ImGui+OpenGL，渲染函数无法渲染字体

正如标题所说，我正在使用ImGui，但我无法让我的渲染函数来渲染字体。

我做过的事情：

1. 已验证我的纹理是否已正确加载 RenderDoc
2. 已验证我的顶点属性指针是否符合ImGui的约定(结构数组(。

下面是我的渲染代码。您还可以在此处查看开发人员的OpenGL示例代码：https://github.com/ocornut/imgui/blob/master/examples/opengl3_example/imgui_impl_glfw_gl3.cpp

// Setup some GL state
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
// Setup orthographic projection
glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
const float ortho_projection[4][4] =
{
    { 2.0f/io.DisplaySize.x, 0.0f,                   0.0f, 0.0f },
    { 0.0f,                  2.0f/-io.DisplaySize.y, 0.0f, 0.0f },
    { 0.0f,                  0.0f,                  -1.0f, 0.0f },
    {-1.0f,                  1.0f,                   0.0f, 1.0f },
};
// Setup the shader. bind() calls glUseProgram and enables/disables the proper vertex attributes
shadeTextured->bind(); 
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, g_FontTexture);
shadeTextured->setUniformM4(Shader::uhi_transform, *(glm::mat4*)&ortho_projection[0][0]);
shadeTextured->setUniformSampler(1, 0);
// Set my vertex attribute pointers for position and tex coords
glVertexAttribPointer(0,
                      2,
                      GL_FLOAT,
                      GL_FALSE,
                      sizeof(ImDrawVert),
                      (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
glVertexAttribPointer(1,
                      2,
                      GL_FLOAT,
                      GL_FALSE,
                      sizeof(ImDrawVert),
                      (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
// Loop through all commands ImGui has 
for (int n = 0; n < draw_data->CmdListsCount; n++) {
    const ImDrawList* cmd_list = draw_data->CmdLists[n];
    const ImDrawIdx* idx_buffer_offset = 0;
    glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
    glBufferData(GL_ARRAY_BUFFER,
                 (GLsizeiptr)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert),
                 (const GLvoid*)cmd_list->VtxBuffer.Data,
                 GL_STREAM_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,
                 (GLsizeiptr)cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx),
                 (const GLvoid*)cmd_list->IdxBuffer.Data,
                 GL_STREAM_DRAW);
    for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++) {
        const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
        glScissor((int)pcmd->ClipRect.x,
                  (int)(fb_height - pcmd->ClipRect.w),
                  (int)(pcmd->ClipRect.z - pcmd->ClipRect.x),
                  (int)(pcmd->ClipRect.w - pcmd->ClipRect.y));
        glDrawElements(GL_TRIANGLES,
                       (GLsizei)pcmd->ElemCount,
                       sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT,
                       idx_buffer_offset);
        idx_buffer_offset += pcmd->ElemCount;
    }
}

这是我编写的(非常非常简单的(着色器。着色器以前曾对按钮进行纹理处理，因此我假设它们在功能上是正确的。

顶点着色器： #version 330 核

layout (location = 0) in vec2 pos;
layout (location = 1) in vec2 texCoord;
out vec2 fragTexCoord;
uniform mat4 transform;
void main() {   
    gl_Position = transform * vec4(pos, 0.0, 1.0);
    fragTexCoord = texCoord;
}

片段着色器：

#version 330 core
out vec4 fragColor;
in vec2 fragTexCoord;
uniform sampler2D sampler;
void main() {
    fragColor = texture(sampler, fragTexCoord);
}

我完全不知所措！任何帮助将不胜感激