Question

我已经按照许多在线教程进行法线贴图，并且在一定程度上让它工作了......

除非多边形垂直于视图矢量，否则我似乎无法正常工作。

我创建了一个视频来说明这一点，因为图片并不足以显示我的意思。

http://www.youtube.com/watch?v=9D4o_zy-61s

我发布了着色器：

顶点：

#version 400
layout (location = 0) in vec3 attribPosition;
layout (location = 1) in vec3 attribNormal;
layout (location = 2) in vec2 attribTexCoord;
layout (location = 3) in vec3 attribTangent;
layout (location = 3) in vec3 attribBinormal;

uniform mat4 mvp;
uniform mat4 mvm;
uniform mat3 nm;
uniform vec3 lightPos_World;

out vec2 vUvs;
out vec3 lightPos_Eye;
out vec3 vertexPos_Eye;
out vec3 normalDir_Eye;
out vec3 normalDir_World;
out mat3 tbnMatrix;

void main()
{
    vUvs = attribTexCoord;
    normalDir_World = attribNormal;
    normalDir_Eye = (nm * attribNormal);
    vec3 t = nm * attribTangent;
    vec3 n = nm * attribNormal;
    vec3 b = nm * cross(n,t);

    mat3 tbnMatrix = mat3(t.x, b.x, n.x,
                          t.y, b.y, n.y,
                          t.z, b.z, n.z);

    vertexPos_Eye = (mvm * vec4(attribPosition,1.0)).xyz;
    lightPos_Eye = (mvm * vec4(lightPos_World,1.0)).xyz;

    gl_Position = mvp * vec4(attribPosition,1.0);
}

片段：

#version 400
layout( location = 0 ) out vec4 frag_main;
struct PointLight{
    vec3 position;
    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
    float shininess;
    float intensity;
};

uniform PointLight light[2];
uniform sampler2D colorTexture;
uniform sampler2D normalTexture;
uniform mat4 mvm;
//  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//  FLAGS - all flags start false;
//  [0][0] = colour map
//  [0][1] = normal map
//  [0][2] = unused
//  [0][3] = show normal map in colour channel
//  [1][0] = use tangent space
//  [1][1] = unused
//  [1][2] = unused
//  [1][3] = unused
//  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
uniform bvec4 flags[2];

in vec3 vertexPos_Eye;
in vec3 normalDir_World;
in vec3 normalDir_Eye;
in vec2 vUvs;
in mat3 tbnMatrix;


void main(){

    uint numLights=2;

    vec3 colorFragment;
    if(flags[0][0]){
        colorFragment = texture(colorTexture,vUvs).xyz; 
    }else{
        colorFragment = vec3(0.5);  
    }

    vec3 normalMapNormal = (texture(normalTexture,vUvs).rgb * 2) - 1;
    vec3 normalDir;
    if(flags[0][1]){
        normalDir = normalize(normalDir_Eye);
    }else{
        normalDir =  normalize(normalMapNormal.rgb);
    }

    vec4 outColor = vec4(1);
    outColor.xyz = vec3(0);

    float duller = 1/numLights;
    for(int i = 0;i< numLights;i++){
        vec3 lightPos_Eye = (mvm * vec4(light[i].position,1.0)).xyz;
        vec3 lightDir_Eye = normalize(lightPos_Eye - vertexPos_Eye);
        vec3 lightDir_Tangent = lightDir_Eye * tbnMatrix;

        vec3 vertDir_Eye = normalize(-vertexPos_Eye);
        vec3 vertDir_Tangent = vertDir_Eye * tbnMatrix;

        vec3 halfDir_Eye = normalize(vertDir_Eye + lightDir_Eye);
        vec3 halfDir_Tangent = halfDir_Eye * tbnMatrix;

        vec3 Ia = colorFragment.xyz * light[i].ambient;
        vec3 Id;
        vec3 Is;

        // tangent space
        Id = (colorFragment.xyz * light[i].diffuse ) * max(dot(lightDir_Tangent, normalDir), 0);
        Is = light[i].specular * pow(max(dot(halfDir_Eye, normalDir), 0), light[i].shininess*2);
        // eye space
        //Id = (colorFragment.xyz * light[i].diffuse ) * max(dot(lightDir_Eye, normalDir), 0);
        //Is = light[i].specular * pow(max(dot(halfDir_Eye, normalDir), 0), light[i].shininess*2);

        outColor.xyz += (Ia + Id + Is);

    }

    if(flags[0][3]){
        outColor.xyz = normalDir;
    }
    frag_main = (outColor);
}

Answer 1

我注意到了这一行：

vec3 b = nm * cross(n,t);

但它应该是：

vec3 b = cross(n,t);

由于nm和n位于所需的相机空间，因此无需再次乘以t。

另一件事：

lightPos_Eye = (mvm * vec4(lightPos_World,1.0)).xyz;

由于lightPos_World位于世界空间（顾名思义），因此您应该将其乘以* world_matrix *，而不是模型视图。或者只是在应用程序代码中计算lightPos_Eye并将其发送到顶点着色器。

很难管理所有这些不同的载体并将它们放在一个适当的空间中。有时，视觉错误非常微妙，难以发现。

正常映射问题

1 个答案: