const float M_PI = 3.14159265358979323846; float ripple2_f(float x) { return 1 - sin((x*x)/M_PI); } float sawtooth_f(float x, float period) { return x - period*floor(x/period); } float ripple_f(float x) { return ripple2_f(sawtooth_f(x, M_PI)); } float dune_f(float x, float z) { return (1 + 0.5*sin(x+z)) * ripple_f(x+0.5*sin(z + (1+0.8*sin(x)))); } float dune2_f(float x, float z) { const float phi = M_PI/4; const float scaling= 12*2*M_PI/sqrt(2); return dune_f( scaling*(cos(phi)*x + sin(phi)*z), scaling*(-sin(phi)*x + cos(phi)*z)); } void main(void) { float x = dune2_f(gl_TexCoord[0].x, gl_TexCoord[0].y); gl_FragColor = vec4 (0.9*x, 0.6*x, 0.2*x, 1); }