Method: Nuklear::Renderer::OpenGL2#draw

Defined in:

ext/nuklear_renderer_opengl2/nuklear_renderer_opengl2.c

#draw(cmd) ⇒ Object

# File 'ext/nuklear_renderer_opengl2/nuklear_renderer_opengl2.c', line 152

VALUE renderer_draw_gl(VALUE self, VALUE cmd) {
  VALUE window_size = rb_funcall(self, rb_intern("window_size"), 0);
  VALUE drawable_size = rb_funcall(self, rb_intern("drawable_size"), 0);
  VALUE window_width = rb_ary_entry(window_size, 0);
  VALUE window_height = rb_ary_entry(window_size, 1);
  VALUE drawable_width = rb_ary_entry(drawable_size, 0);
  VALUE drawable_height = rb_ary_entry(drawable_size, 1);
  int width = FIX2INT(window_width),
      height = FIX2INT(window_height);
  int display_width = FIX2INT(drawable_width),
      display_height = FIX2INT(drawable_height);
  struct nk_vec2 scale;
  scale.x = (float)display_width/(float)width;
  scale.y = (float)display_height/(float)height;

  VALUE clip_rect = rb_hash_aref(cmd, ID2SYM(rb_intern("clip_rect")));
  float x = (float) NUM2DBL(RARRAY_AREF(clip_rect, 0));
  float y = (float) NUM2DBL(RARRAY_AREF(clip_rect, 1));
  float w = (float) NUM2DBL(RARRAY_AREF(clip_rect, 2));
  float h = (float) NUM2DBL(RARRAY_AREF(clip_rect, 3));
  glBindTexture(GL_TEXTURE_2D, (GLuint) NUM2UINT(rb_hash_aref(cmd, ID2SYM(rb_intern("texture_handle")))));
  glScissor((GLint)(x * scale.x),
            (GLint)((height - (GLint)(y + h)) * scale.y),
            (GLint)(w * scale.x),
            (GLint)(h * scale.y));
  unsigned int num_elements = NUM2UINT(rb_hash_aref(cmd, ID2SYM(rb_intern("element_count"))));

  struct nk_buffer *element_buffer = NULL;
  Data_Get_Struct(rb_funcall(self, rb_intern("vertex_indices"), 0), struct nk_buffer, element_buffer);
  const nk_draw_index *offset = (const nk_draw_index *) nk_buffer_memory_const(element_buffer);
  offset += NUM2UINT(rb_hash_aref(cmd, ID2SYM(rb_intern("offset"))));
  glDrawElements(GL_TRIANGLES, (GLsizei)num_elements, GL_UNSIGNED_SHORT, (void *) offset);
  return self;
}