68 lines
2.2 KiB
GLSL
68 lines
2.2 KiB
GLSL
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#version 330 core
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layout(location = 0) in vec4 pos;
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layout(location = 2) in vec4 vertex_color;
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layout(location = 3) in vec4 multitexcoord0;
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out vec2 texcoord;
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out vec4 cloud_color;
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uniform mat4 osg_ModelViewMatrix;
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uniform mat4 osg_ModelViewProjectionMatrix;
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uniform mat4 osg_ViewMatrixInverse;
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uniform vec3 fg_SunDirectionWorld;
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const float shade = 0.8;
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const float cloud_height = 1000.0;
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// sun.glsl
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vec3 get_sun_radiance(vec3 p);
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void cloud_static_common_vert(out vec4 vs_pos, out vec4 ws_pos)
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{
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texcoord = multitexcoord0.st;
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// XXX: Should be sent as an uniform
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mat4 inverseModelViewMatrix = inverse(osg_ModelViewMatrix);
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vec4 ep = inverseModelViewMatrix * vec4(0.0, 0.0, 0.0, 1.0);
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vec4 l = inverseModelViewMatrix * vec4(0.0, 0.0, 1.0, 1.0);
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vec3 u = normalize(ep.xyz - l.xyz);
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vec4 final_pos = vec4(0.0, 0.0, 0.0, 1.0);
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final_pos.x = pos.x;
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final_pos.y = pos.y;
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final_pos.z = pos.z;
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final_pos.xyz += vertex_color.xyz;
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gl_Position = osg_ModelViewProjectionMatrix * final_pos;
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// Determine a lighting normal based on the vertex position from the
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// center of the cloud, so that sprite on the opposite side of the cloud
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// to the sun are darker.
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vec3 n = normalize(vec3(osg_ViewMatrixInverse *
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osg_ModelViewMatrix * vec4(-final_pos.xyz, 0.0)));
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float NdotL = dot(-fg_SunDirectionWorld, n);
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vs_pos = osg_ModelViewMatrix * final_pos;
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ws_pos = osg_ViewMatrixInverse * vs_pos;
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float fogCoord = abs(vs_pos.z);
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float fract = smoothstep(0.0, cloud_height, final_pos.z + cloud_height);
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vec3 sun_radiance = get_sun_radiance(ws_pos.xyz);
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// Determine the shading of the sprite based on its vertical position and
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// position relative to the sun.
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NdotL = min(smoothstep(-0.5, 0.0, NdotL), fract);
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// Determine the shading based on a mixture from the backlight to the front
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vec3 backlight = shade * sun_radiance;
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cloud_color.rgb = mix(backlight, sun_radiance, NdotL);
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// As we get within 100m of the sprite, it is faded out. Equally at large
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// distances it also fades out.
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cloud_color.a = min(smoothstep(100.0, 250.0, fogCoord),
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1.0 - smoothstep(70000.0, 75000.0, fogCoord));
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}
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