v3dv: implement depth bias

This doesn't implement depth bias clamp, which requires to support the
depth bias clamp feature, which we do not advertise as available at present.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>

src/broadcom/vulkan/v3dv_cmd_buffer.c

@@ -49,6 +49,10 @@ const struct v3dv_dynamic_state default_dynamic_state = {
      .back = 0u,
    },
    .blend_constants = { 0.0f, 0.0f, 0.0f, 0.0f },
+   .depth_bias = {
+      .constant_factor = 0.0f,
+      .slope_factor = 0.0f,
+   },
 };
 
 void
@@ -1990,6 +1994,14 @@ cmd_buffer_bind_pipeline_static_state(struct v3dv_cmd_buffer *cmd_buffer,
       }
    }
 
+   if (!(dynamic_mask & V3DV_DYNAMIC_DEPTH_BIAS)) {
+      if (memcmp(&dest->depth_bias, &src->depth_bias,
+                 sizeof(src->depth_bias))) {
+         memcpy(&dest->depth_bias, &src->depth_bias, sizeof(src->depth_bias));
+         dirty |= V3DV_CMD_DIRTY_DEPTH_BIAS;
+      }
+   }
+
    cmd_buffer->state.dynamic.mask = dynamic_mask;
    cmd_buffer->state.dirty |= dirty;
 }
@@ -2538,6 +2550,31 @@ emit_stencil(struct v3dv_cmd_buffer *cmd_buffer)
    }
 }
 
+static void
+emit_depth_bias(struct v3dv_cmd_buffer *cmd_buffer)
+{
+   struct v3dv_pipeline *pipeline = cmd_buffer->state.pipeline;
+   assert(pipeline);
+
+   if (!pipeline->depth_bias.enabled)
+      return;
+
+   struct v3dv_job *job = cmd_buffer->state.job;
+   assert(job);
+
+   v3dv_cl_ensure_space_with_branch(&job->bcl, cl_packet_length(DEPTH_OFFSET));
+
+   struct v3dv_dynamic_state *dynamic = &cmd_buffer->state.dynamic;
+   cl_emit(&job->bcl, DEPTH_OFFSET, bias) {
+      bias.depth_offset_factor = dynamic->depth_bias.slope_factor;
+      bias.depth_offset_units = dynamic->depth_bias.constant_factor;
+      if (pipeline->depth_bias.is_z16)
+         bias.depth_offset_units *= 256.0f;
+   }
+
+   cmd_buffer->state.dirty &= ~V3DV_CMD_DIRTY_DEPTH_BIAS;
+}
+
 static void
 emit_blend(struct v3dv_cmd_buffer *cmd_buffer)
 {
@@ -3113,6 +3150,9 @@ cmd_buffer_emit_pre_draw(struct v3dv_cmd_buffer *cmd_buffer)
    if (*dirty & (V3DV_CMD_DIRTY_PIPELINE | dynamic_stencil_dirty_flags))
       emit_stencil(cmd_buffer);
 
+   if (*dirty & (V3DV_CMD_DIRTY_PIPELINE | V3DV_CMD_DIRTY_DEPTH_BIAS))
+      emit_depth_bias(cmd_buffer);
+
    if (*dirty & (V3DV_CMD_DIRTY_PIPELINE | V3DV_CMD_DIRTY_BLEND_CONSTANTS))
       emit_blend(cmd_buffer);
 
@@ -3375,6 +3415,19 @@ v3dv_CmdSetStencilReference(VkCommandBuffer commandBuffer,
    cmd_buffer->state.dirty |= V3DV_CMD_DIRTY_STENCIL_REFERENCE;
 }
 
+void
+v3dv_CmdSetDepthBias(VkCommandBuffer commandBuffer,
+                     float depthBiasConstantFactor,
+                     float depthBiasClamp,
+                     float depthBiasSlopeFactor)
+{
+   V3DV_FROM_HANDLE(v3dv_cmd_buffer, cmd_buffer, commandBuffer);
+
+   cmd_buffer->state.dynamic.depth_bias.constant_factor = depthBiasConstantFactor;
+   cmd_buffer->state.dynamic.depth_bias.slope_factor = depthBiasSlopeFactor;
+   cmd_buffer->state.dirty |= V3DV_CMD_DIRTY_DEPTH_BIAS;
+}
+
 void
 v3dv_CmdBindDescriptorSets(VkCommandBuffer commandBuffer,
                            VkPipelineBindPoint pipelineBindPoint,

src/broadcom/vulkan/v3dv_meta_clear.c

@@ -226,9 +226,9 @@ create_pipeline(struct v3dv_device *device,
             VK_DYNAMIC_STATE_STENCIL_WRITE_MASK,
             VK_DYNAMIC_STATE_STENCIL_REFERENCE,
             VK_DYNAMIC_STATE_BLEND_CONSTANTS,
+            VK_DYNAMIC_STATE_DEPTH_BIAS,
 #if 0
             VK_DYNAMIC_STATE_LINE_WIDTH,
-            VK_DYNAMIC_STATE_DEPTH_BIAS,
             VK_DYNAMIC_STATE_DEPTH_BOUNDS,
 #endif
          },

src/broadcom/vulkan/v3dv_meta_copy.c

@@ -3046,9 +3046,9 @@ create_pipeline(struct v3dv_device *device,
             VK_DYNAMIC_STATE_STENCIL_WRITE_MASK,
             VK_DYNAMIC_STATE_STENCIL_REFERENCE,
             VK_DYNAMIC_STATE_BLEND_CONSTANTS,
+            VK_DYNAMIC_STATE_DEPTH_BIAS,
 #if 0
             VK_DYNAMIC_STATE_LINE_WIDTH,
-            VK_DYNAMIC_STATE_DEPTH_BIAS,
             VK_DYNAMIC_STATE_DEPTH_BOUNDS,
 #endif
          },

src/broadcom/vulkan/v3dv_pipeline.c

@@ -1539,6 +1539,8 @@ v3dv_dynamic_state_mask(VkDynamicState state)
       return V3DV_DYNAMIC_STENCIL_REFERENCE;
    case VK_DYNAMIC_STATE_BLEND_CONSTANTS:
       return V3DV_DYNAMIC_BLEND_CONSTANTS;
+   case VK_DYNAMIC_STATE_DEPTH_BIAS:
+      return V3DV_DYNAMIC_DEPTH_BIAS;
    default:
       unreachable("Unhandled dynamic state");
    }
@@ -1590,7 +1592,6 @@ pipeline_init_dynamic_state(struct v3dv_pipeline *pipeline,
    }
 
    if (pCreateInfo->pDepthStencilState != NULL) {
-
       if (!(dynamic_states & V3DV_DYNAMIC_STENCIL_COMPARE_MASK)) {
          dynamic->stencil_compare_mask.front =
             pCreateInfo->pDepthStencilState->front.compareMask;
@@ -1620,6 +1621,17 @@ pipeline_init_dynamic_state(struct v3dv_pipeline *pipeline,
              sizeof(dynamic->blend_constants));
    }
 
+   if (pCreateInfo->pRasterizationState &&
+       !pCreateInfo->pRasterizationState->rasterizerDiscardEnable) {
+      if (pCreateInfo->pRasterizationState->depthBiasEnable &&
+          !(dynamic_states & V3DV_DYNAMIC_DEPTH_BIAS)) {
+         dynamic->depth_bias.constant_factor =
+            pCreateInfo->pRasterizationState->depthBiasConstantFactor;
+         dynamic->depth_bias.slope_factor =
+            pCreateInfo->pRasterizationState->depthBiasSlopeFactor;
+      }
+   }
+
    pipeline->dynamic_state.mask = dynamic_states;
 }
 
@@ -1930,6 +1942,44 @@ stencil_op_is_no_op(const VkStencilOpState *stencil)
           stencil->compareOp == VK_COMPARE_OP_ALWAYS;
 }
 
+static void
+enable_depth_bias(struct v3dv_pipeline *pipeline,
+                  const VkGraphicsPipelineCreateInfo *pInfo)
+{
+   assert(pInfo);
+
+   pipeline->depth_bias.enabled = false;
+   pipeline->depth_bias.is_z16 = false;
+
+   if (!pInfo->pRasterizationState ||
+       !pInfo->pRasterizationState->depthBiasEnable ||
+       pInfo->pRasterizationState->rasterizerDiscardEnable)
+      return;
+
+   /* Check the depth/stencil attachment description for the subpass used with
+    * this pipeline.
+    */
+   struct v3dv_render_pass *pass =
+      v3dv_render_pass_from_handle(pInfo->renderPass);
+   assert(pass);
+
+   assert(pInfo->subpass < pass->subpass_count);
+   struct v3dv_subpass *subpass = &pass->subpasses[pInfo->subpass];
+   assert(subpass);
+
+   if (subpass->ds_attachment.attachment == VK_ATTACHMENT_UNUSED)
+      return;
+
+   assert(subpass->ds_attachment.attachment < pass->attachment_count);
+   struct v3dv_render_pass_attachment *att =
+      &pass->attachments[subpass->ds_attachment.attachment];
+
+   if (att->desc.format == VK_FORMAT_D16_UNORM)
+      pipeline->depth_bias.is_z16 = true;
+
+   pipeline->depth_bias.enabled = true;
+}
+
 static void
 pipeline_set_ez_state(struct v3dv_pipeline *pipeline,
                       const VkPipelineDepthStencilStateCreateInfo *ds_info)
@@ -2267,6 +2317,7 @@ pipeline_init(struct v3dv_pipeline *pipeline,
    pack_cfg_bits(pipeline, ds_info, rs_info);
    pack_stencil_cfg(pipeline, ds_info);
    pipeline_set_ez_state(pipeline, ds_info);
+   enable_depth_bias(pipeline, pCreateInfo);
 
    pipeline->primitive_restart =
       pCreateInfo->pInputAssemblyState->primitiveRestartEnable;

src/broadcom/vulkan/v3dv_private.h

@@ -542,7 +542,8 @@ enum v3dv_dynamic_state_bits {
    V3DV_DYNAMIC_STENCIL_WRITE_MASK        = 1 << 3,
    V3DV_DYNAMIC_STENCIL_REFERENCE         = 1 << 4,
    V3DV_DYNAMIC_BLEND_CONSTANTS           = 1 << 5,
-   V3DV_DYNAMIC_ALL                       = (1 << 6) - 1,
+   V3DV_DYNAMIC_DEPTH_BIAS                = 1 << 6,
+   V3DV_DYNAMIC_ALL                       = (1 << 7) - 1,
 };
 
 /* Flags for dirty pipeline state.
@@ -560,6 +561,7 @@ enum v3dv_cmd_dirty_bits {
    V3DV_CMD_DIRTY_BLEND_CONSTANTS           = 1 << 9,
    V3DV_CMD_DIRTY_SHADER_VARIANTS           = 1 << 10,
    V3DV_CMD_DIRTY_OCCLUSION_QUERY           = 1 << 11,
+   V3DV_CMD_DIRTY_DEPTH_BIAS                = 1 << 12,
 };
 
 
@@ -590,6 +592,11 @@ struct v3dv_dynamic_state {
    } stencil_reference;
 
    float blend_constants[4];
+
+   struct {
+      float constant_factor;
+      float slope_factor;
+   } depth_bias;
 };
 
 extern const struct v3dv_dynamic_state default_dynamic_state;
@@ -1297,6 +1304,12 @@ struct v3dv_pipeline {
       uint32_t color_write_masks;
    } blend;
 
+   /* Depth bias */
+   struct {
+      bool enabled;
+      bool is_z16;
+   } depth_bias;
+
    /* Packets prepacked during pipeline creation
     */
    uint8_t cfg_bits[cl_packet_length(CFG_BITS)];