我目前正在为程序Igor Pro构建一个C ++插件。该插件采用三个点阵列（X，Y，Z）并返回一个矩阵，其中包含数据的像素值（float array [windowsize] [windowsize]）。
我已经使用VBO在OpenGL（glew）中开发了一个解决方案，但我觉得它不是最佳解决方案。
1）您认为我应该使用FBO或PBO进行屏幕外渲染吗？我想让它尽可能快地运行。
2）另外，我只想运行一次glutMainLoop。我应该改为FreeGLUT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;
}
答案 0 :(得分：0)
你通过VBO转移你的点云数据，它不会比那更好。
您可以使用PBO异步读取OpenGL帧缓冲区中的数据。
您应该使用FBO将目标帧缓冲区与任何窗口操作隔离开来。
2）另外，我只想运行一次glutMainLoop。我应该改为FreeGLUT吗？
您根本不必运行主循环。您只需要创建一个窗口;在mainloop启动之前它不会显示。您需要窗口来获取OpenGL上下文，但您可以安全地省略mainloop。
不是注册任何回调（它们不会被调用），而是按顺序执行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来使上下文保持最新状态。