某些平台上的OpenGL渲染渲染

Question

我一直在尝试批处理精灵渲染，并且我有一个可以在台式机上正常工作的解决方案。但是，在集成的Intel UHD 620笔记本电脑上尝试使用它时，会收到以下性能警告：

[21:42:03   error] OpenGL: API - Performance - Recompiling fragment shader for program 27
[21:42:03   error] OpenGL: API - Performance -   multisampled FBO 0->1

大概是由于这些性能警告的来源，在我的专用图形卡计算机上花费1-2毫秒的帧在我的笔记本电脑上花费了约100毫秒。

这是我的渲染器代码：

BatchedSpriteRenderer::BatchedSpriteRenderer(ResourceManager &resource_manager)
    : resource_manager(&resource_manager), 
      max_sprites(100000),
      vertex_array(std::make_unique<VertexArray>()),
      vertex_buffer(std::make_unique<VertexBuffer>())
{
    resource_manager.load_shader("batched_texture",
                                 "shaders/texture_batched.vert",
                                 "shaders/texture.frag");

    std::vector<unsigned int> sprite_indices;
    for (int i = 0; i < max_sprites; ++i)
    {
        unsigned int sprite_number = i * 4;
        sprite_indices.push_back(0 + sprite_number);
        sprite_indices.push_back(1 + sprite_number);
        sprite_indices.push_back(2 + sprite_number);
        sprite_indices.push_back(2 + sprite_number);
        sprite_indices.push_back(3 + sprite_number);
        sprite_indices.push_back(0 + sprite_number);
    }
    element_buffer = std::make_unique<ElementBuffer>(sprite_indices.data(), max_sprites * 6);

    VertexBufferLayout layout;
    layout.push<float>(2);
    layout.push<float>(2);
    layout.push<float>(4);
    vertex_array->add_buffer(*vertex_buffer, layout);
}

void BatchedSpriteRenderer::draw(const std::string &texture,
                                 const std::vector<glm::mat4> &transforms,
                                 const glm::mat4 &view)
{
    vertex_array->bind();

    auto shader = resource_manager->shader_store.get("batched_texture");
    shader->bind();

    std::vector<SpriteVertex> vertices;
    vertices.reserve(transforms.size() * 4);
    for (const auto &transform : transforms)
    {
        glm::vec4 transformed_position = transform * glm::vec4(0.0, 1.0, 1.0, 1.0);
        vertices.push_back({glm::vec2(transformed_position.x, transformed_position.y),
                            glm::vec2(0.0, 1.0),
                            glm::vec4(1.0, 1.0, 1.0, 1.0)});
        transformed_position = transform * glm::vec4(0.0, 0.0, 1.0, 1.0);
        vertices.push_back({glm::vec2(transformed_position.x, transformed_position.y),
                            glm::vec2(0.0, 0.0),
                            glm::vec4(1.0, 1.0, 1.0, 1.0)});
        transformed_position = transform * glm::vec4(1.0, 0.0, 1.0, 1.0);
        vertices.push_back({glm::vec2(transformed_position.x, transformed_position.y),
                            glm::vec2(1.0, 0.0),
                            glm::vec4(1.0, 1.0, 1.0, 1.0)});
        transformed_position = transform * glm::vec4(1.0, 1.0, 1.0, 1.0);
        vertices.push_back({glm::vec2(transformed_position.x, transformed_position.y),
                            glm::vec2(1.0, 1.0),
                            glm::vec4(1.0, 1.0, 1.0, 1.0)});
    }
    vertex_buffer->add_data(vertices.data(),
                            sizeof(SpriteVertex) * vertices.size(),
                            GL_DYNAMIC_DRAW);

    shader->set_uniform_mat4f("u_view", view);
    shader->set_uniform_1i("u_texture", 0);

    resource_manager->texture_store.get(texture)->bind();

    glDrawElements(GL_TRIANGLES, transforms.size() * 6, GL_UNSIGNED_INT, 0);
}

希望我的抽象应该是自我解释。每个抽象类（VertexArray，VertexBuffer，ElementBuffer，VertexBufferLayout）管理其等效OpenGL对象的生存期。

以下是使用的着色器：texture_batched.vert

#version 430 core

layout(location = 0)in vec2 v_position; 
layout(location = 1)in vec2 v_tex_coord; 
layout(location = 2)in vec4 v_color; 

out vec4 color; 
out vec2 tex_coord; 

uniform mat4 u_view;

void main()
 {
    tex_coord = v_tex_coord;
    gl_Position = u_view * vec4(v_position, 0.0, 1.0);
    color = v_color;
}

texture.frag

#version 430 core

in vec4 color; 
in vec2 tex_coord; 

out vec4 frag_color; 

uniform sampler2D u_texture; 

void main()
 {
    frag_color = texture(u_texture, tex_coord);
    frag_color *= color;
}

是什么导致这些性能问题，以及如何解决它们？

编辑：我完全忘了提到用它渲染的实际图像完全被弄乱了，当我到达台式机时，我将尝试抓取其正常工作的屏幕快照，但这是残缺的版本：

应该是一个200x200白色圆圈的整齐的网格。

编辑2：我在另一台计算机上尝试过，这次是使用GTX 1050 Ti，它也坏了。这次没有错误消息或警告。该警告可能不相关。

Answer 1

据我所知，它最终与OpenGL无关。

在绘图功能中，我创建了一个称为vertices的向量，然后将所有顶点放入其中。由于某种原因，当我每帧重新创建矢量时，以下push_back调用未正确添加到矢量中。 SpriteVertex结构的成员变得混在一起。因此，不是正确的布局：

pos tex_coord color
pos tex_coord color
pos tex_coord color
pos tex_coord color

它被填充为以下布局：

pos tex_coord color
tex_coord pos color
tex_coord pos color
tex_coord pos color

或者至少有这种效果。

我进行了更改，以使vertices向量成为BatchedSpriteRenderer类的成员，并为最大可能的顶点保留空间。

void BatchedSpriteRenderer::draw(const std::string &texture,
                                 const std::vector<glm::mat4> &transforms,
                                 const glm::mat4 &view)
{
    vertex_array->bind();

    auto shader = resource_manager->shader_store.get("batched_texture");
    shader->bind();

    for (unsigned int i = 0; i < transforms.size(); ++i)
    {
        const auto &transform = transforms[i];

        glm::vec4 transformed_position = transform * glm::vec4(0.0, 1.0, 1.0, 1.0);
        vertices[i * 4] = {glm::vec2(transformed_position.x,
                                     transformed_position.y),
                           glm::vec2(0.0, 1.0),
                           glm::vec4(1.0, 1.0, 1.0, 1.0)};

        transformed_position = transform * glm::vec4(0.0, 0.0, 1.0, 1.0);
        vertices[i * 4 + 1] = {glm::vec2(transformed_position.x,
                                         transformed_position.y),
                               glm::vec2(0.0, 0.0),
                               glm::vec4(1.0, 1.0, 1.0, 1.0)};

        transformed_position = transform * glm::vec4(1.0, 0.0, 1.0, 1.0);
        vertices[i * 4 + 2] = {glm::vec2(transformed_position.x,
                                         transformed_position.y),
                               glm::vec2(1.0, 0.0),
                               glm::vec4(1.0, 1.0, 1.0, 1.0)};

        transformed_position = transform * glm::vec4(1.0, 1.0, 1.0, 1.0);
        vertices[i * 4 + 3] = {glm::vec2(transformed_position.x,
                                         transformed_position.y),
                               glm::vec2(1.0, 1.0),
                               glm::vec4(1.0, 1.0, 1.0, 1.0)};
    }

    vertex_buffer->add_data(vertices.data(),
                            sizeof(SpriteVertex) * (transforms.size() * 4),
                            GL_DYNAMIC_DRAW);

    shader->set_uniform_mat4f("u_view", view);
    shader->set_uniform_1i("u_texture", 0);

    resource_manager->texture_store.get(texture)->bind();

    glDrawElements(GL_TRIANGLES, transforms.size() * 6, GL_UNSIGNED_INT, 0);
}