我目前正在为C++程序Igor Pro构建一个插件。此插件接受三个点数组（X、Y、Z），并返回一个包含数据像素值的矩阵（float array[windowsize][windowsize]）。
我已经用VBOs在OpenGL（glew）中开发了一个解决方案，但我觉得这不是最佳解决方案。
1）你认为我应该对FBO或PBO使用屏幕外渲染吗？我想让它跑得越快越好。
2）另外，我只想运行一次glutMainLoop。我应该换成免费的吗？
/*
RenderTriangle.c
*/
#include "VC10\triangulation.h"
#include "XOPStandardHeaders.h" // Include ANSI headers, Mac headers, IgorXOP.h, XOP.h and XOPSupport.h
#include "glui.h"
// Prototypes
HOST_IMPORT int main(IORecHandle ioRecHandle);
// Global Variables
const int windowSize = 512;
GLuint ID;
int size,el_size;
float* waveX=NULL;
float* waveY=NULL;
float* waveZ=NULL;
waveHndl waveH;
// Custom error codes
#define OLD_IGOR 1 + FIRST_XOP_ERR
#define NON_EXISTENT_WAVE 2 + FIRST_XOP_ERR
#define REQUIRES_SP_OR_DP_WAVE 3 + FIRST_XOP_ERR
#pragma pack(2) // All structures passed to Igor are two-byte aligned.
typedef struct FitParams {
waveHndl waveX;
waveHndl waveY;
waveHndl waveZ;
double result;
} FitParams, *FitParamsPtr;
#pragma pack() // Restore default structure alignment
// Prototypes of the OpenGL callbacks
void init(void);
void display(void);
void idle(void);
void init(void){
float z_val=0;
int point=0;
//Loading data from the text files and applying the Delaunay algorithm
triangulateio tri_data=triangulationWave(waveX,waveY,waveZ);
vector<float>data_vector(tri_data.numberoftriangles*3*6); //3 points with 6 coordinates (position and color)
size=data_vector.size();
double zMin=tri_data.pointattributelist[N_ELEMENTS],zMax=tri_data.pointattributelist[N_ELEMENTS+1];
for (int i_tri = 0; i_tri < tri_data.numberoftriangles; i_tri++) {
for (int i_point = 0; i_point < 3; i_point++) {
z_val=tri_data.pointattributelist[tri_data.trianglelist[i_tri * 3 + i_point]];
z_val=1-((z_val-zMin)/(zMax-zMin)); //normalize and invertion
point=6*(i_tri *3 + i_point);
data_vector[point+0]=tri_data.pointlist[2*tri_data.trianglelist[i_tri * 3 + i_point]];
data_vector[point+1]=tri_data.pointlist[2*tri_data.trianglelist[i_tri * 3 + i_point]+1];
data_vector[point+2]=z_val;
data_vector[point+3]=z_val;
data_vector[point+4]=z_val;
data_vector[point+5]=z_val;
}
}
glewInit();
glEnable(GL_DEPTH_TEST);
glDepthMask(GL_TRUE);
glDepthFunc(GL_LEQUAL);
glDepthRange(-2.0f, 2.0f);
glClearColor(0.0f, 1.0f, 0.0f, 0.0f);
glShadeModel(GL_SMOOTH);
glEnableClientState(GL_VERTEX_ARRAY);
glGenBuffers(1,&ID);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ID);
glBufferData(GL_ELEMENT_ARRAY_BUFFER,size*sizeof(float), &data_vector[0], GL_STATIC_DRAW);
el_size=6*sizeof(float);
}
void display(void){
int zoom = 1;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-2*zoom, 2*zoom,2*zoom,-2*zoom, -5.0f, 5.0f);
glPushMatrix ();
glBindBuffer(GL_ARRAY_BUFFER, ID);
// Pointer for the position of the points
glEnableClientState(GL_VERTEX_ARRAY);
glVertexPointer(3, GL_FLOAT, el_size, 0);
// Pointer for the color of the points
glEnableClientState(GL_COLOR_ARRAY);
glColorPointer(3,GL_FLOAT, el_size,(void*)(el_size/2));
//Draw callback
glDrawArrays(GL_TRIANGLES,0,size/6);
glPopMatrix ();
glFlush();
}
// Idle callback function for OpenGL API
void idle(void){
float* pixels = (float*)malloc(windowSize*windowSize*sizeof(float));
glReadPixels(0, 0, windowSize, windowSize, GL_DEPTH_COMPONENT, GL_FLOAT, pixels);
//
//char waveName[MAX_OBJ_NAME+1];
//CountInt dimensionSizes[MAX_DIMENSIONS+1];
//float* wp;
//strcpy(waveName, "wave0");
//MemClear(dimensionSizes, sizeof(dimensionSizes));
//dimensionSizes[ROWS] = windowSize*windowSize; // Make 1D wave
//wp = (float*)WaveData(waveH); // Get a pointer to the wave data
//for(int i = 0;i < windowSize*windowSize; i++){
// *wp++ =pixels[i];
//}
//glDeleteBuffers(1,&ID);
}
// Main function for the XOP
extern "C" int
RenderTriangle(FitParamsPtr p)
{
waveX=(float*)WaveData(p->waveX);
waveY=(float*)WaveData(p->waveY);
waveZ=(float*)WaveData(p->waveZ);
char *myargv [1];
int myargc=1;
myargv [0]=strdup ("RenderTriangle");
glutInit(&myargc,myargv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_DEPTH | GLUT_RGB);
glutInitWindowSize(windowSize,windowSize);
glutCreateWindow("OpenGL");
init();
glutDisplayFunc(display);
glutIdleFunc(idle);
glutMainLoop();
p->result = 1;
return 0;
}
static XOPIORecResult
RegisterFunction()
{
int funcIndex;
funcIndex = (int)GetXOPItem(0); // Which function invoked ?
switch (funcIndex) {
case 0: // y = RenderTriangle(w,x) (curve fitting function).
return (XOPIORecResult)RenderTriangle; // This function is called using the direct method.
break;
}
return 0;
}
/* XOPEntry()
This is the entry point from the host application to the XOP for all
messages after the INIT message.
*/
extern "C" void
XOPEntry(void)
{
XOPIORecResult result = 0;
switch (GetXOPMessage()) {
case FUNCADDRS:
result = RegisterFunction(); // This tells Igor the address of our function.
break;
}
SetXOPResult(result);
}
/* main(ioRecHandle)
This is the initial entry point at which the host application calls XOP.
The message sent by the host must be INIT.
main() does any necessary initialization and then sets the XOPEntry field of the
ioRecHandle to the address to be called for future messages.
*/
HOST_IMPORT int
main(IORecHandle ioRecHandle)
{
XOPInit(ioRecHandle); // Do standard XOP initialization.
SetXOPEntry(XOPEntry); // Set entry point for future calls.
if (igorVersion < 600) {
SetXOPResult(OLD_IGOR);
return EXIT_FAILURE;
}
SetXOPResult(0);
return EXIT_SUCCESS;
}
最佳答案
VBOs用于传输顶点数据。
你正在通过VBO传输点云数据，这是再好不过的了。
PBO用于传输像素数据。
可以使用PBO从OpenGL帧缓冲区异步读取数据。
FBO可以被吸引。
您应该使用FBO将目标帧缓冲区与任何窗口操作隔离。
2）另外，我只想运行一次glutMainLoop。我应该换成免费的吗？
你根本不需要运行主循环。您只需要创建一个窗口；在主循环启动之前它不会显示。您需要窗口来获取OpenGL上下文，但可以安全地省略主循环。
与其注册任何回调（它们不会被调用），不如按顺序执行OpenGL命令。如果您的库被多次调用，则不必重新创建窗口，但可能需要调用glutSetWindow以使上下文成为当前上下文。
建立一个FBO
吸引外资银行
glReadPixels像素
或者进入PBO和glMapBuffer和memcpy。
或直接进入适当大小的缓冲区。
关于c - 外部功能渲染点云，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/14365649/