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ObjParser and small libvecn refactor

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This commit is contained in:
Astazium 2026-08-05 23:06:16 +03:00
parent 7536ac2736
commit 859935f3b5
2 changed files with 90 additions and 93 deletions
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122
src/coders/obj.cpp
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@ -10,53 +10,69 @@ class ObjParser : BasicParser<char> {
std::vector<glm::vec2> uvs {{0, 0}};
std::vector<glm::vec3> normals {{0, 1, 0}};
// TODO: refactor
void parseFace(Mesh& mesh) {
std::vector<Vertex> vertices;
while (hasNext()) {
auto c = peekInLine();
if (c == '\n') {
break;
} else if (hasNext()) {
uint indices[3] {};
uint i = 0;
do {
char next = peekInLine();
if (is_digit(next)) {
indices[i] = parseSimpleInt(10);
if (hasNext() && peekInLine() == '/') {
pos++;
}
} else if (next == '/') {
pos++;
} else {
break;
}
} while (hasNext() && peekInLine() != '\n' && ++i < 3);
Vertex parseFaceVertex() {
auto parseIndex = [&]() -> uint {
if (!hasNext() || !is_digit(peekInLine())) {
return 0;
}
return parseSimpleInt(10);
};
vertices.push_back(Vertex {
coords[indices[0]], uvs[indices[1]], normals[indices[2]]});
uint coord = parseIndex();
uint uv = 0;
uint normal = 0;
if (hasNext() && peekInLine() == '/') {
pos++;
uv = parseIndex();
if (hasNext() && peekInLine() == '/') {
pos++;
normal = parseIndex();
}
}
if (hasNext() && peekInLine() != '\n') {
skipLine();
}
return Vertex {
coords[coord],
uvs[uv],
normals[normal]
};
}
void triangulate(const std::vector<Vertex>& vertices, std::vector<Vertex>& output) {
if (vertices.size() >= 3) {
for (size_t j = 0; j < vertices.size() - 2; j++) {
mesh.vertices.push_back(vertices[0]);
output.push_back(vertices[0]);
for (size_t i = 1; i < 3; i++) {
mesh.vertices.push_back(vertices[i + j]);
output.push_back(vertices[i + j]);
}
}
}
}
public:
ObjParser(const std::string_view file, const std::string_view src)
: BasicParser(file, src) {
void parseFace(Mesh& mesh) {
std::vector<Vertex> vertices;
while (hasNext() && peekInLine() != '\n') {
vertices.push_back(parseFaceVertex());
}
triangulate(vertices, mesh.vertices);
}
std::unique_ptr<Model> parse() {
// first iteration - collecting vertex data
glm::vec3 parseVec3() {
float x = parseNumber().asNumber();
float y = parseNumber().asNumber();
float z = parseNumber().asNumber();
return glm::vec3 {x, y, z};
}
glm::vec2 parseVec2() {
float x = parseNumber().asNumber();
float y = parseNumber().asNumber();
return glm::vec2 {x, y};
}
void collectVertexData() {
while (hasNext()) {
if (peek() == '#') {
skipLine();
@ -64,27 +80,18 @@ public:
}
auto cmd = parseName();
if (cmd == "v") {
float x = parseNumber().asNumber();
float y = parseNumber().asNumber();
float z = parseNumber().asNumber();
coords.emplace_back(x, y, z);
coords.emplace_back(parseVec3());
} else if (cmd == "vt") {
float u = parseNumber().asNumber();
float v = parseNumber().asNumber();
uvs.emplace_back(u, v);
uvs.emplace_back(parseVec2());
} else if (cmd == "vn") {
float x = parseNumber().asNumber();
float y = parseNumber().asNumber();
float z = parseNumber().asNumber();
normals.emplace_back(x, y, z);
normals.emplace_back(parseVec3());
} else {
skipLine();
}
}
// second iteration - building meshes
reset();
}
auto model = std::make_unique<Model>();
void buildMeshes(Model& model) {
std::string texture;
while (hasNext()) {
if (peek() != '#' && parseName() == "usemtl") {
@ -95,7 +102,7 @@ public:
skipLine();
}
do {
Mesh* mesh = &model->addMesh(texture);
Mesh* mesh = &model.addMesh(texture);
while (hasNext()) {
if (peek() == '#') {
skipLine();
@ -105,7 +112,7 @@ public:
if (cmd == "usemtl") {
skipWhitespace();
texture = readUntilEOL();
mesh = &model->addMesh(texture);
mesh = &model.addMesh(texture);
break;
} else if (cmd == "f") {
parseFace(*mesh);
@ -113,6 +120,19 @@ public:
skipLine();
}
} while (hasNext());
}
public:
ObjParser(const std::string_view file, const std::string_view src)
: BasicParser(file, src) {
}
std::unique_ptr<Model> parse() {
// first iteration - collecting vertex data
collectVertexData();
// second iteration - building meshes
reset();
auto model = std::make_unique<Model>();
buildMeshes(*model);
model->clean();
return model;
}