add letter-/pillar- boxing for aspect ratios outside fo the defined min/max

src/renderer_wgpu.c

@@ -333,6 +333,10 @@ void renderer_frame_set_shader(R_Shader shader) {
     current_shader = shader;
 }
 
+void renderer_frame_set_viewport(float x, float y, float width, float height, float min_depth, float max_depth) {
+    wgpuRenderPassEncoderSetViewport(pass_encoder, x, y, width, height, min_depth, max_depth);
+}
+
 void renderer_frame_draw(R_Buffer vertex_buffer, R_Buffer index_buffer, R_Buffer instance_buffer, Uint32 num_indices, Uint32 num_instances, const R_Draw_Resources *resources) {
     SDL_assert(pass_encoder);