GPUDirectionalLight.hpp

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#pragma once
 
#include "Logger.hpp"
#include "component/DirectionalLight.hpp"
#include "component/Transform.hpp"
#include "glm/glm.hpp"
#include "utils/webgpu.hpp"
#include <entt/core/hashed_string.hpp>
 
namespace DefaultPipeline::Component {
struct GPUDirectionalLight {
    using Id = entt::hashed_string;
 
    glm::mat4 viewProjectionMatrix;
    Id buffer{};
    Id bindGroupData{};
    wgpu::TextureView shadowTextureView;
    uint32_t shadowTextureIndex;
 
    void Update(const Object::Component::DirectionalLight &light, const Object::Component::Transform &transform)
    {
        // Why do we negate the forward vector?
        glm::vec3 lightDirection = -glm::normalize(transform.GetForwardVector() * transform.GetScale());
        glm::vec3 posOfLight = transform.GetPosition();
        glm::mat4 lightProjection = light.projection;
        glm::vec3 target = posOfLight + glm::normalize(lightDirection) * 10.0f;
        auto up = glm::abs(glm::dot(glm::normalize(lightDirection), glm::vec3(0.0f, 1.0f, 0.0f))) > 0.99f ?
                      glm::vec3(1.0f, 0.0f, 0.0f) :
                      glm::vec3(0.0f, 1.0f, 0.0f);
        glm::mat4 lightView = glm::lookAt(posOfLight, target, up);
        glm::mat4 lightSpaceMatrix = lightProjection * lightView;
 
        viewProjectionMatrix = lightSpaceMatrix;
    }
};
}; // namespace DefaultPipeline::Component