Modify Program 12.4 to utilize a height map of your own design. Then add lighting and shadow mapping so that your tessellated terrain casts shadows. This is a complex exercise, because some of the code in the first and second shadow mapping passes will need to be moved to the evaluation shader.

Program 12.4

Java/JOGL application // same as for Bezier surface example, with these changes: gl.glPatchParameteri(GL_PATCH_VERTICES, 4); gl.glDrawArraysInstanced (GL_PATCHES, 0, 4, 64*64); Vertex Shader out vec2 tc; void main(void) {vec2 patch TexCoords[] = vec2[] (vec2(0,0), vec2(1,0), vec2(0,1), vec2(1,1)); // compute an offset for coordinates based on which instance this is int x = gl_InstanceID % 64; int y = gl_InstancelD / 64;