glsl: add support for ARB_texture_multisample

V2: - emit `sample` parameter properly for multisample texelFetch()
    - fix spurious whitespace change
    - introduce a new opcode ir_txf_ms rather than overloading the
      existing ir_txf further. This makes doing the right thing in
      the driver somewhat simpler.

V3: - fix weird whitespace

V4: - don't forget to include the new opcode in tex_opcode_strs[]
      (thanks Kenneth for spotting this)

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
[V2] Reviewed-by: Eric Anholt <eric@anholt.net>
[V2] Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

1 files changed, 23 insertions, 9 deletions

diff --git a/src/glsl/ir_reader.cpp b/src/glsl/ir_reader.cpp
index 4dec4e87e58..22ce03b0d21 100644
--- a/src/glsl/ir_reader.cpp
+++ b/src/glsl/ir_reader.cpp
@@ -911,6 +911,7 @@ ir_reader::read_texture(s_expression *expr)
    s_expression *s_proj = NULL;
    s_list *s_shadow = NULL;
    s_expression *s_lod = NULL;
+   s_expression *s_sample_index = NULL;
 
    ir_texture_opcode op = ir_tex; /* silence warning */
 
@@ -918,6 +919,8 @@ ir_reader::read_texture(s_expression *expr)
       { "tex", s_type, s_sampler, s_coord, s_offset, s_proj, s_shadow };
    s_pattern txf_pattern[] =
       { "txf", s_type, s_sampler, s_coord, s_offset, s_lod };
+   s_pattern txf_ms_pattern[] =
+      { "txf_ms", s_type, s_sampler, s_coord, s_sample_index };
    s_pattern txs_pattern[] =
       { "txs", s_type, s_sampler, s_lod };
    s_pattern other_pattern[] =
@@ -927,6 +930,8 @@ ir_reader::read_texture(s_expression *expr)
       op = ir_tex;
    } else if (MATCH(expr, txf_pattern)) {
       op = ir_txf;
+   } else if (MATCH(expr, txf_ms_pattern)) {
+      op = ir_txf_ms;
    } else if (MATCH(expr, txs_pattern)) {
       op = ir_txs;
    } else if (MATCH(expr, other_pattern)) {
@@ -966,18 +971,20 @@ ir_reader::read_texture(s_expression *expr)
 	 return NULL;
       }
 
-      // Read texel offset - either 0 or an rvalue.
-      s_int *si_offset = SX_AS_INT(s_offset);
-      if (si_offset == NULL || si_offset->value() != 0) {
-	 tex->offset = read_rvalue(s_offset);
-	 if (tex->offset == NULL) {
-	    ir_read_error(s_offset, "expected 0 or an expression");
-	    return NULL;
-	 }
+      if (op != ir_txf_ms) {
+         // Read texel offset - either 0 or an rvalue.
+         s_int *si_offset = SX_AS_INT(s_offset);
+         if (si_offset == NULL || si_offset->value() != 0) {
+            tex->offset = read_rvalue(s_offset);
+            if (tex->offset == NULL) {
+               ir_read_error(s_offset, "expected 0 or an expression");
+               return NULL;
+            }
+         }
       }
    }
 
-   if (op != ir_txf && op != ir_txs) {
+   if (op != ir_txf && op != ir_txf_ms && op != ir_txs) {
       s_int *proj_as_int = SX_AS_INT(s_proj);
       if (proj_as_int && proj_as_int->value() == 1) {
 	 tex->projector = NULL;
@@ -1020,6 +1027,13 @@ ir_reader::read_texture(s_expression *expr)
 	 return NULL;
       }
       break;
+   case ir_txf_ms:
+      tex->lod_info.sample_index = read_rvalue(s_sample_index);
+      if (tex->lod_info.sample_index == NULL) {
+         ir_read_error(NULL, "when reading sample_index in (txf_ms ...)");
+         return NULL;
+      }
+      break;
    case ir_txd: {
       s_expression *s_dx, *s_dy;
       s_pattern dxdy_pat[] = { s_dx, s_dy };