GLSL Shader记录实体ID

这是最核心的地方，在绘制的时候用shader记录实体

Vertex

layout(location = 0) in vec3 a_Position;
layout(location = 1) in vec4 a_Color;
layout(location = 2) in vec2 a_TexCoord;
layout(location = 3) in float a_TexIndex;
layout(location = 4) in float a_TilingFactor;
layout(location = 5) in int a_EntityID;


uniform mat4 u_ViewProjection;

out vec4 v_Color;
out vec2 v_TexCoord;
out flat float v_TexIndex;
out float v_TilingFactor;
out flat int v_EntityID;

void main()
{
    v_Color = a_Color;
    v_TexCoord = a_TexCoord;
    v_TexIndex = a_TexIndex;
    v_TilingFactor = a_TilingFactor;
    v_EntityID = a_EntityID;
    gl_Position = u_ViewProjection * vec4(a_Position, 1.0);
}

Fragment

还是输出两个值，然后把之前的50换成对应的entityID

#type fragment
#version 450

layout(location = 0) out vec4 color;
layout(location = 1) out int color2;

in vec4 v_Color;
in vec2 v_TexCoord;
in flat float v_TexIndex;
in float v_TilingFactor;
in flat int v_EntityID;

uniform sampler2D u_Textures[32];

void main()
{
    vec4 texColor = v_Color;
    ....
    color = texColor;

    color2 = v_EntityID;
}

渲染器：

先给每个绘制函数赋予一个实体ID（默认-1）

对应实现就省略了

        static void DrawQuad(const glm::mat4& transform, const glm::vec4& color, int entityID = -1);
        static void DrawQuad(const glm::mat4& transform, const Ref<Texture2D>& texture, float tilingFactor = 1.0f, const glm::vec4& tintColor = glm::vec4(1.0f), int entityID = -1);

再加一个DrawSprite

根据spriteRenderer的Component进行绘制

        static void DrawSprite(const glm::mat4& transform, SpriteRendererComponent& src, int entityID);

结构变化

主要还是新增entityid带来的变化

    struct QuadVertex
    {
        glm::vec3 Position;
        glm::vec4 Color;
        glm::vec2 TexCoord;
        float TexIndex;
        float TilingFactor;

        // Editor-only
        int EntityID;
    };

Vertexbuffer

    void Renderer2D::Init()
    {
        CD_PROFILE_FUNCTION();
        s_Data.QuadVertexArray = VertexArray::Create();

        s_Data.QuadVertexBuffer = VertexBuffer::Create(s_Data.MaxVertices * sizeof(QuadVertex));
        s_Data.QuadVertexBuffer->SetLayout({
            { ShaderDataType::Float3, "a_Position"     },
            { ShaderDataType::Float4, "a_Color"        },
            { ShaderDataType::Float2, "a_TexCoord"     },
            { ShaderDataType::Float,  "a_TexIndex"     },
            { ShaderDataType::Float,  "a_TilingFactor" },
            { ShaderDataType::Int,    "a_EntityID"     }
            });

Scene绘制

在更新绘制的时候，需要把实体id传入

    void Scene::OnUpdateEditor(Timestep ts, EditorCamera& camera)
    {
        Renderer2D::BeginScene(camera);
        auto group = m_Registry.group<TransformComponent>(entt::get<SpriteRendererComponent>);
        for (auto entity : group)
        {
            auto [transform, sprite] = group.get<TransformComponent, SpriteRendererComponent>(entity);
            Renderer2D::DrawSprite(transform.GetTransform(), sprite, (int)entity);
        }
        Renderer2D::EndScene();
    }

Editor Layer

新增悬停实体

Entity m_HoveredEntity;

每帧判断鼠标悬停实体，并赋予到悬停实体

由于是两个引用来构造赋值，不会创建新的空间，不需要new

        if (mouseX >= 0 && mouseY >= 0 && mouseX < (int)viewportSize.x && mouseY < (int)viewportSize.y)
        {
            int pixelData = m_Framebuffer->ReadPixel(1, mouseX, mouseY);
            m_HoveredEntity = pixelData == -1 ? Entity() : Entity((entt::entity)pixelData, m_ActiveScene.get());
        }

拿到悬停石头后，我们通过Tag组件，将名字显示出来

        ImGui::Text("Hovered Entity: %s", name.c_str());

相当的有实力