Question

我试图绘制512 * 512点，每个点使用它的邻居。例如

glBegin(GL_TRIANGLE_STRIP);
glVertex(x,y,z);
glVertex(x+1,y,z);
glVertex(x,y,z+1);
glVertex(x+1,y,z+1);
glEnd();

问题是它工作得很慢，我知道我可以使用VBO（与CUDA一起工作）但我不知道如何定义VBO以使用GL_TRIANGLE_STRIP以及如何设置顶点的绘制顺序。

Answer 1

使用VBO的一种方法（有变种，使用旧的Vertex Array API，使用glBufferData和其他好东西直接上传数据）。

GLuint vbo; // this variable becomes a handles, keep them safe
GLuint idx;

glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat)*512*512*3, NULL, GL_STATIC_DRAW);
GLfloat *vbuf = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE);
fill_with_vertex_data(vbo);
glUnmapBuffer(GL_ARRAY_BUFFER);

glGenBuffers(1, &idx);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLuint)*512*512*4, NULL, GL_STATIC_DRAW);
GLfloat *ibuf = glMapBuffer(GL_ELEMENT_ARRAY_BUFFER, GL_WRITE);
GLuint restart_index = 0xffff;
fill_with_indices_restart(ibuf, restart_index); // 0xffff is the restart index to be used, delimiting each triangle strip.
glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);

/* ... */

glEnableVertexAttribArray(vertex_position_location);

glBindBuffer(GL_ARRAY_BUFFER, vbo);
glVertexAttrxPointer(vertex_position_location, 3, GL_FLOAT, GL_FALSE, 0, 0);

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, idx);
glPrimitiveRestartIndex(restart_index);
glDrawElements(GL_TRIANGLE_STRIP, 0, count, 0);

使opengl工作（绘画）更快

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