Question

我遇到的问题是模型中的光照看起来好像在每个渲染的模型上都是相反的。我正在照亮一块瓷砖，每块瓷砖都封装了一个8x8较小瓷砖的子集，因此每个较大的瓷砖包含4 * 8 * 8个顶点。

Strange lighting effect...

我在Y方向上将法线设置为1 - 尝试将其反转但当然使得照明点相反，因此场景变暗。还试图扭转所有三角形的缠绕，但这只是产生了一个完全乱码的混乱。我确实将法线和光线位置传递到着色器，但我看不到会产生这种效果的任何东西。我已经在着色器周围戳了一下，改变了各种标志等，但没有修好它谁看过这个吗？我想找些什么来解决它？

这个项目涉及大量代码，所以我只发布我认为相关的内容。

为VBO数据初始化数组：

public void initVBOData(int _worldID, int SIZE, ArrayList<Cube> c){
    int i = 0;

    cubes = c;

    worldID = _worldID;
    QUAD_SIZE = SIZE;

    //the vertices for each tile
    vertBuffer[0] = 1;
    vertBuffer[1] = 1;
    vertBuffer[2] = 1;

    vertBuffer[3] = -1;
    vertBuffer[4] = 1;
    vertBuffer[5] = 1;

    vertBuffer[6] = -1;
    vertBuffer[7] = 1;
    vertBuffer[8] = -1;

    vertBuffer[9] = 1;
    vertBuffer[10] = 1;
    vertBuffer[11] = -1;

    for (int x = 0; x < QUAD_SIZE;x+=1 ){
        for (int z = 0; z < QUAD_SIZE;z+=1 ){

            vertBuffer[i + 0] = vertBuffer[0] + (2 * x);
            vertBuffer[i + 1] = vertBuffer[1];
            vertBuffer[i + 2] = vertBuffer[2] + (2 * z);
            vertBuffer[i + 3] = vertBuffer[3] + (2 * x);
            vertBuffer[i + 4] = vertBuffer[4];
            vertBuffer[i + 5] = vertBuffer[5] + (2 * z);
            vertBuffer[i + 6] = vertBuffer[6] + (2 * x);
            vertBuffer[i + 7] = vertBuffer[7];
            vertBuffer[i + 8] = vertBuffer[8] + (2 * z);
            vertBuffer[i + 9] = vertBuffer[9] + (2 * x);
            vertBuffer[i + 10] = vertBuffer[10];
            vertBuffer[i + 11] = vertBuffer[11] + (2 * z);  
            i+=12;
        }
    }

    //the IBO index values
    i = 0;
    idxBuffer[0] = 1;
    idxBuffer[1] = 0;
    idxBuffer[2] = 3;
    idxBuffer[3] = 3;
    idxBuffer[4] = 2;
    idxBuffer[5] = 1;
    for (int x = 1; x < 64; x++){
        i+=6;
        idxBuffer[0 + i] = (4 * x) + 1;
        idxBuffer[1 + i] = (4 * x) + 0;
        idxBuffer[2 + i] = (4 * x) + 3;
        idxBuffer[3 + i] = (4 * x) + 3;
        idxBuffer[4 + i] = (4 * x) + 2;
        idxBuffer[5 + i] = (4 * x) + 1;
    }

    //the normals for each vertex.
    for (i = 0; i<vertBuffer.length;i+=3){
        normals[0 + i] = 0;
        normals[1 + i] = 1;
        normals[2 + i] = 0;
    }

    //the uvs for texture
    for (i = 0; i < UVs.length; i+=32){
        System.arraycopy(yellow, 0, UVs, i, 8);
        System.arraycopy(red, 0, UVs, i + 8, 8);
        System.arraycopy(green, 0, UVs, i + 16, 8);
        System.arraycopy(blue, 0, UVs, i + 24, 8);
    }
}

灯光位置和方向（在draw（）方法中设置）：

    glfwSwapBuffers(window); // swap the color buffers

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the framebuffer

    //calc rotate camera
    if (updatecamera == true){
        updateCamera();
    }

    glUseProgram(shader.iProgram);

    Vector4f lp = new Vector4f(lightX, lightY, lightZ,1.0f);

    //camera is the 4x matrix representing 'lookAt'
    shader.setUniform(iLightCam, camera);
    shader.setUniform(iLightVec, lp);

片段着色器

#version 430

in vec3 Position;
in vec3 Normal;
in vec2 TexCoord;

//uniform sampler2D Tex1;
layout(binding=0) uniform sampler2D Tex1;

struct LightPos {
    vec4 LightVector;
    mat4 CameraPos;
};
uniform LightPos SetLight;

struct LightInfo {
    vec4 Position; //light pos in eye coords
    vec3 Intensity; //ads light intensity 
};
uniform LightInfo Light;

struct MaterialInfo {
    vec3 Ka; //ambient reflectivity
    vec3 Kd; //diffuse reflectivity
    vec3 Ks; //specular reflectivity
    float Shininess; //specular shininess factor
};
uniform MaterialInfo Material;

layout ( location = 0 ) out vec4 FragColor;

void phongModel (vec3 position, vec3 norm, out vec3 ambanddiff, out vec3 spec)
{

    vec4 LightPosition = SetLight.LightVector * SetLight.CameraPos;

    vec3 s = normalize( vec3(LightPosition) - position);
    vec3 v = normalize( -position.xyz );
    vec3 r = reflect( -s, norm );
    vec3 ambient = Light.Intensity * Material.Ka;
    float sDotN = max( dot( s, norm ), 0.0);
    vec3 diffuse = Light.Intensity * Material.Kd * sDotN;
    spec = vec3(0.0);

    if ( sDotN > 0.0 ) 
        spec = Light.Intensity * Material.Ks * pow(max( dot(r,v), 0.0), Material.Shininess);

    ambanddiff = ambient + diffuse;
}

void main(void) 
{
    vec3 ambanddiff, spec;
    vec4 texColor = texture( Tex1, TexCoord );

    phongModel (Position, Normal, ambanddiff, spec);
    FragColor = vec4(ambanddiff, 1.0) * texColor + vec4(spec, 1.0); 
}

顶点着色器

#version 430

layout (location = 0) in vec3 VertexPosition;
layout (location = 1) in vec3 VertexNormal;
layout (location = 2) in vec2 VertexTexCoord;

out vec3 Position;
out vec3 Normal;
out vec2 TexCoord;

out vec4 MVPPos;

uniform mat4 ModelViewMatrix;
uniform mat3 NormalMatrix;
uniform mat4 ProjectionMatrix;
uniform mat4 MVP;

void main()
{
    TexCoord = VertexTexCoord;
    Normal = normalize( NormalMatrix * VertexNormal );
    Position = vec3( ModelViewMatrix * vec4(VertexPosition,1.0) );
    //gl_Position = MVP * vec4(VertexPosition,1.0);
    MVPPos = MVP * vec4(VertexPosition,1.0);
    gl_Position = MVPPos;
}

Answer 1

三天后我终于明白了。我唯一的线索是灯光以某种方式被颠倒了＃39;所以我花了很多时间改变符号 - 到+，反之亦然，改变各种乘法顺序。最后，错误不在我的着色器中。我传递给＆＃34; ModelViewMatrix＆＃34;的价值。在顶点着色器中计算的顺序错误。

        Matrix4f.mul(model, camera, modelview); 
        shader.setUniform(iModelView, modelview);

应该是：

        Matrix4f.mul(camera, model, modelview); 
        shader.setUniform(iModelView, modelview);

All good now

opengl照明在每个型号上都是相反的

1 个答案: