1#version 120 2 3uniform sampler2D baseTexture; 4uniform float scattering; 5 6varying float fogFactor; 7varying float mie_frag; 8varying float mie_frag_mod; 9varying float z_pos; 10varying float bottom_shade; 11 12varying vec3 internal_pos; 13varying vec3 hazeColor; 14 15vec3 filter_combined (in vec3 color) ; 16 17void main(void) 18{ 19 vec4 base = texture2D( baseTexture, gl_TexCoord[0].st); 20 if (base.a < 0.02) 21 discard; 22 23 float mie_factor = 0.0; 24 float geo_factor = 1.0; 25 26 float mie_sign = 1.0; 27 if (mie_frag < 0.0) {mie_sign = -1.0;} 28 29 if (mie_sign > 0.0) 30 {mie_factor = smoothstep(0.8, 1.0, mie_frag);} 31 else 32 {mie_factor = -1.0 * (1.0 - smoothstep(-1.0, -0.8, mie_frag));} 33 34 mie_factor *= mie_frag_mod; 35 36 // suppress effect in cloud center 37 38 float z_bias = 0.2 * (1.0 - smoothstep(2.0, 3.0, z_pos)); 39 40 geo_factor *= smoothstep(-0.9 - z_bias, -0.4 - z_bias, internal_pos.x) * (1.0 -smoothstep(0.4 + z_bias, 0.9 + z_bias, internal_pos.x)); 41 geo_factor *= smoothstep(-0.9 - z_bias, -0.4 - z_bias, internal_pos.y) * (1.0 -smoothstep(0.4 + z_bias, 0.9 + z_bias, internal_pos.y)); 42 geo_factor *= smoothstep(0, 0.3, internal_pos.z) * (1.0 - smoothstep(0.5, 1.2, internal_pos.z)); 43 44 if (mie_sign > 0.0) 45 { 46 mie_factor *=(1.0 -geo_factor); 47 } 48 49 float transparency = smoothstep(0.0, 0.7, base.a); 50 float opacity = smoothstep(0.7, 1.0, base.a); 51 52 float inverse_mie = 0.0; 53 54 if ((opacity == 0.0) && (mie_sign > 0.0)) // Mie forward scattering enhancing light 55 {mie_factor *= (1.0 - pow(transparency, 2.0));} 56 else if ((opacity == 0.0) && (mie_sign < 0.0)) // Mie forward scattering reducing reflected light 57 { 58 inverse_mie = (1.0 - pow(transparency, 2.0)) * smoothstep(0.65, 0.8, scattering); 59 inverse_mie *= (1.0 - smoothstep(-1.0, -0.5, mie_frag)); 60 } 61 else if (mie_sign > 0.0) // bulk light absorption 62 {mie_factor *= - 4.0 * pow(opacity, 2.0);} 63 64 65 // darken the bulk of the away-facing cloud 66 67 float bulk_shade_factor = (1.0 - 0.6 * geo_factor * smoothstep(0.5, 1.0, mie_frag)); 68 bulk_shade_factor -= 0.3 * smoothstep(0.5, 1.0, mie_frag) * (1.0 - mie_frag_mod) * (1.0 - smoothstep(0.4, 0.5, bottom_shade)); 69 70 71 float mie_enhancement = 1.0 + clamp(mie_factor, 0.0, 1.0); 72 mie_enhancement = mie_enhancement * bulk_shade_factor; 73 74 vec4 finalColor = base * gl_Color; 75 finalColor.rgb *= mie_enhancement * (1.0 - 0.4 * inverse_mie); 76 finalColor.rgb = max(finalColor.rgb, gl_Color.rgb * 1.2 * bottom_shade); 77 78 finalColor.rgb = mix(hazeColor, finalColor.rgb, fogFactor ); 79 finalColor.rgb = filter_combined(finalColor.rgb); 80 81 82 gl_FragColor.rgb = finalColor.rgb; 83 gl_FragColor.a = mix(0.0, finalColor.a, 1.0 - 0.5 * (1.0 - fogFactor)); 84} 85