Merge branch 'primitive-restart-cleanup'

Conflicts:
	docs/relnotes-7.10.html

This branch is a re-do of the primitive-restart branch with all
the intermediate/temporary stuff cleaned out.

6 files changed, 105 insertions, 1 deletions

diff --git a/src/gallium/auxiliary/draw/draw_pt.c b/src/gallium/auxiliary/draw/draw_pt.c
index f44bf2507c6..4078b2a07d0 100644
--- a/src/gallium/auxiliary/draw/draw_pt.c
+++ b/src/gallium/auxiliary/draw/draw_pt.c
@@ -287,6 +287,84 @@ draw_print_arrays(struct draw_context *draw, uint prim, int start, uint count)
 }
 
 
+/** Helper code for below */
+#define PRIM_RESTART_LOOP(elements) \
+   do { \
+      for (i = start; i < end; i++) { \
+         if (elements[i] == info->restart_index) { \
+            if (cur_count > 0) { \
+               /* draw elts up to prev pos */ \
+               draw_pt_arrays(draw, prim, cur_start, cur_count); \
+            } \
+            /* begin new prim at next elt */ \
+            cur_start = i + 1; \
+            cur_count = 0; \
+         } \
+         else { \
+            cur_count++; \
+         } \
+      } \
+      if (cur_count > 0) { \
+         draw_pt_arrays(draw, prim, cur_start, cur_count); \
+      } \
+   } while (0)
+
+
+/**
+ * For drawing prims with primitive restart enabled.
+ * Scan for restart indexes and draw the runs of elements/vertices between
+ * the restarts.
+ */
+static void
+draw_pt_arrays_restart(struct draw_context *draw,
+                       const struct pipe_draw_info *info)
+{
+   const unsigned prim = info->mode;
+   const unsigned start = info->start;
+   const unsigned count = info->count;
+   const unsigned end = start + count;
+   unsigned i, cur_start, cur_count;
+
+   assert(info->primitive_restart);
+
+   if (draw->pt.user.elts) {
+      /* indexed prims (draw_elements) */
+      cur_start = start;
+      cur_count = 0;
+
+      switch (draw->pt.user.eltSize) {
+      case 1:
+         {
+            const ubyte *elt_ub = (const ubyte *) draw->pt.user.elts;
+            PRIM_RESTART_LOOP(elt_ub);
+         }
+         break;
+      case 2:
+         {
+            const ushort *elt_us = (const ushort *) draw->pt.user.elts;
+            PRIM_RESTART_LOOP(elt_us);
+         }
+         break;
+      case 4:
+         {
+            const uint *elt_ui = (const uint *) draw->pt.user.elts;
+            PRIM_RESTART_LOOP(elt_ui);
+         }
+         break;
+      default:
+         assert(0 && "bad eltSize in draw_arrays()");
+      }
+   }
+   else {
+      /* Non-indexed prims (draw_arrays).
+       * Primitive restart should have been handled in the state tracker.
+       */
+      draw_pt_arrays(draw, prim, start, count);
+   }
+}
+
+
+
 /**
  * Non-instanced drawing.
  * \sa draw_arrays_instanced
@@ -395,6 +473,12 @@ draw_vbo(struct draw_context *draw,
 
    for (instance = 0; instance < info->instance_count; instance++) {
       draw->instance_id = instance + info->start_instance;
-      draw_pt_arrays(draw, info->mode, info->start, info->count);
+
+      if (info->primitive_restart) {
+         draw_pt_arrays_restart(draw, info);
+      }
+      else {
+         draw_pt_arrays(draw, info->mode, info->start, info->count);
+      }
    }
 }
diff --git a/src/gallium/docs/source/context.rst b/src/gallium/docs/source/context.rst
index 5342fc25dc1..e09a1304c4d 100644
--- a/src/gallium/docs/source/context.rst
+++ b/src/gallium/docs/source/context.rst
@@ -156,6 +156,15 @@ If there is an index buffer bound, and ``indexed`` field is true, all vertex
 indices will be looked up in the index buffer.  ``min_index``, ``max_index``,
 and ``index_bias`` apply after index lookup.
 
+When drawing indexed primitives, the primitive restart index can be
+used to draw disjoint primitive strips.  For example, several separate
+line strips can be drawn by designating a special index value as the
+restart index.  The ``primitive_restart`` flag enables/disables this
+feature.  The ``restart_index`` field specifies the restart index value.
+
+When primitive restart is in use, array indexes are compared to the
+restart index before adding the index_bias offset.
+
 If a given vertex element has ``instance_divisor`` set to 0, it is said
 it contains per-vertex data and effective vertex attribute address needs
 to be recalculated for every index.
diff --git a/src/gallium/drivers/llvmpipe/lp_screen.c b/src/gallium/drivers/llvmpipe/lp_screen.c
index 96633d93654..ad0ea75b3a3 100644
--- a/src/gallium/drivers/llvmpipe/lp_screen.c
+++ b/src/gallium/drivers/llvmpipe/lp_screen.c
@@ -158,6 +158,8 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT:
    case PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER:
       return 0;
+   case PIPE_CAP_PRIMITIVE_RESTART:
+      return 1;
    case PIPE_CAP_DEPTHSTENCIL_CLEAR_SEPARATE:
       return 1;
    case PIPE_CAP_DEPTH_CLAMP:
diff --git a/src/gallium/drivers/softpipe/sp_screen.c b/src/gallium/drivers/softpipe/sp_screen.c
index 37557d11940..a2bfa1bd8d5 100644
--- a/src/gallium/drivers/softpipe/sp_screen.c
+++ b/src/gallium/drivers/softpipe/sp_screen.c
@@ -112,6 +112,8 @@ softpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
       return 1;
    case PIPE_CAP_STREAM_OUTPUT:
       return 1;
+   case PIPE_CAP_PRIMITIVE_RESTART:
+      return 1;
    case PIPE_CAP_DEPTHSTENCIL_CLEAR_SEPARATE:
       return 0;
    case PIPE_CAP_SHADER_STENCIL_EXPORT:
diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index b6894c09e82..53f7b601ad5 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -452,6 +452,7 @@ enum pipe_cap {
    PIPE_CAP_BLEND_EQUATION_SEPARATE,
    PIPE_CAP_SM3,  /*< Shader Model, supported */
    PIPE_CAP_STREAM_OUTPUT,
+   PIPE_CAP_PRIMITIVE_RESTART,
    /** Maximum texture image units accessible from vertex and fragment shaders
     * combined */
    PIPE_CAP_MAX_COMBINED_SAMPLERS,
diff --git a/src/gallium/include/pipe/p_state.h b/src/gallium/include/pipe/p_state.h
index 9a2b31da50d..fc6dba346da 100644
--- a/src/gallium/include/pipe/p_state.h
+++ b/src/gallium/include/pipe/p_state.h
@@ -457,6 +457,12 @@ struct pipe_draw_info
    int index_bias; /**< a bias to be added to each index */
    unsigned min_index; /**< the min index */
    unsigned max_index; /**< the max index */
+
+   /**
+    * Primitive restart enable/index (only applies to indexed drawing)
+    */
+   boolean primitive_restart;
+   unsigned restart_index;
 };