渲染一个花瓶 - 优化
2022-3-24 ~ 2022-3-29
(0)
在上一节 渲染一个花瓶通过软光栅实现 中，很粗糙地实现了一个软渲染。
今天完善下面 2 个问题：
- 透视插值矫正
- 齐次空间裁剪
一、透视插值矫正
上一节中，我们直接使用重心坐标来插值三角形顶点的所有属性，其实是不大严谨的，因为重心坐标是在屏幕空间求得的，忽略了深度信息。我们的花瓶定点数量接近 6 万，比较细密，导致这个错误比较隐秘，看起来好像一切良好。为了暴露这个问题，我们创建一个只有 4 个顶点的平面，下图是矫正前后的比对效果。
二、齐次空间裁剪
裁剪原理非常简单，超出边界的顶点砍掉，利用新得到的边界交点重新构造三角形。上一节使用的是在屏幕空间进行裁剪，包围盒超出屏幕的部分就砍去。
抛弃边界上的整个三角形：
裁剪后：
通过对平面的裁剪可以更加清晰地了解裁剪的细节：
三、其他
部分矩阵的操作改成了 SIMD 方式，帧率有少许提升。
修复了相机移动时会卡死问题，还有其他一些 BUG.
四、操作
- 拖动鼠标左键：拖动模型
- 滚轮：视野大小缩放 (测试透视矫正时把 fov 调大比较明显)
- 鼠标左键加滚轮：相机前进或后退（视觉效果和缩放视野差不多）
- 空格键：切换三种光照模型
- 按 C 键：颜色贴图
- 按 N 键：法线贴图
- 按 B 键：位移贴图
- 按 L 键：线框模式
- 按 K 键：背面剔除
- 按 A 键：透视插值矫正
- 按 F 键：切换三种裁剪方法
- 按 V 键：显示花瓶
- 按 P 键：显示平面
二进制链接：https://pan.baidu.com/s/107_t2ykiwygdzSv2FDZHYw
提取码：upwv
五、源码
/////////////////////////////////////////////////////////////
// Rendering a Vase
// Platform : Visual Studio 2022 (v143), EasyX_20220116
// Author : 872289455@qq.com
// Date : 2022-03-24
//
#include <ctime>
#include <cassert>
#include <cfloat>
#include <cmath>
#include <vector>
#include <random>
#include <functional>
#include <algorithm>
#include <xmmintrin.h>
#include <fvec.h>
#include <easyx.h>
using std::vector;
#define WIDTH 800
#define HEIGHT 600
#define Z_NEAR (1.f)
#define Z_FAR (50.f)
#define WORLD_UP vec3(0.f, 1.f, 0.f)
#define MODE_FILL 0
#define MODE_LINE 1
#define CLIP_HOMO 0
#define CLIP_HOMO_RAW 1
#define CLIP_SCRN 2
#define COLOR_STRENGTH 0.85f
#define NORMAL_STRENGTH 3.f
#define DISPACE_STRENGTH 0.23f
#define RADIANS(degrees) ((degrees) * 0.0174532925f)
#define DEGREES(radians) ((radians) * 57.295779513f)
#define M_PI 3.14159265358979323846f
///////////////////////////////////////////////////////////////////////////////////
// Math
///////////////////////////////////////////////////////////////////////////////////
struct vec2 {
float x, y;
vec2(float a = 0.f, float b = 0.f) : x(a), y(b) {}
vec2 operator*(float f) {
return vec2(f * x, f * y);
}
vec2 operator-(const vec2 &b) const {
return vec2(x - b.x, y - b.y);
}
vec2 operator+(const vec2 &b) const {
return vec2(x + b.x, y + b.y);
}
};
struct vec3 {
float x, y, z;
vec3(float a = 0.f, float b = 0.f, float c = 0.f) : x(a), y(b), z(c) {}
vec3 operator*(float f) {
return vec3(f * x, f * y, f * z);
}
vec3 operator-() const {
return vec3(-x, -y, -z);
}
vec3 operator-(float f) const {
return vec3(x - f, y - f, z - f);
}
vec3 operator-(const vec3 &b) const {
return vec3(x - b.x, y - b.y, z - b.z);
}
vec3 operator+(const vec3 &b) const {
return vec3(x + b.x, y + b.y, z + b.z);
}
float length() {return sqrtf(x*x+y*y+z*z);}
};
struct vec4 {
__declspec(align(16))
union {
struct { float x, y, z, w; };
struct { float v[4]; };
};
vec4(float a = 0.f, float b = 0.f, float c = 0.f, float d = 0.f) : x(a), y(b), z(c), w(d) {}
vec4(vec3 v, float f = 1.f) : x(v.x), y(v.y), z(v.z), w(f) {}
float& operator[](int i) { return v[i]; }
vec4 operator*(float f) {
__m128 a = _mm_load_ps(&v[0]);
__m128 b = _mm_load1_ps(&f);
vec4 ret;
_mm_store_ps(&ret.v[0], _mm_mul_ps(a, b));
return ret;
}
vec4 operator-(const vec4 &b) const {
return vec4(x - b.x, y - b.y, z - b.z, w -b.w);
}
vec4 operator+(const vec4 &b) const {
return vec4(x + b.x, y + b.y, z + b.z, w + b.w);
}
vec3 to_vec3() {
return vec3(x, y, z);
}
};
vec2 operator*(float f, vec2 vec) {
return vec * f;;
}
vec3 operator*(float f, vec3 vec) {
return vec * f;;
}
vec4 operator*(float f, vec4& vec) {
return vec * f;;
}
float dot(vec3 a, vec3 b) {
return a.x * b.x + a.y * b.y + a.z * b.z;
}
vec3 cross(vec3 a, vec3 b) {
return vec3(a.y * b.z - b.y * a.z,
a.z * b.x - b.z * a.x,
a.x * b.y - b.x * a.y
);
}
vec2 normalize(vec2 v) {
float len_sq = v.x * v.x + v.y * v.y;
if (len_sq < FLT_EPSILON)
return v;
return (1.f / sqrt(len_sq)) * v;
}
vec3 normalize(vec3 v) {
float len_sq = v.x * v.x + v.y * v.y + v.z * v.z;
if (len_sq < FLT_EPSILON)
return v;
return (1.f / sqrt(len_sq)) * v;
}
struct quat {
union {
struct { float x, y, z, w; };
struct { vec3 vec; float scalar; };
};
quat(float angle, vec3 &axis) {
float s = 0.f;
float c = 0.f;
float rads = RADIANS(angle);
axis = normalize(axis);
s = sinf(rads * 0.5f);
c = cosf(rads * 0.5f);
x = s * axis.x;
y = s * axis.y;
z = s * axis.z;
w = c;
}
vec3 rotate(vec3 from) {
vec3 a = 2.f * dot(vec, from) * vec;
vec3 b = (w * w - dot(vec, vec)) * from;
vec3 c = 2.f * w * cross(vec, from);
return a + b + c;
}
};
struct mat3 {
vec3 col[3];
mat3(vec3 c0, vec3 c1, vec3 c2) {
col[0] = c0;
col[1] = c1;
col[2] = c2;
}
vec3 operator*(vec3 v) {
return vec3(
col[0].x * v.x + col[1].x * v.y + col[2].x * v.z,
col[0].y * v.x + col[1].y * v.y + col[2].y * v.z,
col[0].z * v.x + col[1].z * v.y + col[2].z * v.z
);
}
};
__m128 simd_mat4_mul_vec4(__m128 const *m, __m128 &v) {
__m128 v0 = _mm_shuffle_ps(v, v, _MM_SHUFFLE(0, 0, 0, 0));
__m128 v1 = _mm_shuffle_ps(v, v, _MM_SHUFFLE(1, 1, 1, 1));
__m128 v2 = _mm_shuffle_ps(v, v, _MM_SHUFFLE(2, 2, 2, 2));
__m128 v3 = _mm_shuffle_ps(v, v, _MM_SHUFFLE(3, 3, 3, 3));
__m128 m0 = _mm_mul_ps(m[0], v0);
__m128 m1 = _mm_mul_ps(m[1], v1);
__m128 m2 = _mm_mul_ps(m[2], v2);
__m128 m3 = _mm_mul_ps(m[3], v3);
__m128 a0 = _mm_add_ps(m0, m1);
__m128 a1 = _mm_add_ps(m2, m3);
__m128 a2 = _mm_add_ps(a0, a1);
return a2;
}
void simd_mat4_mul(__m128 const *in1, __m128 const *in2, __m128 *out) {
#pragma omp parallel for
for (int i = 0; i < 4; i++) {
__m128 e0 = _mm_shuffle_ps(in2[i], in2[i], _MM_SHUFFLE(0, 0, 0, 0));
__m128 e1 = _mm_shuffle_ps(in2[i], in2[i], _MM_SHUFFLE(1, 1, 1, 1));
__m128 e2 = _mm_shuffle_ps(in2[i], in2[i], _MM_SHUFFLE(2, 2, 2, 2));
__m128 e3 = _mm_shuffle_ps(in2[i], in2[i], _MM_SHUFFLE(3, 3, 3, 3));
__m128 m0 = _mm_mul_ps(in1[0], e0);
__m128 m1 = _mm_mul_ps(in1[1], e1);
__m128 m2 = _mm_mul_ps(in1[2], e2);
__m128 m3 = _mm_mul_ps(in1[3], e3);
__m128 a0 = _mm_add_ps(m0, m1);
__m128 a1 = _mm_add_ps(m2, m3);
__m128 a2 = _mm_add_ps(a0, a1);
out[i] = a2;
}
}
struct mat4;
void M128ToMat4(__m128* in, mat4* out);
void Mat4ToM128(mat4* in, __m128* out);
struct mat4 {
__declspec(align(16))
union {
float v[16];
struct { vec4 col[4]; };
};
mat4(vec4 c0 = vec4(1.f, 0.f, 0.f, 0.f),
vec4 c1 = vec4(0.f, 1.f, 0.f, 0.f),
vec4 c2 = vec4(0.f, 0.f, 1.f, 0.f),
vec4 c3 = vec4(0.f, 0.f, 0.f, 1.f)
){
col[0] = c0;
col[1] = c1;
col[2] = c2;
col[3] = c3;
}
vec4& operator[](int i) { return col[i]; }
mat4 operator*(float f) {
return mat4(f * col[0], f * col[1], f * col[2], f * col[3]);
}
vec4 operator*(vec4 vec) {
__m128 M[4];
vec4 ret;
Mat4ToM128(this, M);
__m128 V = _mm_load_ps(&vec[0]);
__m128 res = simd_mat4_mul_vec4(M, V);
_mm_store_ps(&ret[0], res);
return ret;
}
mat4 operator*(mat4 &m) {
__m128 in1[4];
__m128 in2[4];
__m128 out[4];
mat4 res;
Mat4ToM128(this, in1);
Mat4ToM128(&m, in2);
simd_mat4_mul(in1, in2, out);
M128ToMat4(out, &res);
return res;
}
};
void Mat4ToM128(mat4 *in, __m128 *out) {
#pragma omp parallel for
for (int i = 0; i < 4; i++)
out[i] = _mm_load_ps(&in->col[i][0]);
}
void M128ToMat4(__m128* in, mat4* out) {
#pragma omp parallel for
for (int i = 0; i < 4; i++)
_mm_store_ps(&out->col[i][0], in[i]);
}
void simd_mat4_transpose(__m128 const *in, __m128 *out) {
__m128 tmp0 = _mm_shuffle_ps(in[0], in[1], 0x44);
__m128 tmp2 = _mm_shuffle_ps(in[0], in[1], 0xEE);
__m128 tmp1 = _mm_shuffle_ps(in[2], in[3], 0x44);
__m128 tmp3 = _mm_shuffle_ps(in[2], in[3], 0xEE);
out[0] = _mm_shuffle_ps(tmp0, tmp1, 0x88);
out[1] = _mm_shuffle_ps(tmp0, tmp1, 0xDD);
out[2] = _mm_shuffle_ps(tmp2, tmp3, 0x88);
out[3] = _mm_shuffle_ps(tmp2, tmp3, 0xDD);
}
mat4 transposed(mat4 m) {
__m128 in[4];
__m128 out[4];
Mat4ToM128(&m, in);
simd_mat4_transpose(in, out);
mat4 res;
M128ToMat4(out, &res);
return res;
}
__m128 simd_vec4_dot(const __m128 &v1, const __m128 &v2) {
__m128 const mul0 = _mm_mul_ps(v1, v2);
__m128 const swp0 = _mm_shuffle_ps(mul0, mul0, _MM_SHUFFLE(2, 3, 0, 1));
__m128 const add0 = _mm_add_ps(mul0, swp0);
__m128 const swp1 = _mm_shuffle_ps(add0, add0, _MM_SHUFFLE(0, 1, 2, 3));
__m128 const add1 = _mm_add_ps(add0, swp1);
return add1;
}
// ref to glm
void simd_mat4_inverse(__m128 const *in, __m128 *out) {
__m128 Fac0; {
__m128 Swp0a = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(3, 3, 3, 3));
__m128 Swp0b = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(2, 2, 2, 2));
__m128 Swp00 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(2, 2, 2, 2));
__m128 Swp01 = _mm_shuffle_ps(Swp0a, Swp0a, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp02 = _mm_shuffle_ps(Swp0b, Swp0b, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp03 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(3, 3, 3, 3));
__m128 Mul00 = _mm_mul_ps(Swp00, Swp01);
__m128 Mul01 = _mm_mul_ps(Swp02, Swp03);
Fac0 = _mm_sub_ps(Mul00, Mul01);
}
__m128 Fac1; {
__m128 Swp0a = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(3, 3, 3, 3));
__m128 Swp0b = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(1, 1, 1, 1));
__m128 Swp00 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(1, 1, 1, 1));
__m128 Swp01 = _mm_shuffle_ps(Swp0a, Swp0a, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp02 = _mm_shuffle_ps(Swp0b, Swp0b, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp03 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(3, 3, 3, 3));
__m128 Mul00 = _mm_mul_ps(Swp00, Swp01);
__m128 Mul01 = _mm_mul_ps(Swp02, Swp03);
Fac1 = _mm_sub_ps(Mul00, Mul01);
}
__m128 Fac2; {
__m128 Swp0a = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(2, 2, 2, 2));
__m128 Swp0b = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(1, 1, 1, 1));
__m128 Swp00 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(1, 1, 1, 1));
__m128 Swp01 = _mm_shuffle_ps(Swp0a, Swp0a, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp02 = _mm_shuffle_ps(Swp0b, Swp0b, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp03 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(2, 2, 2, 2));
__m128 Mul00 = _mm_mul_ps(Swp00, Swp01);
__m128 Mul01 = _mm_mul_ps(Swp02, Swp03);
Fac2 = _mm_sub_ps(Mul00, Mul01);
}
__m128 Fac3; {
__m128 Swp0a = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(3, 3, 3, 3));
__m128 Swp0b = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(0, 0, 0, 0));
__m128 Swp00 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(0, 0, 0, 0));
__m128 Swp01 = _mm_shuffle_ps(Swp0a, Swp0a, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp02 = _mm_shuffle_ps(Swp0b, Swp0b, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp03 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(3, 3, 3, 3));
__m128 Mul00 = _mm_mul_ps(Swp00, Swp01);
__m128 Mul01 = _mm_mul_ps(Swp02, Swp03);
Fac3 = _mm_sub_ps(Mul00, Mul01);
}
__m128 Fac4; {
__m128 Swp0a = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(2, 2, 2, 2));
__m128 Swp0b = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(0, 0, 0, 0));
__m128 Swp00 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(0, 0, 0, 0));
__m128 Swp01 = _mm_shuffle_ps(Swp0a, Swp0a, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp02 = _mm_shuffle_ps(Swp0b, Swp0b, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp03 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(2, 2, 2, 2));
__m128 Mul00 = _mm_mul_ps(Swp00, Swp01);
__m128 Mul01 = _mm_mul_ps(Swp02, Swp03);
Fac4 = _mm_sub_ps(Mul00, Mul01);
}
__m128 Fac5; {
__m128 Swp0a = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(1, 1, 1, 1));
__m128 Swp0b = _mm_shuffle_ps(in[3], in[2], _MM_SHUFFLE(0, 0, 0, 0));
__m128 Swp00 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(0, 0, 0, 0));
__m128 Swp01 = _mm_shuffle_ps(Swp0a, Swp0a, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp02 = _mm_shuffle_ps(Swp0b, Swp0b, _MM_SHUFFLE(2, 0, 0, 0));
__m128 Swp03 = _mm_shuffle_ps(in[2], in[1], _MM_SHUFFLE(1, 1, 1, 1));
__m128 Mul00 = _mm_mul_ps(Swp00, Swp01);
__m128 Mul01 = _mm_mul_ps(Swp02, Swp03);
Fac5 = _mm_sub_ps(Mul00, Mul01);
}
__m128 SignA = _mm_set_ps(1.0f, -1.0f, 1.0f, -1.0f);
__m128 SignB = _mm_set_ps(-1.0f, 1.0f, -1.0f, 1.0f);
__m128 Temp0 = _mm_shuffle_ps(in[1], in[0], _MM_SHUFFLE(0, 0, 0, 0));
__m128 Vec0 = _mm_shuffle_ps(Temp0, Temp0, _MM_SHUFFLE(2, 2, 2, 0));
__m128 Temp1 = _mm_shuffle_ps(in[1], in[0], _MM_SHUFFLE(1, 1, 1, 1));
__m128 Vec1 = _mm_shuffle_ps(Temp1, Temp1, _MM_SHUFFLE(2, 2, 2, 0));
__m128 Temp2 = _mm_shuffle_ps(in[1], in[0], _MM_SHUFFLE(2, 2, 2, 2));
__m128 Vec2 = _mm_shuffle_ps(Temp2, Temp2, _MM_SHUFFLE(2, 2, 2, 0));
__m128 Temp3 = _mm_shuffle_ps(in[1], in[0], _MM_SHUFFLE(3, 3, 3, 3));
__m128 Vec3 = _mm_shuffle_ps(Temp3, Temp3, _MM_SHUFFLE(2, 2, 2, 0));
__m128 Mul00 = _mm_mul_ps(Vec1, Fac0);
__m128 Mul01 = _mm_mul_ps(Vec2, Fac1);
__m128 Mul02 = _mm_mul_ps(Vec3, Fac2);
__m128 Sub00 = _mm_sub_ps(Mul00, Mul01);
__m128 Add00 = _mm_add_ps(Sub00, Mul02);
__m128 Inv0 = _mm_mul_ps(SignB, Add00);
__m128 Mul03 = _mm_mul_ps(Vec0, Fac0);
__m128 Mul04 = _mm_mul_ps(Vec2, Fac3);
__m128 Mul05 = _mm_mul_ps(Vec3, Fac4);
__m128 Sub01 = _mm_sub_ps(Mul03, Mul04);
__m128 Add01 = _mm_add_ps(Sub01, Mul05);
__m128 Inv1 = _mm_mul_ps(SignA, Add01);
__m128 Mul06 = _mm_mul_ps(Vec0, Fac1);
__m128 Mul07 = _mm_mul_ps(Vec1, Fac3);
__m128 Mul08 = _mm_mul_ps(Vec3, Fac5);
__m128 Sub02 = _mm_sub_ps(Mul06, Mul07);
__m128 Add02 = _mm_add_ps(Sub02, Mul08);
__m128 Inv2 = _mm_mul_ps(SignB, Add02);
__m128 Mul09 = _mm_mul_ps(Vec0, Fac2);
__m128 Mul10 = _mm_mul_ps(Vec1, Fac4);
__m128 Mul11 = _mm_mul_ps(Vec2, Fac5);
__m128 Sub03 = _mm_sub_ps(Mul09, Mul10);
__m128 Add03 = _mm_add_ps(Sub03, Mul11);
__m128 Inv3 = _mm_mul_ps(SignA, Add03);
__m128 Row0 = _mm_shuffle_ps(Inv0, Inv1, _MM_SHUFFLE(0, 0, 0, 0));
__m128 Row1 = _mm_shuffle_ps(Inv2, Inv3, _MM_SHUFFLE(0, 0, 0, 0));
__m128 Row2 = _mm_shuffle_ps(Row0, Row1, _MM_SHUFFLE(2, 0, 2, 0));
__m128 Det0 = simd_vec4_dot(in[0], Row2);
__m128 Rcp0 = _mm_div_ps(_mm_set1_ps(1.0f), Det0);
out[0] = _mm_mul_ps(Inv0, Rcp0);
out[1] = _mm_mul_ps(Inv1, Rcp0);
out[2] = _mm_mul_ps(Inv2, Rcp0);
out[3] = _mm_mul_ps(Inv3, Rcp0);
}
mat4 inverse(mat4 m) {
__m128 in[4];
__m128 out[4];
mat4 res;
Mat4ToM128(&m, in);
simd_mat4_inverse(in, out);
M128ToMat4(out, &res);
return res;
}
mat4 rotateY(double angle) {
float rad = RADIANS(50.f * angle);
float cs = cos(rad);
float sn = sin(rad);
return mat4(
vec4(cs, 0.f, -sn, 0.f),
vec4(0.f, 1.f, 0.f, 0.f),
vec4(sn, 0.f, cs, 0.f),
vec4(0.f, 0.f, 0.f, 1.f)
);
}
///////////////////////////////////////////////////////////////////////////////////
// Procedural Texturing
///////////////////////////////////////////////////////////////////////////////////
template <typename T>
T lerp(T& a, T& b, float t) {
return a + (b - a) * t;
}
class Noise {
const uint32_t TABLE_SIZE = 0X100U;
const uint32_t TABLE_MASK = 0XFFU;
vector<vector<vec2>> grid;
public:
Noise() {
std::mt19937 gen(static_cast<uint32_t>(time(nullptr)));
std::uniform_real_distribution<float> distrFloat(-1.f, 1.f);
auto randFloat = std::bind(distrFloat, gen);
grid = vector<vector<vec2>> (TABLE_SIZE, vector<vec2>(TABLE_SIZE));
for (uint32_t row = 0; row < TABLE_SIZE; row++)
for (uint32_t col = 0; col < TABLE_SIZE; col++)
grid[row][col] = normalize(vec2(randFloat(), randFloat()));
}
vec3 eval(vec2 p) {
uint32_t x = (uint32_t)std::floor(p.x);
uint32_t y = (uint32_t)std::floor(p.y);
float u = fade(p.x - x);
float v = fade(p.y - y);
uint32_t x0 = x & TABLE_MASK;
uint32_t x1 = (x0 + 1) & TABLE_MASK;
uint32_t y0 = y & TABLE_MASK;
uint32_t y1 = (y0 + 1) & TABLE_MASK;
vec2 lerpx1 = lerp(grid[x0][y0], grid[x1][y0], u);
vec2 lerpx2 = lerp(grid[x0][y1], grid[x1][y1], u);
vec2 lerpy = lerp(lerpx1, lerpx2, v);
return vec3(lerpy.x, lerpy.y, COLOR_STRENGTH);
}
private:
float fade(float t) {
return t * t * t * (t * (t * 6 - 15) + 10);
}
};
struct Image {
int height;
int width;
int channels;
vector<uint8_t> data;
Image(int h = 0, int w = 0, int c = 0, vector<uint8_t> raw = vector<uint8_t>()) : height(h), width(w), channels(c), data(raw) {}
};
vec3 getPixelAt(const Image *map, int x, int y) {
if (x < 0) x = map->width - 1;
if (x >= map->width) x = 0;
if (y < 0) y = map->height - 1;;
if (y >= map->height) y = 0;
float r, g, b;
int ofs = map->channels * (y * map->width + x);
r = g = b = map->channels > 0 ? map->data[ofs + 0] : 0.f;
g = b = map->channels > 1 ? map->data[ofs + 1] : r;
b = map->channels > 2 ? map->data[ofs + 2] : g;
return (1.f / 255.f) * vec3(r, g, b);
}
// vec3 returned in range 0.0 - 1.0
vec3 texture(const Image *map, const vec2& texCoord) {
vec2 uv = texCoord;
int x = int(map->width * uv.x);
int y = int(map->height * uv.y);
float u = map->width * uv.x - x;
float v = map->height * uv.y - y;
vec3 c00 = getPixelAt(map, x, y);
vec3 c10 = getPixelAt(map, x + 1, y);
vec3 c01 = getPixelAt(map, x, y + 1);
vec3 c11 = getPixelAt(map, x + 1, y + 1);
return (1 - u) * (1 - v) * c00 + u * (1 - v) * c10 + (1 - u) * v * c01 + u * v * c11;
}
Image buildColorTexture(void) {
Noise noise;
float baseFreq = 12;
int level = 6;
float amplitudeMult = 0.5f;
float frequencyMult = 1.9f;
int width = 1024;
int height = 1024;
vector<uint8_t> pixels;
pixels.resize(width * height * 3);
float dx = 1.0f / (width - 1);
float dy = 1.0f / (height - 1);
for (int row = 0; row < height; row++) {
for (int col = 0; col < width / 2; col++) {
float x = dx * col;
float y = dy * row;
float freq = baseFreq;
float amplitude = 1.f;
vec3 sumVec;
for (int oct = 0; oct < level; oct++) {
sumVec = sumVec + amplitude * noise.eval(freq * vec2(x, y));
freq *= frequencyMult;
amplitude *= amplitudeMult;
}
sumVec = normalize(sumVec);
float turb = sin(sumVec.y);
int lofs = 3 * (row * width + col);
int rofs = 3 * (row * width + width - 1 - col);
pixels[lofs + 0] = pixels[rofs + 0] = static_cast<uint8_t>((turb * 1.0 + 1.0) * 255.f * 0.5);
pixels[lofs + 1] = pixels[rofs + 1] = static_cast<uint8_t>((turb * 0.7 + 1.0) * 255.f * 0.5);
pixels[lofs + 2] = pixels[rofs + 2] = static_cast<uint8_t>((turb * 0.8 + 1.0) * 255.f * 0.5);
}
}
return Image(width, height, 3, pixels);
}
Image buildColorTextureGrid(void) {
vector<uint8_t> pixels(512 * 512 * 3, 0);
for (int i = 0; i < 512; i++) {
for (int j = 0; j < 512; j++) {
int x = i / 64, y = j / 64;
int ofs = 3 * (i * 512 + j);
if ((x + y) & 1)
pixels[ofs] = pixels[ofs + 1] = 250;
else
pixels[ofs + 1] = pixels[ofs + 2] = 128;
}
}
return Image(512, 512, 3, pixels);
}
Image buildNormalTextureFrom(const Image *src) {
vector<uint8_t> pixels;
pixels.reserve(3 * src->width * src->height);
for (int y = 0; y < src->height; y++) {
for (int x = 0; x < src->width; x++) {
float tl = getPixelAt(src, x - 1, y - 1).length();
float t = getPixelAt(src, x - 1, y).length();
float tr = getPixelAt(src, x - 1, y + 1).length();
float r = getPixelAt(src, x, y + 1).length();
float br = getPixelAt(src, x + 1, y + 1).length();
float b = getPixelAt(src, x + 1, y).length();
float bl = getPixelAt(src, x + 1, y - 1).length();
float l = getPixelAt(src, x, y - 1).length();
float dx = float(tr + 2.f * r + br) - float(tl + 2.f * l + bl);
float dy = float(bl + 2.f * b + br) - float(tl + 2.f * t + tr);
float dz = 1.f / NORMAL_STRENGTH;
vec3 n = normalize(vec3(dx, dy, dz));
pixels.push_back(static_cast<uint8_t>((n.x + 1.0) * 255.f * 0.5));
pixels.push_back(static_cast<uint8_t>((n.y + 1.0) * 255.f * 0.5));
pixels.push_back(static_cast<uint8_t>((n.z + 1.0) * 255.f * 0.5));
}
}
return Image(src->width, src->height, 3, pixels);
}
///////////////////////////////////////////////////////////////////////////////////
// Modeling
///////////////////////////////////////////////////////////////////////////////////
struct Mesh {
vector<vec3> pos;
vector<vec3> normal;
vector<vec3> tangent;
vector<vec2> uv;
vector<int> index;
};
struct Plane : public Mesh {
Plane(float size, int divs) {
assert(size > 1.f);
assert(divs > 0);
float dxz = 2.f * size / divs;
for (int i = 0; i <= divs; i++) {
float z = i * dxz - size;
for (int j = 0; j <= divs; j++) {
float x = j * dxz - size;
pos.push_back(vec3(x, -1E-2F, z));
normal.push_back(vec3(0.f, 1.f, 0.f));
tangent.push_back(vec3(1.f, 0.f, 0.f));
uv.push_back(vec2(float(j) / float(divs), float(i) / float(divs)));
}
}
for (int z = 0; z < divs; z++) {
int start = z * (divs + 1);
int next_start = (z + 1) * (divs + 1);
for (int x = 0; x < divs; x++) {
int next_x = x + 1;
index.push_back(start + x);
index.push_back(next_start + x);
index.push_back(start + next_x);
index.push_back(start + next_x);
index.push_back(next_start + x);
index.push_back(next_start + next_x);
}
}
}
};
struct Vase : public Mesh {
Vase(int y_edges) {
assert(y_edges > 3);
int x_edges = 2 * y_edges;
float dx = 2.f * M_PI / x_edges;
float dy = 2.f * M_PI / y_edges;
for (int y = 0; y <= y_edges; y++) {
float v = y * dy;
float cv = cos(v);
float sv = sin(v);
float r = 2 + sv;
for (int x = 0; x <= x_edges; x++) {
float u = x * dx;
float cu = cos(u);
float su = sin(u);
vec3 tang(cu * cv, 1, su * cv);
vec3 biTangent(-su, 0, cu);
pos.push_back(vec3(r * cu, v, r * su));
tangent.push_back(tang);
normal.push_back(normalize(cross(tang, biTangent)));
uv.push_back(vec2(u / (2 * M_PI), v / (2 * M_PI)));
}
}
for (int y = 0; y < y_edges; y++) {
int start = y * (x_edges + 1);
int next_start = (y + 1) * (x_edges + 1);
for (int x = 0; x < x_edges; x++) {
int next_x = x + 1;
index.push_back(start + x);
index.push_back(next_start + x);
index.push_back(start + next_x);
index.push_back(start + next_x);
index.push_back(next_start + x);
index.push_back(next_start + next_x);
}
}
pos.push_back(vec3());
tangent.push_back(vec3(1.f, 0.f, 0.f));
normal.push_back(vec3(0.f, -1.f, 0.f));
uv.push_back(vec2(0.5, 0.5));
for (int x = 0; x < x_edges; x++) {
index.push_back((int)pos.size() - 1);
index.push_back(x);
index.push_back(x + 1);
normal[x] = vec3(0.f, -1.f, 0.f);
}
normal[x_edges] = vec3(0.f, -1.f, 0.f);
}
};
///////////////////////////////////////////////////////////////////////////////////
// Orbit Camera, events process
///////////////////////////////////////////////////////////////////////////////////
uint8_t activeColorTexture = 1u; // 'C' key
uint8_t activeNormalTexture = 0u; // 'N' key
uint8_t activeDispTexture = 0u; // 'B' key
uint8_t activeLineMode = 0u; // 'L' key
uint8_t cullFace = 0u; // 'K' key
uint8_t selectShader = 0u; // SPACE key.
uint8_t correctCentric = 1u; // 'A' key
uint8_t clipType = CLIP_HOMO; // 'F' key. 0:homogeneous clipping, 1:raw homogeneous clip, 2:screen clipping
uint8_t showVase = 1u; // 'V' key
uint8_t showPlane = 1u; // 'P' key
uint8_t curClipType = clipType; // when rendering a frame, the states should not be changed
class Camera {
vec3 pos, target;
float zoom, aspect;
mat4 projection, view;
public:
Camera(vec3 position, vec3 center, float asp) : pos(position), target(center), zoom(25.f), aspect(asp) {
updateProjection();
updateView();
}
void processInput() {
ExMessage msg;
static bool firstClick = true;
static int lastx, lasty;
while (peekmessage(&msg, EM_MOUSE | EM_KEY)) {
// Drag Left Button: Rotate
if (WM_MOUSEMOVE == msg.message) {
if (false == msg.lbutton) {
firstClick = true;
}
else if (firstClick) {
firstClick = false;
lastx = msg.x;
lasty = msg.y;
}
else {
float xoff = 0.5f * (msg.x - lastx);
float yoff = 0.5f * (msg.y - lasty);
lastx = msg.x;
lasty = msg.y;
mouseMove(xoff, yoff);
}
}
else if (WM_MOUSEWHEEL == msg.message) {
if (msg.lbutton) // Left Button + Scroll: Camera Forward or Backward, have a bug
srcollPosition(-0.01f * msg.wheel);
else // Scroll: field of view
scrollZoom(0.01f * msg.wheel);
}
else if (WM_KEYDOWN == msg.message) {
switch (msg.vkcode) {
case VK_SPACE: selectShader = (selectShader + 1) % 3; break;
case 'F': clipType = (clipType + 1) % 3; break;
case 'C': activeColorTexture ^= 1u; break;
case 'N': activeNormalTexture ^= 1u; break;
case 'B': activeDispTexture ^= 1u; break;
case 'L': activeLineMode ^= 1u; break;
case 'K': cullFace ^= 1u; break;
case 'A': correctCentric ^= 1u; break;
case 'V': showVase ^= 1u; break;
case 'P': showPlane ^= 1u; break;
default: break;
}
}
}
}
mat4& viewMatrix() { return view; }
mat4& projectionMatrix() { return projection;}
vec3& position() { return pos; }
float fov() { return zoom; }
private:
void updateProjection() {
float t = Z_NEAR * tan(RADIANS(0.5f * zoom));
float b = -t;
float r = t * aspect;
float l = -r;
projection[0] = vec4(2 * Z_NEAR / (r - l), 0.f, 0.f, 0.f);
projection[1] = vec4(0.f, 2 * Z_NEAR / (t - b), 0.f, 0.f);
projection[2] = vec4((r + l) / (r - l), (t + b) / (t - b), -(Z_FAR - Z_NEAR) / (Z_FAR - Z_NEAR), -1.f);
projection[3] = vec4(0.f, 0.f, -2 * Z_FAR * Z_NEAR / (Z_FAR - Z_NEAR), 0.f);
}
void updateView() {
vec3 z_axis = normalize(pos - target);
vec3 x_axis = normalize(cross(WORLD_UP, z_axis));
vec3 y_axis = normalize(cross(z_axis, x_axis));
view[0] = vec4(x_axis.x, y_axis.x, z_axis.x, 0.f);
view[1] = vec4(x_axis.y, y_axis.y, z_axis.y, 0.f);
view[2] = vec4(x_axis.z, y_axis.z, z_axis.z, 0.f);
view[3] = vec4(-dot(x_axis, pos), -dot(y_axis, pos), -dot(z_axis, pos), 1.f);
}
void mouseMove(float xoff, float yoff) {
vec3 front = normalize(target - pos);
vec3 right = normalize(cross(front, WORLD_UP));
vec3 up = normalize(cross(right, front));
float angle = DEGREES(acos(dot(front, WORLD_UP)));
if ((yoff < 0 && (angle + yoff < 20)) || (yoff > 0 && (angle + yoff > 160)))
return;
quat qx(-xoff, up);
pos = qx.rotate(pos - target) + target;
front = normalize(target - pos);
right = normalize(cross(front, up));
quat qy(-yoff, right);
pos = qy.rotate(pos - target) + target;
updateView();
}
void srcollPosition(float yoff) {
vec3 front = normalize(target - pos);
vec3 newPos = pos + yoff * front;
vec3 pt = target - newPos;
float len = pt.length();
if (dot(pt, front) <= 0 || len < 3.5f)
return;
pos = newPos;
updateView();
}
void scrollZoom(float yoff) {
if (zoom + yoff > 120 || zoom + yoff < 10)
return;
zoom += yoff;
updateProjection();
}
};
///////////////////////////////////////////////////////////////////////////////////
// Rendering
///////////////////////////////////////////////////////////////////////////////////
struct Vertex {
vec3 pos, normal, tangent, color;
vec2 uv;
Vertex() {}
Vertex(vec3 p, vec3 n, vec3 t, vec3 c, vec2 u) : pos(p), normal(n), tangent(t), color(c), uv(u) {}
Vertex operator+(const Vertex &b) const {
return Vertex(pos + b.pos, normal + b.normal, tangent + b.tangent, color + b.color, uv + b.uv);
}
Vertex operator-(const Vertex& b) const {
return Vertex(pos - b.pos, normal - b.normal, tangent - b.tangent, color - b.color, uv - b.uv);
}
Vertex operator*(float t) {
return Vertex(pos * t, normal * t, tangent * t, color * t, uv * t);
}
};
typedef void (*VERTEX_SHADER)(const Vertex& in, Vertex& out, vec4& mvpPos);
typedef vec3(*FRAGMENT_SHADER)(const Vertex& in);
struct Program {
bool flatHint;
VERTEX_SHADER vertexShader;
FRAGMENT_SHADER fragmentShader;
Program(VERTEX_SHADER vert = nullptr, FRAGMENT_SHADER frag = nullptr, bool isFlat = false) :
vertexShader(vert), fragmentShader(frag), flatHint(isFlat) {}
};
struct Light {
vec3 dir; // Light direction in eye coords.
float La; // Ambient light intensity
float Ld; // Diffuse light intensity
float Ls; // Specular light intensity
Light(vec3 d = vec3(0.f, 1.f, 1.f), float la = 0.03f, float ld = 0.2f, float ls = 0.8f) :
dir(d), La(la), Ld(ld), Ls(ls) {}
};
// Sharing of uniform data between shader programs.
struct perFrameData {
mat4 modelViewMatrix;
mat4 projectionMatrix;
mat4 normalMatrix;
mat4 viewportMatrix;
mat4 MVP;
Image *colorMap;
Image *normalMap;
Image *dispMap;
Light light[4] = {
Light(vec3( 1.0f, 1.f, 1.f)),
Light(vec3(-2.0f, -2.f, 1.f)),
Light(vec3(-0.5f, 0.f, 1.f)),
Light(vec3(-1.0f, 0.f, 0.f))
};
} uniform;
void setMatrixUniform(mat4 &m, mat4 &v, mat4 &p) {
float w2 = WIDTH / 2.f;
float h2 = HEIGHT / 2.f;
uniform.modelViewMatrix = v * m;
uniform.projectionMatrix = p;
uniform.normalMatrix = transposed(inverse(uniform.modelViewMatrix));
uniform.viewportMatrix = mat4(vec4(w2, 0.f, 0.f, 0.f), vec4(0.f, h2, 0.f, 0.f), vec4(0.f, 0.f, 1.f, 0.f), vec4(w2 - 0.5f, h2 - 0.5f, 0.f, 1.f));
uniform.MVP = p * uniform.modelViewMatrix;
}
void clamp(int& value, int l, int r) {
value = min(value, r);
value = max(value, l);
}
#define CLIP_FUNC(name, sign, dir, dir1, dir2) \
float name(vec4 *a, vec4 *b) {\
float t, dx, dy, dz, dw, den;\
dx = (b->x - a->x);\
dy = (b->y - a->y);\
dz = (b->z - a->z);\
dw = (b->w - a->w);\
den = -(sign d ## dir) + dw;\
if (den == 0) t=0;\
else t = (sign a->dir - a->w) / den;\
return t;\
}
CLIP_FUNC(clipXmin, -, x, y, z)
CLIP_FUNC(clipXmax, +, x, y, z)
CLIP_FUNC(clipYmin, -, y, x, z)
CLIP_FUNC(clipYmax, +, y, x, z)
CLIP_FUNC(clipZmin, -, z, x, y)
CLIP_FUNC(clipZmax, +, z, x, y)
float (*clipProc[6])(vec4*, vec4*) = {
clipXmin, clipXmax,
clipYmin, clipYmax,
clipZmin, clipZmax
};
class Render {
DWORD* framebuf;
VERTEX_SHADER vertexShader;
FRAGMENT_SHADER fragmentShader;
vector<float> zbuf;
int drawMode;
bool flatHint;
// every mesh with a draw Context
struct Context {
int vertices;
vector<Vertex> VertexIn;
vector<Vertex> VertexOut;
vector<vec4> mvpPos;
vector<int> index;
Image colorMap;
Image normalMap;
Image dispMap;
};
vector<Context> ctx;
public:
Render() : vertexShader(nullptr), fragmentShader(nullptr), drawMode(MODE_FILL), flatHint(false) {
initgraph(WIDTH, HEIGHT);
setbkcolor(77u << 16 | 76u << 8 | 51u); // RGB
framebuf = GetImageBuffer();
assert(framebuf);
zbuf.resize(WIDTH * HEIGHT);
}
int createBuffersWith(Mesh *msh) {
ctx.push_back(Context());
int vao = ctx.size() - 1;
assert(vao > -1);
assert(msh);
ctx[vao].index = msh->index;
ctx[vao].vertices = (int)msh->pos.size();
ctx[vao].mvpPos.resize(ctx[vao].vertices);
ctx[vao].VertexIn.resize(ctx[vao].vertices);
ctx[vao].VertexOut.resize(ctx[vao].vertices);
for (int i = 0; i < ctx[vao].vertices; i++) {
ctx[vao].VertexIn[i].pos = msh->pos[i];
ctx[vao].VertexIn[i].normal = msh->normal[i];
ctx[vao].VertexIn[i].tangent = msh->tangent[i];
ctx[vao].VertexIn[i].uv = msh->uv[i];
}
return vao;
}
void useProgram(Program& shader) {
flatHint = shader.flatHint;
vertexShader = shader.vertexShader;
fragmentShader = shader.fragmentShader;
}
void clear(void) {
std::fill_n(framebuf, WIDTH * HEIGHT, 51u << 16 | 76u << 8 | 77u); // BGRA
std::fill_n(zbuf.begin(), zbuf.size(), FLT_MAX);
}
void drawElements(int vao) {
assert(vao > -1);
useTexture(vao);
curClipType = clipType;
vector<Vertex>& VertexIn = ctx[vao].VertexIn;
vector<Vertex>& VertexOut = ctx[vao].VertexOut;
vector<vec4>& mvpPos = ctx[vao].mvpPos;
vector<int>& index = ctx[vao].index;
int& vertices = ctx[vao].vertices;
#pragma omp parallel for
for (int i = 0; i < vertices; i++)
vertexShader(VertexIn[i], VertexOut[i], mvpPos[i]);
#pragma omp parallel for
for (int i = 0; i < (int)index.size(); i += 3) {
Vertex vert[3] = { VertexOut[index[i]], VertexOut[index[i + 1]], VertexOut[index[i + 2]] };
vec4 v[3] = {mvpPos[index[i]], mvpPos[index[i + 1]], mvpPos[index[i + 2]] };
int clp[3] = { clipCode(v[0]), clipCode(v[1]), clipCode(v[2]) };
if (curClipType == CLIP_HOMO)
clipTriangle(vert, v, clp, 0);
else {
if ((curClipType == CLIP_HOMO_RAW) && (clp[0] | clp[1] | clp[2]))
continue;
drawTriangle(vert, v);
}
}
}
void bindTexture(int vao, const Image& colorMap, const Image& normalMap, const Image& dispMap) {
assert(vao != -1);
ctx[vao].colorMap = colorMap;
ctx[vao].normalMap = normalMap;
ctx[vao].dispMap = dispMap;
}
void polygonMode(int drawhint) {
drawMode = drawhint;
}
private:
void useTexture(int vao) {
assert(vao != -1);
uniform.colorMap = &ctx[vao].colorMap;
uniform.normalMap = &ctx[vao].normalMap;
uniform.dispMap = &ctx[vao].dispMap;
}
void drawTriangle(Vertex *vert, vec4 *v) {
float hw[3] = { 0 };
for (int i = 0; i < 3; i++) {
v[i] = uniform.viewportMatrix * v[i];
hw[i] = 1.f / v[i].w;
v[i] = v[i] * hw[i];
}
if (cullFace && cross(v[1].to_vec3() - v[0].to_vec3(), v[2].to_vec3() - v[0].to_vec3()).z <= 0)
return;
if (activeLineMode) {
drawLine(v[0], v[1]);
drawLine(v[0], v[2]);
drawLine(v[1], v[2]);
return;
}
int left = (int)min(v[0].x, min(v[1].x, v[2].x));
int right = (int)(1 + max(v[0].x, max(v[1].x, v[2].x)));
int bottom = (int)min(v[0].y, min(v[1].y, v[2].y));
int top = (int)(1 + max(v[0].y, max(v[1].y, v[2].y)));
if (curClipType == CLIP_SCRN) {
clamp(left, 0, WIDTH); clamp(right, 0, WIDTH);
clamp(bottom, 0, HEIGHT); clamp(top, 0, HEIGHT);
}
for (int x = left; x < right; x++) {
for (int y = bottom; y < top; y++) {
vec3 centric = barycentric(x, y, v);
if (insideTriangle(centric)) {
if (flatHint) {
float z = v[1].z;
if (z < zbuf[indexOf(x, y)]) {
zbuf[indexOf(x, y)] = z;
setpixel(x, y, fragmentShader(vert[1]));
}
}
else {
float& a = centric.x, & b = centric.y, & c = centric.z;
// depth value interpolated linearly
float z = a * v[0].z + b * v[1].z + c * v[2].z;
if (correctCentric) {
perspectiveCorrect(centric, hw);
}
if (z < zbuf[indexOf(x, y)]) {
Vertex fragIn;
zbuf[indexOf(x, y)] = z;
fragIn.pos = a * vert[0].pos + b * vert[1].pos + c * vert[2].pos;
fragIn.normal = a * vert[0].normal + b * vert[1].normal + c * vert[2].normal;
fragIn.tangent = a * vert[0].tangent + b * vert[1].tangent + c * vert[2].tangent;
fragIn.color = a * vert[0].color + b * vert[1].color + c * vert[2].color;
fragIn.uv = a * vert[0].uv + b * vert[1].uv + c * vert[2].uv;
setpixel(x, y, fragmentShader(fragIn));
}
}
}
}
}
}
void clipTriangle(Vertex *vert, vec4 *v, int *clp, int clipBit) {
Vertex tmp1, tmp2, ver[3];
vec4 vtmp1, vtmp2, ve[3];
float t = 0.f;
int co = clp[0] | clp[1] | clp[2];
if (co == 0) {
drawTriangle(vert, v);
}
else {
int ca = clp[0] & clp[1] & clp[2];
if (ca) return; // the triangle is completely outside
while (clipBit < 6 && (co & (1 << clipBit)) == 0)
clipBit++;
if (clipBit == 6) return;
int clipMask = 1 << clipBit;
int col = (clp[0] ^ clp[1] ^ clp[2]) & clipMask;
if (col) {
// one point outside, make p0 outside first
if (clp[0] & clipMask) {
ver[0] = vert[0], ver[1] = vert[1], ver[2] = vert[2];
ve[0] = v[0], ve[1] = v[1], ve[2] = v[2];
}
else if (clp[1] & clipMask) {
ver[0] = vert[1], ver[1] = vert[2], ver[2] = vert[0];
ve[0] = v[1], ve[1] = v[2], ve[2] = v[0];
}
else {
ver[0] = vert[2], ver[1] = vert[0], ver[2] = vert[1];
ve[0] = v[2], ve[1] = v[0], ve[2] = v[1];
}
t = clipProc[clipBit](&ve[0], &ve[1]);
tmp1 = lerp(ver[0], ver[1], t);
vtmp1 = lerp(ve[0], ve[1], t);
t = clipProc[clipBit](&ve[2], &ve[0]);
tmp2 = lerp(ver[2], ver[0], t);
vtmp2 = lerp(ve[2], ve[0], t);
Vertex vert1[3] = { ver[1], ver[2], tmp1 };
vec4 v1[3] = { ve[1], ve[2], vtmp1 };
int cl1[3] = { clipCode(v1[0]), clipCode(v1[1]), clipCode(v1[2]) };
clipTriangle(vert1, v1, cl1, clipBit + 1);
Vertex vert2[3] = { tmp2, tmp1, ver[2]};
vec4 v2[3] = { vtmp2, vtmp1, ve[2]};
int cl2[3] = { clipCode(v2[0]), clipCode(v2[1]), clipCode(v2[2]) };
clipTriangle(vert2, v2, cl2, clipBit + 1);
}
else {
// two points outside, make sure p0 inside first
if ((clp[0] & clipMask) == 0) {
ver[0] = vert[0], ver[1] = vert[1], ver[2] = vert[2];
ve[0] = v[0], ve[1] = v[1], ve[2] = v[2];
}
else if ((clp[1] & clipMask) == 0) {
ver[0] = vert[1], ver[1] = vert[2], ver[2] = vert[0];
ve[0] = v[1], ve[1] = v[2], ve[2] = v[0];
}
else {
ver[0] = vert[2], ver[1] = vert[0], ver[2] = vert[1];
ve[0] = v[2], ve[1] = v[0], ve[2] = v[1];
}
t = clipProc[clipBit](&ve[0], &ve[1]);
tmp1 = lerp(ver[0], ver[1], t);
vtmp1 = lerp(ve[0], ve[1], t);
t = clipProc[clipBit](&ve[2], &ve[0]);
tmp2 = lerp(ver[2], ver[0], t);
vtmp2 = lerp(ve[2], ve[0], t);
Vertex vert1[3] = { ver[0], tmp1, tmp2};
vec4 v1[3] = { ve[0], vtmp1, vtmp2};
int cl1[3] = { clipCode(v1[0]), clipCode(v1[1]), clipCode(v1[2]) };
clipTriangle(vert1, v1, cl1, clipBit + 1);
}
}
}
int clipCode(vec4 &v) {
float w = v.w * (1.0f + 1E-5f);
return ((v.x < -w) << 0)| ((v.x > w) << 1) |
((v.y < -w) << 2) | ((v.y > w) << 3) |
((v.z < -w) << 4) | ((v.z > w) << 5);
}
int indexOf(int x, int y) {
return (HEIGHT - 1 - y) * WIDTH + x;
}
void setpixel(int x, int y, vec3 fragColor) {
uint8_t r = (uint8_t)max(0.f, min(255.f, 255.f * fragColor.x));
uint8_t g = (uint8_t)max(0.f, min(255.f, 255.f * fragColor.y));
uint8_t b = (uint8_t)max(0.f, min(255.f, 255.f * fragColor.z));
framebuf[indexOf(x, y)] = 0Xffu << 24 | r << 16 | g << 8 | b; // BGRA
}
bool insideTriangle(vec3& centric) {
return centric.x >= 0.f && centric.x <= 1.f && \
centric.y >= 0.f && centric.y <= 1.f && \
centric.z >= 0.f && centric.z <= 1.f;
}
vec3 barycentric(int x, int y, const vec4* _v) {
vec2 p(static_cast<float>(x), static_cast<float>(y));
vec2 a(_v[0].x, _v[0].y), b(_v[1].x, _v[1].y), c(_v[2].x, _v[2].y);
vec2 v0 = b - a, v1 = c - a, v2 = p - a;
float div = 1.f / (v0.x * v1.y - v1.x * v0.y);
float v = div * (v2.x * v1.y - v1.x * v2.y);
float w = div * (v0.x * v2.y - v2.x * v0.y);
float u = 1.f - v - w;
return vec3(u,v,w);
}
void drawLine(vec4 begin, vec4 end) {
vec3 lineColor(0.45F, 0.73F, 0.19F);
int x0 = int(begin.x);
int y0 = int(begin.y);
int x1 = int(end.x);
int y1 = int(end.y);
if (curClipType == CLIP_SCRN)
if (x0 < 0 || x0 >= WIDTH || y0 < 0 || y0 >= HEIGHT || x1 < 0 || x1 >= WIDTH || y1 < 0 || y1 >= HEIGHT)
return;
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 (setpixel(x0, y0, lineColor), x0 != x1 || y0 != y1) {
int e2 = err;
if (e2 > -dx) { err -= dy; x0 += sx; }
if (e2 < dy) { err += dx; y0 += sy; }
}
}
// https://www.khronos.org/registry/OpenGL/specs/gl/glspec46.core.pdf page 479
void perspectiveCorrect(vec3& centric, const float *hw) {
float &x = centric.x, &y = centric.y, &z = centric.z;
float a = x * hw[0], b = y * hw[1], c = z * hw[2];
float d = 1.f / (a + b + c);
x = a * d;
y = b * d;
z = c * d;
}
};
///////////////////////////////////////////////////////////////////////////////////
// Shaders
///////////////////////////////////////////////////////////////////////////////////
// Common functions for all shaders
vec3 updatePosition(const vec3& old, const vec3& normal, const vec2& uv) {
vec3 out = old;
vec3 h = texture(uniform.dispMap, uv);
float hs = (h.x + h.y + h.z) / 3.f;
float t = 2 * hs - 1;
return old - DISPACE_STRENGTH * t * normal;
}
vec3 updateNormal(vec3 Normal, vec3 Tangent, vec2 uv) {
vec3 N = normalize(Normal);
vec3 T = normalize(Tangent - N * dot(Tangent, N));
vec3 B = normalize(cross(N, T));
mat3 TBN(T, B, N);
vec3 normal = 2.0 * texture(uniform.normalMap, uv) - 1.f;
return normalize(TBN * normal);
}
vec3 blinnPhongColor(const vec3 &pos, const vec3 &n, const vec2 &uv) {
vec3 color(0.3f, 0.3f, 0.3f);
if (activeColorTexture)
color = texture(uniform.colorMap, uv);
float la = 0.f;
vec3 ambient, diffuse, specular;
for (auto &l : uniform.light) {
ambient = ambient + l.La * color;
vec3 s = l.dir;
float sDotN = max(dot(s, n), 0.f);
diffuse = diffuse + l.Ld * sDotN * color;
if (sDotN > 0.0) {
vec3 v = normalize(-pos);
vec3 h = normalize(v + s);
specular = specular + l.Ls * powf(max(dot(h, n), 0), 64) * vec3(0.8f, 0.8f, 0.8f);
}
}
return ambient + diffuse + specular;
}
///////////////////////////////////////////////////////////////////////////////////
// 1. Blinn-Phong Shading: shade each pixel
///////////////////////////////////////////////////////////////////////////////////
void phongVertShader(const Vertex& in, Vertex& out, vec4& mvpPos) {
vec3 pos = in.pos;
if (activeDispTexture)
pos = updatePosition(in.pos, in.normal, in.uv);
out.pos = (uniform.modelViewMatrix * vec4(pos)).to_vec3();
out.normal = normalize((uniform.normalMatrix * vec4(in.normal, 0.f)).to_vec3());
out.tangent = normalize((uniform.normalMatrix * vec4(in.tangent, 0.f)).to_vec3());
out.uv = in.uv;
mvpPos = uniform.MVP * vec4(pos);
}
vec3 phongFragShader(const Vertex& in) {
vec3 N = normalize(in.normal);
if (activeNormalTexture)
N = updateNormal(N, in.tangent, in.uv);
// two-sided shading
vec3 view = normalize(-in.pos);
float vDotN = dot(view, N);
if (vDotN <= 0)
N = -N;
return blinnPhongColor(in.pos, N, in.uv);
}
///////////////////////////////////////////////////////////////////////////////////
// 2. Gouraud Shading: shade each vertext
///////////////////////////////////////////////////////////////////////////////////
void gouraudVertShader(const Vertex& in, Vertex& out, vec4& mvpPos) {
vec3 pos = in.pos;
if (activeDispTexture)
pos = updatePosition(in.pos, in.normal, in.uv);
pos = (uniform.modelViewMatrix * vec4(pos)).to_vec3();
vec3 N = normalize((uniform.normalMatrix * vec4(in.normal, 0.f)).to_vec3());
vec3 T = normalize((uniform.normalMatrix * vec4(in.tangent, 0.f)).to_vec3());
if (activeNormalTexture)
N = updateNormal(N, T, in.uv);
vec3 view = normalize(-pos);
float vDotN = dot(view, N);
if (vDotN < 0)
N = -N;
out.color = blinnPhongColor(pos, N, in.uv);
mvpPos = uniform.projectionMatrix * vec4(pos);
}
vec3 gouraudFragShader(const Vertex& in) {
return in.color;
}
///////////////////////////////////////////////////////////////////////////////////
// 3. Flat Shading: shade each triangle
///////////////////////////////////////////////////////////////////////////////////
void flatVertShader(const Vertex& in, Vertex& out, vec4& mvpPos) {
return gouraudVertShader(in, out, mvpPos);
}
vec3 flatFragShader(const Vertex& in) {
return gouraudFragShader(in);
}
int main() {
TCHAR buf[128];
size_t vn1, tn1, vn2, tn2, vn, tn;
double deltaTime = 0.f;
double lastTime = 0.f;
double currentTime = 0.f;
uint64_t start, now, frequency;
Render render;
Camera camera(vec3(0.f, 15.f, 30.f), vec3(0.f, M_PI, 0.f), (float)WIDTH / (float)HEIGHT);
Mesh* vase = new Vase(64);
Image colorMap = buildColorTexture();
Image normalMap = buildNormalTextureFrom(&colorMap);
int vaoVase = render.createBuffersWith(vase);
render.bindTexture(vaoVase, colorMap, normalMap, colorMap);
vn1 = vase->pos.size();
tn1 = vase->index.size() / 3;
delete vase;
vase = nullptr;
Mesh* plane = new Plane(5.f, 1);
colorMap = buildColorTextureGrid();
normalMap = buildNormalTextureFrom(&colorMap);
int vaoPlane = render.createBuffersWith(plane);
render.bindTexture(vaoPlane, colorMap, normalMap, colorMap);
vn2 = plane->pos.size();
tn2 = plane->index.size() / 3;
delete plane;
plane = nullptr;
Program blinnPhong(phongVertShader, phongFragShader);
Program gouraud(gouraudVertShader, gouraudFragShader);
Program flat(flatVertShader, flatFragShader, true);
Program shaders[3] = {blinnPhong, gouraud, flat};
const TCHAR *shaderName[3] = {_T("blinnPhong"), _T("gouraud"), _T("flat")};
QueryPerformanceCounter((LARGE_INTEGER*)&start);
QueryPerformanceFrequency((LARGE_INTEGER*)&frequency);
BeginBatchDraw();
while (1) {
vn = tn = 0;
QueryPerformanceCounter((LARGE_INTEGER*)&now);
currentTime = (double)(now - start) / frequency;
deltaTime = currentTime - lastTime;
lastTime = currentTime;
mat4 m = rotateY(currentTime);
camera.processInput();
setMatrixUniform(m, camera.viewMatrix(), camera.projectionMatrix());
render.polygonMode(activeLineMode);
render.clear();
render.useProgram(shaders[selectShader]);
if (showVase) {
render.drawElements(vaoVase);
vn += vn1;
tn += tn1;
}
if (showPlane) {
render.drawElements(vaoPlane);
vn += vn2;
tn += tn2;
}
outtextxy(WIDTH / 2, 10, shaderName[selectShader]);
swprintf_s(buf, _T(" vertices : %zu"), vn);
outtextxy(0, 0, buf);
swprintf_s(buf, _T(" triangles : %zu"), tn);
outtextxy(0, 16, buf);
outtextxy(0, 32, L" Scroll : fov");
outtextxy(0, 48, L" Drag LButton : Rotate");
outtextxy(0, 64, L" LButton + Scroll: Forward / Backward");
outtextxy(0, 80, L" Press [C]: Color texture");
outtextxy(0, 96, L" Press [N]: Normal texture");
outtextxy(0, 112, L" Press [B]: Bump texture");
outtextxy(0, 128, L" Press [L]: Line Mode");
outtextxy(0, 144, L" Press [K]: Cull Face");
outtextxy(0, 160, L" Press [Space] : Shaders");
swprintf_s(buf, _T(" Camera Position: (%.3f, %.3f, %.3f)"), camera.position().x, camera.position().y, camera.position().z);
outtextxy(0, 176, buf);
swprintf_s(buf, _T(" Camera Fov: %.3f"), camera.fov());
outtextxy(0, 192, buf);
swprintf_s(buf, _T("fps : %d"), (int)(1.f / deltaTime));
outtextxy(WIDTH - 96, 0, buf);
swprintf_s(buf, _T("time: %.1fms"), 1000 * deltaTime);
outtextxy(WIDTH - 96, 16, buf);
FlushBatchDraw();
}
return 0;
}
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