vbo: Implement method to track the inputs array.

Provided the _DrawVAO and the derived state that is maintained if we have
the _DrawVAO set, implement a method to incrementally update the array of
gl_vertex_array input pointers.

v2: Add some more comments.
    Rename _vbo_array_init to _vbo_init_inputs.
    Rename vbo_context::arrays to vbo_context::draw_arrays.

Signed-off-by: Mathias Fröhlich <Mathias.Froehlich@web.de>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/mesa/vbo/vbo.h

@@ -254,6 +254,42 @@ vbo_sw_primitive_restart(struct gl_context *ctx,
                          const struct _mesa_index_buffer *ib,
                          struct gl_buffer_object *indirect);
 
+
+/**
+ * Utility that tracks and updates the current array entries.
+ */
+struct vbo_inputs
+{
+   /**
+    * Array of inputs to be set to the _DrawArrays pointer.
+    * The array contains pointers into the _DrawVAO and to the vbo modules
+    * current values. The array of pointers is updated incrementally
+    * based on the current and vertex_processing_mode values below.
+    */
+   const struct gl_vertex_array *inputs[VERT_ATTRIB_MAX];
+   /** Those VERT_BIT_'s where the inputs array point to current values. */
+   GLbitfield current;
+   /** Store which aliasing current values - generics or materials - are set. */
+   gl_vertex_processing_mode vertex_processing_mode;
+};
+
+
+/**
+ * Initialize inputs.
+ */
+void
+_vbo_init_inputs(struct vbo_inputs *inputs);
+
+
+/**
+ * Update the gl_vertex_array array inside the vbo_inputs structure
+ * provided the current _VPMode, the provided vao and
+ * the vao's enabled arrays filtered by the filter bitmask.
+ */
+void
+_vbo_update_inputs(struct gl_context *ctx, struct vbo_inputs *inputs);
+
+
 void GLAPIENTRY
 _es_Color4f(GLfloat r, GLfloat g, GLfloat b, GLfloat a);
 

src/mesa/vbo/vbo_context.c

@@ -234,6 +234,7 @@ _vbo_CreateContext(struct gl_context *ctx)
    init_legacy_currval(ctx);
    init_generic_currval(ctx);
    init_mat_currval(ctx);
+   _vbo_init_inputs(&vbo->draw_arrays);
    vbo_set_indirect_draw_func(ctx, vbo_draw_indirect_prims);
 
    /* make sure all VBO_ATTRIB_ values can fit in an unsigned byte */

src/mesa/vbo/vbo_exec.c

@@ -27,6 +27,7 @@
 
 
 #include "main/glheader.h"
+#include "main/arrayobj.h"
 #include "main/mtypes.h"
 #include "main/api_arrayelt.h"
 #include "main/vtxfmt.h"
@@ -240,3 +241,85 @@ vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
    p0->count += p1->count;
    p0->end = p1->end;
 }
+
+
+void
+_vbo_init_inputs(struct vbo_inputs *inputs)
+{
+   inputs->current = 0;
+   inputs->vertex_processing_mode = VP_MODE_FF;
+}
+
+
+/**
+ * Update the vbo_inputs's arrays to point to the vao->_VertexArray arrays
+ * according to the 'enable' bitmask.
+ * \param enable  bitfield of VERT_BIT_x flags.
+ */
+static inline void
+update_vao_inputs(struct gl_context *ctx,
+                  struct vbo_inputs *inputs, GLbitfield enable)
+{
+   const struct gl_vertex_array_object *vao = ctx->Array._DrawVAO;
+
+   /* Make sure we process only arrays enabled in the VAO */
+   assert((enable & ~_mesa_get_vao_vp_inputs(vao)) == 0);
+
+   /* Fill in the client arrays from the VAO */
+   const GLubyte *const map = _mesa_vao_attribute_map[vao->_AttributeMapMode];
+   const struct gl_vertex_array *array = vao->_VertexArray;
+   const struct gl_vertex_array **iarray = &inputs->inputs[0];
+   while (enable) {
+      const int attr = u_bit_scan(&enable);
+      iarray[attr] = &array[map[attr]];
+   }
+}
+
+
+/**
+ * Update the vbo_inputs's arrays to point to the vbo->currval arrays
+ * according to the 'current' bitmask.
+ * \param current  bitfield of VERT_BIT_x flags.
+ */
+static inline void
+update_current_inputs(struct gl_context *ctx,
+                      struct vbo_inputs *inputs, GLbitfield current)
+{
+   gl_vertex_processing_mode mode = ctx->VertexProgram._VPMode;
+
+   /* All previously non current array pointers need update. */
+   GLbitfield mask = current & ~inputs->current;
+   /* On mode change, the slots aliasing with materials need update too */
+   if (mode != inputs->vertex_processing_mode)
+      mask |= current & VERT_BIT_MAT_ALL;
+
+   struct vbo_context *vbo = vbo_context(ctx);
+   const struct gl_vertex_array *const currval = &vbo->currval[0];
+   const struct gl_vertex_array **iarray = &inputs->inputs[0];
+   const GLubyte *const map = _vbo_attribute_alias_map[mode];
+   while (mask) {
+      const int attr = u_bit_scan(&mask);
+      iarray[attr] = &currval[map[attr]];
+   }
+
+   inputs->current = current;
+   inputs->vertex_processing_mode = mode;
+}
+
+
+/**
+ * Update the vbo_inputs's arrays to point to the vao->_VertexArray and
+ * vbo->currval arrays according to Array._DrawVAO and
+ * Array._DrawVAOEnableAttribs.
+ */
+void
+_vbo_update_inputs(struct gl_context *ctx, struct vbo_inputs *inputs)
+{
+   const GLbitfield enable = ctx->Array._DrawVAOEnabledAttribs;
+
+   /* Update array input pointers */
+   update_vao_inputs(ctx, inputs, enable);
+
+   /* The rest must be current inputs. */
+   update_current_inputs(ctx, inputs, ~enable & VERT_BIT_ALL);
+}

src/mesa/vbo/vbo_private.h

@@ -44,6 +44,8 @@ struct _mesa_prim;
 
 struct vbo_context {
    struct gl_vertex_array currval[VBO_ATTRIB_MAX];
+   /* The array of inputs used for _DrawVAO draws. */
+   struct vbo_inputs draw_arrays;
 
    struct vbo_exec_context exec;
    struct vbo_save_context save;