cppLight2d/light.cpp at master · Vovery/cppLight2d · GitHub

History

171 lines (159 loc) · 5 KB

Raw

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

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

#include "svpng.inc"

#include <math.h> // fabsf(), fminf(), fmaxf(), sinf(), cosf(), sqrt()

#include <stdlib.h> // rand(), RAND_MAX

#include <initializer_list>

#include <vector>

#include <iostream>

#include "Shape.h"

using namespace std;

using std::vector;

#define SAFE_DELETE(p) do {delete (p); (p) = NULL;} while (false)

#define TWO_PI 6.28318530718f

#define W 512

#define H 512

#define N 256

#define BIAS 1e-4f

#define MAX_DEPTH 3

#define IS_DEBUG false

unsigned char img[W * H * 3];

void drawLine(int x0, int y0, int x1, int y1) {

int dx = abs(x1 - x0), sx = x0 < x1 ? 1 : -1;

int dy = abs(y1 - y0), sy = y0 < y1 ? 1 : -1;

int err = (dx > dy ? dx : -dy) / 2;

while (*(img + (y0 * W + x0) * 3) = 255, x0 != x1 || y0 != y1) {

int e2 = err;

if (e2 > -dx) { err -= dy; x0 += sx; }

if (e2 < dy) { err += dx; y0 += sy; }

}

class Entity

{

private:

Shape* m_shape;

Color m_emissive;

float m_reflectivity;

public:

Entity(Shape* s, Color e, float r = 0.0) :m_shape(s), m_emissive(e), m_reflectivity(r) {}

Shape* GetShape() { return m_shape; }

Color GetEmissive() { return m_emissive; }

float GetReflectivity() { return m_reflectivity; }

};

class Scene

{

protected:

vector<Entity*> m_entities;

public:

Scene(vector<Entity*> entities) :m_entities(entities) {}

vector<Entity*> GetEntities() { return m_entities; }

Color Reflect(Entity* ent, Point inter, Vector d, int depth)

{

if (depth > MAX_DEPTH || ent->GetReflectivity() == 0.f) return{ 0.f, 0.f,0.f };

Vector normal = ent->GetShape()->GetNormal(inter);

if (normal * d > 0.f) return{ 0.f, 0.f,0.f };

Vector reflect = d.reflect(normal);

return GetColor(inter + reflect * BIAS, reflect, depth);

}

Color GetColor(Point p, Vector d, int depth = 0) //获取p点从d方向收到的emissive

{

Color trace_emissive{ 0.0f, 0.0f, 0.0f };

float distance = 10.0f;

int ent_index = -1;

Point inter;

for (int j = 0; j < m_entities.size(); j++)

{

Point tmp_inter;

if (m_entities[j]->GetShape()->Intersect(p, d, tmp_inter))

{

float new_dist = (tmp_inter - p).len();

if (distance > new_dist)

{

ent_index = j;

distance = new_dist;

inter = tmp_inter;

}

if (ent_index >= 0)

{

if (IS_DEBUG)

drawLine(p.x * 512, p.y * 512, inter.x * 512, inter.y * 512);

Color reflect = Reflect(m_entities[ent_index], inter, d, depth + 1);

return m_entities[ent_index]->GetEmissive() + reflect * m_entities[ent_index]->GetReflectivity();

}

else

return{ 0.0f, 0.0f, 0.0f };

}

Color sample(Point p)

{

Color sum{ 0.0f, 0.0f, 0.0f };

for (int i = 0; i < N; i++)

{

float a = TWO_PI * (i + (float)rand() / RAND_MAX) / N;

sum = sum + GetColor(p, { cosf(a), sinf(a) });

}

return sum / N;

}

};

Shape* GeneratePolygon(std::initializer_list<Point> points)

{

Point sum = { 0.f, 0.f };

for (auto p : points)

{

sum.x += p.x;

sum.y += p.y;

}

Point center = { sum.x / points.size(), sum.y / points.size() };

Shape* si = NULL;

for (auto i = points.begin(); i + 1 != points.end(); i++)

{

Point p1 = *i;

Point p2 = *(i + 1);

Line* l = new Line(p1, p2, center);

if (si)

si = new ShapeIntersect(si, l);

else

si = l;

}

si = new ShapeIntersect(si, new Line(*(points.begin()), *(points.end() - 1), center));

return si;

}

Scene* GenerateScene2()

{

Circle* c1 = new Circle({ 0.5f, 0.6f }, 0.1f);

Circle* c2 = new Circle({ 0.5f, 0.7f }, 0.12f);

Shape* su1 = new ShapeUnion(c1, c2); //两个圆的并

Shape* triangle = GeneratePolygon({ { 0.9f,0.5f },{ 0.7f, 0.5f },{ 0.8f, 0.4f } });

Shape* quad1 = GeneratePolygon({ { 0.3f, 0.4f },{ 0.4f, 0.4f },{ 0.4f, 0.3f },{ 0.3f, 0.3f } });

Shape* quad2 = GeneratePolygon({ { 0.2f, 0.5f },{ 0.3f, 0.5f },{ 0.3f, 0.6f },{ 0.2f, 0.6f } });

Entity* e1 = new Entity(su1, { 1.8f, 0.9f, 0.7f }, 0.0f); //葫芦形的黄光

Entity* e2 = new Entity(triangle, { 0.2f, 0.9f, 1.1f }); //三角形的蓝光

Entity* e3 = new Entity(quad1, { 0.05f, 0.05f, 0.2f }, 0.8f);

Entity* e4 = new Entity(quad2, { 0.05f, 0.05f, 0.2f }, 0.8f);

//Entity* e3 = new Entity(quad, { 0.05f, 0.05f, 0.2f }, 1.0f); //正方形的深蓝色

Shape* s = GeneratePolygon({ { 1.f, 2.f },{ 3.f, 4.f } });

return new Scene({ e1,e2, e3, e4 });

}

Scene* GenerateScene()

{

Circle* c1 = new Circle({ 0.5f, 0.3f }, 0.1f);

Line* l1 = new Line(0.0f, 1.0f, -0.7f);

Entity* e1 = new Entity(c1, { 1.8f, 0.9f, 0.7f }); //葫芦形的黄光

Entity* e2 = new Entity(l1, { 0.0f, 0.0f, 0.0f }, 0.8f); //三角形的蓝光

return new Scene({ e1,e2 });

}

int main() {

Scene* s = GenerateScene2();

unsigned char* p = img;

if (!IS_DEBUG)

for (int y = 0; y < H; y++)

for (int x = 0; x < W; x++, p += 3)

{

Color color = s->sample({ (float)x / W, (float)y / H });

p[0] = (int)fminf(color.r *255.0f, 255.0f);

p[1] = (int)fminf(color.g *255.0f, 255.0f);

p[2] = (int)fminf(color.b *255.0f, 255.0f);

}

else

s->sample({ 0.41f, 0.35f }); //debug

svpng(fopen("reflect.png", "wb"), W, H, img, 0);

}

cppLight2d/light.cpp at master · Vovery/cppLight2d · GitHub

Expand file tree

Breadcrumbs

light.cpp

Latest commit

History

Breadcrumbs

light.cpp

File metadata and controls