anv: Implement "pop-free" clipping

This is the preferred clipping mode since it doesn't mean your points
disappear the moment part of the point crosses over the edge of the
viewport and that lines have weird endpoints at viewport edges.  We've
just never bothered to hook it up until now.

Reviewed-by: Kenneth Graunke <[email protected]>
Reviewed-by: Lionel Landwerlin <[email protected]>

2 files changed, 86 insertions, 4 deletions

diff --git a/src/intel/vulkan/anv_device.c b/src/intel/vulkan/anv_device.c
index 8cb05c8116b..c3ed837c410 100644
--- a/src/intel/vulkan/anv_device.c
+++ b/src/intel/vulkan/anv_device.c
@@ -1516,8 +1516,7 @@ void anv_GetPhysicalDeviceProperties2(
       case VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES: {
          VkPhysicalDevicePointClippingProperties *properties =
             (VkPhysicalDevicePointClippingProperties *) ext;
-         properties->pointClippingBehavior = VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES;
-         anv_finishme("Implement pop-free point clipping");
+         properties->pointClippingBehavior = VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY;
          break;
       }
 
diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_pipeline.c
index e35bb5e3405..5660711692c 100644
--- a/src/intel/vulkan/genX_pipeline.c
+++ b/src/intel/vulkan/genX_pipeline.c
@@ -448,6 +448,79 @@ static const uint32_t vk_to_gen_front_face[] = {
    [VK_FRONT_FACE_CLOCKWISE]                 = 0
 };
 
+/** Returns the final polygon mode for rasterization
+ *
+ * This function takes into account polygon mode, primitive topology and the
+ * different shader stages which might generate their own type of primitives.
+ */
+static VkPolygonMode
+anv_raster_polygon_mode(struct anv_pipeline *pipeline,
+                        const VkPipelineInputAssemblyStateCreateInfo *ia_info,
+                        const VkPipelineRasterizationStateCreateInfo *rs_info)
+{
+   /* Points always override everything.  This saves us from having to handle
+    * rs_info->polygonMode in all of the line cases below.
+    */
+   if (rs_info->polygonMode == VK_POLYGON_MODE_POINT)
+      return VK_POLYGON_MODE_POINT;
+
+   if (anv_pipeline_has_stage(pipeline, MESA_SHADER_GEOMETRY)) {
+      switch (get_gs_prog_data(pipeline)->output_topology) {
+      case _3DPRIM_POINTLIST:
+         return VK_POLYGON_MODE_POINT;
+
+      case _3DPRIM_LINELIST:
+      case _3DPRIM_LINESTRIP:
+      case _3DPRIM_LINELOOP:
+         return VK_POLYGON_MODE_LINE;
+
+      case _3DPRIM_TRILIST:
+      case _3DPRIM_TRIFAN:
+      case _3DPRIM_TRISTRIP:
+      case _3DPRIM_RECTLIST:
+      case _3DPRIM_QUADLIST:
+      case _3DPRIM_QUADSTRIP:
+      case _3DPRIM_POLYGON:
+         return rs_info->polygonMode;
+      }
+      unreachable("Unsupported GS output topology");
+   } else if (anv_pipeline_has_stage(pipeline, MESA_SHADER_TESS_EVAL)) {
+      switch (get_tes_prog_data(pipeline)->output_topology) {
+      case BRW_TESS_OUTPUT_TOPOLOGY_POINT:
+         return VK_POLYGON_MODE_POINT;
+
+      case BRW_TESS_OUTPUT_TOPOLOGY_LINE:
+         return VK_POLYGON_MODE_LINE;
+
+      case BRW_TESS_OUTPUT_TOPOLOGY_TRI_CW:
+      case BRW_TESS_OUTPUT_TOPOLOGY_TRI_CCW:
+         return rs_info->polygonMode;
+      }
+      unreachable("Unsupported TCS output topology");
+   } else {
+      switch (ia_info->topology) {
+      case VK_PRIMITIVE_TOPOLOGY_POINT_LIST:
+         return VK_POLYGON_MODE_POINT;
+
+      case VK_PRIMITIVE_TOPOLOGY_LINE_LIST:
+      case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP:
+      case VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY:
+      case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY:
+         return VK_POLYGON_MODE_LINE;
+
+      case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST:
+      case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP:
+      case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN:
+      case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY:
+      case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY:
+         return rs_info->polygonMode;
+
+      default:
+         unreachable("Unsupported primitive topology");
+      }
+   }
+}
+
 static void
 emit_rs_state(struct anv_pipeline *pipeline,
               const VkPipelineRasterizationStateCreateInfo *rs_info,
@@ -1066,6 +1139,7 @@ emit_cb_state(struct anv_pipeline *pipeline,
 
 static void
 emit_3dstate_clip(struct anv_pipeline *pipeline,
+                  const VkPipelineInputAssemblyStateCreateInfo *ia_info,
                   const VkPipelineViewportStateCreateInfo *vp_info,
                   const VkPipelineRasterizationStateCreateInfo *rs_info)
 {
@@ -1076,9 +1150,16 @@ emit_3dstate_clip(struct anv_pipeline *pipeline,
       clip.StatisticsEnable         = true;
       clip.EarlyCullEnable          = true;
       clip.APIMode                  = APIMODE_D3D,
-      clip.ViewportXYClipTestEnable = true;
       clip.GuardbandClipTestEnable  = true;
 
+      /* Only enable the XY clip test when the final polygon rasterization
+       * mode is VK_POLYGON_MODE_FILL.  We want to leave it disabled for
+       * points and lines so we get "pop-free" clipping.
+       */
+      VkPolygonMode raster_mode =
+         anv_raster_polygon_mode(pipeline, ia_info, rs_info);
+      clip.ViewportXYClipTestEnable = (raster_mode == VK_POLYGON_MODE_FILL);
+
 #if GEN_GEN >= 8
       clip.VertexSubPixelPrecisionSelect = _8Bit;
 #endif
@@ -1952,7 +2033,9 @@ genX(graphics_pipeline_create)(
 
    emit_urb_setup(pipeline);
 
-   emit_3dstate_clip(pipeline, pCreateInfo->pViewportState,
+   emit_3dstate_clip(pipeline,
+                     pCreateInfo->pInputAssemblyState,
+                     pCreateInfo->pViewportState,
                      pCreateInfo->pRasterizationState);
    emit_3dstate_streamout(pipeline, pCreateInfo->pRasterizationState);