color_map_texture(struct gl_context *ctx)
                           texSize, texSize, 1, 1, 0, PIPE_BIND_SAMPLER_VIEW);
    return pt;
 }
-
-/**
- * Try to find a matching sampler view for the given context.
- * If none is found an empty slot is initialized with a
- * template and returned instead.
- */
-struct pipe_sampler_view **
-st_texture_get_sampler_view(struct st_context *st,
-                            struct st_texture_object *stObj)
-{
-   struct pipe_sampler_view **free = NULL;
-   GLuint i;
-
-   for (i = 0; i < stObj->num_sampler_views; ++i) {
-      struct pipe_sampler_view **sv = &stObj->sampler_views[i];
-      /* Is the array entry used ? */
-      if (*sv) {
-         /* check if the context matches */
-         if ((*sv)->context == st->pipe) {
-            return sv;
-         }
-      } else {
-         /* Found a free slot, remember that */
-         free = sv;
-      }
-   }
-
-   /* Couldn't find a slot for our context, create a new one */
-
-   if (!free) {
-      /* Haven't even found a free one, resize the array */
-      GLuint old_size = stObj->num_sampler_views * sizeof(void *);
-      GLuint new_size = old_size + sizeof(void *);
-      stObj->sampler_views = REALLOC(stObj->sampler_views, old_size, new_size);
-      free = &stObj->sampler_views[stObj->num_sampler_views++];
-      *free = NULL;
-   }
-
-   assert(*free == NULL);
-
-   return free;
-}
-
-
-/**
- * For the given texture object, release any sampler views which belong
- * to the calling context.
- */
-void
-st_texture_release_sampler_view(struct st_context *st,
-                                struct st_texture_object *stObj)
-{
-   GLuint i;
-
-   for (i = 0; i < stObj->num_sampler_views; ++i) {
-      struct pipe_sampler_view **sv = &stObj->sampler_views[i];
-
-      if (*sv && (*sv)->context == st->pipe) {
-         pipe_sampler_view_reference(sv, NULL);
-         break;
-      }
-   }
-}
-
-
-/**
- * Release all sampler views attached to the given texture object, regardless
- * of the context.
- */
-void
-st_texture_release_all_sampler_views(struct st_context *st,
-                                     struct st_texture_object *stObj)
-{
-   GLuint i;
-
-   /* XXX This should use sampler_views[i]->pipe, not st->pipe */
-   for (i = 0; i < stObj->num_sampler_views; ++i)
-      pipe_sampler_view_release(st->pipe, &stObj->sampler_views[i]);
-}
-
-
-void
-st_texture_free_sampler_views(struct st_texture_object *stObj)
-{
-   /* NOTE:
-    * We use FREE() here to match REALLOC() above.  Both come from
-    * u_memory.h, not imports.h.  If we mis-match MALLOC/FREE from
-    * those two headers we can trash the heap.
-    */
-   FREE(stObj->sampler_views);
-   stObj->sampler_views = NULL;
-   stObj->num_sampler_views = 0;
-}
diff --git a/src/mesa/state_tracker/st_texture.h b/src/mesa/state_tracker/st_texture.h
index 9c9a05b5605..730843ae321 100644
--- a/src/mesa/state_tracker/st_texture.h
+++ b/src/mesa/state_tracker/st_texture.h
@@ -155,26 +155,6 @@ st_get_stobj_resource(struct st_texture_object *stObj)
 }
 
 
-static inline struct pipe_sampler_view *
-st_create_texture_sampler_view_format(struct pipe_context *pipe,
-                                      struct pipe_resource *texture,
-                                      enum pipe_format format)
-{
-   struct pipe_sampler_view templ;
-
-   u_sampler_view_default_template(&templ, texture, format);
-
-   return pipe->create_sampler_view(pipe, texture, &templ);
-}
-
-static inline struct pipe_sampler_view *
-st_create_texture_sampler_view(struct pipe_context *pipe,
-                               struct pipe_resource *texture)
-{
-   return st_create_texture_sampler_view_format(pipe, texture,
-                                                texture->format);
-}
-
 static inline struct st_texture_object *
 st_get_texture_object(struct gl_context *ctx,
                       const struct gl_program *prog,
@@ -261,20 +241,6 @@ st_texture_image_copy(struct pipe_context *pipe,
 extern struct pipe_resource *
 st_create_color_map_texture(struct gl_context *ctx);
 
-extern struct pipe_sampler_view **
-st_texture_get_sampler_view(struct st_context *st,
-                            struct st_texture_object *stObj);
-
-extern void
-st_texture_release_sampler_view(struct st_context *st,
-                                struct st_texture_object *stObj);
-
-extern void
-st_texture_release_all_sampler_views(struct st_context *st,
-                                     struct st_texture_object *stObj);
-
-void
-st_texture_free_sampler_views(struct st_texture_object *stObj);
 
 bool
 st_etc_fallback(struct st_context *st, struct gl_texture_image *texImage);
diff --git a/src/mesa/state_tracker/st_vdpau.c b/src/mesa/state_tracker/st_vdpau.c
index 4f599dd1ef0..79120579ff5 100644
--- a/src/mesa/state_tracker/st_vdpau.c
+++ b/src/mesa/state_tracker/st_vdpau.c
@@ -43,6 +43,7 @@
 
 #include "st_vdpau.h"
 #include "st_context.h"
+#include "st_sampler_view.h"
 #include "st_texture.h"
 #include "st_format.h"
 #include "st_cb_flush.h"