法向量可视化

绘制物体
绘制物体法向量

VS

#version 450 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;

out VS_OUT {
    vec3 normal;
} vs_out;

uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;

void main(){
    gl_Position = projection * view * model * vec4(aPos, 1.0); 
    
    //法向量旋转矩阵，当物体有旋转缩放操作时，可正确改变其法向量
    mat3 normalMatrix = mat3(transpose(inverse(view * model)));
    
    vs_out.normal = normalize(vec3(projection * vec4(normalMatrix * aNormal, 0.0)));
}

GS

#version 330 core
layout (triangles) in;
layout (line_strip, max_vertices = 6) out;

in VS_OUT {
    vec3 normal;
} gs_in[];

const float MAGNITUDE = 0.1;//调整法线可视长度

out vec3 color;

void GenerateLine(int index)
{
    gl_Position = gl_in[index].gl_Position;
    color = vec3(0.0, 0.0, 0.0);
    EmitVertex();
    gl_Position = gl_in[index].gl_Position + vec4(gs_in[index].normal, 0.0) * MAGNITUDE;
    color = vec3(1.0, 1.0, 1.0);
    EmitVertex();
    EndPrimitive();
}

void main()
{
    GenerateLine(0); // 第一个顶点法线
    GenerateLine(1); // 第二个顶点法线
    GenerateLine(2); // 第三个顶点法线
}

FS

#version 450 core
out vec4 FragColor;

in vec3 color;

void main()
{
FragColor = vec4(color , 1.0);
}

绘制

normalDisplayShader.use();
normalDisplayShader.setMat4("projection", projection);
normalDisplayShader.setMat4("view", view);
normalDisplayShader.setMat4("model", model);
ourModel.Draw(normalDisplayShader);