diff options
Diffstat (limited to 'src/mesh.c')
| -rw-r--r-- | src/mesh.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/src/mesh.c b/src/mesh.c new file mode 100644 index 0000000..68e39d7 --- /dev/null +++ b/src/mesh.c @@ -0,0 +1,232 @@ +#include "mesh.h" + +static int honey_mesh_lua_draw(lua_State* L) +{ + honey_mesh* mesh; + int shader; + honey_lua_parse_arguments(L, 2, + HONEY_USERDATA, &mesh, + HONEY_INTEGER, &shader); + honey_mesh_draw(*mesh, shader); + return 0; +} + +static int honey_mesh_lua_delete(lua_State* L) +{ + honey_mesh* mesh; + honey_lua_parse_arguments(L, 1, HONEY_USERDATA, &mesh); + honey_mesh_delete(*mesh); + return 0; +} + +void honey_setup_mesh(lua_State* L) +{ + honey_lua_element mesh_elements[] = { + { "load", HONEY_FUNCTION, { .function = honey_mesh_load } }, + { "draw", HONEY_FUNCTION, { .function = honey_mesh_lua_draw } }, + { "delete", HONEY_FUNCTION, { .function = honey_mesh_lua_delete } }, + }; + + honey_lua_create_table(L, mesh_elements, 2); +} + +/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ + +static honey_mesh assimp_to_honey_mesh(struct aiMesh* mesh, + struct aiScene* scene) +{ + unsigned int vertex_step = 6; + bool mesh_has_uvs = false; + unsigned int n_vertices = mesh->mNumVertices; + + if (mesh->mTextureCoords[0]) { + mesh_has_uvs = true; + vertex_step = 8; + } + + float* vertices = malloc(sizeof(float) * vertex_step * n_vertices); + for (int i=0; i<n_vertices; i++) { + int j = i*vertex_step; + /* positions */ + vertices[j+0] = mesh->mVertices[i].x; + vertices[j+1] = mesh->mVertices[i].y; + vertices[j+2] = mesh->mVertices[i].z; + + /* normals */ + vertices[j+3] = mesh->mNormals[i].x; + vertices[j+4] = mesh->mNormals[i].y; + vertices[j+5] = mesh->mNormals[i].z; + + /* uvs? */ + if (mesh_has_uvs) { + vertices[j+6] = mesh->mTextureCoords[0][i].x; + vertices[j+7] = mesh->mTextureCoords[0][i].y; + } + } + + unsigned int n_indices = mesh->mNumFaces*3; + unsigned int* indices = malloc(sizeof(unsigned int) * n_indices); + for (int i=0; i<mesh->mNumFaces; i++) { + int j = 3*i; + struct aiFace face = mesh->mFaces[i]; + indices[j+0] = face.mIndices[0]; + indices[j+1] = face.mIndices[1]; + indices[j+2] = face.mIndices[2]; + } + + honey_mesh result; + + if (mesh_has_uvs) { + unsigned int n_attributes = 3; + unsigned int attribute_sizes[] = { 3, 3, 2 }; + honey_mesh_new(&result, + vertices, n_vertices, + n_attributes, attribute_sizes, + indices, n_indices); + } + else { + unsigned int n_attributes = 2; + unsigned int attribute_sizes[] = { 3, 3 }; + honey_mesh_new(&result, + vertices, n_vertices, + n_attributes, attribute_sizes, + indices, n_indices); + } + + free(vertices); + free(indices); + + return result; +} + +/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ + +static void process_nodes_recursively(lua_State* L, + struct aiScene* scene, + struct aiNode* node, + int* n_meshes) +{ + for (int i=0; i<node->mNumMeshes; i++) { + honey_mesh* mesh = lua_newuserdata(L, sizeof(honey_mesh)); + struct aiMesh* assimp_mesh = scene->mMeshes[node->mMeshes[i]]; + *mesh = assimp_to_honey_mesh(assimp_mesh, scene); + lua_rawseti(L, -2, *n_meshes); + (*n_meshes)++; + } + + for (int i=0; i<node->mNumChildren; i++) { + process_nodes_recursively(L, scene, node->mChildren[i], n_meshes); + } +} + +/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ + +int honey_mesh_load(lua_State* L) +{ + char* filename; + honey_lua_parse_arguments(L, 1, HONEY_STRING, &filename); + + int n_meshes = 1; + + struct aiScene* scene = aiImportFile(filename, + aiProcess_Triangulate | + aiProcess_FlipUVs); + if (scene == NULL) { + char* error; + honey_format_string(&error, "could not open file '%s'", filename); + lua_pushstring(L, error); + free(error); + lua_error(L); + } + + if (scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE || + scene->mRootNode == NULL) { + char* error; + honey_format_string(&error, "could not read mesh(es) in '%s'", filename); + lua_pushstring(L, error); + free(error); + lua_error(L); + } + + lua_createtable(L, 0, 0); + + process_nodes_recursively(L, scene, scene->mRootNode, &n_meshes); + + return 1; +} + +/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ + +honey_result honey_mesh_new(honey_mesh* mesh, + float* vertices, + unsigned int n_vertices, + unsigned int n_attributes, + unsigned int* attribute_sizes, + unsigned int* indices, + unsigned int n_indices) { + if (vertices == NULL || n_vertices == 0) { + return HONEY_MESH_BAD_VERTEX_DATA; + } + if (indices == NULL || n_indices == 0) { + return HONEY_MESH_BAD_INDEX_DATA; + } + + unsigned int vertex_size = 0; + for (int i=0; i<n_attributes; i++) { + vertex_size += attribute_sizes[i]; + } + + (*mesh).n_vertices = n_vertices; + (*mesh).n_indices = n_indices; + + glGenVertexArrays(1, &((*mesh).vertex_array)); + glGenBuffers(1, &((*mesh).vertex_buffer)); + glGenBuffers(1, &((*mesh).element_buffer)); + + glBindVertexArray((*mesh).vertex_array); + + glBindBuffer(GL_ARRAY_BUFFER, (*mesh).vertex_buffer); + glBufferData(GL_ARRAY_BUFFER, + vertex_size * n_vertices * sizeof(float), + vertices, GL_STATIC_DRAW); + + glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, (*mesh).element_buffer); + glBufferData(GL_ELEMENT_ARRAY_BUFFER, + n_indices * sizeof(unsigned int), + indices, GL_STATIC_DRAW); + + /* set up vertex attributes */ + unsigned int offset = 0; + for (int i=0; i<n_attributes; i++) { + glEnableVertexAttribArray(i); + glVertexAttribPointer(i, + attribute_sizes[i], + GL_FLOAT, + GL_FALSE, + vertex_size*sizeof(float), + (void*) (offset*sizeof(float))); + offset += attribute_sizes[i]; + } + + glBindVertexArray(0); + + return HONEY_OK; +} + +/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ + +void honey_mesh_draw(honey_mesh mesh, int shader) { + glUseProgram(shader); + + glBindVertexArray(mesh.vertex_array); + glDrawElements(GL_TRIANGLES, mesh.n_indices, GL_UNSIGNED_INT, 0); + glBindVertexArray(0); +} + +/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ + +void honey_mesh_delete(honey_mesh mesh) { + glDeleteVertexArrays(1, &(mesh.vertex_array)); + glDeleteBuffers(1, &(mesh.vertex_buffer)); + glDeleteBuffers(1, &(mesh.element_buffer)); +} |