keep track of UBO buffer offsets so we can update the UBO accurately

1 files changed, 14 insertions, 7 deletions

diff --git a/src/window.cpp b/src/window.cpp
index 279c876..c7b9dba 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -92,6 +92,7 @@ UniformBufferObject UBO{
 	.proj = glm::mat4(1),
 };
 VkDeviceMemory uniformBufferMemory;
+VkDeviceSize paddedUboBufferSize;
 
 // public
 VkBuffer UniformBuffers[MAX_FRAMES_IN_FLIGHT];
@@ -1216,25 +1217,31 @@ void CreateUniformBuffers() {
 	vkBufferCreateInfo.queueFamilyIndexCount = graphicsFamilyIndex == transferFamilyIndex ? 1 : 2;
 	vkBufferCreateInfo.pQueueFamilyIndices = queueFamilyIndexes;
 
-	vkCreateBuffer(vkDevice, &vkBufferCreateInfo, vkAllocator, &UniformBuffers[0]);
+	VkResult result;
+	result = vkCreateBuffer(vkDevice, &vkBufferCreateInfo, vkAllocator, &UniformBuffers[0]);
+	assert(result == VK_SUCCESS);
 
 	VkMemoryRequirements memReqs;
 	vkGetBufferMemoryRequirements(vkDevice, UniformBuffers[0], &memReqs);
+	paddedUboBufferSize = memReqs.size + (memReqs.alignment - (memReqs.size & memReqs.alignment));
 
 	VkMemoryAllocateInfo vkMemoryAllocateInfo;
 	vkMemoryAllocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
 	vkMemoryAllocateInfo.pNext = nullptr;
-	vkMemoryAllocateInfo.allocationSize = memReqs.size * MAX_FRAMES_IN_FLIGHT;
+	vkMemoryAllocateInfo.allocationSize = paddedUboBufferSize * MAX_FRAMES_IN_FLIGHT;
 	vkMemoryAllocateInfo.memoryTypeIndex = FindMemoryTypeIndex(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);
 
-	vkAllocateMemory(vkDevice, &vkMemoryAllocateInfo, vkAllocator, &uniformBufferMemory);
+	result = vkAllocateMemory(vkDevice, &vkMemoryAllocateInfo, vkAllocator, &uniformBufferMemory);
+	assert(result == VK_SUCCESS);
 
 	vkDestroyBuffer(vkDevice, UniformBuffers[0], vkAllocator);
-	vkBufferCreateInfo.size = memReqs.size;
+	vkBufferCreateInfo.size = paddedUboBufferSize;
 
 	for (long i = 0; i < MAX_FRAMES_IN_FLIGHT; ++i) {
-		vkCreateBuffer(vkDevice, &vkBufferCreateInfo, vkAllocator, &UniformBuffers[i]);
-		vkBindBufferMemory(vkDevice, UniformBuffers[i], uniformBufferMemory, memReqs.size * i);
+		result = vkCreateBuffer(vkDevice, &vkBufferCreateInfo, vkAllocator, &UniformBuffers[i]);
+		assert(result == VK_SUCCESS);
+		result = vkBindBufferMemory(vkDevice, UniformBuffers[i], uniformBufferMemory, paddedUboBufferSize * i);
+		assert(result == VK_SUCCESS);
 	}
 }
 
@@ -2456,7 +2463,7 @@ void Render() {
 	// update uniform buffer
 	{
 		void *mappedUboMemory;
-		vkMapMemory(vkDevice, uniformBufferMemory, sizeof(UniformBufferObject) * imageIndex, sizeof(UniformBufferObject), 0, &mappedUboMemory);
+		vkMapMemory(vkDevice, uniformBufferMemory, paddedUboBufferSize * imageIndex, sizeof(UniformBufferObject), 0, &mappedUboMemory);
 		memcpy(mappedUboMemory, &UBO, sizeof(UniformBufferObject));
 		vkUnmapMemory(vkDevice, uniformBufferMemory);
 	}