BillboardSystem.cpp

#include "BillboardSystem.h"
 
#include "Systems/Core/TransformSystem.h"
#include "Systems/Core/SpriteRenderSystem.h"
 
#include "Resources/TextureManager.h"
#include "Resources/MaterialManager.h"
 
#include "Context.h"
 
void Cogs::Core::BillboardSystem::update(Context * context)
{
  auto sprites = context->spriteRenderSystem;
 
  for (const auto & billboard : pool) {
    if (!billboard.image) continue;
    if (billboard.imageSize.x == 0 || billboard.imageSize.y == 0) continue;
 
    auto spriteRenderer = billboard.getComponent<SpriteRenderComponent>();
 
    if (!spriteRenderer->isVisible()) continue;
 
    auto transform = billboard.getComponent<TransformComponent>();
    const auto & localToWorld = context->transformSystem->getLocalToWorld(transform);
    const glm::vec3 worldSpacePosition = glm::vec3(localToWorld * glm::vec4(0, 0, 0, 1.0f));
 
    const glm::vec2 right(billboard.imageSize.x * 0.5f, 0);
    const glm::vec2 up(0, billboard.imageSize.y * 0.5f);
    
    glm::vec2 offset(0, 0);
 
    if (billboard.horizontalAlignment == HorizontalAlignment::Left) offset += right;
    else if (billboard.horizontalAlignment == HorizontalAlignment::Right) offset -= right;
 
    if (billboard.verticalAlignment == VerticalAlignment::Bottom) offset += up;
    else if (billboard.verticalAlignment == VerticalAlignment::Top) offset -= up;
 
    auto batch = sprites->begin(DefaultSpriteMaterial, "ViewTransformPixelSize", billboard.image, billboard.color, billboard.alwaysOnTop);
    sprites->addSprite(spriteRenderer, worldSpacePosition, offset, billboard.imageSize, glm::vec4(0, 1, 1, 0));
 
    if (billboard.flipX || billboard.flipY) {
      batch->material->setVec2Property(batch->material->material->getVec2Key("imageFlip"), glm::vec2(billboard.flipX ? 1 : 0, billboard.flipY ? 1 : 0));
    }
 
    batch->worldPosition = worldSpacePosition;
    batch->bbox = { worldSpacePosition, worldSpacePosition };
    batch->flags |= RenderItemFlags::CalculateDepth;
    batch->blendMode = billboard.blendMode;
    batch->material->options.blendMode = billboard.blendMode;
  }
}