draw/softpipe: add clip vertex support. (v2)

softpipe always clipped using the position vector, however for unclipped
vertices it stored the position in window coordinates, however when position
and clipping are separated, we need to store the clip-space position and
the clip-space vertex clip, so we can interpolate both separately.

This means we have to take the clip space position and store it to use later.

This allows softpipe to pass all the clip-vertex piglit tests.

v2: fix llvm draw regression, the structure being passed into llvm needed
updating, remove some hardcoded ints that should have been enums while there.

Signed-off-by: Dave Airlie <[email protected]>

9 files changed, 58 insertions, 18 deletions

diff --git a/src/gallium/auxiliary/draw/draw_cliptest_tmp.h b/src/gallium/auxiliary/draw/draw_cliptest_tmp.h
index 9e6827cc452..7dba49b2870 100644
--- a/src/gallium/auxiliary/draw/draw_cliptest_tmp.h
+++ b/src/gallium/auxiliary/draw/draw_cliptest_tmp.h
@@ -35,11 +35,13 @@ static boolean TAG(do_cliptest)( struct pt_post_vs *pvs,
    const float *trans = pvs->draw->viewport.translate;
    /* const */ float (*plane)[4] = pvs->draw->plane;
    const unsigned pos = draw_current_shader_position_output(pvs->draw);
+   const unsigned cv = draw_current_shader_clipvertex_output(pvs->draw);
    const unsigned ef = pvs->draw->vs.edgeflag_output;
    const unsigned ucp_enable = pvs->draw->rasterizer->clip_plane_enable;
    const unsigned flags = (FLAGS);
    unsigned need_pipeline = 0;
    unsigned j;
+   unsigned i;
 
    for (j = 0; j < info->count; j++) {
       float *position = out->data[pos];
@@ -49,10 +51,15 @@ static boolean TAG(do_cliptest)( struct pt_post_vs *pvs,
 
       if (flags & (DO_CLIP_XY | DO_CLIP_XY_GUARD_BAND |
                    DO_CLIP_FULL_Z | DO_CLIP_HALF_Z | DO_CLIP_USER)) {
-         out->clip[0] = position[0];
-         out->clip[1] = position[1];
-         out->clip[2] = position[2];
-         out->clip[3] = position[3];
+         float *clipvertex = position;
+
+         if ((flags & DO_CLIP_USER) && cv != pos)
+            clipvertex = out->data[cv];
+
+         for (i = 0; i < 4; i++) {
+            out->clip[i] = clipvertex[i];
+            out->pre_clip_pos[i] = position[i];
+         }
 
          /* Do the hardwired planes first:
           */
@@ -88,7 +95,7 @@ static boolean TAG(do_cliptest)( struct pt_post_vs *pvs,
                ucp_mask &= ~(1 << plane_idx);
                plane_idx += 6;
 
-               if (dot4(position, plane[plane_idx]) < 0) {
+               if (dot4(clipvertex, plane[plane_idx]) < 0) {
                   mask |= 1 << plane_idx;
                }
             }
diff --git a/src/gallium/auxiliary/draw/draw_context.c b/src/gallium/auxiliary/draw/draw_context.c
index 10a20f76178..6d7075e5452 100644
--- a/src/gallium/auxiliary/draw/draw_context.c
+++ b/src/gallium/auxiliary/draw/draw_context.c
@@ -692,6 +692,16 @@ draw_current_shader_position_output(const struct draw_context *draw)
 
 
 /**
+ * Return the index of the shader output which will contain the
+ * vertex position.
+ */
+uint
+draw_current_shader_clipvertex_output(const struct draw_context *draw)
+{
+   return draw->vs.clipvertex_output;
+}
+
+/**
  * Return a pointer/handle for a driver/CSO rasterizer object which
  * disabled culling, stippling, unfilled tris, etc.
  * This is used by some pipeline stages (such as wide_point, aa_line
diff --git a/src/gallium/auxiliary/draw/draw_llvm.c b/src/gallium/auxiliary/draw/draw_llvm.c
index cf97e82a63c..50c7e254deb 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_llvm.c
@@ -268,15 +268,16 @@ static LLVMTypeRef
 create_jit_vertex_header(struct gallivm_state *gallivm, int data_elems)
 {
    LLVMTargetDataRef target = gallivm->target;
-   LLVMTypeRef elem_types[3];
+   LLVMTypeRef elem_types[4];
    LLVMTypeRef vertex_header;
    char struct_name[24];
 
    util_snprintf(struct_name, 23, "vertex_header%d", data_elems);
 
-   elem_types[0]  = LLVMIntTypeInContext(gallivm->context, 32);
-   elem_types[1]  = LLVMArrayType(LLVMFloatTypeInContext(gallivm->context), 4);
-   elem_types[2]  = LLVMArrayType(elem_types[1], data_elems);
+   elem_types[DRAW_JIT_VERTEX_VERTEX_ID]  = LLVMIntTypeInContext(gallivm->context, 32);
+   elem_types[DRAW_JIT_VERTEX_CLIP]  = LLVMArrayType(LLVMFloatTypeInContext(gallivm->context), 4);
+   elem_types[DRAW_JIT_VERTEX_PRE_CLIP_POS]  = LLVMArrayType(LLVMFloatTypeInContext(gallivm->context), 4);
+   elem_types[DRAW_JIT_VERTEX_DATA]  = LLVMArrayType(elem_types[1], data_elems);
 
 #if HAVE_LLVM >= 0x0300
    vertex_header = LLVMStructCreateNamed(gallivm->context, struct_name);
@@ -307,6 +308,9 @@ create_jit_vertex_header(struct gallivm_state *gallivm, int data_elems)
    LP_CHECK_MEMBER_OFFSET(struct vertex_header, clip,
                           target, vertex_header,
                           DRAW_JIT_VERTEX_CLIP);
+   LP_CHECK_MEMBER_OFFSET(struct vertex_header, pre_clip_pos,
+                          target, vertex_header,
+                          DRAW_JIT_VERTEX_PRE_CLIP_POS);
    LP_CHECK_MEMBER_OFFSET(struct vertex_header, data,
                           target, vertex_header,
                           DRAW_JIT_VERTEX_DATA);
diff --git a/src/gallium/auxiliary/draw/draw_llvm.h b/src/gallium/auxiliary/draw/draw_llvm.h
index edd1a08e3db..31fc2db05bd 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.h
+++ b/src/gallium/auxiliary/draw/draw_llvm.h
@@ -80,6 +80,7 @@ enum {
 enum {
    DRAW_JIT_VERTEX_VERTEX_ID = 0,
    DRAW_JIT_VERTEX_CLIP,
+   DRAW_JIT_VERTEX_PRE_CLIP_POS,
    DRAW_JIT_VERTEX_DATA
 };
 
@@ -123,13 +124,16 @@ struct draw_jit_context
    lp_build_struct_get_ptr(_gallivm, _ptr, DRAW_JIT_CTX_TEXTURES, "textures")
 
 #define draw_jit_header_id(_gallivm, _ptr)              \
-   lp_build_struct_get_ptr(_gallivm, _ptr, 0, "id")
+   lp_build_struct_get_ptr(_gallivm, _ptr, DRAW_JIT_VERTEX_VERTEX_ID, "id")
 
 #define draw_jit_header_clip(_gallivm, _ptr) \
-   lp_build_struct_get_ptr(_gallivm, _ptr, 1, "clip")
+   lp_build_struct_get_ptr(_gallivm, _ptr, DRAW_JIT_VERTEX_CLIP, "clip")
+
+#define draw_jit_header_pre_clip_pos(_gallivm, _ptr) \
+   lp_build_struct_get_ptr(_gallivm, _ptr, DRAW_JIT_VERTEX_PRE_CLIP_POS, "pre_clip_pos")
 
 #define draw_jit_header_data(_gallivm, _ptr)            \
-   lp_build_struct_get_ptr(_gallivm, _ptr, 2, "data")
+   lp_build_struct_get_ptr(_gallivm, _ptr, DRAW_JIT_VERTEX_DATA, "data")
 
 
 #define draw_jit_vbuffer_stride(_gallivm, _ptr)         \
diff --git a/src/gallium/auxiliary/draw/draw_pipe_clip.c b/src/gallium/auxiliary/draw/draw_pipe_clip.c
index e1eabe22288..fbc8f675129 100644
--- a/src/gallium/auxiliary/draw/draw_pipe_clip.c
+++ b/src/gallium/auxiliary/draw/draw_pipe_clip.c
@@ -118,6 +118,7 @@ static void interp( const struct clip_stage *clip,
 {
    const unsigned nr_attrs = draw_current_shader_outputs(clip->stage.draw);
    const unsigned pos_attr = draw_current_shader_position_output(clip->stage.draw);
+   const unsigned clip_attr = draw_current_shader_clipvertex_output(clip->stage.draw);
    unsigned j;
 
    /* Vertex header.
@@ -130,12 +131,14 @@ static void interp( const struct clip_stage *clip,
    /* Interpolate the clip-space coords.
     */
    interp_attr(dst->clip, t, in->clip, out->clip);
+   /* interpolate the clip-space position */
+   interp_attr(dst->pre_clip_pos, t, in->pre_clip_pos, out->pre_clip_pos);
 
    /* Do the projective divide and viewport transformation to get
     * new window coordinates:
     */
    {
-      const float *pos = dst->clip;
+      const float *pos = dst->pre_clip_pos;
       const float *scale = clip->stage.draw->viewport.scale;
       const float *trans = clip->stage.draw->viewport.translate;
       const float oow = 1.0f / pos[3];
@@ -149,8 +152,8 @@ static void interp( const struct clip_stage *clip,
    /* Other attributes
     */
    for (j = 0; j < nr_attrs; j++) {
-      if (j != pos_attr)
-         interp_attr(dst->data[j], t, in->data[j], out->data[j]);
+      if (j != pos_attr && j != clip_attr)
+        interp_attr(dst->data[j], t, in->data[j], out->data[j]);
    }
 }
 
diff --git a/src/gallium/auxiliary/draw/draw_private.h b/src/gallium/auxiliary/draw/draw_private.h
index 91112eb96b4..aa9b602a353 100644
--- a/src/gallium/auxiliary/draw/draw_private.h
+++ b/src/gallium/auxiliary/draw/draw_private.h
@@ -76,6 +76,7 @@ struct vertex_header {
    unsigned vertex_id:16;
 
    float clip[4];
+   float pre_clip_pos[4];
 
    /* This will probably become float (*data)[4] soon:
     */
@@ -230,6 +231,7 @@ struct draw_context
       uint num_vs_outputs;  /**< convenience, from vertex_shader */
       uint position_output;
       uint edgeflag_output;
+      uint clipvertex_output;
 
       /** TGSI program interpreter runtime state */
       struct tgsi_exec_machine *machine;
@@ -378,7 +380,7 @@ void draw_gs_destroy( struct draw_context *draw );
  */
 uint draw_current_shader_outputs(const struct draw_context *draw);
 uint draw_current_shader_position_output(const struct draw_context *draw);
-
+uint draw_current_shader_clipvertex_output(const struct draw_context *draw);
 int draw_alloc_extra_vertex_attrib(struct draw_context *draw,
                                    uint semantic_name, uint semantic_index);
 void draw_remove_extra_vertex_attribs(struct draw_context *draw);
diff --git a/src/gallium/auxiliary/draw/draw_pt_fetch.c b/src/gallium/auxiliary/draw/draw_pt_fetch.c
index b0032e5ad0e..a6cc1834e6c 100644
--- a/src/gallium/auxiliary/draw/draw_pt_fetch.c
+++ b/src/gallium/auxiliary/draw/draw_pt_fetch.c
@@ -74,9 +74,9 @@ draw_pt_fetch_prepare(struct pt_fetch *fetch,
    /* Leave the clipmask/edgeflags/pad/vertex_id untouched
     */
    dst_offset += 1 * sizeof(float);
-   /* Just leave the clip[] array untouched.
+   /* Just leave the clip[] and pre_clip_pos[] array untouched.
     */
-   dst_offset += 4 * sizeof(float);
+   dst_offset += 8 * sizeof(float);
 
    if (instance_id_index != ~0) {
       num_extra_inputs++;
diff --git a/src/gallium/auxiliary/draw/draw_vs.c b/src/gallium/auxiliary/draw/draw_vs.c
index bc1c90b0f3a..150653c669a 100644
--- a/src/gallium/auxiliary/draw/draw_vs.c
+++ b/src/gallium/auxiliary/draw/draw_vs.c
@@ -120,6 +120,7 @@ draw_create_vertex_shader(struct draw_context *draw,
    if (vs)
    {
       uint i;
+      bool found_clipvertex = FALSE;
       for (i = 0; i < vs->info.num_outputs; i++) {
          if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_POSITION &&
              vs->info.output_semantic_index[i] == 0)
@@ -127,7 +128,14 @@ draw_create_vertex_shader(struct draw_context *draw,
          else if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_EDGEFLAG &&
              vs->info.output_semantic_index[i] == 0)
             vs->edgeflag_output = i;
+         else if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_CLIPVERTEX &&
+                  vs->info.output_semantic_index[i] == 0) {
+            found_clipvertex = TRUE;
+            vs->clipvertex_output = i;
+         }
       }
+      if (!found_clipvertex)
+         vs->clipvertex_output = vs->position_output;
    }
 
    assert(vs);
@@ -147,6 +155,7 @@ draw_bind_vertex_shader(struct draw_context *draw,
       draw->vs.num_vs_outputs = dvs->info.num_outputs;
       draw->vs.position_output = dvs->position_output;
       draw->vs.edgeflag_output = dvs->edgeflag_output;
+      draw->vs.clipvertex_output = dvs->clipvertex_output;
       dvs->prepare( dvs, draw );
    }
    else {
diff --git a/src/gallium/auxiliary/draw/draw_vs.h b/src/gallium/auxiliary/draw/draw_vs.h
index 49229f8164b..a3b90faa24b 100644
--- a/src/gallium/auxiliary/draw/draw_vs.h
+++ b/src/gallium/auxiliary/draw/draw_vs.h
@@ -111,6 +111,7 @@ struct draw_vertex_shader {
    struct tgsi_shader_info info;
    unsigned position_output;
    unsigned edgeflag_output;
+   unsigned clipvertex_output;
 
    /* Extracted from shader:
     */