85 lines
2.7 KiB
GLSL
85 lines
2.7 KiB
GLSL
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#version 120
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uniform sampler2D baseTexture;
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uniform float scattering;
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varying float fogFactor;
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varying float mie_frag;
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varying float mie_frag_mod;
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varying float z_pos;
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varying float bottom_shade;
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varying vec3 internal_pos;
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varying vec3 hazeColor;
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vec3 filter_combined (in vec3 color) ;
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void main(void)
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{
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vec4 base = texture2D( baseTexture, gl_TexCoord[0].st);
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if (base.a < 0.02)
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discard;
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float mie_factor = 0.0;
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float geo_factor = 1.0;
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float mie_sign = 1.0;
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if (mie_frag < 0.0) {mie_sign = -1.0;}
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if (mie_sign > 0.0)
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{mie_factor = smoothstep(0.8, 1.0, mie_frag);}
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else
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{mie_factor = -1.0 * (1.0 - smoothstep(-1.0, -0.8, mie_frag));}
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mie_factor *= mie_frag_mod;
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// suppress effect in cloud center
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float z_bias = 0.2 * (1.0 - smoothstep(2.0, 3.0, z_pos));
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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));
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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));
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geo_factor *= smoothstep(0, 0.3, internal_pos.z) * (1.0 - smoothstep(0.5, 1.2, internal_pos.z));
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if (mie_sign > 0.0)
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{
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mie_factor *=(1.0 -geo_factor);
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}
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float transparency = smoothstep(0.0, 0.7, base.a);
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float opacity = smoothstep(0.7, 1.0, base.a);
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float inverse_mie = 0.0;
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if ((opacity == 0.0) && (mie_sign > 0.0)) // Mie forward scattering enhancing light
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{mie_factor *= (1.0 - pow(transparency, 2.0));}
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else if ((opacity == 0.0) && (mie_sign < 0.0)) // Mie forward scattering reducing reflected light
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{
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inverse_mie = (1.0 - pow(transparency, 2.0)) * smoothstep(0.65, 0.8, scattering);
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inverse_mie *= (1.0 - smoothstep(-1.0, -0.5, mie_frag));
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}
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else if (mie_sign > 0.0) // bulk light absorption
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{mie_factor *= - 4.0 * pow(opacity, 2.0);}
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// darken the bulk of the away-facing cloud
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float bulk_shade_factor = (1.0 - 0.6 * geo_factor * smoothstep(0.5, 1.0, mie_frag));
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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));
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float mie_enhancement = 1.0 + clamp(mie_factor, 0.0, 1.0);
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mie_enhancement = mie_enhancement * bulk_shade_factor;
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vec4 finalColor = base * gl_Color;
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finalColor.rgb *= mie_enhancement * (1.0 - 0.4 * inverse_mie);
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finalColor.rgb = max(finalColor.rgb, gl_Color.rgb * 1.2 * bottom_shade);
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finalColor.rgb = mix(hazeColor, finalColor.rgb, fogFactor );
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finalColor.rgb = filter_combined(finalColor.rgb);
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gl_FragColor.rgb = finalColor.rgb;
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gl_FragColor.a = mix(0.0, finalColor.a, 1.0 - 0.5 * (1.0 - fogFactor));
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}
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