Reuse vertex array objects for common structures with DSA

Slashes the number of VAOs required and the amount of setup required.

4 files changed, 51 insertions, 35 deletions

diff --git a/game/scenary/foliage.cpp b/game/scenary/foliage.cpp
index b5b409e..ff00af4 100644
--- a/game/scenary/foliage.cpp
+++ b/game/scenary/foliage.cpp
@@ -20,6 +20,8 @@ namespace {
 	}
 }
 
+std::weak_ptr<glVertexArray> Foliage::commonInstanceVAO, Foliage::commonInstancePointVAO;
+
 std::any
 Foliage::createAt(const Location & position) const
 {
@@ -38,10 +40,15 @@ Foliage::postLoad()
 {
 	texture = getTexture();
 	glDebugScope _ {0};
-	bodyMesh->configureVAO(instanceVAO, 0)
-			.addAttribs<LocationVertex, &LocationVertex::rotation, &LocationVertex::position>(1);
-	instancePointVAO.configure().addAttribs<LocationVertex, &LocationVertex::position, &LocationVertex::yaw>(0);
-
+	if (!(instanceVAO = commonInstanceVAO.lock())) {
+		commonInstanceVAO = instanceVAO = std::make_shared<glVertexArray>();
+		bodyMesh->configureVAO(*instanceVAO, 0)
+				.addAttribs<LocationVertex, &LocationVertex::rotation, &LocationVertex::position>(1);
+	}
+	if (!(instancePointVAO = commonInstancePointVAO.lock())) {
+		commonInstancePointVAO = instancePointVAO = std::make_shared<glVertexArray>();
+		instancePointVAO->configure().addAttribs<LocationVertex, &LocationVertex::position, &LocationVertex::yaw>(0);
+	}
 	const auto & size = bodyMesh->getDimensions().size;
 	billboardSize = billboardTextureSizeForObject(size);
 	ShadowStenciller::configureStencilTexture(shadowStencil, {billboardSize, billboardSize});
@@ -93,7 +100,7 @@ void
 Foliage::render(const SceneShader & shader, const Frustum &) const
 {
 	if (instancePartitions.first) {
-		glDebugScope _ {instanceVAO};
+		glDebugScope _ {*instanceVAO};
 		std::ignore = instances.size();
 		if (const auto count = instancePartitions.first - instancePartitions.second.first) {
 			glDebugScope _ {0, "Billboard"};
@@ -102,8 +109,8 @@ Foliage::render(const SceneShader & shader, const Frustum &) const
 			billboard[0].bind(0);
 			billboard[1].bind(1);
 			billboard[2].bind(2);
-			glBindVertexArray(instancePointVAO);
-			instancePointVAO.useBuffer(0, instances);
+			glBindVertexArray(*instancePointVAO);
+			instancePointVAO->useBuffer(0, instances);
 			glDrawArrays(GL_POINTS, static_cast<GLint>(instancePartitions.second.first), static_cast<GLsizei>(count));
 			glBindVertexArray(0);
 		}
@@ -113,8 +120,8 @@ Foliage::render(const SceneShader & shader, const Frustum &) const
 			if (texture) {
 				texture->bind(0);
 			}
-			instanceVAO.useBuffer(1, instances);
-			bodyMesh->drawInstanced(instanceVAO, static_cast<GLsizei>(count));
+			instanceVAO->useBuffer(1, instances);
+			bodyMesh->drawInstanced(*instanceVAO, static_cast<GLsizei>(count));
 		}
 	}
 }
@@ -123,15 +130,15 @@ void
 Foliage::shadows(const ShadowMapper & mapper, const Frustum &) const
 {
 	if (instancePartitions.second.second) {
-		glDebugScope _ {instanceVAO};
+		glDebugScope _ {*instanceVAO};
 		std::ignore = instances.size();
 		if (const auto count = instancePartitions.second.second - instancePartitions.second.first) {
 			glDebugScope _ {0, "Billboard"};
 			const auto dimensions = bodyMesh->getDimensions();
 			mapper.stencilShadowProgram.use(dimensions.centre, dimensions.size);
 			shadowStencil.bind(0);
-			glBindVertexArray(instancePointVAO);
-			instancePointVAO.useBuffer(0, instances);
+			glBindVertexArray(*instancePointVAO);
+			instancePointVAO->useBuffer(0, instances);
 			glDrawArrays(GL_POINTS, static_cast<GLint>(instancePartitions.second.first), static_cast<GLsizei>(count));
 			glBindVertexArray(0);
 		}
@@ -144,8 +151,8 @@ Foliage::shadows(const ShadowMapper & mapper, const Frustum &) const
 			else {
 				mapper.dynamicPointInst.use();
 			}
-			instanceVAO.useBuffer(1, instances);
-			bodyMesh->drawInstanced(instanceVAO, static_cast<GLsizei>(count));
+			instanceVAO->useBuffer(1, instances);
+			bodyMesh->drawInstanced(*instanceVAO, static_cast<GLsizei>(count));
 		}
 	}
 }
diff --git a/game/scenary/foliage.h b/game/scenary/foliage.h
index bf98d55..c599649 100644
--- a/game/scenary/foliage.h
+++ b/game/scenary/foliage.h
@@ -12,8 +12,8 @@ class Location;
 class Foliage : public Asset, public Renderable, public StdTypeDefs<Foliage> {
 	Mesh::Ptr bodyMesh;
 	Texture::Ptr texture;
-	glVertexArray instanceVAO;
-	glVertexArray instancePointVAO;
+	std::shared_ptr<glVertexArray> instanceVAO, instancePointVAO;
+	static std::weak_ptr<glVertexArray> commonInstanceVAO, commonInstancePointVAO;
 
 public:
 	[[nodiscard]] std::any createAt(const Location &) const override;
diff --git a/game/scenary/illuminator.cpp b/game/scenary/illuminator.cpp
index a0ea5be..4398853 100644
--- a/game/scenary/illuminator.cpp
+++ b/game/scenary/illuminator.cpp
@@ -5,6 +5,9 @@
 
 static_assert(std::is_constructible_v<Illuminator>);
 
+std::weak_ptr<glVertexArray> Illuminator::commonInstanceVAO, Illuminator::commonInstancesSpotLightVAO,
+		Illuminator::commonInstancesPointLightVAO;
+
 std::any
 Illuminator::createAt(const Location & position) const
 {
@@ -41,25 +44,32 @@ Illuminator::postLoad()
 	}
 	texture = getTexture();
 	glDebugScope _ {0};
-	bodyMesh->configureVAO(instanceVAO, 0)
-			.addAttribs<LocationVertex, &LocationVertex::first, &LocationVertex::second>(1);
-	if (!spotLight.empty()) {
-		instancesSpotLightVAO.emplace();
-		instancesSpotLightVAO->configure()
-				.addAttribs<SpotLightVertex, &SpotLightVertex::position, &SpotLightVertex::direction,
-						&SpotLightVertex::colour, &SpotLightVertex::kq, &SpotLightVertex::arc>(0)
+	if (!(instanceVAO = commonInstanceVAO.lock())) {
+		commonInstanceVAO = instanceVAO = std::make_shared<glVertexArray>();
+		bodyMesh->configureVAO(*instanceVAO, 0)
 				.addAttribs<LocationVertex, &LocationVertex::first, &LocationVertex::second>(1);
+	}
+	if (!spotLight.empty()) {
+		if (!(instancesSpotLightVAO = commonInstancesSpotLightVAO.lock())) {
+			commonInstancesSpotLightVAO = instancesSpotLightVAO = std::make_shared<glVertexArray>();
+			instancesSpotLightVAO->configure()
+					.addAttribs<SpotLightVertex, &SpotLightVertex::position, &SpotLightVertex::direction,
+							&SpotLightVertex::colour, &SpotLightVertex::kq, &SpotLightVertex::arc>(0)
+					.addAttribs<LocationVertex, &LocationVertex::first, &LocationVertex::second>(1);
+		}
 		std::transform(
 				spotLight.begin(), spotLight.end(), std::back_inserter(spotLightInstances), [this](const auto & s) {
 					return instancesSpotLight.acquire(*s);
 				});
 	}
 	if (!pointLight.empty()) {
-		instancesPointLightVAO.emplace();
-		instancesPointLightVAO->configure()
-				.addAttribs<PointLightVertex, &PointLightVertex::position, &PointLightVertex::colour,
-						&PointLightVertex::kq>(0)
-				.addAttribs<LocationVertex, &LocationVertex::first, &LocationVertex::second>(1);
+		if (!(instancesPointLightVAO = commonInstancesPointLightVAO.lock())) {
+			commonInstancesPointLightVAO = instancesPointLightVAO = std::make_shared<glVertexArray>();
+			instancesPointLightVAO->configure()
+					.addAttribs<PointLightVertex, &PointLightVertex::position, &PointLightVertex::colour,
+							&PointLightVertex::kq>(0)
+					.addAttribs<LocationVertex, &LocationVertex::first, &LocationVertex::second>(1);
+		}
 		std::transform(
 				pointLight.begin(), pointLight.end(), std::back_inserter(pointLightInstances), [this](const auto & s) {
 					return instancesPointLight.acquire(*s);
@@ -71,13 +81,13 @@ void
 Illuminator::render(const SceneShader & shader, const Frustum &) const
 {
 	if (const auto count = instances.size()) {
-		glDebugScope _ {instanceVAO};
+		glDebugScope _ {*instanceVAO};
 		shader.basicInst.use();
 		if (texture) {
 			texture->bind(0);
 		}
-		instanceVAO.useBuffer(1, instances);
-		bodyMesh->drawInstanced(instanceVAO, static_cast<GLsizei>(count));
+		instanceVAO->useBuffer(1, instances);
+		bodyMesh->drawInstanced(*instanceVAO, static_cast<GLsizei>(count));
 	}
 }
 
@@ -85,7 +95,7 @@ void
 Illuminator::lights(const SceneShader & shader) const
 {
 	if (const auto count = instances.size()) {
-		glDebugScope _ {instanceVAO};
+		glDebugScope _ {*instanceVAO};
 		if (const auto scount = instancesSpotLight.size()) {
 			glDebugScope _ {*instancesSpotLightVAO, "Spot lights"};
 			shader.spotLightInst.use();
diff --git a/game/scenary/illuminator.h b/game/scenary/illuminator.h
index 200ba40..7b6e7ad 100644
--- a/game/scenary/illuminator.h
+++ b/game/scenary/illuminator.h
@@ -11,8 +11,8 @@ class Location;
 class Illuminator : public Asset, public Renderable, public StdTypeDefs<Illuminator> {
 	Mesh::Ptr bodyMesh;
 	Texture::Ptr texture;
-	glVertexArray instanceVAO;
-	std::optional<glVertexArray> instancesSpotLightVAO, instancesPointLightVAO;
+	std::shared_ptr<glVertexArray> instanceVAO, instancesSpotLightVAO, instancesPointLightVAO;
+	static std::weak_ptr<glVertexArray> commonInstanceVAO, commonInstancesSpotLightVAO, commonInstancesPointLightVAO;
 
 public:
 	[[nodiscard]] std::any createAt(const Location &) const override;
@@ -42,7 +42,6 @@ public:
 		bool persist(Persistence::PersistenceStore & store) override;
 	};
 
-public:
 	using LocationVertex = std::pair<glm::mat3, GlobalPosition3D>;
 	mutable InstanceVertices<LocationVertex> instances;
 	mutable InstanceVertices<SpotLightVertex> instancesSpotLight;