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ssloy / tinyrenderer

A brief computer graphics / rendering course
https://github.com/ssloy/tinyrenderer/wiki
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Help, i have an error related to the vector library #141

Closed zai1208 closed 3 months ago

zai1208 commented 3 months ago

here is the code

#include <vector>
#include <iostream>
#include "geometry.h"
#include "tgaimage.h"

const int width = 200;
const int height = 200;

//Model *model = NULL;

const TGAColor white = TGAColor(255, 255, 255, 255);
const TGAColor red   = TGAColor(255, 0,   0,   255);

void line(Vec2i p0, Vec2i p1, TGAImage &image, TGAColor colour) {

    bool steep = false;
    if (std::abs(p0.x-p1.x)<std::abs(p0.y-p1.y)) {
        std::swap(p0.x, p0.y);
        std::swap(p1.x, p1.y);
        steep = true;
    }

    if (p0.x>p1.x) {
        std::swap(p0.x, p1.x);
        std::swap(p0.y, p1.y);
    }

    for (float x=p0.x; x<=p1.x; x++) {
        float t = (x-p0.x)/(float)(p1.x-p0.x);
        int y = p0.y*(1.-t) + p1.y*t;
        if (steep) {
            image.set(y,x, colour);
        }
        else {
            image.set(x,y, colour);
        }

    }
}

Vec3f barycentric(Vec2i *pts, Vec2i P) {
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
    /* `pts` and `P` has integer value as coordinates
       so `abs(u[2])` < 1 means `u[2]` is 0, that means
       triangle is degenerate, in this case return something with negative coordinates */
    if (std::abs(u.z)<1) return Vec3f(-1,1,1);
    return Vec3f(1.f-(u.x+u.y)/u.z, u.y/u.z, u.x/u.z);
}

void triangle(Vec2i *pts, TGAImage &image, TGAColor color) {
    Vec2i bboxmin(image.get_width()-1,  image.get_height()-1);
    Vec2i bboxmax(0, 0);
    Vec2i clamp(image.get_width()-1, image.get_height()-1);
    for (int i=0; i<3; i++) {
        bboxmin.x = std::max(0, std::min(bboxmin.x, pts[i].x));
    bboxmin.y = std::max(0, std::min(bboxmin.y, pts[i].y));

    bboxmax.x = std::min(clamp.x, std::max(bboxmax.x, pts[i].x));
    bboxmax.y = std::min(clamp.y, std::max(bboxmax.y, pts[i].y));
    }
    Vec2i P;
    for (P.x=bboxmin.x; P.x<=bboxmax.x; P.x++) {
        for (P.y=bboxmin.y; P.y<=bboxmax.y; P.y++) {
            Vec3f bc_screen  = barycentric(pts, P);
            if (bc_screen.x<0 || bc_screen.y<0 || bc_screen.z<0) continue;
            image.set(P.x, P.y, color);
        }
    }
}

int main(int argc, char** argv) {
    /*
    if (2==argc) {
            model = new Model(argv[1]);
        } else {
            model = new Model("Downloads/tinyrenderer/obj/african_head.obj");
        }
    */
    TGAImage image(width, height, TGAImage::RGB);

    Vec2i pts[3] = {Vec2i(10,10), Vec2i(100, 30), Vec2i(190, 160)};

    triangle(pts, image, white);

    /*
    for (int i=0; i<model->nfaces(); i++) {
        std::vector<int> face = model->face(i);
        for (int j=0; j<3; j++) {
            Vec3f v0 = model->vert(face[j]);
            Vec3f v1 = model->vert(face[(j+1)%3]);
            int x0 = (v0.x+1.)*width/2.;
            int y0 = (v0.y+1.)*height/2.;
            int x1 = (v1.x+1.)*width/2.;
            int y1 = (v1.y+1.)*height/2.;
            line(x0, y0, x1, y1, image, white);
        }
    }
    */

    image.flip_vertically(); // i want to have the origin at the left bottom corner of the image
    image.write_tga_file("Downloads/tinyrenderer/output.tga");
    return 0;
}

and here is the output of make:

g++ -Wall  -c  main.cpp -o main.o -O3
main.cpp:46:27: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                    ~~~~~~^~
main.cpp:46:37: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                              ~~~~~~^~
main.cpp:46:48: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                         ~~~~~~^~
main.cpp:46:58: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                   ~~~~~~^~
main.cpp:46:69: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                              ~~~~~~^~
main.cpp:46:74: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                                        ~^~
main.cpp:46:91: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                                                    ~~~~~~^~
main.cpp:46:101: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                                                              ~~~~~~^~
main.cpp:46:112: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                                                                         ~~~~~~^~
main.cpp:46:122: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                                                                                   ~~~~~~^~
main.cpp:46:133: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                                                                                              ~~~~~~^~
main.cpp:46:138: error: type 'Vec2i' (aka 'Vec2<int>') does not provide a subscript operator
    Vec3f u = Vec3f(pts[2][0]-pts[0][0], pts[1][0]-pts[0][0], pts[0][0]-P[0])^Vec3f(pts[2][1]-pts[0][1], pts[1][1]-pts[0][1], pts[0][1]-P[1]);
                                                                                                                                        ~^~
12 errors generated.
make: *** [main.o] Error 1
WSQS commented 3 months ago

Can you show your "geometry.h" file? It should defined the class Vec3.

zai1208 commented 3 months ago

here it is:

#ifndef __GEOMETRY_H__
#define __GEOMETRY_H__

#include <cmath>

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

template <class t> struct Vec2 {
    union {
        struct {t u, v;};
        struct {t x, y;};
        t raw[2];
    };
    Vec2() : u(0), v(0) {}
    Vec2(t _u, t _v) : u(_u),v(_v) {}
    inline Vec2<t> operator +(const Vec2<t> &V) const { return Vec2<t>(u+V.u, v+V.v); }
    inline Vec2<t> operator -(const Vec2<t> &V) const { return Vec2<t>(u-V.u, v-V.v); }
    inline Vec2<t> operator *(float f)          const { return Vec2<t>(u*f, v*f); }
    template <class > friend std::ostream& operator<<(std::ostream& s, Vec2<t>& v);
};

template <class t> struct Vec3 {
    union {
        struct {t x, y, z;};
        struct { t ivert, iuv, inorm; };
        t raw[3];
    };
    Vec3() : x(0), y(0), z(0) {}
    Vec3(t _x, t _y, t _z) : x(_x),y(_y),z(_z) {}
    inline Vec3<t> operator ^(const Vec3<t> &v) const { return Vec3<t>(y*v.z-z*v.y, z*v.x-x*v.z, x*v.y-y*v.x); }
    inline Vec3<t> operator +(const Vec3<t> &v) const { return Vec3<t>(x+v.x, y+v.y, z+v.z); }
    inline Vec3<t> operator -(const Vec3<t> &v) const { return Vec3<t>(x-v.x, y-v.y, z-v.z); }
    inline Vec3<t> operator *(float f)          const { return Vec3<t>(x*f, y*f, z*f); }
    inline t       operator *(const Vec3<t> &v) const { return x*v.x + y*v.y + z*v.z; }
    float norm () const { return std::sqrt(x*x+y*y+z*z); }
    Vec3<t> & normalize(t l=1) { *this = (*this)*(l/norm()); return *this; }
    template <class > friend std::ostream& operator<<(std::ostream& s, Vec3<t>& v);
};

typedef Vec2<float> Vec2f;
typedef Vec2<int>   Vec2i;
typedef Vec3<float> Vec3f;
typedef Vec3<int>   Vec3i;

template <class t> std::ostream& operator<<(std::ostream& s, Vec2<t>& v) {
    s << "(" << v.x << ", " << v.y << ")\n";
    return s;
}

template <class t> std::ostream& operator<<(std::ostream& s, Vec3<t>& v) {
    s << "(" << v.x << ", " << v.y << ", " << v.z << ")\n";
    return s;
}

#endif //__GEOMETRY_H__
WSQS commented 3 months ago

adding a following member function to Vec2 should fix the problem.

inline t &operator[](unsigned const int i) { return raw[i]; }
zai1208 commented 3 months ago

It worked! Thank you.