From 733de81496dda6a99842dcf7e37f175f73d60ca6 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <icculus@icculus.org>
Date: Mon, 18 Aug 2008 11:16:05 -0400
Subject: [PATCH] Removed all the unnecessary POSITION0 tapdancing.

Technically, this fixes the glsl profile on Mac OS X, but really, it's fixing
 it everywhere; we were just getting lucky on other platforms.

--HG--
branch : trunk
---
 mojoshader.c        | 32 ++++++--------------------------
 mojoshader_opengl.c | 37 +++++++++++++++----------------------
 2 files changed, 21 insertions(+), 48 deletions(-)

diff --git a/mojoshader.c b/mojoshader.c
index 67c4eb36..699fdf10 100644
--- a/mojoshader.c
+++ b/mojoshader.c
@@ -4110,9 +4110,7 @@ static void emit_ARB1_attribute(Context *ctx, RegisterType regtype, int regnum,
 
         if (regtype == REG_TYPE_INPUT)
         {
-            int attr = 0;  // POSITION0 _must_ be vertex.attrib[0]!
-            if ((usage != MOJOSHADER_USAGE_POSITION) || (index != 0))
-                attr = ++ctx->assigned_vertex_attributes;
+            const int attr = ctx->assigned_vertex_attributes++;
             push_output(ctx, &ctx->globals);
             output_line(ctx, "ATTRIB %s = vertex.attrib[%d];", varname, attr);
             pop_output(ctx);
@@ -7505,31 +7503,13 @@ static void process_definitions(Context *ctx)
                                       (TextureType) item->index);
     } // for
 
-    // ...and attributes... (find input POSITION0 here, so it's always first).
+    // ...and attributes...
     for (item = ctx->attributes.next; item != NULL; item = item->next)
     {
-        if ( (item->regtype == REG_TYPE_INPUT) &&
-             (item->usage == MOJOSHADER_USAGE_POSITION) && (item->index == 0) )
-        {
-            ctx->attribute_count++;
-            ctx->profile->attribute_emitter(ctx, item->regtype, item->regnum,
-                                            MOJOSHADER_USAGE_POSITION, 0,
-                                            item->writemask, item->misc);
-            break;
-        } // if
-    } // for
-
-    // ...and attributes... (everything but input POSITION0).
-    for (item = ctx->attributes.next; item != NULL; item = item->next)
-    {
-        if ( (item->regtype != REG_TYPE_INPUT) ||
-             (item->usage != MOJOSHADER_USAGE_POSITION) || (item->index != 0) )
-        {
-            ctx->attribute_count++;
-            ctx->profile->attribute_emitter(ctx, item->regtype, item->regnum,
-                                            item->usage, item->index,
-                                            item->writemask, item->misc);
-        } // if
+        ctx->attribute_count++;
+        ctx->profile->attribute_emitter(ctx, item->regtype, item->regnum,
+                                        item->usage, item->index,
+                                        item->writemask, item->misc);
     } // for
 } // process_definitions
 
diff --git a/mojoshader_opengl.c b/mojoshader_opengl.c
index 6a6c1fb5..cb730a95 100644
--- a/mojoshader_opengl.c
+++ b/mojoshader_opengl.c
@@ -1496,34 +1496,27 @@ void MOJOSHADER_glSetVertexAttribute(MOJOSHADER_usage usage,
 
     const GLenum gl_type = opengl_attr_type(type);
     const GLboolean norm = (normalized) ? GL_TRUE : GL_FALSE;
+    const int count = ctx->bound_program->attribute_count;
     GLuint gl_index = 0;
+    int i;
 
-    // We have to map POSITION0 to generic vertex attribute 0; the
-    //  GL_ARB_vertex_shader spec says this is equivalent to using
-    //  glVertexPointer(), but without the limitations of that entry point.
-
-    if ((usage != MOJOSHADER_USAGE_POSITION) || (index != 0))
+    for (i = 0; i < count; i++)
     {
-        int i;
-        const int count = ctx->bound_program->attribute_count;
-        for (i = 0; i < count; i++)
-        {
-            const AttributeMap *map = &ctx->bound_program->attributes[i];
-            const MOJOSHADER_attribute *a = map->attribute;
+        const AttributeMap *map = &ctx->bound_program->attributes[i];
+        const MOJOSHADER_attribute *a = map->attribute;
 
-            // !!! FIXME: is this array guaranteed to be sorted by usage?
-            // !!! FIXME:  if so, we can break if a->usage > usage.
+        // !!! FIXME: is this array guaranteed to be sorted by usage?
+        // !!! FIXME:  if so, we can break if a->usage > usage.
 
-            if ((a->usage == usage) && (a->index == index))
-            {
-                gl_index = map->location;
-                break;
-            } // if
-        } // for
+        if ((a->usage == usage) && (a->index == index))
+        {
+            gl_index = map->location;
+            break;
+        } // if
+    } // for
 
-        if (gl_index == 0)
-            return;  // nothing to do, this shader doesn't use this stream.
-    } // if
+    if (i == count)
+        return;  // nothing to do, this shader doesn't use this stream.
 
     // these happen to work in both ARB1 and GLSL, but if something alien
     //  shows up, we'll have to split these into profile*() functions.