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]）。
我已经通过使用 VBO 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) 你认为我应该使用 FBO 或 PBO 的屏幕外渲染吗？我想让它尽可能快地运行。
2）另外，我只想运行一次 glutMainLoop 。我应该换成 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;
}