Question

我有一个光源照亮一个定义为

的平面

glBegin(GL_QUADS);
    glVertexAttrib3f(attribLoc, 0.0, 0.0, 1.0); // need to specify only once since the 
                                            // normal at all 4 vertexs' are the same
    glVertex3f(-200.0, -200.0, 0.0);
    glVertex3f(200.0, -200.0, 0.0);
    glVertex3f(200.0, 200.0, 0.0);
    glVertex3f(-200.0, 200.0, 0.0);
glEnd();

片段着色器仅计算漫反射组件。当光源
时，一切都很好在飞机前面。当我将光源移到飞机后面时，我仍然看到了一个亮点。我期待＆＃34; 0＆＃34;在这种情况下，每个像素的漫反射贡献。

diplay，reshape和shaders ......

void display(void){
    int attribLoc;
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    gluLookAt(0, 0, 5, 0, 0, 0, 0.0, 1.0, 10.0);   

    shader.bind();
    attribLoc = glGetAttribLocation(shader.id(), "app_to_vertex_normal"); 

    glUniform3f(glGetUniformLocation(shader.id(), "LightPos"), 0.0, 0.0, -2.0);

    // Setting the Material properties
    glUniform3f(glGetUniformLocation(shader.id(), "mdiffuse"), 0.6, 0.6, 0.6); 

    // Setting the Light properties
    glUniform3f(glGetUniformLocation(shader.id(), "ldiffuse"), 0.6, 0.6, 0.6); 

    glBegin(GL_QUADS);
    glVertexAttrib3f(attribLoc, 0.0, 0.0, 1.0); 

    glVertex3f(-200.0, -200.0, 0.0);
    glVertex3f(200.0, -200.0, 0.0);
    glVertex3f(200.0, 200.0, 0.0);
    glVertex3f(-200.0, 200.0, 0.0);
    glEnd();
    shader.unbind();

    glutSwapBuffers();
    }

    void reshape(int w, int h){
    glViewport(0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum(-300.0, 300.0, -300.0, 300.0, 5.0, 20.0); //(Perspective)
    glMatrixMode(GL_MODELVIEW);
    }

The Vertex shader
    #version 140
    in vec3 app_to_vertex_normal;
    out vec3 vertex_to_fragment_normal;
    out vec3 vertex_in_eye_coord;

    void main() {            
    // Set the position of the current vertex 
    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;

    vertex_in_eye_coord = vec3(gl_ModelViewMatrix * gl_Vertex);


    vertex_to_fragment_normal = gl_NormalMatrix*app_to_vertex_normal;

}


The fragment shader
#version 140

in vec3 vertex_to_fragment_normal;
in vec3 vertex_in_eye_coord;

uniform vec3 LightPos;

// Material properties 
uniform vec3 mdiffuse;

// Light properties 
uniform vec3 ldiffuse;

void main() {
vec3 vertex_to_light;
vec3 norm;

float diffuse_mult;
vec3 diffuse_comp;


// Diffuse component 
norm = normalize(vertex_to_fragment_normal);
vertex_to_light = normalize(LightPos-vertex_in_eye_coord);
diffuse_mult = max(dot(vertex_to_light, norm), 0.0);
diffuse_comp = diffuse_mult*ldiffuse*mdiffuse;  


gl_FragColor = vec4(diffuse_comp, 1.0); 

}

GLSL着色器错误地着色平面

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