mesa: more transform feedback infrastructure

Includes GL_ARB_transform_feedback2 which encapsulates transform feedback
state in objects.

14 files changed, 736 insertions, 34 deletions

diff --git a/src/mesa/SConscript b/src/mesa/SConscript
index bf4ad6d2619..9408e2d2f69 100644
--- a/src/mesa/SConscript
+++ b/src/mesa/SConscript
@@ -176,6 +176,7 @@ if env['platform'] != 'winddk':
 		'state_tracker/st_cb_readpixels.c',
 		'state_tracker/st_cb_strings.c',
 		'state_tracker/st_cb_texture.c',
+		'state_tracker/st_cb_xformfb.c',
 		'state_tracker/st_context.c',
 		'state_tracker/st_debug.c',
 		'state_tracker/st_draw.c',
diff --git a/src/mesa/drivers/common/driverfuncs.c b/src/mesa/drivers/common/driverfuncs.c
index e518c000ddd..ca5eb5c7552 100644
--- a/src/mesa/drivers/common/driverfuncs.c
+++ b/src/mesa/drivers/common/driverfuncs.c
@@ -47,6 +47,9 @@
 #if FEATURE_ARB_sync
 #include "main/syncobj.h"
 #endif
+#if FEATURE_EXT_transform_feedback
+#include "main/transformfeedback.h"
+#endif
 
 #include "shader/program.h"
 #include "shader/shader_api.h"
@@ -205,6 +208,10 @@ _mesa_init_driver_functions(struct dd_function_table *driver)
    driver->DeleteArrayObject = _mesa_delete_array_object;
    driver->BindArrayObject = NULL;
 
+#if FEATURE_EXT_transform_feedback
+   _mesa_init_transform_feedback_functions(driver);
+#endif
+
    /* T&L stuff */
    driver->NeedValidate = GL_FALSE;
    driver->ValidateTnlModule = NULL;
diff --git a/src/mesa/main/dd.h b/src/mesa/main/dd.h
index cab8f34404d..53e44533cb3 100644
--- a/src/mesa/main/dd.h
+++ b/src/mesa/main/dd.h
@@ -1038,6 +1038,22 @@ struct dd_function_table {
 					     void *image_handle);
 #endif
 
+#if FEATURE_EXT_transform_feedback
+   struct gl_transform_feedback_object *
+        (*NewTransformFeedback)(GLcontext *ctx, GLuint name);
+   void (*DeleteTransformFeedback)(GLcontext *ctx,
+                                   struct gl_transform_feedback_object *obj);
+   void (*BeginTransformFeedback)(GLcontext *ctx, GLenum mode,
+                                  struct gl_transform_feedback_object *obj);
+   void (*EndTransformFeedback)(GLcontext *ctx,
+                                struct gl_transform_feedback_object *obj);
+   void (*PauseTransformFeedback)(GLcontext *ctx,
+                                  struct gl_transform_feedback_object *obj);
+   void (*ResumeTransformFeedback)(GLcontext *ctx,
+                                   struct gl_transform_feedback_object *obj);
+   void (*DrawTransformFeedback)(GLcontext *ctx, GLenum mode,
+                                 struct gl_transform_feedback_object *obj);
+#endif
 };
 
 
diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index 4c8d4ccfa22..1748ce2733b 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -86,6 +86,7 @@ static const struct {
    { OFF, "GL_ARB_texture_non_power_of_two",   F(ARB_texture_non_power_of_two)},
    { OFF, "GL_ARB_texture_rectangle",          F(NV_texture_rectangle) },
    { ON,  "GL_ARB_transpose_matrix",           F(ARB_transpose_matrix) },
+   { OFF, "GL_ARB_transform_feedback2",        F(ARB_transform_feedback2) },
    { OFF, "GL_ARB_vertex_array_bgra",          F(EXT_vertex_array_bgra) },
    { OFF, "GL_ARB_vertex_array_object",        F(ARB_vertex_array_object) },
    { ON,  "GL_ARB_vertex_buffer_object",       F(ARB_vertex_buffer_object) },
diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index 2e8b0a4e8c7..8230723f26f 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -7786,7 +7786,7 @@ _mesa_GetBooleanIndexedv( GLenum pname, GLuint index, GLboolean *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetBooleanIndexedv(index=%u), index", pname);
             return;
          }
-         params[0] = INT64_TO_BOOLEAN(ctx->TransformFeedback.Offset[index]);
+         params[0] = INT64_TO_BOOLEAN(ctx->TransformFeedback.CurrentObject->Offset[index]);
          break;
       case GL_TRANSFORM_FEEDBACK_BUFFER_SIZE:
          CHECK_EXT1(EXT_transform_feedback);
@@ -7794,7 +7794,7 @@ _mesa_GetBooleanIndexedv( GLenum pname, GLuint index, GLboolean *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetBooleanIndexedv(index=%u), index", pname);
             return;
          }
-         params[0] = INT64_TO_BOOLEAN(ctx->TransformFeedback.Size[index]);
+         params[0] = INT64_TO_BOOLEAN(ctx->TransformFeedback.CurrentObject->Size[index]);
          break;
       case GL_TRANSFORM_FEEDBACK_BUFFER_BINDING:
          CHECK_EXT1(EXT_transform_feedback);
@@ -7802,7 +7802,7 @@ _mesa_GetBooleanIndexedv( GLenum pname, GLuint index, GLboolean *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetBooleanIndexedv(index=%u), index", pname);
             return;
          }
-         params[0] = INT_TO_BOOLEAN(ctx->TransformFeedback.Buffers[index]->Name);
+         params[0] = INT_TO_BOOLEAN(ctx->TransformFeedback.CurrentObject->Buffers[index]->Name);
          break;
       default:
          goto invalid_enum_error;
@@ -7850,7 +7850,7 @@ _mesa_GetIntegerIndexedv( GLenum pname, GLuint index, GLint *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetIntegerIndexedv(index=%u), index", pname);
             return;
          }
-         params[0] = INT64_TO_INT(ctx->TransformFeedback.Offset[index]);
+         params[0] = INT64_TO_INT(ctx->TransformFeedback.CurrentObject->Offset[index]);
          break;
       case GL_TRANSFORM_FEEDBACK_BUFFER_SIZE:
          CHECK_EXT1(EXT_transform_feedback);
@@ -7858,7 +7858,7 @@ _mesa_GetIntegerIndexedv( GLenum pname, GLuint index, GLint *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetIntegerIndexedv(index=%u), index", pname);
             return;
          }
-         params[0] = INT64_TO_INT(ctx->TransformFeedback.Size[index]);
+         params[0] = INT64_TO_INT(ctx->TransformFeedback.CurrentObject->Size[index]);
          break;
       case GL_TRANSFORM_FEEDBACK_BUFFER_BINDING:
          CHECK_EXT1(EXT_transform_feedback);
@@ -7866,7 +7866,7 @@ _mesa_GetIntegerIndexedv( GLenum pname, GLuint index, GLint *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetIntegerIndexedv(index=%u), index", pname);
             return;
          }
-         params[0] = ctx->TransformFeedback.Buffers[index]->Name;
+         params[0] = ctx->TransformFeedback.CurrentObject->Buffers[index]->Name;
          break;
       default:
          goto invalid_enum_error;
@@ -7915,7 +7915,7 @@ _mesa_GetInteger64Indexedv( GLenum pname, GLuint index, GLint64 *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetInteger64Indexedv(index=%u), index", pname);
             return;
          }
-         params[0] = ctx->TransformFeedback.Offset[index];
+         params[0] = ctx->TransformFeedback.CurrentObject->Offset[index];
          break;
       case GL_TRANSFORM_FEEDBACK_BUFFER_SIZE:
          CHECK_EXT1(EXT_transform_feedback);
@@ -7923,7 +7923,7 @@ _mesa_GetInteger64Indexedv( GLenum pname, GLuint index, GLint64 *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetInteger64Indexedv(index=%u), index", pname);
             return;
          }
-         params[0] = ctx->TransformFeedback.Size[index];
+         params[0] = ctx->TransformFeedback.CurrentObject->Size[index];
          break;
       case GL_TRANSFORM_FEEDBACK_BUFFER_BINDING:
          CHECK_EXT1(EXT_transform_feedback);
@@ -7931,7 +7931,7 @@ _mesa_GetInteger64Indexedv( GLenum pname, GLuint index, GLint64 *params )
             _mesa_error(ctx, GL_INVALID_VALUE, "glGetInteger64Indexedv(index=%u), index", pname);
             return;
          }
-         params[0] = (GLint64)(ctx->TransformFeedback.Buffers[index]->Name);
+         params[0] = (GLint64)(ctx->TransformFeedback.CurrentObject->Buffers[index]->Name);
          break;
       default:
          goto invalid_enum_error;
diff --git a/src/mesa/main/get_gen.py b/src/mesa/main/get_gen.py
index d7c543f3681..0e9c9a8666b 100644
--- a/src/mesa/main/get_gen.py
+++ b/src/mesa/main/get_gen.py
@@ -1178,15 +1178,15 @@ IndexedStateVars = [
 
 	# GL_EXT_transform_feedback
 	( "GL_TRANSFORM_FEEDBACK_BUFFER_START", GLint64,
-	  ["ctx->TransformFeedback.Offset[index]"],
+	  ["ctx->TransformFeedback.CurrentObject->Offset[index]"],
 	  "ctx->Const.MaxTransformFeedbackSeparateAttribs",
 	  NoState, ["EXT_transform_feedback"] ),
 	( "GL_TRANSFORM_FEEDBACK_BUFFER_SIZE", GLint64,
-	  ["ctx->TransformFeedback.Size[index]"],
+	  ["ctx->TransformFeedback.CurrentObject->Size[index]"],
 	  "ctx->Const.MaxTransformFeedbackSeparateAttribs",
 	  NoState, ["EXT_transform_feedback"] ),
 	( "GL_TRANSFORM_FEEDBACK_BUFFER_BINDING", GLint,
-	  ["ctx->TransformFeedback.Buffers[index]->Name"],
+	  ["ctx->TransformFeedback.CurrentObject->Buffers[index]->Name"],
 	  "ctx->Const.MaxTransformFeedbackSeparateAttribs",
 	  NoState, ["EXT_transform_feedback"] ),
 
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 81ab17c6987..c34d9bac4a0 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2034,24 +2034,46 @@ struct gl_shader_state
 
 
 /**
- * Context state for transform feedback.
+ * Transform feedback object state
  */
-struct gl_transform_feedback
+struct gl_transform_feedback_object
 {
+   GLuint Name;  /**< AKA the object ID */
+   GLint RefCount;
    GLboolean Active;  /**< Is transform feedback enabled? */
-   GLenum Mode;       /**< GL_POINTS, GL_LINES or GL_TRIANGLES */
+   GLboolean Paused;  /**< Is transform feedback paused? */
+
+   /** The feedback buffers */
+   GLuint BufferNames[MAX_FEEDBACK_ATTRIBS];
+   struct gl_buffer_object *Buffers[MAX_FEEDBACK_ATTRIBS];
+
    /** Start of feedback data in dest buffer */
    GLintptr Offset[MAX_FEEDBACK_ATTRIBS];
    /** Max data to put into dest buffer (in bytes) */
    GLsizeiptr Size[MAX_FEEDBACK_ATTRIBS];
+};
+
+
+/**
+ * Context state for transform feedback.
+ */
+struct gl_transform_feedback
+{
+   GLenum Mode;       /**< GL_POINTS, GL_LINES or GL_TRIANGLES */
+
    GLboolean RasterDiscard;  /**< GL_RASTERIZER_DISCARD */
 
    /** The general binding point (GL_TRANSFORM_FEEDBACK_BUFFER) */
    struct gl_buffer_object *CurrentBuffer;
 
-   /** The feedback buffers */
-   GLuint BufferNames[MAX_FEEDBACK_ATTRIBS];
-   struct gl_buffer_object *Buffers[MAX_FEEDBACK_ATTRIBS];
+   /** The table of all transform feedback objects */
+   struct _mesa_HashTable *Objects;
+
+   /** The current xform-fb object (GL_TRANSFORM_FEEDBACK_BINDING) */
+   struct gl_transform_feedback_object *CurrentObject;
+
+   /** The default xform-fb object (Name==0) */
+   struct gl_transform_feedback_object *DefaultObject;
 };
 
 
@@ -2480,6 +2502,7 @@ struct gl_extensions
    GLboolean ARB_texture_float;
    GLboolean ARB_texture_mirrored_repeat;
    GLboolean ARB_texture_non_power_of_two;
+   GLboolean ARB_transform_feedback2;
    GLboolean ARB_transpose_matrix;
    GLboolean ARB_vertex_array_object;
    GLboolean ARB_vertex_buffer_object;
diff --git a/src/mesa/main/transformfeedback.c b/src/mesa/main/transformfeedback.c
index 74519ba38a6..528e7d954b9 100644
--- a/src/mesa/main/transformfeedback.c
+++ b/src/mesa/main/transformfeedback.c
@@ -33,6 +33,7 @@
 #include "buffers.h"
 #include "bufferobj.h"
 #include "context.h"
+#include "hash.h"
 #include "transformfeedback.h"
 
 #include "shader/prog_parameter.h"
@@ -40,6 +41,47 @@
 
 
 /**
+ * Do reference counting of transform feedback buffers.
+ */
+static void
+reference_transform_feedback_object(struct gl_transform_feedback_object **ptr,
+                                    struct gl_transform_feedback_object *obj)
+{
+   if (*ptr == obj)
+      return;
+
+   if (*ptr) {
+      /* Unreference the old object */
+      struct gl_transform_feedback_object *oldObj = *ptr;
+
+      ASSERT(oldObj->RefCount > 0);
+      oldObj->RefCount--;
+
+      if (oldObj->RefCount == 0) {
+         GET_CURRENT_CONTEXT(ctx);
+         if (ctx)
+            ctx->Driver.DeleteTransformFeedback(ctx, oldObj);
+      }
+
+      *ptr = NULL;
+   }
+   ASSERT(!*ptr);
+
+   if (obj) {
+      /* reference new object */
+      if (obj->RefCount == 0) {
+         _mesa_problem(NULL, "referencing deleted transform feedback object");
+         *ptr = NULL;
+      }
+      else {
+         obj->RefCount++;
+         *ptr = obj;
+      }
+   }
+}
+
+
+/**
  * Check if the given primitive mode (as in glBegin(mode)) is compatible
  * with the current transform feedback mode (if it's enabled).
  * This is to be called from glBegin(), glDrawArrays(), glDrawElements(), etc.
@@ -49,7 +91,7 @@
 GLboolean
 _mesa_validate_primitive_mode(GLcontext *ctx, GLenum mode)
 {
-   if (ctx->TransformFeedback.Active) {
+   if (ctx->TransformFeedback.CurrentObject->Active) {
       switch (mode) {
       case GL_POINTS:
          return ctx->TransformFeedback.Mode == GL_POINTS;
@@ -74,7 +116,7 @@ _mesa_validate_primitive_mode(GLcontext *ctx, GLenum mode)
 GLboolean
 _mesa_validate_transform_feedback_buffers(GLcontext *ctx)
 {
-
+   /* XXX to do */
    return GL_TRUE;
 }
 
@@ -86,29 +128,173 @@ _mesa_validate_transform_feedback_buffers(GLcontext *ctx)
 void
 _mesa_init_transform_feedback(GLcontext *ctx)
 {
+   if (!ctx->Driver.NewTransformFeedback) {
+      /* this feature/extension may not be supported by the driver */
+      return;
+   }
+
+   ctx->TransformFeedback.DefaultObject =
+      ctx->Driver.NewTransformFeedback(ctx, 0);
+
+   assert(ctx->TransformFeedback.DefaultObject->RefCount == 1);
+
+   reference_transform_feedback_object(&ctx->TransformFeedback.CurrentObject,
+                                       ctx->TransformFeedback.DefaultObject);
+
+   assert(ctx->TransformFeedback.DefaultObject->RefCount == 2);
+
+   ctx->TransformFeedback.Objects = _mesa_NewHashTable();
+
    _mesa_reference_buffer_object(ctx,
                                  &ctx->TransformFeedback.CurrentBuffer,
                                  ctx->Shared->NullBufferObj);
 }
 
 
+
+/**
+ * Callback for _mesa_HashDeleteAll().
+ */
+static void
+delete_cb(GLuint key, void *data, void *userData)
+{
+   GLcontext *ctx = (GLcontext *) userData;
+   struct gl_transform_feedback_object *obj =
+      (struct gl_transform_feedback_object *) data;
+
+   ctx->Driver.DeleteTransformFeedback(ctx, obj);
+}
+
+
 /**
  * Per-context free/clean-up for transform feedback.
  */
 void
 _mesa_free_transform_feedback(GLcontext *ctx)
 {
+   if (!ctx->Driver.NewTransformFeedback) {
+      /* this feature/extension may not be supported by the driver */
+      return;
+   }
+
    _mesa_reference_buffer_object(ctx,
                                  &ctx->TransformFeedback.CurrentBuffer,
                                  NULL);
+
+   /* Delete all feedback objects */
+   _mesa_HashDeleteAll(ctx->TransformFeedback.Objects, delete_cb, ctx);
+
+   /* Delete the default feedback object */
+   assert(ctx->Driver.DeleteTransformFeedback);
+   ctx->Driver.DeleteTransformFeedback(ctx, ctx->TransformFeedback.DefaultObject);
+
+   ctx->TransformFeedback.CurrentObject = NULL;
 }
 
 
+/** Default fallback for ctx->Driver.NewTransformFeedback() */
+static struct gl_transform_feedback_object *
+new_transform_feedback(GLcontext *ctx, GLuint name)
+{
+   struct gl_transform_feedback_object *obj;
+   obj = CALLOC_STRUCT(gl_transform_feedback_object);
+   if (obj) {
+      obj->Name = name;
+      obj->RefCount = 1;
+   }
+   return obj;
+}
+
+/** Default fallback for ctx->Driver.DeleteTransformFeedback() */
+static void
+delete_transform_feedback(GLcontext *ctx,
+                          struct gl_transform_feedback_object *obj)
+{
+   GLuint i;
+
+   for (i = 0; i < Elements(obj->Buffers); i++) {
+      _mesa_reference_buffer_object(ctx, &obj->Buffers[i], NULL);
+   }
+
+   free(obj);
+}
+
+/** Default fallback for ctx->Driver.BeginTransformFeedback() */
+static void
+begin_transform_feedback(GLcontext *ctx, GLenum mode,
+                         struct gl_transform_feedback_object *obj)
+{
+   /* nop */
+}
+
+/** Default fallback for ctx->Driver.EndTransformFeedback() */
+static void
+end_transform_feedback(GLcontext *ctx,
+                       struct gl_transform_feedback_object *obj)
+{
+   /* nop */
+}
+
+/** Default fallback for ctx->Driver.PauseTransformFeedback() */
+static void
+pause_transform_feedback(GLcontext *ctx,
+                         struct gl_transform_feedback_object *obj)
+{
+   /* nop */
+}
+
+/** Default fallback for ctx->Driver.ResumeTransformFeedback() */
+static void
+resume_transform_feedback(GLcontext *ctx,
+                          struct gl_transform_feedback_object *obj)
+{
+   /* nop */
+}
+
+/** Default fallback for ctx->Driver.DrawTransformFeedback() */
+static void
+draw_transform_feedback(GLcontext *ctx, GLenum mode,
+                        struct gl_transform_feedback_object *obj)
+{
+   /* XXX to do */
+   /*
+    * Get number of vertices in obj's feedback buffer.
+    * Call ctx->Exec.DrawArrays(mode, 0, count);
+    */
+}
+
+
+/**
+ * Plug in default device driver functions for transform feedback.
+ * Most drivers will override some/all of these.
+ */
+void
+_mesa_init_transform_feedback_functions(struct dd_function_table *driver)
+{
+   driver->NewTransformFeedback = new_transform_feedback;
+   driver->DeleteTransformFeedback = delete_transform_feedback;
+   driver->BeginTransformFeedback = begin_transform_feedback;
+   driver->EndTransformFeedback = end_transform_feedback;
+   driver->PauseTransformFeedback = pause_transform_feedback;
+   driver->ResumeTransformFeedback = resume_transform_feedback;
+   driver->DrawTransformFeedback = draw_transform_feedback;
+}
+
+
+
+/**
+ ** Begin API functions
+ **/
+
+
 void GLAPIENTRY
 _mesa_BeginTransformFeedback(GLenum mode)
 {
+   struct gl_transform_feedback_object *obj;
    GET_CURRENT_CONTEXT(ctx);
 
+   obj = ctx->TransformFeedback.CurrentObject;
+
    switch (mode) {
    case GL_POINTS:
    case GL_LINES:
@@ -120,29 +306,38 @@ _mesa_BeginTransformFeedback(GLenum mode)
       return;
    }
 
-   if (ctx->TransformFeedback.Active) {
+   if (obj->Active) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBeginTransformFeedback(already active)");
       return;
    }
 
-   ctx->TransformFeedback.Active = GL_TRUE;
+   obj->Active = GL_TRUE;
    ctx->TransformFeedback.Mode = mode;
+
+   assert(ctx->Driver.BeginTransformFeedback);
+   ctx->Driver.BeginTransformFeedback(ctx, mode, obj);
 }
 
 
 void GLAPIENTRY
 _mesa_EndTransformFeedback(void)
 {
+   struct gl_transform_feedback_object *obj;
    GET_CURRENT_CONTEXT(ctx);
 
-   if (!ctx->TransformFeedback.Active) {
+   obj = ctx->TransformFeedback.CurrentObject;
+
+   if (!obj->Active) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glEndTransformFeedback(not active)");
       return;
    }
 
-   ctx->TransformFeedback.Active = GL_FALSE;
+   ctx->TransformFeedback.CurrentObject->Active = GL_FALSE;
+
+   assert(ctx->Driver.EndTransformFeedback);
+   ctx->Driver.EndTransformFeedback(ctx, obj);
 }
 
 
@@ -154,6 +349,9 @@ bind_buffer_range(GLcontext *ctx, GLuint index,
                   struct gl_buffer_object *bufObj,
                   GLintptr offset, GLsizeiptr size)
 {
+   struct gl_transform_feedback_object *obj =
+      ctx->TransformFeedback.CurrentObject;
+
    /* The general binding point */
    _mesa_reference_buffer_object(ctx,
                                  &ctx->TransformFeedback.CurrentBuffer,
@@ -161,13 +359,13 @@ bind_buffer_range(GLcontext *ctx, GLuint index,
 
    /* The per-attribute binding point */
    _mesa_reference_buffer_object(ctx,
-                                 &ctx->TransformFeedback.Buffers[index],
+                                 &obj->Buffers[index],
                                  bufObj);
 
-   ctx->TransformFeedback.BufferNames[index] = bufObj->Name;
+   obj->BufferNames[index] = bufObj->Name;
 
-   ctx->TransformFeedback.Offset[index] = offset;
-   ctx->TransformFeedback.Size[index] = size;
+   obj->Offset[index] = offset;
+   obj->Size[index] = size;
 }
 
 
@@ -179,6 +377,7 @@ void GLAPIENTRY
 _mesa_BindBufferRange(GLenum target, GLuint index,
                       GLuint buffer, GLintptr offset, GLsizeiptr size)
 {
+   struct gl_transform_feedback_object *obj;
    struct gl_buffer_object *bufObj;
    GET_CURRENT_CONTEXT(ctx);
 
@@ -187,7 +386,9 @@ _mesa_BindBufferRange(GLenum target, GLuint index,
       return;
    }
 
-   if (ctx->TransformFeedback.Active) {
+   obj = ctx->TransformFeedback.CurrentObject;
+
+   if (obj->Active) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferRange(transform feedback active)");
       return;
@@ -235,16 +436,19 @@ _mesa_BindBufferRange(GLenum target, GLuint index,
 void GLAPIENTRY
 _mesa_BindBufferBase(GLenum target, GLuint index, GLuint buffer)
 {
+   struct gl_transform_feedback_object *obj;
    struct gl_buffer_object *bufObj;
-   GET_CURRENT_CONTEXT(ctx);
    GLsizeiptr size;
+   GET_CURRENT_CONTEXT(ctx);
 
    if (target != GL_TRANSFORM_FEEDBACK_BUFFER) {
       _mesa_error(ctx, GL_INVALID_ENUM, "glBindBufferBase(target)");
       return;
    }
 
-   if (ctx->TransformFeedback.Active) {
+   obj = ctx->TransformFeedback.CurrentObject;
+
+   if (obj->Active) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferRange(transform feedback active)");
       return;
@@ -280,6 +484,7 @@ void GLAPIENTRY
 _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, GLuint buffer,
                           GLintptr offset)
 {
+   struct gl_transform_feedback_object *obj;
    struct gl_buffer_object *bufObj;
    GET_CURRENT_CONTEXT(ctx);
    GLsizeiptr size;
@@ -289,7 +494,9 @@ _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, GLuint buffer,
       return;
    }
 
-   if (ctx->TransformFeedback.Active) {
+   obj = ctx->TransformFeedback.CurrentObject;
+
+   if (obj->Active) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferRange(transform feedback active)");
       return;
@@ -433,3 +640,242 @@ _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index,
    }
 }
 
+
+
+static struct gl_transform_feedback_object *
+lookup_transform_feedback_object(GLcontext *ctx, GLuint name)
+{
+   if (name == 0) {
+      return ctx->TransformFeedback.DefaultObject;
+   }
+   else
+      return (struct gl_transform_feedback_object *)
+         _mesa_HashLookup(ctx->TransformFeedback.Objects, name);
+}
+
+
+/**
+ * Create new transform feedback objects.   Transform feedback objects
+ * encapsulate the state related to transform feedback to allow quickly
+ * switching state (and drawing the results, below).
+ * Part of GL_ARB_transform_feedback2.
+ */
+void GLAPIENTRY
+_mesa_GenTransformFeedbacks(GLsizei n, GLuint *names)
+{
+   GLuint first;
+   GET_CURRENT_CONTEXT(ctx);
+
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (n < 0) {
+      _mesa_error(ctx, GL_INVALID_VALUE, "glGenTransformFeedbacks(n < 0)");
+      return;
+   }
+
+   if (!names)
+      return;
+
+   /* we don't need contiguous IDs, but this might be faster */
+   first = _mesa_HashFindFreeKeyBlock(ctx->TransformFeedback.Objects, n);
+   if (first) {
+      GLsizei i;
+      for (i = 0; i < n; i++) {
+         struct gl_transform_feedback_object *obj
+            = ctx->Driver.NewTransformFeedback(ctx, first + i);
+         if (!obj) {
+            _mesa_error(ctx, GL_OUT_OF_MEMORY, "glGenTransformFeedbacks");
+            return;
+         }
+         names[i] = first + i;
+         _mesa_HashInsert(ctx->TransformFeedback.Objects, first + i, obj);
+      }
+   }
+   else {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glGenTransformFeedbacks");
+   }
+}
+
+
+/**
+ * Is the given ID a transform feedback object?
+ * Part of GL_ARB_transform_feedback2.
+ */
+GLboolean GLAPIENTRY
+_mesa_IsTransformFeedback(GLuint name)
+{
+   GET_CURRENT_CONTEXT(ctx);
+
+   ASSERT_OUTSIDE_BEGIN_END_WITH_RETVAL(ctx, GL_FALSE);
+
+   if (name && lookup_transform_feedback_object(ctx, name))
+      return GL_TRUE;
+   else
+      return GL_FALSE;
+}
+
+
+/**
+ * Bind the given transform feedback object.
+ * Part of GL_ARB_transform_feedback2.
+ */
+void GLAPIENTRY
+_mesa_BindTransformFeedback(GLenum target, uint name)
+{
+   struct gl_transform_feedback_object *obj;
+   GET_CURRENT_CONTEXT(ctx);
+
+   if (target != GL_TRANSFORM_FEEDBACK) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glBindTransformFeedback(target)");
+      return;
+   }
+
+   if (ctx->TransformFeedback.CurrentObject->Active &&
+       !ctx->TransformFeedback.CurrentObject->Paused) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "glBindTransformFeedback(transform is active, or not paused)");
+      return;
+   }
+
+   obj = lookup_transform_feedback_object(ctx, name);
+   if (!obj) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "glBindTransformFeedback(name=%u)", name);
+      return;
+   }
+
+   reference_transform_feedback_object(&ctx->TransformFeedback.CurrentObject,
+                                       obj);
+}
+
+
+/**
+ * Delete the given transform feedback objects.
+ * Part of GL_ARB_transform_feedback2.
+ */
+void GLAPIENTRY
+_mesa_DeleteTransformFeedbacks(GLsizei n, const GLuint *names)
+{
+   GLint i;
+   GET_CURRENT_CONTEXT(ctx);
+
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (n < 0) {
+      _mesa_error(ctx, GL_INVALID_VALUE, "glDeleteTransformFeedbacks(n < 0)");
+      return;
+   }
+
+   if (!names)
+      return;
+
+   for (i = 0; i < n; i++) {
+      if (names[i] > 0) {
+         struct gl_transform_feedback_object *obj
+            = lookup_transform_feedback_object(ctx, names[i]);
+         if (obj) {
+            if (obj->Active) {
+               _mesa_error(ctx, GL_INVALID_OPERATION,
+                           "glDeleteTransformFeedbacks(object %u is active)",
+                           names[i]);
+               return;
+            }
+            _mesa_HashRemove(ctx->TransformFeedback.Objects, names[i]);
+            /* unref, but object may not be deleted until later */
+            reference_transform_feedback_object(&obj, NULL);
+         }
+      }
+   }
+}
+
+
+/**
+ * Pause transform feedback.
+ * Part of GL_ARB_transform_feedback2.
+ */
+void GLAPIENTRY
+_mesa_PauseTransformFeedback(void)
+{
+   struct gl_transform_feedback_object *obj;
+   GET_CURRENT_CONTEXT(ctx);
+
+   obj = ctx->TransformFeedback.CurrentObject;
+
+   if (!obj->Active || obj->Paused) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+           "glPauseTransformFeedback(feedback not active or already paused)");
+      return;
+   }
+
+   obj->Paused = GL_TRUE;
+
+   assert(ctx->Driver.PauseTransformFeedback);
+   ctx->Driver.PauseTransformFeedback(ctx, obj);
+}
+
+
+/**
+ * Resume transform feedback.
+ * Part of GL_ARB_transform_feedback2.
+ */
+void GLAPIENTRY
+_mesa_ResumeTransformFeedback(void)
+{
+   struct gl_transform_feedback_object *obj;
+   GET_CURRENT_CONTEXT(ctx);
+
+   obj = ctx->TransformFeedback.CurrentObject;
+
+   if (!obj->Active || !obj->Paused) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "glPauseTransformFeedback(feedback not active or not paused)");
+      return;
+   }
+
+   obj->Paused = GL_FALSE;
+
+   assert(ctx->Driver.ResumeTransformFeedback);
+   ctx->Driver.ResumeTransformFeedback(ctx, obj);
+}
+
+
+/**
+ * Draw the vertex data in a transform feedback object.
+ * \param mode  GL_POINTS, GL_LINES, GL_TRIANGLE_STRIP, etc.
+ * \param name  the transform feedback object
+ * The number of vertices comes from the transform feedback object.
+ * User still has to setup of the vertex attribute info with
+ * glVertexPointer, glColorPointer, etc.
+ * Part of GL_ARB_transform_feedback2.
+ */
+void GLAPIENTRY
+_mesa_DrawTransformFeedback(GLenum mode, GLuint name)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   struct gl_transform_feedback_object *obj =
+      lookup_transform_feedback_object(ctx, name);
+
+   if (!obj) {
+      _mesa_error(ctx, GL_INVALID_VALUE,
+                  "glDrawTransformFeedback(name = %u)", name);
+      return;
+   }
+
+   /* XXX check if EndTransformFeedback has never been called while
+    * the object was bound
+    */
+
+   assert(ctx->Driver.DrawTransformFeedback);
+   ctx->Driver.DrawTransformFeedback(ctx, mode, obj);
+}
+
+
+/*
+XXX misc to do:
+
+glGet*() for
+
+GL_TRANSFORM_FEEDBACK_BUFFER_PAUSED
+GL_TRANSFORM_FEEDBACK_BUFFER_ACTIVE
+GL_TRANSFORM_FEEDBACK_BINDING
+*/
diff --git a/src/mesa/main/transformfeedback.h b/src/mesa/main/transformfeedback.h
index e89cc414736..53cc4565916 100644
--- a/src/mesa/main/transformfeedback.h
+++ b/src/mesa/main/transformfeedback.h
@@ -41,6 +41,12 @@ extern void
 _mesa_free_transform_feedback(GLcontext *ctx);
 
 
+extern void
+_mesa_init_transform_feedback_functions(struct dd_function_table *driver);
+
+
+/*** GL_EXT_transform_feedback ***/
+
 extern void GLAPIENTRY
 _mesa_BeginTransformFeedback(GLenum mode);
 
@@ -68,4 +74,29 @@ _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index,
                                   GLsizei *size, GLenum *type, GLchar *name);
 
 
+
+/*** GL_ARB_transform_feedback2 ***/
+
+extern void GLAPIENTRY
+_mesa_GenTransformFeedbacks(GLsizei n, GLuint *names);
+
+extern GLboolean GLAPIENTRY
+_mesa_IsTransformFeedback(GLuint name);
+
+extern void GLAPIENTRY
+_mesa_BindTransformFeedback(GLenum target, uint name);
+
+extern void GLAPIENTRY
+_mesa_DeleteTransformFeedbacks(GLsizei n, const GLuint *names);
+
+extern void GLAPIENTRY
+_mesa_PauseTransformFeedback(void);
+
+extern void GLAPIENTRY
+_mesa_ResumeTransformFeedback(void);
+
+extern void GLAPIENTRY
+_mesa_DrawTransformFeedback(GLenum mode, GLuint name);
+
+
 #endif /* TRANSFORM_FEEDBACK_H */
diff --git a/src/mesa/shader/shader_api.c b/src/mesa/shader/shader_api.c
index 4ff032d4ec8..505c7bb46f9 100644
--- a/src/mesa/shader/shader_api.c
+++ b/src/mesa/shader/shader_api.c
@@ -1517,12 +1517,14 @@ static void
 _mesa_link_program(GLcontext *ctx, GLuint program)
 {
    struct gl_shader_program *shProg;
+   struct gl_transform_feedback_object *obj =
+      ctx->TransformFeedback.CurrentObject;
 
    shProg = _mesa_lookup_shader_program_err(ctx, program, "glLinkProgram");
    if (!shProg)
       return;
 
-   if (ctx->TransformFeedback.Active && shProg == ctx->Shader.CurrentProgram) {
+   if (obj->Active && shProg == ctx->Shader.CurrentProgram) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glLinkProgram(transform feedback active");
       return;
@@ -1591,8 +1593,10 @@ void
 _mesa_use_program(GLcontext *ctx, GLuint program)
 {
    struct gl_shader_program *shProg;
+   struct gl_transform_feedback_object *obj =
+      ctx->TransformFeedback.CurrentObject;
 
-   if (ctx->TransformFeedback.Active) {
+   if (obj->Active) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glUseProgram(transform feedback active)");
       return;
diff --git a/src/mesa/sources.mak b/src/mesa/sources.mak
index 55523fad1d3..5c2aa92132d 100644
--- a/src/mesa/sources.mak
+++ b/src/mesa/sources.mak
@@ -210,6 +210,7 @@ STATETRACKER_SOURCES = \
 	state_tracker/st_cb_readpixels.c \
 	state_tracker/st_cb_strings.c \
 	state_tracker/st_cb_texture.c \
+	state_tracker/st_cb_xformfb.c \
 	state_tracker/st_context.c \
 	state_tracker/st_debug.c \
 	state_tracker/st_draw.c \
diff --git a/src/mesa/state_tracker/st_cb_xformfb.c b/src/mesa/state_tracker/st_cb_xformfb.c
new file mode 100644
index 00000000000..fb48b57eb53
--- /dev/null
+++ b/src/mesa/state_tracker/st_cb_xformfb.c
@@ -0,0 +1,129 @@
+/**************************************************************************
+ * 
+ * Copyright 2010 VMware, Inc.
+ * All Rights Reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ **************************************************************************/
+
+
+/**
+ * Transform feedback functions.
+ *
+ * \author Brian Paul
+ */
+
+
+#include "main/imports.h"
+#include "main/context.h"
+#include "main/transformfeedback.h"
+
+#include "st_cb_xformfb.h"
+
+
+#if 0
+static struct gl_transform_feedback_object *
+st_new_transform_feedback(GLcontext *ctx, GLuint name)
+{
+   struct gl_transform_feedback_object *obj;
+   obj = CALLOC_STRUCT(gl_transform_feedback_object);
+   if (obj) {
+      obj->Name = name;
+      obj->RefCount = 1;
+   }
+   return obj;
+}
+#endif
+
+#if 0
+static void
+st_delete_transform_feedback(GLcontext *ctx,
+                             struct gl_transform_feedback_object *obj)
+{
+   GLuint i;
+
+   for (i = 0; i < Elements(obj->Buffers); i++) {
+      _mesa_reference_buffer_object(ctx, &obj->Buffers[i], NULL);
+   }
+
+   free(obj);
+}
+#endif
+
+
+static void
+st_begin_transform_feedback(GLcontext *ctx, GLenum mode,
+                            struct gl_transform_feedback_object *obj)
+{
+   /* to-do */
+}
+
+
+static void
+st_end_transform_feedback(GLcontext *ctx,
+                          struct gl_transform_feedback_object *obj)
+{
+   /* to-do */
+}
+
+
+static void
+st_pause_transform_feedback(GLcontext *ctx,
+                            struct gl_transform_feedback_object *obj)
+{
+   /* to-do */
+}
+
+
+static void
+st_resume_transform_feedback(GLcontext *ctx,
+                             struct gl_transform_feedback_object *obj)
+{
+   /* to-do */
+}
+
+
+static void
+st_draw_transform_feedback(GLcontext *ctx, GLenum mode,
+                           struct gl_transform_feedback_object *obj)
+{
+   /* XXX to do */
+   /*
+    * Get number of vertices in obj's feedback buffer.
+    * Call ctx->Exec.DrawArrays(mode, 0, count);
+    */
+}
+
+
+void
+st_init_xformfb_functions(struct dd_function_table *functions)
+{
+   /* let core Mesa plug in its functions */
+   _mesa_init_transform_feedback_functions(functions);
+
+   /* then override a few: */
+   functions->BeginTransformFeedback = st_begin_transform_feedback;
+   functions->EndTransformFeedback = st_end_transform_feedback;
+   functions->PauseTransformFeedback = st_pause_transform_feedback;
+   functions->ResumeTransformFeedback = st_resume_transform_feedback;
+   functions->DrawTransformFeedback = st_draw_transform_feedback;
+}
diff --git a/src/mesa/state_tracker/st_cb_xformfb.h b/src/mesa/state_tracker/st_cb_xformfb.h
new file mode 100644
index 00000000000..d6c354e5a56
--- /dev/null
+++ b/src/mesa/state_tracker/st_cb_xformfb.h
@@ -0,0 +1,36 @@
+/**************************************************************************
+ * 
+ * Copyright 2010 VMware, Inc.
+ * All Rights Reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ **************************************************************************/
+
+#ifndef ST_CB_XFORMFB_H
+#define ST_CB_XFORMFB_H
+
+
+extern void
+st_init_xformfb_functions(struct dd_function_table *functions);
+
+
+#endif /* ST_CB_XFORMFB_H */
diff --git a/src/mesa/state_tracker/st_context.c b/src/mesa/state_tracker/st_context.c
index e8a3926e6db..93406141f65 100644
--- a/src/mesa/state_tracker/st_context.c
+++ b/src/mesa/state_tracker/st_context.c
@@ -54,6 +54,9 @@
 #include "st_cb_queryobj.h"
 #include "st_cb_readpixels.h"
 #include "st_cb_texture.h"
+#if FEATURE_EXT_transform_feedback
+#include "st_cb_xformfb.h"
+#endif
 #include "st_cb_flush.h"
 #include "st_cb_strings.h"
 #include "st_atom.h"
@@ -335,5 +338,9 @@ void st_init_driver_functions(struct dd_function_table *functions)
    st_init_flush_functions(functions);
    st_init_string_functions(functions);
 
+#if FEATURE_EXT_transform_feedback
+   st_init_xformfb_functions(functions);
+#endif
+
    functions->UpdateState = st_invalidate_state;
 }