我有一个关于交错vbo的问题。我有一个看起来像这样的结构
struct VertexData{
float x,y,z; //vertex coordinates
float normalx,normaly,normalz; //vertex normal
float cx,cy,cz; //vertex color
};
这就是我创建VBO,VAO,IBO的方式:
//creat OpenGL objects to use in drawing
unsigned int gl_vertex_array_object, gl_vertex_buffer_object, gl_index_buffer_object;
//vertex array object
glGenVertexArrays(1, &gl_vertex_array_object);
glBindVertexArray(gl_vertex_array_object);
//vertex buffer object -> we hold the vertices
glGenBuffers(1,&gl_vertex_buffer_object);
glBindBuffer(GL_ARRAY_BUFFER, gl_vertex_buffer_object);
glBufferData(GL_ARRAY_BUFFER, vertices.size()*sizeof(VertexData), &vertices[0], GL_STATIC_DRAW);
//index buffer object -> we hold the index of vertex
glGenBuffers(1,&gl_index_buffer_object);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gl_index_buffer_object);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size()*sizeof(unsigned int), &indices[0], GL_STATIC_DRAW);
//the connection between attributes, interleaved data
glEnableVertexAttribArray(0);
glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,sizeof(VertexData),(void*)0); //send positions on pipe 0
glEnableVertexAttribArray(1);
glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,sizeof(VertexData),(void*)(sizeof(float)*3)); //send normals on pipe 1
glEnableVertexAttribArray(2);
glVertexAttribPointer(2,3,GL_FLOAT,GL_FALSE,sizeof(VertexData),(void*)(3*sizeof(float)*3)); //send colors on pipe 2
glEnableClientState(GL_NORMAL_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glNormalPointer(GL_FLOAT,sizeof(VertexData),(void*)(sizeof(float)*3));
glColorPointer(3,GL_FLOAT,sizeof(VertexData),(void*)(3*sizeof(float)*3));
vao = gl_vertex_array_object;
vbo = gl_vertex_buffer_object;
ibo = gl_index_buffer_object;
num_indices = indices.size();
如果我的VBO是VertexData的向量,是否意味着它是交错的?我上面发送的数据是否正确?有步幅和偏移? 这一切都在另一堂课上。这是我如何加载网格并在主类
中绘制它 //load
teren::loadTerrain("resurse\\heightmap.bmp","resurse\\heightmap_color.bmp",mesh_vao_ground, mesh_vbo_ground, mesh_ibo_ground, mesh_num_indices_ground,20);
//draw
glUniformMatrix4fv(glGetUniformLocation(gl_program_shader_curent, "model_matrix"),1,false,glm::value_ptr(matrice_translatie));
glBindVertexArray(mesh_vao_ground);
glDrawElements(GL_TRIANGLES, mesh_num_indices_ground, GL_UNSIGNED_INT, 0);
我的地形已被绘制,但它有一种奇怪的颜色。它有粉红色和蓝色等等,看起来不像我得到我的顶点颜色的彩色图像。这是我的gourard顶点着色器:
layout(location = 0) in vec3 in_position;
layout(location = 1) in vec3 in_normal;
layout(location = 2) in vec3 in_color;
uniform mat4 model_matrix, view_matrix, projection_matrix;
uniform vec3 light_position;
uniform vec3 eye_position;
uniform int material_shininess;
uniform float material_kd;
uniform float material_ks;
out vec3 light;
void main(){
gl_Position = projection_matrix*view_matrix*model_matrix*vec4(in_position,1.0);
float fDiffuseIntensity = material_kd * max(0.0, dot(normalize(in_normal), normalize(light_position)));
light = material_ks * in_color * fDiffuseIntensity;
}
我的gourard片段着色器:
in vec3 light;
out vec4 out_color;
void main()
{
out_color = vec4(light,1.0);
}
我现在真的被困住了。这是我的着色器或我的vbo /属性等问题,甚至两者都有问题。我真的很感激一些帮助。(PS:如果在顶点着色器中我改为light = in_color,一切都是白色的。)我也有一个在地形上方旋转的光。这是一张正在发生的事情的照片: http://i44.tinypic.com/69j0cg.jpg
答案 0 :(得分:4)
这一行:
glVertexAttribPointer(2,3,GL_FLOAT,GL_FALSE,sizeof(VertexData),(void*)(3*sizeof(float)*3));
应该是:
glVertexAttribPointer(2,3,GL_FLOAT,GL_FALSE,sizeof(VertexData),(void*)(sizeof(float)*6));
你也不需要这些东西:
glEnableClientState(GL_NORMAL_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glNormalPointer(GL_FLOAT,sizeof(VertexData),(void*)(sizeof(float)*3));
glColorPointer(3,GL_FLOAT,sizeof(VertexData),(void*)(3*sizeof(float)*3));
其余的都是正确的。
是否意味着它是交错的?
是
语言律师可能会告诉您,由于允许编译器在VertexData
结构内的任何位置添加填充,将这些数据传递给GL的正确方法是手动转换VertexData
的向量到漂浮物的缓冲区。实际上,没有编译器垫在这样的结构中浮动。