Question

我已经使用此加载了一个对象（.obj）模型（来自此tutorial）：

void Model::loadOBJ(const char * path, std::vector < vector3 > & out_vertices,    std::vector < vector2 > & out_uvs, std::vector < vector3 > & out_normals){
std::vector<unsigned int> vertexIndices, uvIndices, normalIndices;
std::vector<vector3> temp_vertices;
std::vector<vector2> temp_uvs;
std::vector<vector3> temp_normals;

FILE * file = fopen(path, "r");
if (file == NULL)
    return;
while (1){
    char lineHeader[128];
    int res = fscanf(file, "%s", lineHeader);
    if (res == EOF)
        break;
    if (strcmp(lineHeader, "v") == 0){
        vector3 vertex;
        fscanf(file, "%f %f %f\n", &vertex.x, &vertex.y, &vertex.z);
        temp_vertices.push_back(vertex);
    }else if (strcmp(lineHeader, "vt") == 0){
        vector2 uv;
        fscanf(file, "%f %f\n", &uv.x, &uv.y);
        temp_uvs.push_back(uv);
    }else if (strcmp(lineHeader, "f") == 0){
        std::string vertex1, vertex2, vertex3;
        unsigned int vertexIndex[3], uvIndex[3], normalIndex[3];
        int matches = fscanf(file, "%d/%d/%d %d/%d/%d %d/%d/%d\n", &vertexIndex[0], &uvIndex[0], &normalIndex[0], &vertexIndex[1], &uvIndex[1], &normalIndex[1], &vertexIndex[2], &uvIndex[2], &normalIndex[2]);
        if (matches != 9){
            exit(matches);
            return;}
        vertexIndices.push_back(vertexIndex[0]);
        vertexIndices.push_back(vertexIndex[1]);
        vertexIndices.push_back(vertexIndex[2]);
        uvIndices.push_back(uvIndex[0]);
        uvIndices.push_back(uvIndex[1]);
        uvIndices.push_back(uvIndex[2]);
        normalIndices.push_back(normalIndex[0]);
        normalIndices.push_back(normalIndex[1]);
        normalIndices.push_back(normalIndex[2]);
    }
}   
for (unsigned int i = 0; i < vertexIndices.size(); i++){
    unsigned int vertexIndex = vertexIndices[i];
    vector3 vertex = temp_vertices[vertexIndex - 1];
    out_vertices.push_back(vertex);
}
for (unsigned int i = 0; i < uvIndices.size(); i++){
    unsigned int uvIndex = uvIndices[i];
    vector2 uv = temp_uvs[uvIndex - 1];
    //vertex.normalise();
    out_uvs.push_back(uv);
}
}

我用

绘制它

void Model::draw()
{   
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture);
glBegin(GL_TRIANGLES);
glPushMatrix();
glLoadIdentity();
glClearColor(0.0, 0.0, 0.0, 0.0);
glColor3f(1, 1, 1);
for (int l_index = 0; l_index < vertices.size(); l_index++)
{
    glTexCoord2f(uvs[l_index].x, uvs[l_index].y);
    glVertex3f(vertices[l_index].x * 5, vertices[l_index].y * 5, vertices[l_index].z * 5);
}
glDisable(GL_TEXTURE_2D);
glEnd();
}

模型正确加载并保存.obj文件中的法线，uv和顶点。

我如何为此制作着色器？

Answer 1

您将需要阅读有关GLSL基础知识的一些教程。由于模型包含xyz位置，uv纹理坐标和xyz法线，因此这些将是您的顶点着色器的输入。顶点着色器将使用您的世界/视图/投影矩阵将顶点转换为剪辑空间，将纹理坐标传递给像素着色器，并且像素着色器将从纹理贴图中查找颜色。

在Opengl中为加载的OBJ模型创建着色器

1 个答案: