143 lines
4.0 KiB
C++
143 lines
4.0 KiB
C++
#include <cassert>
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#include <glad/glad.h>
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#include <map>
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#include <string>
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#include "util.hpp"
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#include "body.hpp"
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#include "shaders.hpp"
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using namespace std;
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enum class ParserState {
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PREFIX,
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VERTEX,
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FACE,
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FACE_SKIP,
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};
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static map<string, ObjData> cache;
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bool _parse_obj(ObjData* data, const char* obj_filepath);
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bool load_body(Body* out_body, const char* obj_filepath) {
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ObjData data;
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if (auto it = cache.find(obj_filepath); it != cache.end()) {
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data = it->second;
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} else if (_parse_obj(&data, obj_filepath)) {
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cache[obj_filepath] = data;
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} else {
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return false;
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}
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// Need a good validation check here. This is a stand in.
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if (data.verts_len == 0 || data.faces_len == 0) {
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printf("Obj file appears incomplete or corrupted. Num verts %d. Num Faces %d.\n", data.verts_len,
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data.faces_len);
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return false;
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}
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uint vao, vbo, ebo;
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vao = 0;
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vbo = 0;
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ebo = 0;
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glGenVertexArrays(1, &vao);
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glGenBuffers(1, &vbo);
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glGenBuffers(1, &ebo);
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glBindVertexArray(vao);
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glBindBuffer(GL_ARRAY_BUFFER, vbo);
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glBufferData(GL_ARRAY_BUFFER, data.verts_len * sizeof(float), data.verts, GL_STATIC_DRAW);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
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glBufferData(GL_ELEMENT_ARRAY_BUFFER, data.faces_len * sizeof(int), data.faces, GL_STATIC_DRAW);
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
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glEnableVertexAttribArray(0);
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*out_body = { .pose = glm::mat4(1), .ebo = ebo, .vao = vao, .vbo = vbo, .shader = 0, .data = data };
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return true;
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}
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void draw_body(const Body& b) {
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use_shader(b.shader);
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set_uniform(b.shader, "global_t", glm::scale(b.pose, glm::vec3(b.scale)));
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set_uniform(b.shader, "color", b.color);
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glBindVertexArray(b.vao);
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glDrawElements(GL_TRIANGLES, b.data.faces_len, GL_UNSIGNED_INT, 0);
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}
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void create_new_sphere(Body* b, float scale, glm::vec4 color) {
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assert(load_body(b, "Icosphere.obj"));
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b->scale = scale;
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b->color = color;
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}
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// I need to write a good obj file parser at some point. This is basically garbage
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bool _parse_obj(ObjData* data, const char* obj_filepath) {
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string source;
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if (!read_file(&source, obj_filepath)) {
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return {};
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}
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size_t num_verts = 0;
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size_t num_faces = 0;
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for (int i = 1; i < source.size(); i++) {
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if (source[i] == ' ' && source[i - 1] == 'v') {
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num_verts++;
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} else if (source[i] == ' ' && source[i - 1] == 'f') {
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num_faces++;
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}
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}
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float* verts = (float*)malloc(sizeof(float) * num_verts * 3);
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int* faces = (int*)malloc(sizeof(int) * num_faces * 3);
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int vert_i = 0;
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int face_i = 0;
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// Get ready for the parsing loop
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ParserState state = ParserState::PREFIX;
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int start = 0;
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for (int i = 1; i < source.size(); i++) {
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switch (state) {
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case ParserState::PREFIX:
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if (source[i - 1] == 'v' && source[i] == ' ') {
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state = ParserState::VERTEX;
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start = i + 1;
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} else if (i > 0 && source[i - 1] == 'f' && source[i] == ' ') {
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state = ParserState::FACE;
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start = i + 1;
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}
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break;
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case ParserState::VERTEX:
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if (iswspace(source[i])) {
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verts[vert_i++] = atof(&source[start]);
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start = i + 1;
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}
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break;
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case ParserState::FACE:
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if (source[i] == '/') {
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state = ParserState::FACE_SKIP;
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faces[face_i++] = atoi(&source[start]) - 1;
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}
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break;
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case ParserState::FACE_SKIP:
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if (iswspace(source[i])) {
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state = ParserState::FACE;
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start = i + 1;
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}
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}
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if (source[i] == '\n' || source[i] == '\r') {
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state = ParserState::PREFIX;
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continue;
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}
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}
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*data = { .verts = verts, .verts_len = vert_i, .faces = faces, .faces_len = face_i };
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return true;
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}
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