From 0c4cf3b9eb7de6624a844ae9ac9d2ba6b2ef3ac2 Mon Sep 17 00:00:00 2001
From: FernandoS27 <fsahmkow27@gmail.com>
Date: Tue, 30 Mar 2021 21:52:06 +0200
Subject: [PATCH] shader: Implement ClipDistance

---
 .../backend/spirv/emit_context.cpp                  |  9 +++++++++
 src/shader_recompiler/backend/spirv/emit_context.h  |  3 +++
 .../backend/spirv/emit_spirv_context_get_set.cpp    | 13 +++++++++++++
 .../ir_opt/collect_shader_info_pass.cpp             | 10 ++++++++++
 src/shader_recompiler/shader_info.h                 |  1 +
 5 files changed, 36 insertions(+)

diff --git a/src/shader_recompiler/backend/spirv/emit_context.cpp b/src/shader_recompiler/backend/spirv/emit_context.cpp
index c8ce58254..2e3e3346d 100644
--- a/src/shader_recompiler/backend/spirv/emit_context.cpp
+++ b/src/shader_recompiler/backend/spirv/emit_context.cpp
@@ -176,6 +176,9 @@ void EmitContext::DefineCommonTypes(const Info& info) {
         AddCapability(spv::Capability::Float64);
         F64.Define(*this, TypeFloat(64), "f64");
     }
+    if (info.stores_clip_distance) {
+      Array8F32 = Name(TypeArray(F32[1], Constant(U32[1], 8)), "array_8_f32");
+    }
 }
 
 void EmitContext::DefineCommonConstants() {
@@ -502,6 +505,12 @@ void EmitContext::DefineOutputs(const Info& info) {
         }
         output_point_size = DefineOutput(*this, F32[1], spv::BuiltIn::PointSize);
     }
+    if (info.stores_clip_distance) {
+        if (stage == Stage::Fragment) {
+            throw NotImplementedException("Storing PointSize in Fragment stage");
+        }
+        clip_distances = DefineOutput(*this, Array8F32, spv::BuiltIn::ClipDistance);
+    }
     for (size_t i = 0; i < info.stores_generics.size(); ++i) {
         if (info.stores_generics[i]) {
             output_generics[i] = DefineOutput(*this, F32[4]);
diff --git a/src/shader_recompiler/backend/spirv/emit_context.h b/src/shader_recompiler/backend/spirv/emit_context.h
index 3965869f0..bffe1558c 100644
--- a/src/shader_recompiler/backend/spirv/emit_context.h
+++ b/src/shader_recompiler/backend/spirv/emit_context.h
@@ -67,6 +67,8 @@ public:
     VectorTypes F16;
     VectorTypes F64;
 
+    Id Array8F32{};
+
     Id true_value{};
     Id false_value{};
     Id u32_zero_value{};
@@ -105,6 +107,7 @@ public:
     Id base_vertex{};
     Id front_face{};
     Id point_coord{};
+    Id clip_distances{};
 
     Id fswzadd_lut_a{};
     Id fswzadd_lut_b{};
diff --git a/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp b/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
index d02761f32..2eaeb29de 100644
--- a/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
+++ b/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
@@ -44,6 +44,19 @@ Id OutputAttrPointer(EmitContext& ctx, IR::Attribute attr) {
     case IR::Attribute::PositionZ:
     case IR::Attribute::PositionW:
         return ctx.OpAccessChain(ctx.output_f32, ctx.output_position, element_id());
+    case IR::Attribute::ClipDistance0:
+    case IR::Attribute::ClipDistance1:
+    case IR::Attribute::ClipDistance2:
+    case IR::Attribute::ClipDistance3:
+    case IR::Attribute::ClipDistance4:
+    case IR::Attribute::ClipDistance5:
+    case IR::Attribute::ClipDistance6:
+    case IR::Attribute::ClipDistance7: {
+        const u32 base{static_cast<u32>(IR::Attribute::ClipDistance0)};
+        const u32 index{static_cast<u32>(attr) - base};
+        const Id clip_num{ctx.Constant(ctx.U32[1], index)};
+        return ctx.OpAccessChain(ctx.output_f32, ctx.clip_distances, clip_num);
+    }
     default:
         throw NotImplementedException("Read attribute {}", attr);
     }
diff --git a/src/shader_recompiler/ir_opt/collect_shader_info_pass.cpp b/src/shader_recompiler/ir_opt/collect_shader_info_pass.cpp
index 730d3e91e..50ffc4c19 100644
--- a/src/shader_recompiler/ir_opt/collect_shader_info_pass.cpp
+++ b/src/shader_recompiler/ir_opt/collect_shader_info_pass.cpp
@@ -71,6 +71,16 @@ void SetAttribute(Info& info, IR::Attribute attribute) {
     case IR::Attribute::PositionW:
         info.stores_position = true;
         break;
+    case IR::Attribute::ClipDistance0:
+    case IR::Attribute::ClipDistance1:
+    case IR::Attribute::ClipDistance2:
+    case IR::Attribute::ClipDistance3:
+    case IR::Attribute::ClipDistance4:
+    case IR::Attribute::ClipDistance5:
+    case IR::Attribute::ClipDistance6:
+    case IR::Attribute::ClipDistance7:
+        info.stores_clip_distance = true;
+        break;
     default:
         throw NotImplementedException("Set attribute {}", attribute);
     }
diff --git a/src/shader_recompiler/shader_info.h b/src/shader_recompiler/shader_info.h
index c9f6d9ef7..a62ad1e79 100644
--- a/src/shader_recompiler/shader_info.h
+++ b/src/shader_recompiler/shader_info.h
@@ -81,6 +81,7 @@ struct Info {
     std::array<bool, 32> stores_generics{};
     bool stores_position{};
     bool stores_point_size{};
+    bool stores_clip_distance{};
 
     bool uses_fp16{};
     bool uses_fp64{};