An image transforming apparatus for transforming an input video signal representing a two dimensional image into a transformed video signal representing a three-dimensional surface and for depicting illumination of the image is provided. The image transforming apparatus includes a device for defining the three-dimensional surface, a device for providing a mapping data signal for transforming the input signal into the three-dimensional surface, a device for transforming the input video signal in accordance with the mapping data signal so as to generate the transformed video signal, a device for storing a plurality of illumination pattern data signals each of which depicts differential illumination of the transformed video signals, a device for mixing the illumination pattern signals in accordance with the mapping data signal so that the mixing ratio of the illumination pattern signals is varied and a device for depicting illumination to the transformed video signal in accordance with the mixed illumination pattern signal. An effect surface, which is an externally defined three-dimensional surface on which the image information processed in accordance with special effect processing is mapped, is changed in shape and the image information is mapped to suit to the so-changed effect surface by controlling the mixing ratio to present a realistic image.