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#include "chfb.h"
#include <array>
#include <cmath>
#include <vector>
#include "math_vector.h"
#include "vertex.h"
#include "tri_vertex.h"
#include "vertex_data.h"
CharacterFrameBuffer::CharacterFrameBuffer(unsigned int w, unsigned int h) {
resize(w, h);
}
void CharacterFrameBuffer::resize(unsigned int w, unsigned int h) {
this->w = w;
this->h = h;
chars_vector.resize(w * h);
depth_buf.resize(w * h);
clear();
}
unsigned int CharacterFrameBuffer::width() const {
return w;
}
unsigned int CharacterFrameBuffer::height() const {
return h;
}
const char* CharacterFrameBuffer::chars() const {
return chars_vector.data();
}
void CharacterFrameBuffer::clear() {
std::fill(chars_vector.begin(), chars_vector.end(), ' ');
std::fill(depth_buf.begin(), depth_buf.end(), 1.f);
face_ind = -1;
}
void CharacterFrameBuffer::_draw_cropped_triangle(TriangleVertex3 triangle) {
std::array<Vertex3*, 3> sorted_vs = { &triangle.vertex1, &triangle.vertex2, &triangle.vertex3 };
#define SWAP_IF_LT(X,Y) ({\
if (sorted_vs[X]->point.y < sorted_vs[Y]->point.y) {\
Vertex3* 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);
#undef SWAP_IF_LT
Vertex3 middle_vl = *sorted_vs[1];
float fac = (sorted_vs[1]->point.y - sorted_vs[0]->point.y) / (sorted_vs[2]->point.y - sorted_vs[0]->point.y);
Vertex3 middle_vr{
{
sorted_vs[0]->point.x + fac * (sorted_vs[2]->point.x - sorted_vs[0]->point.x),
sorted_vs[1]->point.y,
sorted_vs[0]->point.z + fac * (sorted_vs[2]->point.z - sorted_vs[0]->point.z)
},
VertexData::lerp(sorted_vs[0]->data, sorted_vs[2]->data, fac)
};
if (middle_vr.point.x < middle_vl.point.x) {
Vertex3 temp = middle_vr;
middle_vr = middle_vl;
middle_vl = temp;
}
// top triangle
{
if (sorted_vs[0]->point.y != sorted_vs[1]->point.y) {
int top_y = static_cast<int>(std::floor(sorted_vs[0]->point.y + 1.f));
int bottom_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y - 1.f));
for (int y = top_y; y <= bottom_y; y++) {
float iy = static_cast<float>(y);
float s = (iy - sorted_vs[0]->point.y) / (sorted_vs[1]->point.y - sorted_vs[0]->point.y);
float xl = sorted_vs[0]->point.x + s * (middle_vl.point.x - sorted_vs[0]->point.x);
float xr = sorted_vs[0]->point.x + s * (middle_vr.point.x - sorted_vs[0]->point.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);
// depth and vd don't take into account perspective
float depth = sorted_vs[0]->point.z + s * (middle_vl.point.z - sorted_vs[0]->point.z + t * (middle_vr.point.z - middle_vl.point.z));
// VertexData vd = VertexData::bilerp(sorted_vs[0]->data, middle_vl.data, middle_vr.data, s, t);
if (depth < depth_buf[x + y * w]) {
depth_buf[x + y * w] = depth;
chars_vector[x + y * w] = face_char();
}
}
}
}
}
// bottom triangle
{
if (sorted_vs[1]->point.y != sorted_vs[2]->point.y) {
int bottom_y = static_cast<int>(std::floor(sorted_vs[2]->point.y));
int top_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y));
for (int y = top_y; y <= bottom_y; y++) {
float iy = static_cast<float>(y);
float s = (iy - sorted_vs[2]->point.y) / (sorted_vs[1]->point.y - sorted_vs[2]->point.y);
float xl = sorted_vs[2]->point.x + s * (middle_vl.point.x - sorted_vs[2]->point.x);
float xr = sorted_vs[2]->point.x + s * (middle_vr.point.x - sorted_vs[2]->point.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);
// depth and vd don't take into account perspective
float depth = sorted_vs[2]->point.z + s * (middle_vl.point.z - sorted_vs[2]->point.z + t * (middle_vr.point.z - middle_vl.point.z));
// VertexData vd = VertexData::bilerp(sorted_vs[2]->data, middle_vl.data, middle_vr.data, s, t);
if (depth < depth_buf[x + y * w]) {
depth_buf[x + y * w] = depth;
chars_vector[x + y * w] = face_char();
}
}
}
}
}
}
void CharacterFrameBuffer::draw_triangle(TriangleVertex4 triangle) {
face_ind++;
for (auto t1 : triangle.crop_z_out(-1.f, 1.f)) {
for (auto t2 : t1.div_by_w().crop_xy_out(-1.f, 1.f, -1.f, 1.f)) {
MathVector2 pp1 = t2.vertex1.point.xy(),
pp2 = t2.vertex2.point.xy(),
pp3 = t2.vertex3.point.xy();
if ((pp2 - pp1).det(pp3 - pp1) >= 0.f) continue;
t2.vertex1.point = (t2.vertex1.point + MathVector3{1.f, 1.f, 0.f}) / 2.f;
t2.vertex2.point = (t2.vertex2.point + MathVector3{1.f, 1.f, 0.f}) / 2.f;
t2.vertex3.point = (t2.vertex3.point + MathVector3{1.f, 1.f, 0.f}) / 2.f;
float fw = static_cast<float>(w), fh = static_cast<float>(h);
t2.vertex1.point.x = t2.vertex1.point.x * fw - .5f;
t2.vertex1.point.y = t2.vertex1.point.y * fh - .5f;
t2.vertex2.point.x = t2.vertex2.point.x * fw - .5f;
t2.vertex2.point.y = t2.vertex2.point.y * fh - .5f;
t2.vertex3.point.x = t2.vertex3.point.x * fw - .5f;
t2.vertex3.point.y = t2.vertex3.point.y * fh - .5f;
_draw_cropped_triangle(t2);
}
}
}
char CharacterFrameBuffer::face_char() const {
int n = 1 + face_ind / 2;
return (n < 10 ? '0' : 'A' - 10) + n;
}
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