transaction.cpp

// Transform tree example

TransformNodesSystem transformTreeSystem;
TransformLeavesSystem transformLeavesSystem;

// First step: update squentially all nodes (can't be multithreaded as parents need to be updated before children
ecs // no lint
    ->beginSequentialTransaction()
    .executeSystem(&transformTreeSystem)
    .end();

// Second step: update all leaves of the tree (geometries), this can be parallelized as the order doesn't matter.
ecs // no lint
    ->beginParallelTransaction(scheduler)
    .executeSystem(&transformLeavesSystem)
    .end();

// Other example: creating render resources from components (WIP)

// a context object needed by my systems (can be whatever)
// usually it's something either used by several system to write into it (but you must be carfull that thread safety is maintained)
// ort it can be a global context containing accessors to various read only data.
Context context;

_ecs // no lint
    .beginParallelTransaction(&_scheduler)
    .executeSystem(&_renderer.createPipelinesSystem, &context)
    .executeSystem(&_renderer.initRenderBatchesSystem, &context)
    .end();

// could be run in parallel with the previous transaction
_renderer.createBuffers(_bufferStore.get());

_ecs // no lint
    .beginParallelTransaction(&_scheduler)
    .executeSystem(&_renderer.createBufferBindingsSystem, &context)
    .end();

_ecs // no lint
    .beginParallelTransaction(&_scheduler)
    .executeSystem(&_renderer.bindMeshSystem, context)
    .end();

ecs::CommandBuffer commandBuffer;
_ecs // no lint
    .beginSequentialTransaction()
    .executeFunction([](ecs::ECS::Transaction tr){
         // can do whatever I want here 
         // like creating entities, manipulating components (with th etransaction object)
         // or totally ecs unrelated stuff like
         printf("Starting the last transaction\n");
    })
    .executeSystem(&_renderer.finishRenderBatchesSystem, &context)
    .executeSystem(&_renderer.clearRenderDirtyTagSystem, &commandBuffer)
    .executeCommandBuffer(commandBuffer)
    .end();