Fixed random seed when run in benchmark mode, use default random engine instead of fixed mersene twister

Refs #269

examples/computecloth/computecloth.cpp

@@ -115,7 +115,6 @@ public:
 		camera.setRotation(glm::vec3(-30.0f, -45.0f, 0.0f));
 		camera.setTranslation(glm::vec3(0.0f, 0.0f, -3.5f));
 		settings.overlay = true;
-		srand((unsigned int)time(NULL));
 	}
 
 	~VulkanExample()
@@ -669,12 +668,11 @@ public:
 			// todo: base on frametime
 			//compute.ubo.deltaT = frameTimer * 0.0075f;
 
-			std::mt19937 rg((unsigned)time(nullptr));
-			std::uniform_real_distribution<float> rd(1.0f, 6.0f);
-
 			if (simulateWind) {
-				compute.ubo.gravity.x = cos(glm::radians(-timer * 360.0f)) * (rd(rg) - rd(rg));
+				std::default_random_engine rndEngine(benchmark.active ? 0 : (unsigned)time(nullptr));
-				compute.ubo.gravity.z = sin(glm::radians(timer * 360.0f)) * (rd(rg) - rd(rg));
+				std::uniform_real_distribution<float> rd(1.0f, 6.0f);
+				compute.ubo.gravity.x = cos(glm::radians(-timer * 360.0f)) * (rd(rndEngine) - rd(rndEngine));
+				compute.ubo.gravity.z = sin(glm::radians(timer * 360.0f)) * (rd(rndEngine) - rd(rndEngine));
 			}
 			else {
 				compute.ubo.gravity.x = 0.0f;

examples/computenbody/computenbody.cpp

@@ -289,7 +289,7 @@ public:
 		// Initial particle positions
 		std::vector<Particle> particleBuffer(numParticles);
 
-		std::mt19937 rndGen(static_cast<uint32_t>(time(0)));
+		std::default_random_engine rndEngine(benchmark.active ? 0 : (unsigned)time(nullptr));
 		std::normal_distribution<float> rndDist(0.0f, 1.0f);
 
 		for (uint32_t i = 0; i < static_cast<uint32_t>(attractors.size()); i++)
@@ -307,15 +307,15 @@ public:
 				else
 				{
 					// Position					
-					glm::vec3 position(attractors[i] + glm::vec3(rndDist(rndGen), rndDist(rndGen), rndDist(rndGen)) * 0.75f);
+					glm::vec3 position(attractors[i] + glm::vec3(rndDist(rndEngine), rndDist(rndEngine), rndDist(rndEngine)) * 0.75f);
 					float len = glm::length(glm::normalize(position - attractors[i]));
 					position.y *= 2.0f - (len * len);
 
 					// Velocity
 					glm::vec3 angular = glm::vec3(0.5f, 1.5f, 0.5f) * (((i % 2) == 0) ? 1.0f : -1.0f);
-					glm::vec3 velocity = glm::cross((position - attractors[i]), angular) + glm::vec3(rndDist(rndGen), rndDist(rndGen), rndDist(rndGen) * 0.025f);
+					glm::vec3 velocity = glm::cross((position - attractors[i]), angular) + glm::vec3(rndDist(rndEngine), rndDist(rndEngine), rndDist(rndEngine) * 0.025f);
 
-					float mass = (rndDist(rndGen) * 0.5f + 0.5f) * 75.0f;
+					float mass = (rndDist(rndEngine) * 0.5f + 0.5f) * 75.0f;
 					particle.pos = glm::vec4(position, mass);
 					particle.vel = glm::vec4(velocity, 0.0f);
 				}

examples/computeparticles/computeparticles.cpp

@@ -233,14 +233,13 @@ public:
 	// Setup and fill the compute shader storage buffers containing the particles
 	void prepareStorageBuffers()
 	{
-		std::mt19937 rGenerator;
+		std::default_random_engine rndEngine(benchmark.active ? 0 : (unsigned)time(nullptr));
-		std::uniform_real_distribution<float> rDistribution(-1.0f, 1.0f);
+		std::uniform_real_distribution<float> rndDist(-1.0f, 1.0f);
 
 		// Initial particle positions
 		std::vector<Particle> particleBuffer(PARTICLE_COUNT);
-		for (auto& particle : particleBuffer)
+		for (auto& particle : particleBuffer) {
-		{
+			particle.pos = glm::vec2(rndDist(rndEngine), rndDist(rndEngine));
-			particle.pos = glm::vec2(rDistribution(rGenerator), rDistribution(rGenerator));
 			particle.vel = glm::vec2(0.0f);
 			particle.gradientPos.x = particle.pos.x / 2.0f;
 		}

examples/dynamicuniformbuffer/dynamicuniformbuffer.cpp

@@ -446,12 +446,11 @@ public:
 		VK_CHECK_RESULT(uniformBuffers.dynamic.map());
 
 		// Prepare per-object matrices with offsets and random rotations
-		std::mt19937 rndGen(static_cast<uint32_t>(time(0)));
+		std::default_random_engine rndEngine(benchmark.active ? 0 : (unsigned)time(nullptr));
 		std::normal_distribution<float> rndDist(-1.0f, 1.0f);
-		for (uint32_t i = 0; i < OBJECT_INSTANCES; i++)
+		for (uint32_t i = 0; i < OBJECT_INSTANCES; i++) {
-		{
+			rotations[i] = glm::vec3(rndDist(rndEngine), rndDist(rndEngine), rndDist(rndEngine)) * 2.0f * (float)M_PI;
-			rotations[i] = glm::vec3(rndDist(rndGen), rndDist(rndGen), rndDist(rndGen)) * 2.0f * (float)M_PI;
+			rotationSpeeds[i] = glm::vec3(rndDist(rndEngine), rndDist(rndEngine), rndDist(rndEngine));
-			rotationSpeeds[i] = glm::vec3(rndDist(rndGen), rndDist(rndGen), rndDist(rndGen));
 		}
 
 		updateUniformBuffers();

examples/indirectdraw/indirectdraw.cpp

@@ -594,16 +594,15 @@ public:
 		std::vector<InstanceData> instanceData;
 		instanceData.resize(objectCount);
 
-		std::mt19937 rndGenerator((unsigned)time(NULL));
+		std::default_random_engine rndEngine(benchmark.active ? 0 : (unsigned)time(nullptr));
 		std::uniform_real_distribution<float> uniformDist(0.0f, 1.0f);
 
-		for (uint32_t i = 0; i < objectCount; i++)
+		for (uint32_t i = 0; i < objectCount; i++) {
-		{
+			instanceData[i].rot = glm::vec3(0.0f, float(M_PI) * uniformDist(rndEngine), 0.0f);
-			instanceData[i].rot = glm::vec3(0.0f, float(M_PI) * uniformDist(rndGenerator), 0.0f);
+			float theta = 2 * float(M_PI) * uniformDist(rndEngine);
-			float theta = 2 * float(M_PI) * uniformDist(rndGenerator);
+			float phi = acos(1 - 2 * uniformDist(rndEngine));
-			float phi = acos(1 - 2 * uniformDist(rndGenerator));
 			instanceData[i].pos = glm::vec3(sin(phi) * cos(theta), 0.0f, cos(phi)) * PLANT_RADIUS;
-			instanceData[i].scale = 1.0f + uniformDist(rndGenerator) * 2.0f;
+			instanceData[i].scale = 1.0f + uniformDist(rndEngine) * 2.0f;
 			instanceData[i].texIndex = i / OBJECT_INSTANCE_COUNT;
 		}
 

examples/instancing/instancing.cpp

@@ -441,7 +441,7 @@ public:
 		std::vector<InstanceData> instanceData;
 		instanceData.resize(INSTANCE_COUNT);
 
-		std::mt19937 rndGenerator(benchmark.active ? 0 : (unsigned)time(NULL));
+		std::default_random_engine rndGenerator(benchmark.active ? 0 : (unsigned)time(nullptr));
 		std::uniform_real_distribution<float> uniformDist(0.0, 1.0);
 		std::uniform_int_distribution<uint32_t> rndTextureIndex(0, textures.rocks.layerCount);
 

examples/multithreading/multithreading.cpp

@@ -118,6 +118,8 @@ public:
 	// View frustum for culling invisible objects
 	vks::Frustum frustum;
 
+	std::default_random_engine rndEngine;
+
 	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
 	{
 		zoom = -32.5f;
@@ -134,11 +136,10 @@ public:
 #else
 		std::cout << "numThreads = " << numThreads << std::endl;
 #endif
-		srand(time(NULL));
-
 		threadPool.setThreadCount(numThreads);
-
 		numObjectsPerThread = 512 / numThreads;
+		rndEngine.seed(benchmark.active ? 0 : (unsigned)time(nullptr));
+		paused = true;
 	}
 
 	~VulkanExample()
@@ -167,7 +168,8 @@ public:
 
 	float rnd(float range)
 	{
-		return range * (rand() / double(RAND_MAX));
+		std::uniform_real_distribution<float> rndDist(0.0f, range);
+		return rndDist(rndEngine);
 	}
 
 	// Create all threads and initialize shader push constants
@@ -193,11 +195,7 @@ public:
 		uint32_t posX = 0;
 		uint32_t posZ = 0;
 
-		std::mt19937 rndGenerator((unsigned)time(NULL));
+		for (uint32_t i = 0; i < numThreads; i++) {
-		std::uniform_real_distribution<float> uniformDist(0.0f, 1.0f);
-
-		for (uint32_t i = 0; i < numThreads; i++)
-		{
 			ThreadData *thread = &threadData[i];
 			
 			// Create one command pool for each thread
@@ -219,10 +217,9 @@ public:
 			thread->pushConstBlock.resize(numObjectsPerThread);
 			thread->objectData.resize(numObjectsPerThread);
 
-			for (uint32_t j = 0; j < numObjectsPerThread; j++)
+			for (uint32_t j = 0; j < numObjectsPerThread; j++) {
-			{
+				float theta = 2.0f * float(M_PI) * rnd(1.0f);
-				float theta = 2.0f * float(M_PI) * uniformDist(rndGenerator);
+				float phi = acos(1.0f - 2.0f * rnd(1.0f));
-				float phi = acos(1.0f - 2.0f * uniformDist(rndGenerator));
 				thread->objectData[j].pos = glm::vec3(sin(phi) * cos(theta), 0.0f, cos(phi)) * 35.0f;
 
 				thread->objectData[j].rotation = glm::vec3(0.0f, rnd(360.0f), 0.0f);
@@ -268,15 +265,16 @@ public:
 		vkCmdBindPipeline(cmdBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.phong);
 
 		// Update
-		objectData->rotation.y += 2.5f * objectData->rotationSpeed * frameTimer;
+		if (!paused) {
-		if (objectData->rotation.y > 360.0f)
+			objectData->rotation.y += 2.5f * objectData->rotationSpeed * frameTimer;
-		{
+			if (objectData->rotation.y > 360.0f) {
-			objectData->rotation.y -= 360.0f;
+				objectData->rotation.y -= 360.0f;
+			}
+			objectData->deltaT += 0.15f * frameTimer;
+			if (objectData->deltaT > 1.0f)
+				objectData->deltaT -= 1.0f;
+			objectData->pos.y = sin(glm::radians(objectData->deltaT * 360.0f)) * 2.5f;
 		}
-		objectData->deltaT += 0.15f * frameTimer;
-		if (objectData->deltaT > 1.0f)
-			objectData->deltaT -= 1.0f;
-		objectData->pos.y = sin(glm::radians(objectData->deltaT * 360.0f)) * 2.5f;
 
 		objectData->model = glm::translate(glm::mat4(1.0f), objectData->pos);
 		objectData->model = glm::rotate(objectData->model, -sinf(glm::radians(objectData->deltaT * 360.0f)) * 0.25f, glm::vec3(objectData->rotationDir, 0.0f, 0.0f));
@@ -593,8 +591,7 @@ public:
 
 		// Wait for fence to signal that all command buffers are ready
 		VkResult fenceRes;
-		do
+		do {
-		{
 			fenceRes = vkWaitForFences(device, 1, &renderFence, VK_TRUE, 100000000);
 		} while (fenceRes == VK_TIMEOUT);
 		VK_CHECK_RESULT(fenceRes);

examples/particlefire/particlefire.cpp

@@ -11,6 +11,7 @@
 #include <string.h>
 #include <assert.h>
 #include <vector>
+#include <random>
 
 #define GLM_FORCE_RADIANS
 #define GLM_FORCE_DEPTH_ZERO_TO_ONE
@@ -123,6 +124,8 @@ public:
 
 	std::vector<Particle> particleBuffer;
 
+	std::default_random_engine rndEngine;
+
 	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
 	{
 		zoom = -75.0f;
@@ -131,7 +134,7 @@ public:
 		settings.overlay = true;
 		zoomSpeed *= 1.5f;
 		timerSpeed *= 8.0f;
-		srand(time(NULL));
+		rndEngine.seed(benchmark.active ? 0 : (unsigned)time(nullptr));
 	}
 
 	~VulkanExample()
@@ -217,7 +220,8 @@ public:
 
 	float rnd(float range)
 	{
-		return range * (rand() / float(RAND_MAX));
+		std::uniform_real_distribution<float> rndDist(0.0f, range);
+		return rndDist(rndEngine);
 	}
 
 	void initParticle(Particle *particle, glm::vec3 emitterPos)

examples/ssao/ssao.cpp

@@ -1007,17 +1007,16 @@ public:
 		updateUniformBufferSSAOParams();
 
 		// SSAO
+		std::default_random_engine rndEngine(benchmark.active ? 0 : (unsigned)time(nullptr));
 		std::uniform_real_distribution<float> rndDist(0.0f, 1.0f);
-		std::random_device rndDev;
-		std::default_random_engine rndGen;
 
 		// Sample kernel
 		std::vector<glm::vec4> ssaoKernel(SSAO_KERNEL_SIZE);
 		for (uint32_t i = 0; i < SSAO_KERNEL_SIZE; ++i)
 		{
-			glm::vec3 sample(rndDist(rndGen) * 2.0 - 1.0, rndDist(rndGen) * 2.0 - 1.0, rndDist(rndGen));
+			glm::vec3 sample(rndDist(rndEngine) * 2.0 - 1.0, rndDist(rndEngine) * 2.0 - 1.0, rndDist(rndEngine));
 			sample = glm::normalize(sample);
-			sample *= rndDist(rndGen);
+			sample *= rndDist(rndEngine);
 			float scale = float(i) / float(SSAO_KERNEL_SIZE);
 			scale = lerp(0.1f, 1.0f, scale * scale);
 			ssaoKernel[i] = glm::vec4(sample * scale, 0.0f);
@@ -1035,7 +1034,7 @@ public:
 		std::vector<glm::vec4> ssaoNoise(SSAO_NOISE_DIM * SSAO_NOISE_DIM);
 		for (uint32_t i = 0; i < static_cast<uint32_t>(ssaoNoise.size()); i++)
 		{
-			ssaoNoise[i] = glm::vec4(rndDist(rndGen) * 2.0f - 1.0f, rndDist(rndGen) * 2.0f - 1.0f, 0.0f, 0.0f);
+			ssaoNoise[i] = glm::vec4(rndDist(rndEngine) * 2.0f - 1.0f, rndDist(rndEngine) * 2.0f - 1.0f, 0.0f, 0.0f);
 		}
 		// Upload as texture
 		textures.ssaoNoise.fromBuffer(ssaoNoise.data(), ssaoNoise.size() * sizeof(glm::vec4), VK_FORMAT_R32G32B32A32_SFLOAT, SSAO_NOISE_DIM, SSAO_NOISE_DIM, vulkanDevice, queue, VK_FILTER_NEAREST);

examples/subpasses/subpasses.cpp

@@ -1009,7 +1009,7 @@ public:
 			glm::vec3(1.0f, 1.0f, 0.0f),
 		};
 
-		std::mt19937 rndGen(benchmark.active ? 0 : (unsigned)time(NULL));
+		std::default_random_engine rndGen(benchmark.active ? 0 : (unsigned)time(nullptr));
 		std::uniform_real_distribution<float> rndDist(-1.0f, 1.0f);
 		std::uniform_int_distribution<uint32_t> rndCol(0, static_cast<uint32_t>(colors.size()-1));
 

examples/texturesparseresidency/texturesparseresidency.cpp

@@ -962,7 +962,7 @@ public:
 	void fillVirtualTexture(int32_t &mipLevel)
 	{
 		vkDeviceWaitIdle(device);
-		std::default_random_engine rndEngine(std::random_device{}());
+		std::default_random_engine rndEngine(benchmark.active ? 0 : (unsigned)time(nullptr));
 		std::uniform_real_distribution<float> rndDist(0.0f, 1.0f);
 		std::vector<VkImageBlit> imageBlits;
 		for (auto& page : texture.pages)