opengl - テクスチャが表示されず、メッシュが黒く表示される

Question

OpenGL アプリでテクスチャリングを機能させようとするたびに、明らかな何かを見逃しているようで、デバッグに何時間も費やしてしまいます。それは再び起こりました。かなり長い間、コードを古い動作中のアプリと比較しようとしてきましたが、テクスチャがまったく表示されないため、まだ何かが欠けています. メッシュが黒く見えます。OpenGL エラーは発生しません。

問題を絞り込むための助けに非常に感謝しています。

これが私のコードの一部です。間違いはコードのこれらの領域にあると確信しています。

OpenGL.cpp:

bool OpenGL::enable_attribs_and_uniforms(GLuint program_id)
{
    glGenVertexArrays(1, &this->vao_id);
    glBindVertexArray(this->vao_id);

    this->pos_a_loc = glGetAttribLocation(program_id, "pos_a");
    this->uv_a_loc = glGetAttribLocation(program_id, "uv_a");
    if (this->pos_a_loc == -1 || /*this->color_a_loc == -1 ||*/ this->uv_a_loc == -1)
    {
        std::cerr << "OpenGL Warning: Failed to get attribute locations, probably because at least one attribute isn't being used in the shader program. Attributes get optimized out if they don't affect the output of the shader program in any way.\n\n";
    }

    glEnableVertexAttribArray(this->pos_a_loc);
    glEnableVertexAttribArray(this->uv_a_loc);

    this->p_mat_u_loc = glGetUniformLocation(program_id, "p_mat_u");
    this->v_mat_u_loc = glGetUniformLocation(program_id, "v_mat_u");
    this->m_mat_u_loc = glGetUniformLocation(program_id, "m_mat_u");
    this->mvp_mat_u_loc = glGetUniformLocation(program_id, "mvp_mat_u");
    this->tex_samp_u_loc = glGetUniformLocation(program_id, "tex_samp_u");
    if (this->p_mat_u_loc == -1 || this->v_mat_u_loc == -1 ||
        this->m_mat_u_loc == -1 || this->mvp_mat_u_loc == -1 ||
        this->tex_samp_u_loc == -1)
    {
        std::cerr << "OpenGL Warning: Failed to get all uniform locations, probably because at least one uniform isn't being used in the shader program. Uniforms get optimized out if they don't affect the output of the shader program in any way.\n\n";
    }

    check_gl_error();

    return true;
}

void OpenGL::fill_buffers(std::vector<Object*>& objs)
{
    std::vector<Object*>::iterator it;
    for (it = objs.begin(); it != objs.end(); ++it)
    {
        GLuint vb_pos_id;
        glGenBuffers(1, &vb_pos_id);
        glBindBuffer(GL_ARRAY_BUFFER, vb_pos_id);
        glBufferData(GL_ARRAY_BUFFER, (*it)->v_pos.size() * sizeof(glm::vec3), &(*it)->v_pos[0], GL_STATIC_DRAW);
        this->vb_pos_ids.push_back(vb_pos_id);

        (*it)->tex_filenames[0] = "some_texture.png";

        SDL_Surface* tex_surface = IMG_Load((*it)->tex_filenames[0].c_str());
        if (!tex_surface)
        {
            std::cerr << "Texture Error: Couldn't open texture file: " << (*it)->tex_filenames[0] << "\n\n";
            return;
        }

        GLuint tex_samp_id;
        glGenTextures(1, &tex_samp_id);
        glBindTexture(GL_TEXTURE_2D, tex_samp_id);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex_surface->w, tex_surface->h, 0,
            GL_RGBA, GL_UNSIGNED_BYTE, tex_surface->pixels);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        this->tex_samp_ids.push_back(tex_samp_id);

        GLuint vb_uv_id;
        glGenBuffers(1, &vb_uv_id);
        glBindBuffer(GL_ARRAY_BUFFER, vb_uv_id);
        glBufferData(GL_ARRAY_BUFFER, (*it)->v_uv.size() * sizeof(glm::vec2), &(*it)->v_uv[0], GL_STATIC_DRAW);
        this->vb_uv_ids.push_back(vb_uv_id);
    }

    check_gl_error();

    return;
}


void OpenGL::draw(std::vector<Object*>& objs)   // draws GL_TRIANGLES
{
    std::vector<Object*>::iterator objs_it;
    std::vector<GLuint>::iterator vb_pos_it;
    std::vector<GLuint>::iterator vb_col_it;
    std::vector<GLuint>::iterator vb_uv_it;
    unsigned int i = 0;
    for (objs_it = objs.begin(), vb_pos_it = this->vb_pos_ids.begin(),
         vb_col_it = this->vb_col_ids.begin(), vb_uv_it = this->vb_uv_ids.begin();
         objs_it != objs.end(); ++objs_it, ++vb_pos_it, ++vb_col_it, ++vb_uv_it, ++i)
    {
        (*objs_it)->m_mat = glm::rotate((*objs_it)->m_mat, 1.0f, glm::vec3(0.0f, 1.0f, 0.0f));

        this->mvp_mat = this->p_mat * this->v_mat * (*objs_it)->m_mat;

        // send attribs to vertex shader
        glBindBuffer(GL_ARRAY_BUFFER, (*vb_pos_it));
        glVertexAttribPointer(this->pos_a_loc, 3, GL_FLOAT, GL_FALSE, 0, 0);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, this->tex_samp_ids[i]);

        glBindBuffer(GL_ARRAY_BUFFER, (*vb_uv_it));
        glVertexAttribPointer(this->uv_a_loc, 2, GL_FLOAT, GL_FALSE, 0, 0);

        // send uniforms to vertex shader
        glUniformMatrix4fv(this->p_mat_u_loc, 1, GL_FALSE, &this->p_mat[0][0]);
        glUniformMatrix4fv(this->v_mat_u_loc, 1, GL_FALSE, &this->v_mat[0][0]);
        glUniformMatrix4fv(this->m_mat_u_loc, 1, GL_FALSE, &(*objs_it)->m_mat[0][0]);
        glUniformMatrix4fv(this->mvp_mat_u_loc, 1, GL_FALSE, &this->mvp_mat[0][0]);
        glUniform1i(this->tex_samp_u_loc, 0);

        // draw
        glDrawArrays(GL_TRIANGLES, 0, (*objs_it)->v_pos.size());

        check_gl_error();
        glGetError();   // clear GL error before next iteration
    }

    return;
}

シンプルな.vsh:

#version 330 core

in vec3 pos_a;
in vec2 uv_a;

uniform mat4 p_mat_u;
uniform mat4 v_mat_u;
uniform mat4 m_mat_u;
uniform mat4 mvp_mat_u;

out vec2 uv_v;

void main()
{
    gl_Position = mvp_mat_u * vec4(pos_a, 1.0);
    uv_v = uv_a;
}

simple.fsh:

#version 330 core

smooth in vec2 uv_v;

uniform sampler2D tex_samp_u;

out vec4 color_o;

void main()
{
    color_o = texture2D(tex_samp_u, uv_v);
}