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main.cpp
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main.cpp
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#include <vector>
#include <limits>
#include <iostream>
#include "tgaimage.h"
#include "model.h"
#include "geometry.h"
#include "our_gl.h"
Model *model = NULL;
const int width = 800;
const int height = 800;
Vec3f light_dir(1,1,1);
Vec3f eye(1,1,3);
Vec3f center(0,0,0);
Vec3f up(0,1,0);
struct Shader : public IShader {
mat<2,3,float> varying_uv; // triangle uv coordinates, written by the vertex shader, read by the fragment shader
mat<4,3,float> varying_tri; // triangle coordinates (clip coordinates), written by VS, read by FS
mat<3,3,float> varying_nrm; // normal per vertex to be interpolated by FS
mat<3,3,float> ndc_tri; // triangle in normalized device coordinates
virtual Vec4f vertex(int iface, int nthvert) {
varying_uv.set_col(nthvert, model->uv(iface, nthvert));
varying_nrm.set_col(nthvert, proj<3>((Projection*ModelView).invert_transpose()*embed<4>(model->normal(iface, nthvert), 0.f)));
Vec4f gl_Vertex = Projection*ModelView*embed<4>(model->vert(iface, nthvert));
varying_tri.set_col(nthvert, gl_Vertex);
ndc_tri.set_col(nthvert, proj<3>(gl_Vertex/gl_Vertex[3]));
return gl_Vertex;
}
virtual bool fragment(Vec3f bar, TGAColor &color) {
Vec3f bn = (varying_nrm*bar).normalize();
Vec2f uv = varying_uv*bar;
mat<3,3,float> A;
A[0] = ndc_tri.col(1) - ndc_tri.col(0);
A[1] = ndc_tri.col(2) - ndc_tri.col(0);
A[2] = bn;
mat<3,3,float> AI = A.invert();
Vec3f i = AI * Vec3f(varying_uv[0][1] - varying_uv[0][0], varying_uv[0][2] - varying_uv[0][0], 0);
Vec3f j = AI * Vec3f(varying_uv[1][1] - varying_uv[1][0], varying_uv[1][2] - varying_uv[1][0], 0);
mat<3,3,float> B;
B.set_col(0, i.normalize());
B.set_col(1, j.normalize());
B.set_col(2, bn);
Vec3f n = (B*model->normal(uv)).normalize();
float diff = std::max(0.f, n*light_dir);
color = model->diffuse(uv)*diff;
return false;
}
};
int main(int argc, char** argv) {
if (2>argc) {
std::cerr << "Usage: " << argv[0] << " obj/model.obj" << std::endl;
return 1;
}
float *zbuffer = new float[width*height];
for (int i=width*height; i--; zbuffer[i] = -std::numeric_limits<float>::max());
TGAImage frame(width, height, TGAImage::RGB);
lookat(eye, center, up);
viewport(width/8, height/8, width*3/4, height*3/4);
projection(-1.f/(eye-center).norm());
light_dir = proj<3>((Projection*ModelView*embed<4>(light_dir, 0.f))).normalize();
for (int m=1; m<argc; m++) {
model = new Model(argv[m]);
Shader shader;
for (int i=0; i<model->nfaces(); i++) {
for (int j=0; j<3; j++) {
shader.vertex(i, j);
}
triangle(shader.varying_tri, shader, frame, zbuffer);
}
delete model;
}
frame.flip_vertically(); // to place the origin in the bottom left corner of the image
frame.write_tga_file("framebuffer.tga");
delete [] zbuffer;
return 0;
}