MatlEditor/Plane.cpp at master · sharjith/MatlEditor · GitHub

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#include "Plane.h"

#include <cstdio>
#include <cmath>

Plane::Plane(QOpenGLShaderProgram* prog, float xsize, float zsize, int xdivs, int zdivs, float smax, float tmax):
	TriangleMesh(prog, "Plane")
{
    std::vector<GLfloat> p(3 * (xdivs + 1) * (zdivs + 1));
	std::vector<GLfloat> n(3 * (xdivs + 1) * (zdivs + 1));
    std::vector<GLfloat> tex(2 * (xdivs + 1) * (zdivs + 1));
    std::vector<GLuint> el(6 * xdivs * zdivs);

    float x2 = xsize / 2.0f;
    float z2 = zsize / 2.0f;
    float iFactor = (float)zsize / zdivs;
    float jFactor = (float)xsize / xdivs;
    float texi = smax / zdivs;
    float texj = tmax / xdivs;
    float x, z;
    int vidx = 0, tidx = 0;
    for( int i = 0; i <= zdivs; i++ ) {
        z = iFactor * i - z2;
        for( int j = 0; j <= xdivs; j++ ) {
            x = jFactor * j - x2;
            p[vidx] = x;
            p[vidx+1] = 0.0f;
            p[vidx+2] = z;
			n[vidx] = 0.0f;
			n[vidx+1] = 1.0f;
			n[vidx+2] = 0.0f;

            tex[tidx] = j * texi;
            tex[tidx+1] = i * texj;

            vidx += 3;
            tidx += 2;
        }
    }

    GLuint rowStart, nextRowStart;
    int idx = 0;
    for( int i = 0; i < zdivs; i++ ) {
        rowStart = (GLuint)( i * (xdivs+1) );
        nextRowStart = (GLuint)( (i+1) * (xdivs+1));
        for( int j = 0; j < xdivs; j++ ) {
            el[idx] = rowStart + j;
            el[idx+1] = nextRowStart + j;
            el[idx+2] = nextRowStart + j + 1;
            el[idx+3] = rowStart + j;
            el[idx+4] = nextRowStart + j + 1;
            el[idx+5] = rowStart + j + 1;
            idx += 6;
        }
    }

    initBuffers(&el, &p, &n, &tex);
}