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#include "mesh.h"
void honey_setup_mesh(lua_State* L)
{
honey_lua_element mesh_elements[] = {
{ "new", HONEY_FUNCTION, { .function = honey_mesh_new } },
{ "draw", HONEY_FUNCTION, { .function = honey_mesh_draw } },
{ "delete", HONEY_FUNCTION, { .function = honey_mesh_delete } },
};
honey_lua_create_table(L, mesh_elements, 3);
}
/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
int honey_mesh_new(lua_State* L)
{
float* vertices;
unsigned int* indices;
int n_vertices, n_indices;
honey_lua_parse_arguments(L, 5,
HONEY_USERDATA, &vertices,
HONEY_USERDATA, &indices,
HONEY_TABLE,
HONEY_INTEGER, &n_vertices,
HONEY_INTEGER, &n_indices);
size_t n_attributes = lua_objlen(L, 3);
unsigned int* attribute_sizes = malloc(n_attributes * sizeof(unsigned int));
if (attribute_sizes == NULL) {
lua_pushstring(L, "failed to allocate memory for vertex attributes");
lua_error(L);
}
unsigned int vertex_size = 0;
for (int i=0; i<n_attributes; i++) {
lua_rawgeti(L, 2, i+1);
attribute_sizes[i] = lua_tointeger(L, -1);
vertex_size += attribute_sizes[i];
}
lua_pop(L, n_attributes);
honey_mesh* mesh = lua_newuserdata(L, sizeof(honey_mesh));
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);
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);
free(attribute_sizes);
return 1;
}
/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
int honey_mesh_draw(lua_State* L)
{
honey_mesh* mesh;
int shader;
honey_lua_parse_arguments(L, 2,
HONEY_USERDATA, &mesh,
HONEY_INTEGER, &shader);
glUseProgram(shader);
glBindVertexArray(mesh->vertex_array);
glDrawElements(GL_TRIANGLES, mesh->n_indices, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
}
/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
int honey_mesh_delete(lua_State* L)
{
honey_mesh* mesh;
honey_lua_parse_arguments(L, 1, HONEY_USERDATA, &mesh);
glDeleteVertexArrays(1, &(mesh->vertex_array));
glDeleteBuffers(1, &(mesh->vertex_buffer));
glDeleteBuffers(1, &(mesh->element_buffer));
}
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