138 lines
3.5 KiB
C
138 lines
3.5 KiB
C
#ifndef BECS_H
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#define BECS_H
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#include <stdint.h>
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#include <stddef.h>
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typedef struct BECS_ComponentArray BECS_ComponentArray;
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typedef struct BECS_Properties BECS_Properties;
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typedef struct BECS_ECS BECS_ECS;
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size_t BECS_GetMinMemorySize(BECS_Properties props);
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BECS_ECS *BECS_Init(void *memory, size_t size, BECS_Properties *props);
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int32_t BECS_AddComponent(BECS_ECS *ecs, uint32_t entityID, uint64_t componentBitMask, void *component);
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#define MAX_ENTITY_COUNT 100
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#ifdef BECS_IMPLEMENTATION
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#ifdef MAX_ENTITY_COUNT
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struct BECS_ComponentArray {
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uint32_t lastEntityAdded;
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size_t unitSize;
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uint32_t length;
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uint32_t capacity;
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void *array;
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};
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struct BECS_Properties {
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uint32_t maxEntities;
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uint32_t numComponents;
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size_t *componentSizes;
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};
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struct BECS_ECS {
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uint64_t *bitMasks;
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BECS_Properties props;
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BECS_ComponentArray *componentSets;
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};
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size_t BECS_GetMinMemorySize
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(BECS_Properties props)
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{
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size_t totalSize = 0;
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totalSize += sizeof(BECS_ECS);
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totalSize += sizeof(BECS_ComponentArray) * props.numComponents;
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for (uint32_t i = 0; i < props.numComponents; i++)
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{
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totalSize += props.componentSizes[i] * props.maxEntities;
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totalSize += sizeof(uint64_t);
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}
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return totalSize;
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}
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BECS_ECS *BECS_Init
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(void *memory, size_t size, BECS_Properties *props)
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{
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BECS_ECS *ecs = (BECS_ECS *)memory;
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uint64_t *bitMasks = (uint64_t *)(ecs + 1);
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BECS_ComponentArray *componentSets = (BECS_ComponentArray *)((uint8_t *)(ecs + 1) + props->maxEntities);
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ecs->bitMasks = bitMasks;
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ecs->componentSets = componentSets;
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ecs->props = *props;
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for (uint32_t i = 0; i < props->maxEntities; i++)
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{
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ecs->bitMasks[i] = 0;
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}
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for (uint32_t i = 0; i < props->numComponents; i++)
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{
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ecs->componentSets[i].unitSize = props->componentSizes[i];
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ecs->componentSets[i].capacity = ecs->componentSets[i].unitSize * props->maxEntities;
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ecs->componentSets[i].lastEntityAdded = props->maxEntities + 1;
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ecs->componentSets[i].length = 0;
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}
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uint32_t index = 0;
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// FIX: This is completely fucked. I feel like I am overcomplicating this... Might be easier to use a defined constant :/
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for (uint32_t i = 0; i < props->numComponents; i++)
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{
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uint32_t index = i;
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if (index - 1 > props->numComponents)
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{
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index = 1;
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}
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ecs->componentSets[index - 1].array = componentSets + 4;
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}
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return ecs;
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}
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int32_t
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BECS_AddComponent(BECS_ECS *ecs, uint32_t entityID, uint64_t componentBitMask, void *component)
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{
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int32_t result = 0;
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if (componentBitMask == 0)
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{
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return result;
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}
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uint32_t componentType = 0;
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while (!(componentBitMask & 1))
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{
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componentBitMask >>= 1;
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componentType++;
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}
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ecs->bitMasks[entityID] = ecs->bitMasks[entityID] | componentBitMask;
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uint32_t insertIndex = ecs->componentSets[componentType].length;
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if (insertIndex > ecs->props.maxEntities)
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{
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return result;
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}
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size_t componentSize = ecs->props.componentSizes[componentType];
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uint8_t *componentArray = (uint8_t *)ecs->componentSets[componentType].array;
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uint8_t *source = (uint8_t *)component;
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componentArray += componentSize;
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while (componentSize > 0)
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{
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*componentArray = *source;
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componentSize--;
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}
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ecs->componentSets[componentType].length++;
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result = 1;
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return result;
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}
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// int32_t
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// BECS_RemoveComponent()
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// {
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// }
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#endif
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#endif
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#endif
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