radv: Disable NGG culling when conservative overestimation is used.

Even when small primitive culling is disabled, the face culling algorithm
in ac_nir_cull can delete tiny triangles when their area is almost zero.

Cc: mesa-stable
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20987>

diff --git a/src/amd/vulkan/radv_cmd_buffer.c b/src/amd/vulkan/radv_cmd_buffer.c
index 43a8e96..eecebad 100644 (file)
--- a/src/amd/vulkan/radv_cmd_buffer.c
+++ b/src/amd/vulkan/radv_cmd_buffer.c
@@ -187,7 +187,7 @@ radv_bind_dynamic_state(struct radv_cmd_buffer *cmd_buffer, const struct radv_dy
 
    RADV_CMP_COPY(vk.ts.patch_control_points, RADV_DYNAMIC_PATCH_CONTROL_POINTS);
    RADV_CMP_COPY(vk.ts.domain_origin, RADV_DYNAMIC_TESS_DOMAIN_ORIGIN);
- 
+
    RADV_CMP_COPY(vk.rs.line.width, RADV_DYNAMIC_LINE_WIDTH);
    RADV_CMP_COPY(vk.rs.depth_bias.constant, RADV_DYNAMIC_DEPTH_BIAS);
    RADV_CMP_COPY(vk.rs.depth_bias.clamp, RADV_DYNAMIC_DEPTH_BIAS);
@@ -235,7 +235,7 @@ radv_bind_dynamic_state(struct radv_cmd_buffer *cmd_buffer, const struct radv_dy
    RADV_CMP_COPY(vk.cb.logic_op, RADV_DYNAMIC_LOGIC_OP);
    RADV_CMP_COPY(vk.cb.color_write_enables, RADV_DYNAMIC_COLOR_WRITE_ENABLE);
    RADV_CMP_COPY(vk.cb.logic_op_enable, RADV_DYNAMIC_LOGIC_OP_ENABLE);
- 
+
    RADV_CMP_COPY(vk.fsr.fragment_size.width, RADV_DYNAMIC_FRAGMENT_SHADING_RATE);
    RADV_CMP_COPY(vk.fsr.fragment_size.height, RADV_DYNAMIC_FRAGMENT_SHADING_RATE);
    RADV_CMP_COPY(vk.fsr.combiner_ops[0], RADV_DYNAMIC_FRAGMENT_SHADING_RATE);
@@ -8401,6 +8401,12 @@ radv_get_ngg_culling_settings(struct radv_cmd_buffer *cmd_buffer, bool vp_y_inve
    const struct radv_graphics_pipeline *pipeline = cmd_buffer->state.graphics_pipeline;
    const struct radv_dynamic_state *d = &cmd_buffer->state.dynamic;
 
+   /* Disable shader culling entirely when conservative overestimate is used.
+    * The face culling algorithm can delete very tiny triangles (even if unintended).
+    */
+   if (d->vk.rs.conservative_mode == VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT)
+      return radv_nggc_none;
+
    /* Cull every triangle when rasterizer discard is enabled. */
    if (d->vk.rs.rasterizer_discard_enable)
       return radv_nggc_front_face | radv_nggc_back_face;
@@ -8422,12 +8428,10 @@ radv_get_ngg_culling_settings(struct radv_cmd_buffer *cmd_buffer, bool vp_y_inve
    if (d->vk.rs.cull_mode & VK_CULL_MODE_BACK_BIT)
       nggc_settings |= radv_nggc_back_face;
 
-   /* Small primitive culling is only valid when conservative overestimation is not used. It's also
-    * disabled for user sample locations because small primitive culling assumes a sample
-    * position at (0.5, 0.5). */
-   bool uses_conservative_overestimate =
-      d->vk.rs.conservative_mode == VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT;
-   if (!uses_conservative_overestimate && !pipeline->uses_user_sample_locations) {
+   /* Small primitive culling assumes a sample position at (0.5, 0.5)
+    * so don't enable it with user sample locations.
+    */
+   if (!pipeline->uses_user_sample_locations) {
       nggc_settings |= radv_nggc_small_primitives;
 
       /* small_prim_precision = num_samples / 2^subpixel_bits