280 lines
6.6 KiB
C++
280 lines
6.6 KiB
C++
#define _USE_MATH_DEFINES
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#include <vector>
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#include <algorithm>
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#include <limits>
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#include "tgaimage.h"
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#include "model.h"
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#include "geometry.h"
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#include "renderer.h"
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#include "util_window.h"
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#include <ctime>
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#define DEG2RAD M_PI/180
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#define HORIZONTAL_CAMERA_SPEED 1
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#define NEAR_CLIP_PLANE 0.1
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#define FAR_CLIP_PLANE 5
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const TGAColor white = TGAColor(255, 255, 255, 255);
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const TGAColor red = TGAColor(255, 0, 0, 255);
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const TGAColor green = TGAColor(0, 255, 0, 255);
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const TGAColor blue = TGAColor(0, 0, 255, 255);
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const int depth = 255;
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int angle_hor = 0;
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int angle_ver = 0;
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bool wireframe = false;
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Model* model = new Model("african_head.obj");
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float* z_buffer = new float[screen_width * screen_height];
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Vec3f light_dir = Vec3f(0, 0, 1).normalize();
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Vec3f eye(0, 0, 5);
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Vec3f center(0, 0, 0);
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Matrix viewport(int x, int y, int w, int h) {
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Matrix m = Matrix::identity();
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m[0][3] = x + w / 2.f;
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m[1][3] = y + h / 2.f;
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m[2][3] = depth / 2.f;
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m[0][0] = w / 2.f;
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m[1][1] = h / 2.f;
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m[2][2] = depth / 2.f;
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return m;
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}
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void line(Vec3f p0, Vec3f p1, TGAColor color)
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{
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bool steep = false;
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if (std::abs(p0[0] - p1[0]) < std::abs(p0[1] - p1[1])) {
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std::swap(p0[0], p0[1]);
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std::swap(p1[0], p1[1]);
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steep = true;
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}
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if (p0[0] > p1[0]) {
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std::swap(p0[0], p1[0]);
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std::swap(p0[1], p1[1]);
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}
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int dx = p1[0] - p0[0];
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int dy = p1[1] - p0[1];
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int derror2 = std::abs(dy) * 2;
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int error2 = 0;
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int y = p0[1];
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int y_step = p1[1] > p0[1] ? 1 : -1;
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int dx_2 = 2 * dx;
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for (int x = p0[0]; x <= p1[0]; x++) {
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if (steep) {
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set_pixel(y, x, color_to_int(color));
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}
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else {
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set_pixel(x, y, color_to_int(color));
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}
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error2 += derror2;
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if (error2 > dx) {
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y += (y_step);
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error2 -= dx_2;
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}
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}
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}
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Vec3f barycentric(Vec3f* pts, Vec3f P)
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{
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Vec3f u = cross(
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Vec3f(pts[2][0] - pts[0][0], pts[1][0] - pts[0][0], pts[0][0] - P[0]), // AC_x, AB_x, distance_x
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Vec3f(pts[2][1] - pts[0][1], pts[1][1] - pts[0][1], pts[0][1] - P[1]) // AC_y, AB_y, distance_y
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);
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if (std::abs(u[2]) < 1) return Vec3f(-1, 1, 1);
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return Vec3f(1.f - (u.x + u.y) / u.z, u.y / u.z, u.x / u.z);
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}
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void triangle(
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Vec3f* pts, // Needed
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Vec2f* diff_pts, // Should be removed
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Model* model,
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float* intensities)
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{
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if (pts[0].y == pts[1].y && pts[0].y == pts[2].y) return; // i dont care about degenerate triangles
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if (pts[0].y > pts[1].y) {
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std::swap(pts[0], pts[1]);
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if(diff_pts)
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std::swap(diff_pts[0], diff_pts[1]);
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if(intensities)
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std::swap(intensities[0], intensities[1]);
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}
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if (pts[0].y > pts[2].y) {
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std::swap(pts[0], pts[2]);
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if(diff_pts)
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std::swap(diff_pts[0], diff_pts[2]);
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if(intensities)
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std::swap(intensities[0], intensities[2]);
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}
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if (pts[1].y > pts[2].y) {
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std::swap(pts[1], pts[2]);
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if(diff_pts)
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std::swap(diff_pts[1], diff_pts[2]);
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if(intensities)
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std::swap(intensities[1], intensities[2]);
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}
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if (wireframe)
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{
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line(pts[0], pts[1], white);
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line(pts[1], pts[2], white);
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line(pts[2], pts[0], white);
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return;
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}
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Vec2i bounding_box_min(screen_width - 1, screen_height - 1);
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Vec2i bounding_box_max(0, 0);
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Vec2i clamp(screen_width - 1, screen_height - 1);
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TGAColor color = white;
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for (int i = 0; i < 3; i++) {
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for (int j = 0; j < 2; j++) {
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bounding_box_min[j] = std::fmax(0, std::fmin(bounding_box_min[j], (int)pts[i][j]));
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bounding_box_max[j] = std::fmin(clamp[j], std::fmax(bounding_box_max[j], (int)pts[i][j]));
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}
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}
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Vec3f P;
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for (P.x = bounding_box_min.x; P.x <= bounding_box_max.x; P.x++) {
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for (P.y = bounding_box_min.y; P.y <= bounding_box_max.y; P.y++) {
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Vec3f bc_coord = barycentric(pts, P);
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if (bc_coord.x < 0 || bc_coord.y < 0 || bc_coord.z < 0) continue;
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float intensity =
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intensities[0]
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+ (intensities[1] - intensities[0]) * bc_coord[1]
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+ (intensities[2] - intensities[0]) * bc_coord[2];
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// Interpolating Z using the barycentric coordinates
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P.z = 0;
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for (int i = 0; i < 3; i++) P.z += pts[i][2] * bc_coord[i];
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// Coloring according to the Z-Buffer
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if (P.z > z_buffer[(int)(P.x + P.y * screen_width)] && P.z > NEAR_CLIP_PLANE)
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{
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z_buffer[(int)(P.x + P.y * screen_width)] = P.z;
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// If diff_pts (Diffusemap Points) were passed, then find the
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// color of the current pixel
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if (diff_pts) {
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Vec2f diff_pt =
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diff_pts[0]
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+ (diff_pts[1] - diff_pts[0]) * bc_coord[1]
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+ (diff_pts[2] - diff_pts[0]) * bc_coord[2];
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color = model->diffuse(diff_pt);
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}
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color = color * intensity;
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set_pixel(P.x, P.y, color_to_int(color));
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}
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}
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}
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}
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int color_to_int(TGAColor col) {
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return (col[2] << 16) | (col[1] << 8) | col[0];
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}
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void clear_zbuffer()
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{
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for (int i = 0; i < screen_width * screen_height; i++)
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z_buffer[i] = INT_MIN;
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}
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Matrix lookat(Vec3f eye, Vec3f center, Vec3f up) {
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Vec3f z = (eye-center).normalize();
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Vec3f x = cross(up,z).normalize();
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Vec3f y = cross(z,x).normalize();
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Matrix Minv = Matrix::identity();
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Matrix Tr = Matrix::identity();
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for (int i=0; i<3; i++) {
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Minv[0][i] = x[i];
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Minv[1][i] = y[i];
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Minv[2][i] = z[i];
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Tr[i][3] = -center[i];
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}
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return Minv*Tr;
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}
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void move_camera_right() {
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angle_hor += HORIZONTAL_CAMERA_SPEED;
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}
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void move_camera_left() {
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angle_hor -= HORIZONTAL_CAMERA_SPEED;
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}
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void move_camera_up() {
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angle_ver += HORIZONTAL_CAMERA_SPEED;
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}
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void move_camera_down() {
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angle_ver -= HORIZONTAL_CAMERA_SPEED;
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}
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Matrix ViewPort = Matrix::identity();
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Matrix Projection = Matrix::identity();
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Matrix ModelView = Matrix::identity();
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void render()
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{
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Vec3f forward = Vec3f(sinf(angle_hor * DEG2RAD), -sinf(angle_ver * DEG2RAD), -cosf(angle_hor*DEG2RAD)*cosf(angle_ver*DEG2RAD));
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Vec3f right = Vec3f(sinf(angle_hor*DEG2RAD + M_PI_2), 0, 0);
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center = eye + forward;
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ViewPort = viewport(0, 0, screen_width, screen_height);
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ModelView = lookat(eye, center, cross(right, forward));
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Projection[3][2] = -1.f / (forward).norm();
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Matrix z = ViewPort * Projection * ModelView * model->Transform;// *Projection * ModelView;// * model->Transform;// *Projection * ModelView * model->Transform;
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clear_zbuffer();
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for (int i = 0; i < model->nfaces(); i++)
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{
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std::vector<int> face = model->face(i);
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Vec3f screen_coords[3];
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Vec3f world_coords[3];
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Vec2f diffuse_coords[3];
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float intensities[3];
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bool out = true;
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for (int j = 0; j < 3; j++)
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{
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Vec3f v = model->vert(face[j]);
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Vec4f v4(v);
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Vec3f coord(z * v4);
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if (coord.x > 0 && coord.x < screen_height)
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out = false;
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screen_coords[j] = coord;
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world_coords[j] = v;
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diffuse_coords[j] = model->uv(i, j);
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intensities[j] = model->normal(i, j) * light_dir;
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}
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if (out) continue;
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triangle(screen_coords, diffuse_coords, model, intensities);
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}
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}
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