i965: Generalize GL_FIXED VS w/a support

Next few patches build on this to add other workarounds
for packed formats.

V2: rename BRW_ATTRIB_WA_COMPONENTS to BRW_ATTRIB_WA_COMPONENT_MASK;
V3 (Kayden): remove separate bit for ES3 signed normalization

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp

@@ -815,13 +815,13 @@ vec4_visitor::visit(ir_variable *ir)
        * come in as floating point conversions of the integer values.
        */
       for (int i = ir->location; i < ir->location + type_size(ir->type); i++) {
-	 if (!c->key.gl_fixed_input_size[i])
-	    continue;
-
-	 dst_reg dst = *reg;
-         dst.type = brw_type_for_base_type(ir->type);
-	 dst.writemask = (1 << c->key.gl_fixed_input_size[i]) - 1;
-	 emit(MUL(dst, src_reg(dst), src_reg(1.0f / 65536.0f)));
+         uint8_t wa_flags = c->key.gl_attrib_wa_flags[i];
+         if (wa_flags & BRW_ATTRIB_WA_COMPONENT_MASK) {
+            dst_reg dst = *reg;
+            dst.type = brw_type_for_base_type(ir->type);
+            dst.writemask = (1 << (wa_flags & BRW_ATTRIB_WA_COMPONENT_MASK)) - 1;
+            emit(MUL(dst, src_reg(dst), src_reg(1.0f / 65536.0f)));
+         }
       }
       break;
 

src/mesa/drivers/dri/i965/brw_vs.c

@@ -362,9 +362,9 @@ brw_vs_debug_recompile(struct brw_context *brw,
    }
 
    for (unsigned int i = 0; i < VERT_ATTRIB_MAX; i++) {
-      found |= key_debug("GL_FIXED rescaling",
-                         old_key->gl_fixed_input_size[i],
-                         key->gl_fixed_input_size[i]);
+      found |= key_debug("Vertex attrib w/a flags",
+                         old_key->gl_attrib_wa_flags[i],
+                         key->gl_attrib_wa_flags[i]);
    }
 
    found |= key_debug("user clip flags",
@@ -446,9 +446,10 @@ static void brw_upload_vs_prog(struct brw_context *brw)
 
    /* BRW_NEW_VERTICES */
    for (i = 0; i < VERT_ATTRIB_MAX; i++) {
+      /* TODO: flag w/a for packed vertex formats here too */
       if (vp->program.Base.InputsRead & BITFIELD64_BIT(i) &&
 	  brw->vb.inputs[i].glarray->Type == GL_FIXED) {
-	 key.gl_fixed_input_size[i] = brw->vb.inputs[i].glarray->Size;
+	 key.gl_attrib_wa_flags[i] = brw->vb.inputs[i].glarray->Size;
       }
    }
 

src/mesa/drivers/dri/i965/brw_vs.h

@@ -39,13 +39,24 @@
 #include "brw_program.h"
 #include "program/program.h"
 
+/**
+ * The VF can't natively handle certain types of attributes, such as GL_FIXED
+ * or most 10_10_10_2 types.  These flags enable various VS workarounds to
+ * "fix" attributes at the beginning of shaders.
+ */
+#define BRW_ATTRIB_WA_COMPONENT_MASK    7  /* mask for GL_FIXED scale channel count */
+#define BRW_ATTRIB_WA_NORMALIZE     8   /* normalize in shader */
+#define BRW_ATTRIB_WA_BGRA          16  /* swap r/b channels in shader */
+#define BRW_ATTRIB_WA_SIGN          32  /* interpret as signed in shader */
+#define BRW_ATTRIB_WA_SCALE         64  /* interpret as scaled in shader */
 
 struct brw_vs_prog_key {
    GLuint program_string_id;
-   /**
-    * Number of channels of the vertex attribute that need GL_FIXED rescaling
+
+   /*
+    * Per-attribute workaround flags
     */
-   uint8_t gl_fixed_input_size[VERT_ATTRIB_MAX];
+   uint8_t gl_attrib_wa_flags[VERT_ATTRIB_MAX];
 
    /**
     * True if at least one clip flag is enabled, regardless of whether the