add triangles filled

This commit is contained in:
Tyrel Souza 2024-04-25 00:02:48 -04:00
parent bf2cf4ef01
commit b36fec7ba1
3 changed files with 94 additions and 13 deletions

View File

@ -7,8 +7,6 @@
#include "array.h" #include "array.h"
triangle_t *triangles_to_render = NULL; triangle_t *triangles_to_render = NULL;
vec3_t camera_position = {0, 0, 0}; vec3_t camera_position = {0, 0, 0};
@ -73,11 +71,12 @@ float check_backface_culling(const vec3_t *transformed_vertices) {// Check backf
// Get vector subtraction of B-A and C-A // Get vector subtraction of B-A and C-A
vec3_t vector_ab = vec3_sub(vector_b, vector_a); vec3_t vector_ab = vec3_sub(vector_b, vector_a);
vec3_t vector_ac = vec3_sub(vector_c, vector_a); vec3_t vector_ac = vec3_sub(vector_c, vector_a);
vec3_normalize(&vector_ab);
vec3_normalize(&vector_ac);
// Get cross product to get the Normal N (to find perpendicular) // Get cross product to get the Normal N (to find perpendicular)
// This is because left-handed coordinate system // This is because left-handed coordinate system
vec3_t normal = vec3_cross(vector_ab, vector_ac); // CLOCKWISE so A-B then A-C vec3_t normal = vec3_cross(vector_ab, vector_ac); // CLOCKWISE so A-B then A-C
// normalize the Face Normal // normalize the Face Normal
vec3_normalize(&normal); vec3_normalize(&normal);
@ -145,24 +144,27 @@ void update(void) {
} }
void render(void) { void render(void) {
// draw_grid(); draw_grid();
// triangle array size // triangle array size
int num_triangles = array_length(triangles_to_render); int num_triangles = array_length(triangles_to_render);
for (int i = 0; i < num_triangles; i++) { for (int i = 0; i < num_triangles; i++) {
triangle_t triangle = triangles_to_render[i]; triangle_t triangle = triangles_to_render[i];
uint32_t color = 0xFFFFFF00; uint32_t color = 0xFFFFFF00;
for (int j = 0; j < 3; j++) { draw_filled_triangle(triangle.points[0].x, triangle.points[0].y,
draw_rect(triangle.points[j].x, triangle.points[j].y, 3, 3, color);
}
draw_triangle(triangle.points[0].x, triangle.points[0].y,
triangle.points[1].x, triangle.points[1].y, triangle.points[1].x, triangle.points[1].y,
triangle.points[2].x, triangle.points[2].y, triangle.points[2].x, triangle.points[2].y,
color); color);
draw_triangle(triangle.points[0].x, triangle.points[0].y,
triangle.points[1].x, triangle.points[1].y,
triangle.points[2].x, triangle.points[2].y,
0xFF000000);
} }
render_color_buffer(); render_color_buffer();
clear_color_buffer(0xFF000000); clear_color_buffer(0xFF000000);

View File

@ -1,3 +1,78 @@
#include "triangle.h" #include "triangle.h"
#include "display.h"
// TODO
void int_swap(int *a, int *b) {
int tmp = *a;
*a = *b;
*b = tmp;
}
void fill_flat_bottom_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color) {
// Start from top (x0, y0)
// calculate slope 1 and slope 2
// Y is independent as we loop over Y, we want the delta X change.
float inv_slope_1 = (float) (x1 - x0) / (float) (y1 - y0);
float inv_slope_2 = (float) (x2 - x0) / (float) (y2 - y0);
// start x_start and x_end from top vertex (x0,y0);
float x_start = x0;
float x_end = x0;
// loop all scan lines from y0 to y2
for (int y = y0; y <= y2; y++) {
draw_line(
x_start, y,
x_end, y,
color);
x_start += inv_slope_1;
x_end += inv_slope_2;
}
}
void fill_flat_top_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color) {
// start from bottom
// calculate slope 1 and slope 2
// Y is independent as we loop over Y, we want the delta X change.
float inv_slope_1 = (float) (x2 - x0) / (float) (y2 - y0);
float inv_slope_2 = (float) (x2 - x1) / (float) (y2 - y1);
// start x_start and x_end from top vertex (x0,y0);
float x_start = x2;
float x_end = x2;
// loop all scan lines from y0 to y2
for (int y = y2; y >= y0; y--) {
draw_line(
x_start, y,
x_end, y,
color);
x_start -= inv_slope_1;
x_end -= inv_slope_2;
}
}
void draw_filled_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color) {
//we need to sort the y coords (y0 < y1 < y2)
if (y0 > y1) {
int_swap(&y0, &y1);
int_swap(&x0, &x1);
}
if (y1 > y2) {
int_swap(&y1, &y2);
int_swap(&x1, &x2);
}
if (y0 > y1) {
int_swap(&y0, &y1);
int_swap(&x0, &x1);
}
if (y1 == y2) {
fill_flat_bottom_triangle(x0, y0, x1, y1, x2, y2, color);
} else if (y0 == y2) {
fill_flat_top_triangle(x0, y0, x1, x1, x2, y2, color);
} else {
int My = y1;
int Mx = ((float) ((x2 - x0) * (y1 - y0)) / (float) (y2 - y0)) + (float) x0;
fill_flat_bottom_triangle(x0, y0, x1, y1, Mx, My, color);
fill_flat_top_triangle(x1, y1, Mx, My, x2, y2, color);
}
}

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@ -2,6 +2,7 @@
#define RENDERER_TRIANGLE_H #define RENDERER_TRIANGLE_H
#include "vector.h" #include "vector.h"
#include <stdint.h>
typedef struct { typedef struct {
int a; int a;
@ -13,4 +14,7 @@ typedef struct {
vec2_t points[3]; vec2_t points[3];
} triangle_t; } triangle_t;
void draw_filled_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color);
#endif //RENDERER_TRIANGLE_H #endif //RENDERER_TRIANGLE_H