3d-renderer/scripts/triangle.c
2025-07-08 22:40:11 -07:00

61 lines
1.9 KiB
C

#include "triangle.h"
#include "display.h"
// TODO: Create implementation for triangle.h functions
int compare_vec2_t(const void* a, const void* b) {
const vec2_t* arg1 = (const vec2_t*)a;
const vec2_t* arg2 = (const vec2_t*)b;
if (arg1->y < arg2->y) return -1;
if (arg1->y > arg2->y) return 1;
return 0;
}
void fill_flat_bottom_triangle(triangle_t triangle) {
}
void fill_flat_top_triangle(triangle_t triangle) {
}
vec2_t triangle_midpoint(triangle_t triangle) {
// sort by y
int temp = 0, min_idx = 0, mid_idx = 1, max_idx = 2;
if (triangle.points[min_idx].y > triangle.points[mid_idx].y) {
temp = min_idx; min_idx = mid_idx; mid_idx = temp;
}
if (triangle.points[min_idx].y > triangle.points[max_idx].y) {
temp = min_idx; min_idx = max_idx; max_idx = temp;
}
if (triangle.points[mid_idx].y > triangle.points[max_idx].y) {
temp = mid_idx; mid_idx = max_idx; max_idx = temp;
}
// check for division by zero
if (triangle.points[max_idx].y == triangle.points[min_idx].y) {
// Degenerate case, return something reasonable
return triangle.points[mid_idx]; // or some fallback
}
vec2_t midpoint;
midpoint.y = triangle.points[mid_idx].y;
midpoint.x = (((triangle.points[max_idx].x - triangle.points[min_idx].x) * (triangle.points[mid_idx].y - triangle.points[min_idx].y)) / (triangle.points[max_idx].y - triangle.points[min_idx].y)) + triangle.points[min_idx].x;
triangle_t flat_top, flat_bottom;
flat_bottom.points[0] = triangle.points[min_idx];
flat_bottom.points[1] = triangle.points[mid_idx];
flat_bottom.points[2] = midpoint;
flat_top.points[0] = triangle.points[mid_idx];
flat_top.points[1] = triangle.points[max_idx];
flat_top.points[2] = midpoint;
draw_triangle(flat_bottom, 0xFF00FF00);
draw_triangle(flat_top, 0xF0000FF);
return midpoint;
}