becs/becs.h

105 lines
2.4 KiB
C

#ifndef BECS_H
#define BECS_H
#ifdef BECS_IMPLEMENTATION
#include <stdint.h>
typedef struct BECS_ComponentArray {
uint32_t lastEntityAdded;
size_t unitSize;
uint32_t length;
uint32_t capacity;
void *array;
} BECS_ComponentArray;
typedef struct BECS_Properties {
uint32_t maxEntities;
uint32_t numComponents;
size_t *componentSizes;
} BECS_Properties;
typedef struct BECS_ECS {
uint64_t *bitMasks;
BECS_Properties props;
BECS_ComponentArray *componentSets;
} BECS_ECS;
size_t BECS_GetMinMemorySize
(BECS_Properties props)
{
size_t totalSize = 0;
totalSize += sizeof(BECS_ECS);
totalSize += sizeof(BECS_ComponentArray) * props.numComponents;
for (uint32_t i = 0; i < props.numComponents; i++)
{
totalSize += props.componentSizes[i] * props.maxEntities;
totalSize += sizeof(uint64_t);
}
return totalSize;
}
BECS_ECS *BECS_Init
(void *memory, size_t size, BECS_Properties *props)
{
BECS_ECS *ecs = (BECS_ECS *)memory;
uint64_t *bitMasks = (uint64_t *)(ecs + 1);
BECS_ComponentArray *componentSets = (BECS_ComponentArray *)(bitMasks + props->maxEntities);
ecs->bitMasks = bitMasks;
ecs->componentSets = componentSets;
ecs->props = *props;
ecs->bitMasks = 0;
for (uint32_t i = 0; i < props->numComponents; i++)
{
ecs->componentSets[i].length = 0;
}
return ecs;
}
int32_t
BECS_AddComponent(BECS_ECS *ecs, uint32_t entityID, uint64_t componentBitMask, void *component)
{
int32_t result = 0;
if (componentBitMask == 0)
{
return result;
}
uint32_t componentType = 0;
while (!(componentBitMask & 1))
{
componentBitMask >>= 1;
componentType++;
}
ecs->bitMasks[entityID] = ecs->bitMasks[entityID] | componentBitMask;
uint32_t insertIndex = ecs->componentSets[componentType].length;
if (insertIndex > ecs->props.maxEntities)
{
return result;
}
size_t componentSize = ecs->props.componentSizes[componentType];
uint8_t *componentArray = (uint8_t *)ecs->componentSets[componentType].array;
uint8_t *source = (uint8_t *)component;
componentArray += componentSize;
while (componentSize > 0)
{
*componentArray = *source;
componentSize--;
}
ecs->componentSets[componentType].length++;
result = 1;
return result;
}
// int32_t
// BECS_RemoveComponent()
// {
// }
#endif
#endif