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Fix filling triangles

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This commit is contained in:
Abdelrahman Said 2024-07-28 23:09:16 +01:00
parent 98231b582b
commit dc09a45085
2 changed files with 14 additions and 9 deletions
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2
src/main.c
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@ -28,7 +28,7 @@ int main(void) {
return TINY_EXIT_IMAGE_INIT_FAILED;
}
Model model = load_obj_file(arena, "resources/triangle.obj");
Model model = load_obj_file(arena, "resources/head.obj");
if (IS_NULL_MODEL(model)) {
return TINY_EXIT_MODEL_LOAD_FAILED;
}

21
src/obj.c
View File

@ -7,6 +7,11 @@
#include <stdio.h>
#define TRIANGLE_VERTICES 3
#define dot_v2(V1, V2) ((f32)V1.x * (f32)V2.x + (f32)V1.y * (f32)V2.y)
#define dot_v3(V1, V2) \
((f32)V1.x * (f32)V2.x + (f32)V1.y * (f32)V2.y + (f32)V1.z * (f32)V2.z)
#define V2(T, ELEM_T, X0, Y0, X1, Y1) \
((T){(ELEM_T)X1 - (ELEM_T)X0, (ELEM_T)Y1 - (ELEM_T)Y0})
typedef struct triangle_bbox TriangleBBox;
struct triangle_bbox {
@ -149,18 +154,18 @@ internal void fill_triangle(Image *img, Vertex vertices[TRIANGLE_VERTICES],
get_image_coordinates(&(vertices[1]), img, &v1x, &v1y);
get_image_coordinates(&(vertices[2]), img, &v2x, &v2y);
V2i ab = {.x = (i64)v1x - (i64)v0x, .y = (i64)v1y - (i64)v0y};
V2i ac = {.x = (i64)v2x - (i64)v0x, .y = (i64)v2y - (i64)v0y};
f32 d00 = (f32)ab.x * (f32)ab.x + (f32)ab.y + (f32)ab.y;
f32 d01 = (f32)ab.x * (f32)ac.x + (f32)ab.y + (f32)ac.y;
f32 d11 = (f32)ac.x * (f32)ac.x + (f32)ac.y + (f32)ac.y;
V2i ab = V2(V2i, i64, v0x, v0y, v1x, v1y);
V2i ac = V2(V2i, i64, v0x, v0y, v2x, v2y);
f32 d00 = dot_v2(ab, ab);
f32 d01 = dot_v2(ab, ac);
f32 d11 = dot_v2(ac, ac);
f32 denom = (f32)d00 * (f32)d11 - (f32)d01 * (f32)d01;
V2i ap;
V3f coords;
for (u64 y = bbox.y0; y < bbox.y1; ++y) {
for (u64 x = bbox.x0; x < bbox.x1; ++x) {
ap = (V2i){.x = (i64)x - (i64)v0x, .y = (i64)y - (i64)v0y};
ap = V2(V2i, i64, v0x, v0y, x, y);
coords = get_barycentric_coords(d00, d01, d11, denom, &ab, &ac, &ap);
if (coords.x < 0.0f || coords.y < 0.0f || coords.z < 0.0f) {
continue;
@ -190,8 +195,8 @@ internal TriangleBBox get_triangle_bbox(const Image *img,
internal V3f get_barycentric_coords(f32 d00, f32 d01, f32 d11, f32 denom,
const V2i *ab, const V2i *ac,
const V2i *ap) {
f32 d20 = (f32)ap->x * (f32)ab->x + (f32)ap->y + (f32)ab->y;
f32 d21 = (f32)ap->x * (f32)ac->x + (f32)ap->y + (f32)ac->y;
f32 d20 = dot_v2((*ap), (*ab));
f32 d21 = dot_v2((*ap), (*ac));
f32 v = (d11 * d20 - d01 * d21) / denom;
f32 w = (d00 * d21 - d01 * d20) / denom;