[Mesa-dev] [PATCH 1/3] glsl: Adds an horizontal_location fields to ir_variable.

[Vincent Lejeune]

This field allows to address output variables more precisely
(varyings won't have to "hold" a whole register if they are not vec4).
---
 src/gallium/state_trackers/dri/drm/dri2.c |    3 +++
 src/glsl/ir.cpp                           |    1 +
 src/glsl/ir.h                             |   22 ++++++++++++++++++++++
 src/glsl/ir_clone.cpp                     |    1 +
 src/mesa/drivers/dri/i965/brw_fs.cpp      |    4 ++--
 5 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/gallium/state_trackers/dri/drm/dri2.c b/src/gallium/state_trackers/dri/drm/dri2.c
index afd91ee..4c08a02 100644
--- a/src/gallium/state_trackers/dri/drm/dri2.c
+++ b/src/gallium/state_trackers/dri/drm/dri2.c
@@ -316,6 +316,9 @@ dri2_allocate_buffer(__DRIscreen *sPriv,
 
    switch (format) {
       case 32:
+         pf = PIPE_FORMAT_B8G8R8A8_UNORM;
+         break;
+      case 24:
          pf = PIPE_FORMAT_B8G8R8X8_UNORM;
          break;
       case 16:
diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index a5eca5a..a4c93ce 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -1335,6 +1335,7 @@ ir_variable::ir_variable(const struct glsl_type *type, const char *name,
    this->pixel_center_integer = false;
    this->depth_layout = ir_depth_layout_none;
    this->used = false;
+   this->horizontal_location = 0;
 
    if (type && type->base_type == GLSL_TYPE_SAMPLER)
       this->read_only = true;
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 1faae3c..cf0e444 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -396,6 +396,28 @@ public:
     * slot has not been assigned, the value will be -1.
     */
    int location;
+   
+   /**
+    * Storage starting component for this variable
+    * 
+    * Variable storage can be 4-bytes aligned instead of 16-bytes aligned to
+    * preserve space, for instance a vec2 can be stored in FILE[location].yz
+    * and in this case, its starting_component is y (eq to 1).
+    * 
+    * Register can be seen as a 2D array as follow :
+    * - Locations are assigned to rows,
+    * - Components are assigned to columns.
+    *
+    *  0:  [ 0.x  0.y  0.z  0.w]
+    *  1:  [ 1.x  1.y  1.z  1.w]
+    *  2:  [ 2.x  2.y  2.z  2.w]
+    *  ...
+    *  n:  [ n.x  n.y  n.z  n.w]
+    *
+    * Thus we refers this as "horizontal_location" (vertical location is 
+    * the above "location" field).
+    */
+    unsigned horizontal_location:2;
 
    /**
     * Built-in state that backs this uniform
diff --git a/src/glsl/ir_clone.cpp b/src/glsl/ir_clone.cpp
index c63615c..17e800a 100644
--- a/src/glsl/ir_clone.cpp
+++ b/src/glsl/ir_clone.cpp
@@ -46,6 +46,7 @@ ir_variable::clone(void *mem_ctx, struct hash_table *ht) const
    var->invariant = this->invariant;
    var->interpolation = this->interpolation;
    var->location = this->location;
+   var->horizontal_location = this->horizontal_location;
    var->warn_extension = this->warn_extension;
    var->origin_upper_left = this->origin_upper_left;
    var->pixel_center_integer = this->pixel_center_integer;
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 6ecaa6c..d095e86 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -462,7 +462,7 @@ fs_visitor::emit_general_interpolation(ir_variable *ir)
 	     * field of the setup reg.
 	     */
 	    for (unsigned int k = 0; k < type->vector_elements; k++) {
-	       struct brw_reg interp = interp_reg(location, k);
+	       struct brw_reg interp = interp_reg(location, k + ir->horizontal_location);
 	       interp = suboffset(interp, 3);
                interp.type = reg->type;
 	       emit(FS_OPCODE_CINTERP, attr, fs_reg(interp));
@@ -482,7 +482,7 @@ fs_visitor::emit_general_interpolation(ir_variable *ir)
 		   k == 3 && !(c->key.proj_attrib_mask & (1 << location))) {
 		  emit(BRW_OPCODE_MOV, attr, fs_reg(1.0f));
 	       } else {
-		  struct brw_reg interp = interp_reg(location, k);
+		  struct brw_reg interp = interp_reg(location, k + ir->horizontal_location);
                   brw_wm_barycentric_interp_mode barycoord_mode;
                   if (interpolation_mode == INTERP_QUALIFIER_SMOOTH)
                      barycoord_mode = BRW_WM_PERSPECTIVE_PIXEL_BARYCENTRIC;
-- 
1.7.7