turnip: update LRZ state based on stencil test state

Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7186>

src/freedreno/vulkan/tu_cmd_buffer.c

@@ -2250,7 +2250,7 @@ tu_CmdSetDepthBounds(VkCommandBuffer commandBuffer,
                    A6XX_RB_Z_BOUNDS_MAX(maxDepthBounds));
 }
 
-static void
+void
 update_stencil_mask(uint32_t *value, VkStencilFaceFlags face, uint32_t mask)
 {
    if (face & VK_STENCIL_FACE_FRONT_BIT)
@@ -2283,6 +2283,8 @@ tu_CmdSetStencilWriteMask(VkCommandBuffer commandBuffer,
    update_stencil_mask(&cmd->state.dynamic_stencil_wrmask, faceMask, writeMask);
 
    tu_cs_emit_regs(&cs, A6XX_RB_STENCILWRMASK(.dword = cmd->state.dynamic_stencil_wrmask));
+
+   cmd->state.dirty |= TU_CMD_DIRTY_LRZ;
 }
 
 void
@@ -3353,6 +3355,64 @@ tu6_lrz_depth_mode(struct A6XX_GRAS_LRZ_CNTL *gras_lrz_cntl,
    return lrz_direction;
 }
 
+/* update lrz state based on stencil-test func:
+ *
+ * Conceptually the order of the pipeline is:
+ *
+ *
+ *   FS -> Alpha-Test  ->  Stencil-Test  ->  Depth-Test
+ *                              |                |
+ *                       if wrmask != 0     if wrmask != 0
+ *                              |                |
+ *                              v                v
+ *                        Stencil-Write      Depth-Write
+ *
+ * Because Stencil-Test can have side effects (Stencil-Write) prior
+ * to depth test, in this case we potentially need to disable early
+ * lrz-test. See:
+ *
+ * https://www.khronos.org/opengl/wiki/Per-Sample_Processing
+ */
+static void
+tu6_lrz_stencil_op(struct A6XX_GRAS_LRZ_CNTL *gras_lrz_cntl,
+                   VkCompareOp func,
+                   bool stencil_write,
+                   bool *invalidate_lrz)
+{
+   switch (func) {
+   case VK_COMPARE_OP_ALWAYS:
+      /* nothing to do for LRZ, but for stencil test when stencil-
+       * write is enabled, we need to disable lrz-test, since
+       * conceptually stencil test and write happens before depth-test.
+       */
+      if (stencil_write) {
+         gras_lrz_cntl->enable = false;
+         gras_lrz_cntl->z_test_enable = false;
+         *invalidate_lrz = true;
+      }
+      break;
+   case VK_COMPARE_OP_NEVER:
+      /* fragment never passes, disable lrz_write for this draw. */
+      gras_lrz_cntl->lrz_write = false;
+      break;
+   default:
+      /* whether the fragment passes or not depends on result
+       * of stencil test, which we cannot know when doing binning
+       * pass.
+       */
+      gras_lrz_cntl->lrz_write = false;
+      /* similarly to the VK_COMPARE_OP_ALWAYS case, if there are side-
+       * effects from stencil test we need to disable lrz-test.
+       */
+      if (stencil_write) {
+         gras_lrz_cntl->enable = false;
+         gras_lrz_cntl->z_test_enable = false;
+         *invalidate_lrz = true;
+      }
+      break;
+   }
+}
+
 static struct A6XX_GRAS_LRZ_CNTL
 tu6_calculate_lrz_state(struct tu_cmd_buffer *cmd,
                         const uint32_t a)
@@ -3383,8 +3443,27 @@ tu6_calculate_lrz_state(struct tu_cmd_buffer *cmd,
    /* Invalidate LRZ and disable write if stencil test is enabled */
    bool stencil_test_enable = cmd->state.rb_stencil_cntl & A6XX_RB_STENCIL_CONTROL_STENCIL_ENABLE;
    if (stencil_test_enable) {
-      force_disable_write = true;
-      invalidate_lrz = true;
+      bool stencil_front_writemask =
+         (pipeline->dynamic_state_mask & BIT(VK_DYNAMIC_STATE_STENCIL_WRITE_MASK)) ?
+         (cmd->state.dynamic_stencil_wrmask & 0xff) :
+         (pipeline->stencil_wrmask & 0xff);
+
+      bool stencil_back_writemask =
+         (pipeline->dynamic_state_mask & BIT(VK_DYNAMIC_STATE_STENCIL_WRITE_MASK)) ?
+         ((cmd->state.dynamic_stencil_wrmask & 0xff00) >> 8) :
+         (pipeline->stencil_wrmask & 0xff00) >> 8;
+
+      VkCompareOp stencil_front_compare_op =
+         (cmd->state.rb_stencil_cntl & A6XX_RB_STENCIL_CONTROL_FUNC__MASK) >> A6XX_RB_STENCIL_CONTROL_FUNC__SHIFT;
+
+      VkCompareOp stencil_back_compare_op =
+         (cmd->state.rb_stencil_cntl & A6XX_RB_STENCIL_CONTROL_FUNC_BF__MASK) >> A6XX_RB_STENCIL_CONTROL_FUNC_BF__SHIFT;
+
+      tu6_lrz_stencil_op(&gras_lrz_cntl, stencil_front_compare_op,
+                         stencil_front_writemask, &invalidate_lrz);
+
+      tu6_lrz_stencil_op(&gras_lrz_cntl, stencil_back_compare_op,
+                         stencil_back_writemask, &invalidate_lrz);
    }
 
    if (force_disable_write)

src/freedreno/vulkan/tu_pipeline.c

@@ -2708,8 +2708,9 @@ tu_pipeline_builder_parse_depth_stencil(struct tu_pipeline_builder *builder,
    }
 
    if (tu_pipeline_static_state(pipeline, &cs, VK_DYNAMIC_STATE_STENCIL_WRITE_MASK, 2)) {
-      tu_cs_emit_regs(&cs, A6XX_RB_STENCILWRMASK(.wrmask = ds_info->front.writeMask & 0xff,
-                                                 .bfwrmask = ds_info->back.writeMask & 0xff));
+      update_stencil_mask(&pipeline->stencil_wrmask,  VK_STENCIL_FACE_FRONT_BIT, ds_info->front.writeMask);
+      update_stencil_mask(&pipeline->stencil_wrmask,  VK_STENCIL_FACE_BACK_BIT, ds_info->back.writeMask);
+      tu_cs_emit_regs(&cs, A6XX_RB_STENCILWRMASK(.dword = pipeline->stencil_wrmask));
    }
 
    if (tu_pipeline_static_state(pipeline, &cs, VK_DYNAMIC_STATE_STENCIL_REFERENCE, 2)) {

src/freedreno/vulkan/tu_private.h

@@ -1105,6 +1105,7 @@ struct tu_pipeline
    uint32_t gras_su_cntl, gras_su_cntl_mask;
    uint32_t rb_depth_cntl, rb_depth_cntl_mask;
    uint32_t rb_stencil_cntl, rb_stencil_cntl_mask;
+   uint32_t stencil_wrmask;
 
    bool rb_depth_cntl_disable;
 
@@ -1651,4 +1652,7 @@ TU_DEFINE_NONDISP_HANDLE_CASTS(tu_sampler_ycbcr_conversion, VkSamplerYcbcrConver
 /* for TU_FROM_HANDLE with both VkFence and VkSemaphore: */
 #define tu_syncobj_from_handle(x) ((struct tu_syncobj*) (uintptr_t) (x))
 
+void
+update_stencil_mask(uint32_t *value, VkStencilFaceFlags face, uint32_t mask);
+
 #endif /* TU_PRIVATE_H */