OpenGL阴影贴图几乎可以正常工作

我正在尝试按照教程将实时阴影映射添加到我的Minecraft类克隆中：此处

首先会发生什么：

据我所知，阴影贴图是否正确渲染？问题似乎出在最后一遍。

我创建深度纹理：

glGenFramebuffers(1, &m_frameBufferId);
glBindFramebuffer(GL_FRAMEBUFFER, m_frameBufferId);
glGenTextures(1, &m_depthTexture);
glBindTexture(GL_TEXTURE_2D, m_depthTexture);
glTexImage2D(GL_TEXTURE_2D, 0,GL_DEPTH_COMPONENT16, 1024, 1024, 0,GL_DEPTH_COMPONENT, GL_FLOAT, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); 
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_NONE);

glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, m_depthTexture, 0);
glDrawBuffer(GL_NONE);

注意：我还尝试将GL_COMPARE_R_TO_TEXTURE与着色器中的sampler2DShadow结合使用。结果一样。

然后运行两遍：

// ====================    Shadow    =====================
glBindFramebuffer(GL_FRAMEBUFFER, m_frameBufferId);
glViewport(0, 0, 1024, 1024);

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

ShadowShader->Bind();
VCSceneGraph::Instance->RenderGraph();


// ====================    Final    =======================
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glViewport(0, 0, 1280, 800);

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

VoxelShader->Bind();
VCSceneGraph::Instance->RenderGraph();

阴影着色器代码：

// ====================    Vert    =====================
#version 330 core\n

in vec4 vertexPosition_modelspace;
uniform mat4 depthMVP;

void main()
{
    gl_Position =  depthMVP * vertexPosition_modelspace;
}

// ====================    Frag    =====================
#version 330 core\n

out float fragmentdepth;

void main()
{
    fragmentdepth = gl_FragCoord.z;
}

最终通过（Voxel Shader）代码：

// ====================    Vert    =====================
#version 330 core\n

in vec3 position;
in int normal;
in vec4 color;

out vec4 colorVarying;
out vec4 ShadowCoord;

uniform mat4 modelViewProjectionMatrix;
uniform mat4 DepthBiasMVP;

void main()
{
    gl_Position =  modelViewProjectionMatrix * vec4(position, 1);
    ShadowCoord = DepthBiasMVP * vec4(position, 1);
    colorVarying = color;
}

// ====================    Frag    =====================
#version 330 core\n

in vec4 colorVarying;
in vec4 ShadowCoord;

out vec4 color;

uniform sampler2D  shadowMap;

void main()
{
    float visibility = 1.0;

    if ( texture(shadowMap, ShadowCoord.xy).z  <  ShadowCoord.z)
    {
        visibility = 0.5;
    }

    color.xyz = colorVarying.xyz * visibility;
    color.w = colorVarying.w;
}

我怀疑我的问题出在更新最终通行证制服的代码中：

// Re-create the exact same MVP matrix that was used for the shadow pass
glm::mat4 depthProjectionMatrix = glm::ortho<float>( -30, 30, -30, 30, -100, 100);
glm::mat4 depthViewMatrix = glm::lookAt(glm::vec3(0.5f, 2, 2), glm::vec3(0,0,0), glm::vec3(0,1,0));
depthViewMatrix = glm::translate(depthViewMatrix, -15.0f, 30.0f, 0.0f);
glm::mat4 depthMVP = depthProjectionMatrix * depthViewMatrix;// * modelMatrix;

// Multiply it be the bias matrix
glm::mat4 biasMatrix
(
    0.5, 0.0, 0.0, 0.0,
    0.0, 0.5, 0.0, 0.0,
    0.0, 0.0, 0.5, 0.0,
    0.5, 0.5, 0.5, 1.0
);

glm::mat4 depthBiasMVP = biasMatrix * depthMVP;

// Create Camera's MVP
VCCamera* currentCamera = VCSceneGraph::Instance->CurrentRenderingCamera;
glm::mat4 ProjectionMatrix = currentCamera->ProjectionMatrix;
glm::mat4 ViewMatrix = currentCamera->ViewMatrix;
glm::mat4 MVP = ProjectionMatrix * ViewMatrix;// * modelMatrix;

// Update uniforms
glUniformMatrix4fv(m_unifMVP, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(m_unifDepthMVP, 1, GL_FALSE, &depthBiasMVP[0][0]);

编辑：

我通过使“阴影”纹理与窗口具有相同的分辨率来解决此问题。但是，我无法解释为什么可以解决此问题。如果有人想破解，我会接受您的回答。预期的输出是这样的：

我还应该指出，完整的源代码可以在GitHub上找到。