#version 400 uniform float u; int foo(int a, const int b, in int c, const in int d, out int e, inout int f) { int sum = a + b + c + d + f; // no e, it is out only // sum should be 47 now a *= 64; // no b, it is read only c *= 64; // no d, it is read only e = 64 * 16; // e starts undefined f *= 64; sum += a + 64 * b + c + 64 * d + e + f; // everything has a value now, totaling of 64(1+2+4+8+16+32) = 64*63 = 4032 // sum should be 4032 + 47 = 4079 return sum; } int foo2(float a, vec3 b, out int r) { r = int(3.0 * a); return int(5.0 * b.y); } int foo3() { if (u > 3.2) { discard; return 1000000; } return 2000000; } void main() { int e; int t = 2; struct s { ivec4 t; } f; f.t.y = 32; // test the different qualifers int color = foo(1, 2, t+t, 8, e, f.t.y); color += 128 * (e + f.t.y); // right side should be 128(64(16 + 32)) = 393216 // sum should be 4079 + 393216 = 397295 // test conversions float arg; float ret; ret = foo2(4, ivec3(1,2,3), arg); // ret = 10, param = 12.0 color += int(ret + arg); // adds 22, for total of 397317 color += foo3(); // theoretically, add 2000000, for total of 2397317 gl_FragColor = vec4(color); }