3d-renderer/scripts/triangle.c
2025-07-11 21:08:11 -07:00

94 lines
3.6 KiB
C

#include "triangle.h"
#include <math.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;
}
#define FUNC (int)ceilf
#define FUNC2 (int)floorf
uint32_t invert_rgb(uint32_t color) {
uint32_t a = color & 0xFF000000; // Alpha channel
uint32_t rgb = color & 0x00FFFFFF; // RGB channels
rgb = ~rgb & 0x00FFFFFF; // Invert RGB only
return a | rgb;
}
void fill_flat_bottom_triangle(const triangle_t* triangle, color_t color) {
float inv_slope_1 = (triangle->points[1].x - triangle->points[0].x) / (triangle->points[1].y - triangle->points[0].y);
float inv_slope_2 = (triangle->points[2].x - triangle->points[0].x) / (triangle->points[2].y - triangle->points[0].y);;
float x_start = triangle->points[0].x, x_end = triangle->points[0].x;
for (int x = FUNC(triangle->points[0].y); x <= FUNC2(triangle->points[2].y); x++) {
//draw_rect((int)triangle->points[0].x, i, 1, 1, 0xFFFF0000);
draw_line(FUNC(x_start), x, FUNC2(x_end), x, color);
x_start += inv_slope_1;
x_end += inv_slope_2;
}
}
void fill_flat_top_triangle(const triangle_t* triangle, color_t color) {
float inv_slope_1 = (triangle->points[2].x - triangle->points[0].x) / (triangle->points[2].y - triangle->points[0].y);
float inv_slope_2 = (triangle->points[2].x - triangle->points[1].x) / (triangle->points[2].y - triangle->points[1].y);;
float x_start = triangle->points[2].x, x_end = triangle->points[2].x;
for (int y = FUNC2(triangle->points[2].y); y >= FUNC(triangle->points[0].y); y--) {
//draw_rect((int)triangle->points[0].x, i, 1, 1, 0xFFFF0000);
draw_line(FUNC(x_start), y, FUNC2(x_end), y, color);
x_start -= inv_slope_1;
x_end -= inv_slope_2;
}
}
void draw_filled_triangle(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;
}
color_t color = triangle.color ? triangle.color : 0xFF00FF00; // Default to 0xFF00FF00 if not setr; // Default color if not set
if (triangle.points[mid_idx].y == triangle.points[max_idx].y) {
fill_flat_bottom_triangle(&triangle, color);
} else if (triangle.points[min_idx].y == triangle.points[mid_idx].y) {
fill_flat_top_triangle(&triangle, color);
}
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] = midpoint;
flat_top.points[2] = triangle.points[max_idx];
fill_flat_bottom_triangle(&flat_bottom, color);
fill_flat_top_triangle(&flat_top, (color));
}