Grass Collision: Performance and visual improvements

doodlum · Mar 27, 2023 · 011ba45 · 011ba45
1 parent 0c69d7a
commit 011ba45
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Showing 4 changed files with 43 additions and 16 deletions.
diff --git a/features/Grass Collision/Shaders/Features/GrassCollision.ini b/features/Grass Collision/Shaders/Features/GrassCollision.ini
@@ -1,2 +1,2 @@
 [Info]
-Version = 1-0-0
+Version = 1-0-1
diff --git a/features/Grass Collision/Shaders/RunGrass/GrassCollision.hlsli b/features/Grass Collision/Shaders/RunGrass/GrassCollision.hlsli
@@ -1,6 +1,8 @@
 
 cbuffer GrassCollisionPerFrame : register(b4)
 {
+	float3 boundCentre;
+	float boundRadius;
 	bool  EnableGrassCollision;
 	float RadiusMultiplier;
 	float DisplacementMultiplier;
@@ -16,28 +18,36 @@ StructuredBuffer<StructuredCollision> collisions : register(t0);
 
 float3 GetDisplacedPosition(float3 position, float alpha)
 {		
+	float3 worldPosition = mul(World, float4(position, 1)).xyz;
 	float3 displacement = 0;
-
+
+	// Player bound culling
+	{
+		float dist = distance(boundCentre, worldPosition);
+		if (dist > boundRadius)
+		{
+			return 0;
+		}
+	}
+
 	if (EnableGrassCollision){
 		uint counter = 0;
 		uint collision_count, dummy;
 		collisions.GetDimensions(collision_count, dummy);
 		for (uint collision_index = 0; collision_index < collision_count; collision_index++)
 		{
-			float3 worldPosition = mul(World, float4(position, 1)).xyz;
-
 			StructuredCollision collision = collisions[collision_index];
-			collision.radius *= RadiusMultiplier;
 
 			float dist = distance(collision.centre, worldPosition);
 			float power = smoothstep(collision.radius, 0.0, dist);
 			float3 direction = worldPosition - collision.centre;
+			direction.y = 0; // stops expanding/stretching
 			direction = normalize(direction);
-			float3 shift = direction * power * alpha;
-			shift.z = -abs(shift.z);
-			displacement += shift.xyz * DisplacementMultiplier;
+			float3 shift = power * direction;
+			shift.z -= power; // bias downwards
+			displacement += shift.xyz;
 		}
 	}
 
-	return displacement;
+	return displacement * saturate(alpha * alpha * 5) * DisplacementMultiplier;
 }
diff --git a/src/Features/GrassCollision.cpp b/src/Features/GrassCollision.cpp
@@ -15,15 +15,18 @@ void GrassCollision::DrawSettings()
 	if (ImGui::BeginTabItem("Grass Collision")) {
 		if (ImGui::TreeNodeEx("Grass Collision", ImGuiTreeNodeFlags_DefaultOpen)) {
 			ImGui::Text("Allows player collision to modify grass position.");
+
 			ImGui::Checkbox("Enable Grass Collision", (bool*)&settings.EnableGrassCollision);
 			ImGui::Text("Distance from collision centres to apply collision");
 			ImGui::SliderFloat("Radius Multiplier", &settings.RadiusMultiplier, 0.0f, 8.0f);
+
 			ImGui::Text("Strength of each collision on grass position.");
 			ImGui::SliderFloat("Displacement Multiplier", &settings.DisplacementMultiplier, 0.0f, 16.0f);
+
 			ImGui::TreePop();
 		}
-		ImGui::EndTabItem();
 
+		ImGui::EndTabItem();
 	}
 }
 
@@ -49,7 +52,7 @@ static bool GetShapeBound(RE::NiAVObject* a_node, RE::NiPoint3& centerPos, float
 		if (shape) {
 			float upExtent = shape->GetMaximumProjection(RE::hkVector4{ 0.0f, 0.0f, 1.0f, 0.0f }) * RE::bhkWorld::GetWorldScaleInverse();
 			float downExtent = shape->GetMaximumProjection(RE::hkVector4{ 0.0f, 0.0f, -1.0f, 0.0f }) * RE::bhkWorld::GetWorldScaleInverse();
-			auto z_extent = upExtent + downExtent;
+			auto z_extent = (upExtent + downExtent) / 2.0f;
 
 			float forwardExtent = shape->GetMaximumProjection(RE::hkVector4{ 0.0f, 1.0f, 0.0f, 0.0f }) * RE::bhkWorld::GetWorldScaleInverse();
 			float backwardExtent = shape->GetMaximumProjection(RE::hkVector4{ 0.0f, -1.0f, 0.0f, 0.0f }) * RE::bhkWorld::GetWorldScaleInverse();
@@ -86,7 +89,7 @@ static bool GetShapeBound(RE::bhkNiCollisionObject* Colliedobj, RE::NiPoint3& ce
 		if (shape) {
 			float upExtent = shape->GetMaximumProjection(RE::hkVector4{ 0.0f, 0.0f, 1.0f, 0.0f }) * RE::bhkWorld::GetWorldScaleInverse();
 			float downExtent = shape->GetMaximumProjection(RE::hkVector4{ 0.0f, 0.0f, -1.0f, 0.0f }) * RE::bhkWorld::GetWorldScaleInverse();
-			auto z_extent = upExtent + downExtent;
+			auto z_extent = (upExtent + downExtent) / 2.0f;
 
 			float forwardExtent = shape->GetMaximumProjection(RE::hkVector4{ 0.0f, 1.0f, 0.0f, 0.0f }) * RE::bhkWorld::GetWorldScaleInverse();
 			float backwardExtent = shape->GetMaximumProjection(RE::hkVector4{ 0.0f, -1.0f, 0.0f, 0.0f }) * RE::bhkWorld::GetWorldScaleInverse();
@@ -114,12 +117,13 @@ void GrassCollision::UpdateCollisions()
 	std::vector<CollisionSData> collisionsData{};
 
 	if (auto player = RE::PlayerCharacter::GetSingleton()) {
-		using namespace RE;
 		if (auto root = player->Get3D(false)) {
-			BSVisit::TraverseScenegraphCollision(root, [&](bhkNiCollisionObject* a_object) -> BSVisit::BSVisitControl {
+			auto position = player->GetPosition();
+			RE::BSVisit::TraverseScenegraphCollision(root, [&](RE::bhkNiCollisionObject* a_object) -> RE::BSVisit::BSVisitControl {
 				RE::NiPoint3 centerPos;
 				float radius;
 				if (GetShapeBound(a_object, centerPos, radius)) {
+					radius *= settings.RadiusMultiplier;
 					CollisionSData data{};
 					data.centre.x = centerPos.x - state->m_PosAdjust.x;
 					data.centre.y = centerPos.y - state->m_PosAdjust.y;
@@ -128,7 +132,7 @@ void GrassCollision::UpdateCollisions()
 					currentCollisionCount++;
 					collisionsData.push_back(data);
 				}
-				return BSVisit::BSVisitControl::kContinue;
+				return RE::BSVisit::BSVisitControl::kContinue;
 			});
 		}
 	}
@@ -174,11 +178,22 @@ void GrassCollision::UpdateCollisions()
 void GrassCollision::ModifyGrass(const RE::BSShader*, const uint32_t)
 {
 	if (updatePerFrame) {
-		UpdateCollisions();
+		if (settings.EnableGrassCollision) {
+			UpdateCollisions();
+		}
 
 		PerFrame perFrameData{};
 		ZeroMemory(&perFrameData, sizeof(perFrameData));
 
+		auto state = BSGraphics::RendererShadowState::QInstance();
+		auto shaderState = BSGraphics::ShaderState::QInstance();
+
+		auto bound = shaderState->kCachedPlayerBound;
+		perFrameData.boundCentre.x = bound.center.x - state->m_PosAdjust.x;
+		perFrameData.boundCentre.y = bound.center.y - state->m_PosAdjust.y;
+		perFrameData.boundCentre.z = bound.center.z - state->m_PosAdjust.z;
+		perFrameData.boundRadius = bound.radius * settings.RadiusMultiplier;
+
 		perFrameData.Settings = settings;
 
 		perFrame->Update(perFrameData);

diff --git a/src/Features/GrassCollision.h b/src/Features/GrassCollision.h
@@ -25,6 +25,8 @@ class GrassCollision
 
 	struct alignas(16) PerFrame
 	{
+		DirectX::XMFLOAT3 boundCentre;
+		float boundRadius;
 		Settings Settings;
 		float pad0;
 	};