gallium: add a texture target to sampler view and a CAP to use it

This allows a sampler view to have a different texture target than the
underlying resource. This will be used to implement the type casting
between 2d arrays and cube maps as specified in ARB_texture_view.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/auxiliary/util/u_sampler.c

@@ -45,6 +45,7 @@ default_template(struct pipe_sampler_view *view,
    /* XXX: Check if format is compatible with texture->format.
     */
 
+   view->target = texture->target;
    view->format = format;
    view->u.tex.first_level = 0;
    view->u.tex.last_level = texture->last_level;

src/gallium/docs/source/screen.rst

@@ -226,6 +226,10 @@ The integer capabilities:
 * ``PIPE_CAP_CONDITIONAL_RENDER_INVERTED``: Whether the driver supports inverted
   condition for conditional rendering.
 * ``PIPE_CAP_MAX_VERTEX_ATTRIB_STRIDE``: The maximum supported vertex stride.
+* ``PIPE_CAP_SAMPLER_VIEW_TARGET``: Whether the sampler view's target can be
+  different than the underlying resource's, as permitted by
+  ARB_texture_view. For example a 2d array texture may be reinterpreted as a
+  cube (array) texture and vice-versa.
 
 
 .. _pipe_capf:

src/gallium/drivers/freedreno/freedreno_screen.c

@@ -220,6 +220,7 @@ fd_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 	case PIPE_CAP_DRAW_INDIRECT:
 	case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
 	case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+	case PIPE_CAP_SAMPLER_VIEW_TARGET:
 		return 0;
 
 	/* Stream output. */

src/gallium/drivers/i915/i915_screen.c

@@ -234,6 +234,7 @@ i915_get_param(struct pipe_screen *screen, enum pipe_cap cap)
    case PIPE_CAP_BUFFER_MAP_PERSISTENT_COHERENT:
    case PIPE_CAP_DRAW_INDIRECT:
    case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
+   case PIPE_CAP_SAMPLER_VIEW_TARGET:
       return 0;
 
    case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:

src/gallium/drivers/ilo/ilo_screen.c

@@ -438,6 +438,7 @@ ilo_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_DRAW_INDIRECT:
    case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
    case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+   case PIPE_CAP_SAMPLER_VIEW_TARGET:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/llvmpipe/lp_screen.c

@@ -253,6 +253,7 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
    case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
+   case PIPE_CAP_SAMPLER_VIEW_TARGET:
       return 0;
    case PIPE_CAP_FAKE_SW_MSAA:
       return 1;

src/gallium/drivers/nouveau/nv30/nv30_screen.c

@@ -155,6 +155,7 @@ nv30_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_DRAW_INDIRECT:
    case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
    case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+   case PIPE_CAP_SAMPLER_VIEW_TARGET:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/nouveau/nv50/nv50_screen.c

@@ -203,6 +203,7 @@ nv50_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_COMPUTE:
    case PIPE_CAP_DRAW_INDIRECT:
    case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+   case PIPE_CAP_SAMPLER_VIEW_TARGET:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/nouveau/nvc0/nvc0_screen.c

@@ -187,6 +187,7 @@ nvc0_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_TGSI_VS_LAYER_VIEWPORT:
    case PIPE_CAP_FAKE_SW_MSAA:
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
+   case PIPE_CAP_SAMPLER_VIEW_TARGET:
       return 0;
 
    case PIPE_CAP_VENDOR_ID:

src/gallium/drivers/r300/r300_screen.c

@@ -180,6 +180,7 @@ static int r300_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
         case PIPE_CAP_DRAW_INDIRECT:
         case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
         case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+        case PIPE_CAP_SAMPLER_VIEW_TARGET:
             return 0;
 
         /* SWTCL-only features. */

src/gallium/drivers/r600/r600_pipe.c

@@ -320,6 +320,7 @@ static int r600_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 	case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
 	case PIPE_CAP_DRAW_INDIRECT:
 	case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+	case PIPE_CAP_SAMPLER_VIEW_TARGET:
 		return 0;
 
 	/* Stream output. */

src/gallium/drivers/radeonsi/si_pipe.c

@@ -244,6 +244,7 @@ static int si_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 	case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
 	case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
 	case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+	case PIPE_CAP_SAMPLER_VIEW_TARGET:
 		return 0;
 
 	case PIPE_CAP_TEXTURE_BORDER_COLOR_QUIRK:

src/gallium/drivers/softpipe/sp_screen.c

@@ -198,6 +198,7 @@ softpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
    case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
+   case PIPE_CAP_SAMPLER_VIEW_TARGET:
       return 0;
    case PIPE_CAP_FAKE_SW_MSAA:
       return 1;

src/gallium/drivers/svga/svga_screen.c

@@ -280,6 +280,7 @@ svga_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_DRAW_INDIRECT:
    case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
    case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+   case PIPE_CAP_SAMPLER_VIEW_TARGET:
       return 0;
    case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:
       return 64;

src/gallium/drivers/vc4/vc4_screen.c

@@ -161,6 +161,7 @@ vc4_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
         case PIPE_CAP_DRAW_INDIRECT:
         case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
         case PIPE_CAP_CONDITIONAL_RENDER_INVERTED:
+        case PIPE_CAP_SAMPLER_VIEW_TARGET:
                 return 0;
 
                 /* Stream output. */

src/gallium/include/pipe/p_defines.h

@@ -570,6 +570,7 @@ enum pipe_cap {
    PIPE_CAP_UMA = 107,
    PIPE_CAP_CONDITIONAL_RENDER_INVERTED = 108,
    PIPE_CAP_MAX_VERTEX_ATTRIB_STRIDE = 109,
+   PIPE_CAP_SAMPLER_VIEW_TARGET = 110,
 };
 
 #define PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 (1 << 0)

src/gallium/include/pipe/p_state.h

@@ -361,6 +361,7 @@ struct pipe_surface
 struct pipe_sampler_view
 {
    struct pipe_reference reference;
+   enum pipe_texture_target target; /**< PIPE_TEXTURE_x */
    enum pipe_format format;      /**< typed PIPE_FORMAT_x */
    struct pipe_resource *texture; /**< texture into which this is a view  */
    struct pipe_context *context; /**< context this view belongs to */