我正在用OpenGL制作3D游戏,它基本上拥有一个完全由AABB立方体制成的世界。我创建了这个以制作24个verticie立方体:
void CBox::UpdateDimensions( float w, float h, float d, Vertex3f c )
{
width = w;
height = h;
depth = d;
center = c;
Vertex3f verticies[24];
GLfloat vboverticies[72];
GLfloat vbonormals[18];
//Top face
verticies[0] = Vertex3f(-width / 2.0f,height / 2.0f, -depth / 2.0f);
verticies[1] = Vertex3f(-width / 2.0f,height / 2.0f, depth / 2.0f);
verticies[2] = Vertex3f(width / 2.0f,height / 2.0f, depth / 2.0f);
verticies[3] = Vertex3f(width / 2.0f,height / 2.0f, -depth / 2.0f);
//Bottom face
verticies[4] = Vertex3f(-width / 2.0f,-height / 2.0f, -depth / 2.0f);
verticies[5] = Vertex3f(width / 2.0f,-height / 2.0f, -depth / 2.0f);
verticies[6] = Vertex3f(width / 2.0f,-height / 2.0f, depth / 2.0f);
verticies[7] = Vertex3f(-width / 2.0f,-height / 2.0f, depth / 2.0f);
//Left face
verticies[8] = Vertex3f(-width / 2.0f,-height / 2.0f, -depth / 2.0f);
verticies[9] = Vertex3f(-width / 2.0f,-height / 2.0f, depth / 2.0f);
verticies[10] =Vertex3f(-width / 2.0f,height / 2.0f, depth / 2.0f);
verticies[11] =Vertex3f(-width / 2.0f,height / 2.0f, -depth / 2.0f);
//Right face
verticies[12] =Vertex3f(width / 2.0f,-height / 2.0f, -depth / 2.0f);
verticies[13] =Vertex3f(width / 2.0f,height / 2.0f, -depth / 2.0f);
verticies[14] =Vertex3f(width / 2.0f,height / 2.0f, depth / 2.0f);
verticies[15] =Vertex3f(width / 2.0f,-height / 2.0f, depth / 2.0f);
//Front face
verticies[16] =Vertex3f(-width / 2.0f,-height / 2.0f, depth / 2.0f);
verticies[17] =Vertex3f(width / 2.0f,-height / 2.0f, depth / 2.0f);
verticies[18] =Vertex3f(width / 2.0f,height / 2.0f, depth / 2.0f);
verticies[19] =Vertex3f(-width / 2.0f,height / 2.0f, depth / 2.0f);
//Back face
verticies[20] =Vertex3f(-width / 2.0f,-height / 2.0f, -depth / 2.0f);
verticies[21] =Vertex3f(-width / 2.0f,height / 2.0f, -depth / 2.0f);
verticies[22] =Vertex3f(width / 2.0f,height / 2.0f, -depth / 2.0f);
verticies[23] =Vertex3f(width / 2.0f,-height / 2.0f, -depth / 2.0f);
for(int i = 0; i < 24; i++)
{
verticies[i].x += center.x;
verticies[i].y += center.y;
verticies[i].z += center.z;
}
int count = 0;
for(int i = 0; i < 24; ++i)
{
vboverticies[count] = verticies[i].x;
count++;
vboverticies[count] = verticies[i].y;
count++;
vboverticies[count] = verticies[i].z;
count++;
}
//glNormal3f(0.0, 1.0f, 0.0f);
//glNormal3f(0.0, -1.0f, 0.0f);
//glNormal3f(-1.0, 0.0f, 0.0f);
//glNormal3f(1.0, 0.0f, 0.0f);
//glNormal3f(0.0, 0.0f, 1.0f);
//glNormal3f(0.0, 0.0f, -1.0f);
vbonormals[0] = (0.0);
vbonormals[1] = (1.0);
vbonormals[2] = (0.0);
vbonormals[3] = (0.0);
vbonormals[4] = (-1.0);
vbonormals[5] = (0.0);
vbonormals[6] = (-1.0);
vbonormals[7] = (0.0);
vbonormals[8] = (0.0);
vbonormals[9] = (1.0);
vbonormals[10]= (0.0);
vbonormals[11]= (0.0);
vbonormals[12]= (0.0);
vbonormals[13]= (0.0);
vbonormals[14]= (1.0);
vbonormals[15]= (0.0);
vbonormals[16]= (0.0);
vbonormals[17]= (-1.0);
RecalculateMinAndMax();
//Create the VBO
glDeleteBuffers(1, &vboID);
glGenBuffersARB(1, &vboID);
glBindBufferARB(GL_ARRAY_BUFFER, vboID);
glBufferDataARB(GL_ARRAY_BUFFER, (72 * sizeof(GLfloat)) +
(18 * sizeof(GLfloat)) , NULL, GL_STATIC_DRAW);
glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, 0, 72 * sizeof(GLfloat), vboverticies);
glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, 72 * sizeof(GLfloat),
18 * sizeof(GLfloat), vbonormals);
}
我想知道的是,如果只通过向显卡上传8个顶点而不是24个来实现这个目的吗?
呈现这些的最快方法是什么?
由于
答案 0 :(得分:2)
我想知道的是,如果有一种方法可以通过上传8个顶点来实现这一点 显卡而不是24?
看一下glDrawElements。我看到你使用VBO,EBO也很有用。如果你的大多数元素具有相同的几何形状(似乎它们有),你可以使用glDrawElementsInstanced。