无法使用 OpenGL 显示纹理

Question

在我使用 opengl 4.5 的 Windows 计算机上，我似乎无法让我的纹理出现在屏幕上。我收到的只是黑屏。对于我的代码，我首先开发了一个小的 Vector 类来容纳所有顶点属性信息：

Vector3D.h

struct Position
{
    Position();
    Position(float x, float y, float z);
    float x;
    float y;
    float z;
};

Position::Position()
{}

Position::Position(float x, float y, float z) :
    x(x), y(y), z(z)
{}

struct Color
{
    GLubyte r;
    GLubyte g;
    GLubyte b;
    GLubyte a;
};

struct TextureCoordinate
{
    float u;
    float v;
};

struct Vector3D
{
    Vector3D();
    Vector3D(float x, float y, float z);

    Position position;
    Color color;
    TextureCoordinate textCoordinate;

    void setUV(float u, float v);
};

Vector3D::Vector3D()
{}

Vector3D::Vector3D(float x, float y, float z) :
    position(x, y, z)
{}

void Vector3D::setUV(float u, float v)
{
    this->textCoordinate.u = u;
    this->textCoordinate.v = v;
}

然后我有一个精灵类，通过它我使用 Init() 函数初始化顶点属性：

Sprite.cpp

void Sprite::Init(float x, float y, float width, float height)
{
    this->x = x;
    this->y = y;
    this->width = width;
    this->height = height;

    if (vboID == 0)
        glGenBuffers(1, &vboID);

    Vector3D vertexData[6]{
        Vector3D {x + width, y + height, 1.0f},
        Vector3D {x, y + height, 1.0f },
        Vector3D {x, y, 1.0f},
        Vector3D {x, y, 1.0f},
        Vector3D {x + width, y, 1.0f},
        Vector3D {x + width, y + height, 1.0f},
    };

    for (int i = 0; i < 6; ++i)
    {
        vertexData[i].color.r = 0;
        vertexData[i].color.g = 155;
        vertexData[i].color.b = 200;
    };

    vertexData[0].setUV(1.0f, 1.0f);
    vertexData[1].setUV(0.0f, 1.0f);
    vertexData[2].setUV(0.0f, 0.0f);
    vertexData[3].setUV(0.0f, 0.0f);
    vertexData[4].setUV(1.0f, 0.0f);
    vertexData[5].setUV(1.0f, 1.0f);

    glBindBuffer(GL_ARRAY_BUFFER, vboID);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertexData), vertexData, GL_STATIC_DRAW);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

然后我在 sprite 类中有绘制函数，它显然会重新绑定以纠正 VBO 并绘制图像：

Sprite.cpp

void Sprite::Draw()
{
    glBindBuffer(GL_ARRAY_BUFFER, vboID);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vector3D), (void*)offsetof(Vector3D, position));
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vector3D), (void*)offsetof(Vector3D, textCoordinate));

    glDrawArrays(GL_TRIANGLES, 0, 6);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

最后，我在这里的 main 函数中调用上面的所有内容（我还使用 SDL 和图像加载库 stb）：

main.cpp

int main(int agrc, char** argv)
{
    window.Initialize();
    playerSprite.Init(-1.0f, -1.0f, 1.0f, 1.0f);

    GameState gamestate{ GameState::PLAY };

    SDL_Event evnt;

    int32 x, y, currentChannels;
    int32 forceChannels = 4;
    uchar8* imageData = 0;
    imageData = stbi_load("CharImage.png", &x, &y, &currentChannels, forceChannels);

    if (imageData == nullptr)
    {
        LOG("ERROR: Could not load image file!");
    };

    GLuint texture;
    glGenTextures(1, &texture);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
    glTextureParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTextureParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTextureParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTextureParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);


    Blz::OpenGL::ShaderProgram colorShaderProgram;
    colorShaderProgram.Compile();
    colorShaderProgram.Link();
    colorShaderProgram.Bind();

    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);

    while (gamestate != GameState::EXIT)
    {
        unsigned int startTime = SDL_GetTicks();

        //Game Logic Update
        while (SDL_PollEvent(&evnt))
        {
            switch (evnt.type)
            {
            case SDL_QUIT:
                gamestate = GameState::EXIT;

            default:
                break;
            }
        }

        window.ClearBuffers();

        playerSprite.Draw();

        window.SwapBuffers();
    }

    return 0;
}

另外，这是我的着色器：

顶点着色器

#version 430

layout(location=0) in vec3 vertexPosition;
layout(location=1) in vec2 textCoord;

out vec2 TextureCoord;

void main()
{
    gl_Position = vec4(vertexPosition, 1.0f);
    TextureCoord = textCoord;
}; 

片段着色器

#version 430

out vec4 daColor;
in vec2 TextureCoord;

uniform sampler2D basicTexture;

void main()
{
    vec4 texel = texture(basicTexture, TextureCoord);
    daColor = texel;
};

Answer 1

在这样的时代，我希望有一个更好的替代跨平台图形编程的方法，因为 openGL 真的是一团糟。我的图像没有显示的原因是因为我正在设置参数：

glTextureParameteri()

而不是表面上正确的：

glTexParameteri()

........