fc27175690
Previously we required 6 shader attributes to pass in all the required information for the building shader. By using packing techniques this has been reduced to 4. This should improve support for integrated graphics cards.
311 lines
10 KiB
GLSL
311 lines
10 KiB
GLSL
// -*-C++-*-
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#version 120
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#extension GL_EXT_draw_instanced : enable
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// Shader that uses OpenGL state values to do per-pixel lighting
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//
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// The only light used is gl_LightSource[0], which is assumed to be
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// directional.
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//
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// Diffuse colors come from the gl_Color, ambient from the material. This is
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// equivalent to osg::Material::DIFFUSE.
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// Haze part added by Thorsten Renk, Oct. 2011
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#define MODE_OFF 0
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#define MODE_DIFFUSE 1
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#define MODE_AMBIENT_AND_DIFFUSE 2
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attribute vec3 instancePosition; // (x,y,z)
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attribute vec3 instanceScale; // (width, depth, height)
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attribute vec3 attrib1; // Generic packed attributes
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attribute vec3 attrib2;
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// The constant term of the lighting equation that doesn't depend on
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// the surface normal is passed in gl_{Front,Back}Color. The alpha
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// component is set to 1 for front, 0 for back in order to work around
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// bugs with gl_FrontFacing in the fragment shader.
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varying vec4 diffuse_term;
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varying vec3 normal;
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varying vec3 relPos;
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//varying float earthShade;
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//varying float yprime;
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//varying float vertex_alt;
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varying float yprime_alt;
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varying float mie_angle;
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uniform int colorMode;
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uniform float hazeLayerAltitude;
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uniform float terminator;
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uniform float terrain_alt;
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uniform float avisibility;
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uniform float visibility;
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uniform float overcast;
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//uniform float scattering;
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uniform float ground_scattering;
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uniform bool use_IR_vision;
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// This is the value used in the skydome scattering shader - use the same here for consistency?
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const float EarthRadius = 5800000.0;
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const float terminator_width = 200000.0;
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float earthShade;
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//float mie_angle;
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float light_func (in float x, in float a, in float b, in float c, in float d, in float e)
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{
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//x = x - 0.5;
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// use the asymptotics to shorten computations
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if (x < -15.0) {return 0.0;}
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return e / pow((1.0 + a * exp(-b * (x-c)) ),(1.0/d));
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}
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const float c_precision = 128.0;
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const float c_precisionp1 = c_precision + 1.0;
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vec3 float2vec(float value) {
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vec3 val;
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val.x = mod(value, c_precisionp1) / c_precision;
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val.y = mod(floor(value / c_precisionp1), c_precisionp1) / c_precision;
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val.z = floor(value / (c_precisionp1 * c_precisionp1)) / c_precision;
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return val;
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}
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void main()
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{
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vec4 light_diffuse;
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vec4 light_ambient;
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float yprime;
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float lightArg;
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float intensity;
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float vertex_alt;
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float scattering;
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vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
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// Unpack generic attributes
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vec3 attr1 = float2vec(attrib1.x);
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vec3 attr2 = float2vec(attrib1.z);
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vec3 attr3 = float2vec(attrib2.x);
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// Determine the rotation for the building.
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float sr = sin(6.28 * attr1.x);
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float cr = cos(6.28 * attr1.x);
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vec3 position = gl_Vertex.xyz;
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// Adjust the very top of the roof to match the rooftop scaling. This shapes
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// the rooftop - gambled, gabled etc. These vertices are identified by gl_Color.z
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position.x = (1.0 - gl_Color.z) * position.x + gl_Color.z * ((position.x + 0.5) * attr3.z - 0.5);
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position.y = (1.0 - gl_Color.z) * position.y + gl_Color.z * (position.y * attrib2.y );
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// Adjust pitch of roof to the correct height. These vertices are identified by gl_Color.z
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// Scale down by the building height (instanceScale.z) because
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// immediately afterwards we will scale UP the vertex to the correct scale.
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position.z = position.z + gl_Color.z * attrib1.y / instanceScale.z;
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position = position * instanceScale.xyz;
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// Rotation of the building and movement into position
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position.xy = vec2(dot(position.xy, vec2(cr, sr)), dot(position.xy, vec2(-sr, cr)));
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position = position + instancePosition.xyz;
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gl_Position = gl_ModelViewProjectionMatrix * vec4(position,1.0);
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// Texture coordinates are stored as:
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// - a separate offset (x0, y0) for the wall (wtex0x, wtex0y), and roof (rtex0x, rtex0y)
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// - a semi-shared (x1, y1) so that the front and side of the building can have
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// different texture mappings
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//
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// The vertex color value selects between them:
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// gl_Color.x=1 indicates front/back walls
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// gl_Color.y=1 indicates roof
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// gl_Color.z=1 indicates top roof vertexs (used above)
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// gl_Color.a=1 indicates sides
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// Finally, the roof texture is on the right of the texture sheet
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float wtex0x = attr1.y; // Front/Side texture X0
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float wtex0y = attr1.z; // Front/Side texture Y0
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float rtex0x = attr2.z; // Roof texture X0
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float rtex0y = attr3.x; // Roof texture Y0
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float wtex1x = attr2.x; // Front/Roof texture X1
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float stex1x = attr3.y; // Side texture X1
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float wtex1y = attr2.y; // Front/Roof/Side texture Y1
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vec2 tex0 = vec2(sign(gl_MultiTexCoord0.x) * (gl_Color.x*wtex0x + gl_Color.y*rtex0x + gl_Color.a*wtex0x),
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gl_Color.x*wtex0y + gl_Color.y*rtex0y + gl_Color.a*wtex0y);
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vec2 tex1 = vec2(gl_Color.x*wtex1x + gl_Color.y*wtex1x + gl_Color.a*stex1x,
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wtex1y);
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gl_TexCoord[0].x = tex0.x + gl_MultiTexCoord0.x * tex1.x;
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gl_TexCoord[0].y = tex0.y + gl_MultiTexCoord0.y * tex1.y;
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// Rotate the normal.
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normal = gl_Normal;
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normal.xy = vec2(dot(normal.xy, vec2(cr, sr)), dot(normal.xy, vec2(-sr, cr)));
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normal = gl_NormalMatrix * normal;
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vec4 ambient_color, diffuse_color;
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if (colorMode == MODE_DIFFUSE) {
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diffuse_color = vec4(1.0,1.0,1.0,1.0);
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ambient_color = gl_FrontMaterial.ambient;
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} else if (colorMode == MODE_AMBIENT_AND_DIFFUSE) {
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diffuse_color = vec4(1.0,1.0,1.0,1.0);
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ambient_color = vec4(1.0,1.0,1.0,1.0);
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} else {
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diffuse_color = gl_FrontMaterial.diffuse;
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ambient_color = gl_FrontMaterial.ambient;
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}
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// here start computations for the haze layer
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// we need several geometrical quantities
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// first current altitude of eye position in model space
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vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);
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// and relative position to vector
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relPos = gl_Vertex.xyz + gl_Color.xyz - ep.xyz;
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// unfortunately, we need the distance in the vertex shader, although the more accurate version
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// is later computed in the fragment shader again
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float dist = length(relPos);
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// altitude of the vertex in question, somehow zero leads to artefacts, so ensure it is at least 100m
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vertex_alt = max(gl_Vertex.z + gl_Color.z,100.0);
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scattering = ground_scattering + (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, vertex_alt);
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// branch dependent on daytime
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if (terminator < 1000000.0) // the full, sunrise and sunset computation
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{
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// establish coordinates relative to sun position
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vec3 lightFull = (gl_ModelViewMatrixInverse * gl_LightSource[0].position).xyz;
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vec3 lightHorizon = normalize(vec3(lightFull.x,lightFull.y, 0.0));
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// yprime is the distance of the vertex into sun direction
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yprime = -dot(relPos, lightHorizon);
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// this gets an altitude correction, higher terrain gets to see the sun earlier
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yprime_alt = yprime - sqrt(2.0 * EarthRadius * vertex_alt);
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// two times terminator width governs how quickly light fades into shadow
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// now the light-dimming factor
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earthShade = 0.6 * (1.0 - smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt)) + 0.4;
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// parametrized version of the Flightgear ground lighting function
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lightArg = (terminator-yprime_alt)/100000.0;
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// directional scattering for low sun
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if (lightArg < 10.0)
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{mie_angle = (0.5 * dot(normalize(relPos), normalize(lightFull)) ) + 0.5;}
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else
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{mie_angle = 1.0;}
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light_diffuse.b = light_func(lightArg, 1.330e-05, 0.264, 3.827, 1.08e-05, 1.0);
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light_diffuse.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
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light_diffuse.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
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light_diffuse.a = 1.0;
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light_diffuse = light_diffuse * scattering;
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light_ambient.r = light_func(lightArg, 0.236, 0.253, 1.073, 0.572, 0.33);
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light_ambient.g = light_ambient.r * 0.4/0.33;
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light_ambient.b = light_ambient.r * 0.5/0.33;
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light_ambient.a = 1.0;
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// correct ambient light intensity and hue before sunrise
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if (earthShade < 0.5)
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{
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//light_ambient = light_ambient * (0.4 + 0.6 * smoothstep(0.2, 0.5, earthShade));
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intensity = length(light_ambient.rgb);
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light_ambient.rgb = intensity * normalize(mix(light_ambient.rgb, shadedFogColor, 1.0 -smoothstep(0.4, 0.8,earthShade) ));
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intensity = length(light_diffuse.rgb);
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light_diffuse.rgb = intensity * normalize(mix(light_diffuse.rgb, shadedFogColor, 1.0 -smoothstep(0.4, 0.7,earthShade) ));
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}
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// the haze gets the light at the altitude of the haze top if the vertex in view is below
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// but the light at the vertex if the vertex is above
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vertex_alt = max(vertex_alt,hazeLayerAltitude);
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if (vertex_alt > hazeLayerAltitude)
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{
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if (dist > 0.8 * avisibility)
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{
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vertex_alt = mix(vertex_alt, hazeLayerAltitude, smoothstep(0.8*avisibility, avisibility, dist));
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yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
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}
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}
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else
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{
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vertex_alt = hazeLayerAltitude;
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yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
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}
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}
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else // the faster, full-day version without lightfields
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{
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//vertex_alt = max(gl_Vertex.z,100.0);
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earthShade = 1.0;
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mie_angle = 1.0;
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if (terminator > 3000000.0)
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{light_diffuse = vec4 (1.0, 1.0, 1.0, 1.0);
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light_ambient = vec4 (0.33, 0.4, 0.5, 1.0); }
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else
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{
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lightArg = (terminator/100000.0 - 10.0)/20.0;
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light_diffuse.b = 0.78 + lightArg * 0.21;
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light_diffuse.g = 0.907 + lightArg * 0.091;
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light_diffuse.r = 0.904 + lightArg * 0.092;
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light_diffuse.a = 1.0;
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light_ambient.r = 0.316 + lightArg * 0.016;
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light_ambient.g = light_ambient.r * 0.4/0.33;
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light_ambient.b = light_ambient.r * 0.5/0.33;
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light_ambient.a = 1.0;
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}
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light_diffuse = light_diffuse * scattering;
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yprime_alt = -sqrt(2.0 * EarthRadius * hazeLayerAltitude);
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}
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if (use_IR_vision)
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{
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light_ambient.rgb = max(light_ambient.rgb, vec3 (0.5, 0.5, 0.5));
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}
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// default lighting based on texture and material using the light we have just computed
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diffuse_term = diffuse_color* light_diffuse;
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vec4 constant_term = gl_FrontMaterial.emission + ambient_color *
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(gl_LightModel.ambient + light_ambient);
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// Super hack: if diffuse material alpha is less than 1, assume a
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// transparency animation is at work
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if (gl_FrontMaterial.diffuse.a < 1.0)
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diffuse_term.a = gl_FrontMaterial.diffuse.a;
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else
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diffuse_term.a = 1.0;
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// Another hack for supporting two-sided lighting without using
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// gl_FrontFacing in the fragment shader.
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gl_FrontColor.rgb = constant_term.rgb;
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gl_BackColor.rgb = constant_term.rgb;
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//gl_FrontColor.a = mie_angle; gl_BackColor.a = mie_angle;
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}
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