1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
#include "renderer.h"
#include <array>
#include <cmath>
#include <algorithm>
#include <memory>
#include "math/vector.h"
#include "o3d/vertex.h"
#include "o3d/deriv_vertex.h"
#include "o3d/tri.h"
#include "o3d/tri_deriv.h"
#include "o3d/vertex_data.h"
using namespace engine;
Renderer::Renderer(std::unique_ptr<fb::FrameBuffer> fb) : fb{std::move(fb)} {
depth_buf.resize(this->fb->width() * this->fb->height());
}
void Renderer::resize(unsigned int w, unsigned int h) {
fb->resize(w, h);
depth_buf.resize(fb->width() * fb->height());
}
unsigned int Renderer::width() const {
return fb->width();
}
unsigned int Renderer::height() const {
return fb->height();
}
void Renderer::clear() {
std::fill(depth_buf.begin(), depth_buf.end(), 1.f);
fb->clear();
}
enum TriangleSide { top, bottom };
void Renderer::_draw_cropped_triangle(const o3d::Triangle& root, const o3d::TriangleDerived& triangle) {
std::array<const o3d::DerivedVertex*, 3> sorted_vs = { &triangle.derived_vertex1, &triangle.derived_vertex2, &triangle.derived_vertex3 };
{
const auto swap_if_lt = [&](auto x, auto y) {
if (sorted_vs[x]->vertex.y < sorted_vs[y]->vertex.y) {
auto temp = sorted_vs[x];
sorted_vs[x] = sorted_vs[y];
sorted_vs[y] = temp;
}
};
swap_if_lt(1, 0);
swap_if_lt(2, 1);
swap_if_lt(1, 0);
}
auto middle_vl = *sorted_vs[1];
const float fac = (sorted_vs[1]->vertex.y - sorted_vs[0]->vertex.y) / (sorted_vs[2]->vertex.y - sorted_vs[0]->vertex.y);
const float fac_b0 = (1.f - fac) / sorted_vs[0]->vertex.w / ((1.f - fac) / sorted_vs[0]->vertex.w + fac / sorted_vs[2]->vertex.w);
o3d::DerivedVertex middle_vr{
{
sorted_vs[0]->vertex.x + fac * (sorted_vs[2]->vertex.x - sorted_vs[0]->vertex.x),
sorted_vs[1]->vertex.y,
fac_b0 * sorted_vs[0]->vertex.z + (1.f - fac_b0) * sorted_vs[2]->vertex.z,
1.f / (1.f / sorted_vs[0]->vertex.w + fac * (1.f / sorted_vs[2]->vertex.w - 1.f / sorted_vs[0]->vertex.w))
},
fac_b0 * sorted_vs[0]->b0 + (1.f - fac_b0) * sorted_vs[2]->b0,
fac_b0 * sorted_vs[0]->b1 + (1.f - fac_b0) * sorted_vs[2]->b1
};
if (middle_vr.vertex.x < middle_vl.vertex.x) {
auto temp = middle_vr;
middle_vr = middle_vl;
middle_vl = temp;
}
const auto _draw_cropped_triangle_side = [&]<TriangleSide side>() {
const int vertex_end_index = ([&]() { if constexpr (side == TriangleSide::top) return 0; else return 2; })();
const o3d::DerivedVertex& vertex_end = *sorted_vs[vertex_end_index];
if (vertex_end.vertex.y == sorted_vs[1]->vertex.y)
return;
int top_y;
int bottom_y;
if constexpr (side == TriangleSide::top) {
top_y = static_cast<int>(std::floor(vertex_end.vertex.y + 1.f));
bottom_y = static_cast<int>(std::ceil(sorted_vs[1]->vertex.y - 1.f));
} else {
bottom_y = static_cast<int>(std::floor(vertex_end.vertex.y));
top_y = static_cast<int>(std::ceil(sorted_vs[1]->vertex.y));
}
for (int y = top_y; y <= bottom_y; y++) {
float iy = static_cast<float>(y);
float s = (iy - vertex_end.vertex.y) / (sorted_vs[1]->vertex.y - vertex_end.vertex.y);
float sub_bb0 = 1.f - s;
float xl = vertex_end.vertex.x + s * (middle_vl.vertex.x - vertex_end.vertex.x);
float xr = vertex_end.vertex.x + s * (middle_vr.vertex.x - vertex_end.vertex.x);
int left_x = static_cast<int>(std::ceil(xl));
int right_x = static_cast<int>(std::ceil(xr - 1.f));
for (int x = left_x; x <= right_x; x++) {
float ix = static_cast<float>(x);
float t = (ix - xl) / (xr - xl);
float sub_bb1 = s * (1.f - t);
float b_fac = 1.f / (sub_bb0 / vertex_end.vertex.w + sub_bb1 / middle_vl.vertex.w + (1.f - sub_bb0 - sub_bb1) / middle_vr.vertex.w);
float sub_b0 = b_fac * sub_bb0 / vertex_end.vertex.w;
float sub_b1 = b_fac * sub_bb1 / middle_vl.vertex.w;
float b0 = sub_b0 * vertex_end.b0 + sub_b1 * middle_vl.b0 + (1.f - sub_b0 - sub_b1) * middle_vr.b0;
float b1 = sub_b0 * vertex_end.b1 + sub_b1 * middle_vl.b1 + (1.f - sub_b0 - sub_b1) * middle_vr.b1;
math::Vector3 loc{
b0 * root.vertex1.vertex.x + b1 * root.vertex2.vertex.x + (1.f - b0 - b1) * root.vertex3.vertex.x,
b0 * root.vertex1.vertex.y + b1 * root.vertex2.vertex.y + (1.f - b0 - b1) * root.vertex3.vertex.y,
b0 * root.vertex1.vertex.z + b1 * root.vertex2.vertex.z + (1.f - b0 - b1) * root.vertex3.vertex.z
};
if (loc.z < depth_buf[x + y * fb->width()]) {
depth_buf[x + y * fb->width()] = loc.z;
fb->draw_point(x, y, loc, o3d::VertexData::bilerp(root.vertex1.data, root.vertex2.data, root.vertex3.data, b0, b1));
}
}
}
};
_draw_cropped_triangle_side.operator()<TriangleSide::top>();
_draw_cropped_triangle_side.operator()<TriangleSide::bottom>();
}
void Renderer::draw_triangle(o3d::Triangle triangle) {
for (auto t1 : triangle.to_derived().crop_z_out(-1.f, 1.f)) {
for (auto t2 : t1.div_by_w().perspective_crop_xy_out(-1.f, 1.f, -1.f, 1.f)) {
auto pp1 = t2.derived_vertex1.vertex.xy();
auto pp2 = t2.derived_vertex2.vertex.xy();
auto pp3 = t2.derived_vertex3.vertex.xy();
if ((pp2 - pp1).det(pp3 - pp1) >= 0.f) continue;
float fw_over_2 = static_cast<float>(fb->width()) / 2.f, fh_over_2 = static_cast<float>(fb->height()) / 2.f;
t2.derived_vertex1.vertex.x = (t2.derived_vertex1.vertex.x + 1.f) * fw_over_2 - .5f;
t2.derived_vertex1.vertex.y = (t2.derived_vertex1.vertex.y + 1.f) * fh_over_2 - .5f;
t2.derived_vertex2.vertex.x = (t2.derived_vertex2.vertex.x + 1.f) * fw_over_2 - .5f;
t2.derived_vertex2.vertex.y = (t2.derived_vertex2.vertex.y + 1.f) * fh_over_2 - .5f;
t2.derived_vertex3.vertex.x = (t2.derived_vertex3.vertex.x + 1.f) * fw_over_2 - .5f;
t2.derived_vertex3.vertex.y = (t2.derived_vertex3.vertex.y + 1.f) * fh_over_2 - .5f;
_draw_cropped_triangle(triangle, t2);
}
}
}
|
