tinyrenderer/src/model/obj.c
2024-09-14 00:22:36 +01:00

88 lines
2.3 KiB
C

#include "obj.h"
#include "mem_arena.h"
#include "pam.h"
#include "typed_list.h"
#include "vec.h"
#include <stdio.h>
Model load_obj_file(Arena *arena, const char *filename, const char *diffuse, const char *tangent) {
if (!arena) {
return INVALID_MODEL;
}
FILE *fp = fopen(filename, "r");
if (!fp) {
return INVALID_MODEL;
}
Model model = (Model){
.vertices = list_create(V3f, arena),
.normals = list_create(V3f, arena),
.texture_coordinates = list_create(V2f, arena),
.triangles = list_create(Triangle, arena),
};
if (!(model.vertices) || !(model.normals) || !(model.texture_coordinates) || !(model.triangles)) {
return INVALID_MODEL;
}
char line[8192];
char identifier[8];
V3f vertex;
V3f normal;
V2f coord;
Triangle triangle;
f32 vx, vy, vz;
f32 nx, ny, nz;
f32 u, v;
u64 fp0, fp1, fp2;
u64 vn0, vn1, vn2;
u64 tx0, tx1, tx2;
while (fgets(line, 8191, fp) != NULL) {
sscanf(line, "%s", identifier);
if (strncmp(identifier, "v", 8) == 0) {
sscanf(line + 2, "%f %f %f", &vx, &vy, &vz);
vertex.x = vx;
vertex.y = vy;
vertex.z = vz;
list_append(V3f, arena, model.vertices, vertex);
} else if (strncmp(identifier, "vn", 8) == 0) {
sscanf(line + 2, "%f %f %f", &nx, &ny, &nz);
normal.x = nx;
normal.y = ny;
normal.z = nz;
list_append(V3f, arena, model.normals, normal);
} else if (strncmp(identifier, "vt", 8) == 0) {
sscanf(line + 2, "%f %f", &u, &v);
coord.u = u;
coord.v = 1.0f - v;
list_append(V2f, arena, model.texture_coordinates, coord);
} else if (strncmp(identifier, "f", 8) == 0) {
sscanf(line + 2, "%lu/%lu/%lu %lu/%lu/%lu %lu/%lu/%lu",
&fp0, &tx0, &vn0,
&fp1, &tx1, &vn1,
&fp2, &tx2, &vn2);
// OBJ indices start from 1
triangle.p0 = fp0 - 1;
triangle.p1 = fp1 - 1;
triangle.p2 = fp2 - 1;
triangle.tx0 = tx0 - 1;
triangle.tx1 = tx1 - 1;
triangle.tx2 = tx2 - 1;
triangle.n0 = vn0 - 1;
triangle.n1 = vn1 - 1;
triangle.n2 = vn2 - 1;
list_append(Triangle, arena, model.triangles, triangle);
}
}
if (diffuse) {
model.texture = load_p6_image(arena, diffuse);
}
if (tangent) {
model.normal = load_p6_image(arena, tangent);
}
return model;
}