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c++ - 来自 FBO 的反射纹理得到正确的图像

问题描述

我正在使用 A FBO 来捕捉四边形表面上方的反射。前提是在水面下移动相机，然后将场景渲染到fbo，然后恢复到原来的观看位置，如下所示：

WaterFrameBuffer fbos;


Water test(fbos.getReflectionTexture(), fbos.getRefractionTexture());
render->addWater(&test);
while (!glfwWindowShouldClose(window))
{
    GLfloat currentFrame = (float)glfwGetTime();
    deltaTime = currentFrame - lastFrame;
    lastFrame = currentFrame;
    gameController->update(deltaTime);

    //reflection buffer
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    fbos.bindReflectionFrameBuffer();
    float distance = 2 * (gameController->getGameCamera()->GetCameraPosition().y - 0);
    gameController->getGameCamera()->GetCameraPosition().y -= distance;
    gameController->getGameCamera()->flipPitch();
    render->renderScene();
    gameController->getGameCamera()->GetCameraPosition().y += distance;
    gameController->getGameCamera()->flipPitch();
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);

    //refraction buffer
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    fbos.bindRefractionFrameBuffer();
    render->renderScene();
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);

    render->renderScene();
    render->renderWater();
    glfwSwapBuffers(window);
}

但是我得到了这个结果：折射+反射

折射图像是正确的，但是反射没有拍摄正确的图像。这本身就是反射在此处输入图像描述

这是我正在使用的片段着色器：

  #version 330 core
   in vec3 ourColor;
   in vec4 clipSpace;
   in vec2 texC;
    out vec4 color;

 // Texture samplers
   uniform sampler2D reflectTex;
   uniform sampler2D refractTex;
   //uniform sampler2D dudvTex;
void main()
{
   vec3 ndc = (clipSpace.xyz / clipSpace.w)/ 2.0 + 0.5;
   vec2 reflectTexCoords = vec2(ndc.x, -ndc.y);
   vec2 refractTexCoords = vec2(ndc.x, ndc.y);

   //vec2 distortion1 = texture(dudvTex, vec2(texC.x, texC.y)).rg*2.0 - 1.0;
   //reflectTexCoords += distortion1;
   //refractTexCoords += distortion1;

    vec4 reflect = texture(reflectTex, reflectTexCoords);
    vec4 refract = texture(reflectTex, refractTexCoords);
    color = reflect;//mix(reflect,refract,0.5);
}

顶点着色器：

  #version 330 core
  layout (location = 0) in vec3 position;
   layout (location = 1) in vec3 color;
  layout (location = 2) in vec2 texCoord;

   out vec3 ourColor;
   out vec4 clipSpace;
   out vec2 texC;
   uniform mat4 model;
   uniform mat4 view;
   uniform mat4 projection;
   const float tiling = 6.0;
   void main()
   {
       clipSpace = projection*view*model *vec4(position, 1.0f);
       gl_Position = clipSpace;
       ourColor = color;
       texC = texCoord;
    }

任何想法如何解决此问题或获取反射图像的替代方法？

标签： c++openglglfw

解决方案

GL_TEXTURE_WRAP_S我假设您已经为和GL_TEXTURE_WRAP_Tto设置了纹理包裹参数GL_CLAMP_TO_EDGE。见glTexParameter。

这会导致任何纹理坐标都被限制在范围内[0+1/(2*texturSize), 1-1/(2*textureSize)]。

要解决您的问题，您必须使用纹理包装参数GL_REPEAT，或者您必须确保纹理坐标在 [0.0, 1.0] 范围内。

上图中的问题是y纹理坐标( )的分量取反-ndc.y，导致纹理坐标在[0.0, -1.0]范围内。将坐标移动到范围 [1.0, 0.0] 并1.0 - ndc.y改用：

vec2 reflectTexCoords = vec2(ndc.x, 1.0 - ndc.y);

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