working rotation and zoom. pan bad

src/body.cpp

@@ -0,0 +1,120 @@
+#include <cassert>
+#include <glad/glad.h>
+#include "util.hpp"
+#include "body.hpp"
+#include "shaders.hpp"
+
+enum class ParserState {
+    PREFIX,
+    VERTEX,
+    FACE,
+    FACE_SKIP,
+};
+
+bool load_body(body* out_body, const char* obj_filepath) {
+    array<char> source;
+    if (!read_file(&source, obj_filepath)) {
+        return false;
+    }
+
+    size_t num_verts = 0;
+    size_t num_faces = 0;
+    for (int i = 1; i < source.len; i++) {
+        if (source[i] == ' ' && source[i - 1] == 'v') {
+            num_verts++;
+        } else if (source[i] == ' ' && source[i - 1] == 'f') {
+            num_faces++;
+        }
+    }
+
+    array<float> verts = { (float*)malloc(sizeof(float) * num_verts * 3), num_verts * 3 };
+    array<int> faces = { (int*)malloc(sizeof(int) * num_faces * 3), num_faces*3 };
+
+    // Get ready for the parsing loop
+    ParserState state = ParserState::PREFIX;
+    int vert_i = 0;
+    int face_i = 0;
+    int start = 0;
+
+    for (int i = 1; i < source.len; i++) {
+        if (source[i] == '\n') {
+            state = ParserState::PREFIX;
+            continue;
+        }
+        switch (state) {
+        case ParserState::PREFIX:
+            if (source[i - 1] == 'v' && source[i] == ' ') {
+                state = ParserState::VERTEX;
+                start = i + 1;
+            } else if (i > 0 && source[i - 1] == 'f' && source[i] == ' ') {
+                state = ParserState::FACE;
+                start = i + 1;
+            }
+            break;
+        case ParserState::VERTEX:
+            if (source[i] == ' ' || source[i] == '\r' || source[i] == '\n') {
+                verts[vert_i] = atof(&source[start])/1.5;
+                vert_i++;
+                start = i + 1;
+            }
+            break;
+        case ParserState::FACE:
+            if (source[i] == '/') {
+                state = ParserState::FACE_SKIP;
+                faces[face_i] = atoi(&source[start]) - 1;
+                face_i++;
+            }
+            break;
+        case ParserState::FACE_SKIP:
+            if (source[i] == ' ') {
+                state = ParserState::FACE;
+                start = i + 1;
+            }
+        }
+    }
+
+    // Need a good validation check here. This is a stand in.
+    if (verts.len == 0 || faces.len == 0) {
+        printf(
+            "Obj file appears incomplete or corrupted. Num verts %zu. Num Faces %zu.\n", verts.len, faces.len);
+        return false;
+    }
+
+    uint vao, vbo, ebo;
+
+    glGenVertexArrays(1, &vao);
+    glGenBuffers(1, &vbo);
+    glGenBuffers(1, &ebo);
+
+    glBindVertexArray(vao);
+
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER, verts.len * sizeof(float), verts.data, GL_STATIC_DRAW);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, faces.len * sizeof(int), faces.data, GL_STATIC_DRAW);
+
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+    glEnableVertexAttribArray(0);
+
+    *out_body = { .pose = glm::mat4(1),
+        .ebo = ebo,
+        .vao = vao,
+        .vbo = vbo,
+        .shader = 0,
+        .verts = verts,
+        .faces = faces,
+        .color = glm::vec4(0.5, 0.5, 0.5, 1)
+    };
+
+    return true;
+}
+
+void draw_body(const body& b) {
+    use_shader(b.shader);
+    set_uniform(b.shader, "global_t", b.pose);
+    set_uniform(b.shader, "color", b.color);
+    glBindVertexArray(b.vao);
+    glDrawElements(GL_TRIANGLES, b.faces.len, GL_UNSIGNED_INT, 0);
+    //glDisableVertexAttribArray(0);
+}