// This file has been automatically generated from resource file src/Shaders/SkydomBackground.fs static const char Shaders_SkydomBackground_fs[] = "// Constants\n" "const float M_PI = 3.1415926535;\n" "const float THE_EARTH_RADIUS = 6360e3;\n" "const vec3 THE_EARTH_CENTER = vec3 (0.0, -THE_EARTH_RADIUS, 0.0);\n" "const float THE_ATMO_RADIUS = 6380e3; // atmosphere radius (6420e3?)\n" "const float THE_G = 0.76; // anisotropy of the medium (papers use 0.76)\n" "const float THE_G2 = THE_G * THE_G;\n" "const float THE_HR = 8000.0; // Thickness of the atmosphere\n" "const float THE_HM = 1000.0; // Same as above but for Mie\n" "const vec3 THE_BETA_R = vec3 (5.8e-6, 13.5e-6, 33.1e-6); // Reyleigh scattering normal earth\n" "const vec3 THE_BETA_M = vec3 (21e-6); // Normal Mie scattering\n" "\n" "// Parameters\n" "const float THE_SunAttenuation = 1.0; // sun intensity\n" "const float THE_EyeHeight = 100.0; // viewer height\n" "const float THE_HorizonWidth = 0.002;\n" "const int THE_NbSamples = 8;\n" "const int THE_NbSamplesLight = 8; // integral sampling rate (might highly hit performance)\n" "const float THE_SunPower = 5.0;\n" "const float THE_StarTreshold = 0.98;\n" "\n" "// Uniforms\n" "uniform vec3 uSunDir;\n" "uniform float uTime;\n" "uniform float uCloudy;\n" "uniform float uFog;\n" "\n" "float hash13 (in vec3 p3)\n" "{\n" " p3 = fract (p3 * 0.1031);\n" " p3 += dot (p3, p3.zyx + 31.32);\n" " return fract ((p3.x + p3.y) * p3.z);\n" "}\n" "\n" "float hash12 (in vec2 p)\n" "{\n" " vec3 p3 = fract (vec3(p.xyx) * .1031);\n" " p3 += dot (p3, p3.yzx + 33.33);\n" " return fract ((p3.x + p3.y) * p3.z);\n" "}\n" "\n" "float smoothStarField (in vec2 theSamplePos)\n" "{\n" " vec2 aFract = fract (theSamplePos);\n" " vec2 aFloorSample = floor (theSamplePos);\n" " float v1 = hash12 (aFloorSample);\n" " float v2 = hash12 (aFloorSample + vec2( 0.0, 1.0 ));\n" " float v3 = hash12 (aFloorSample + vec2( 1.0, 0.0 ));\n" " float v4 = hash12 (aFloorSample + vec2( 1.0, 1.0 ));\n" "\n" " vec2 u = aFract * aFract * (3.0 - 2.0 * aFract);\n" "\n" " return mix(v1, v2, u.x) +\n" " (v3 - v1) * u.y * (1.0 - u.x) +\n" " (v4 - v2) * u.x * u.y;\n" "}\n" "\n" "float noisyStarField (in vec2 theSamplePos)\n" "{\n" " float aStarVal = smoothStarField (theSamplePos);\n" " if (aStarVal >= THE_StarTreshold)\n" " {\n" " aStarVal = pow ((aStarVal - THE_StarTreshold) / (1.0 - THE_StarTreshold), 6.0);\n" " }\n" " else\n" " {\n" " aStarVal = 0.0;\n" " }\n" " return aStarVal;\n" "}\n" "\n" "float smoothNoise (in vec3 theCoord)\n" "{\n" " vec3 anInt = floor (theCoord);\n" " vec3 anFract = fract (theCoord);\n" " anFract = anFract * anFract * (3.0 - (2.0 * anFract));\n" " return mix(mix(mix(hash13(anInt ),\n" " hash13(anInt + vec3(1.0, 0.0, 0.0)), anFract.x),\n" " mix(hash13(anInt + vec3(0.0, 1.0, 0.0)),\n" " hash13(anInt + vec3(1.0, 1.0, 0.0)), anFract.x), anFract.y),\n" " mix(mix(hash13(anInt + vec3(0.0, 0.0, 1.0)),\n" " hash13(anInt + vec3(1.0, 0.0, 1.0)), anFract.x),\n" " mix(hash13(anInt + vec3(0.0, 1.0, 1.0)),\n" " hash13(anInt + vec3(1.0, 1.0, 1.0)), anFract.x), anFract.y), anFract.z);\n" "}\n" "\n" "float fnoise (in vec3 theCoord, in float theTime)\n" "{\n" " theCoord *= .25;\n" " float aNoise;\n" "\n" " aNoise = 0.5000 * smoothNoise (theCoord);\n" " theCoord = theCoord * 3.02; theCoord.y -= theTime * 0.2;\n" " aNoise += 0.2500 * smoothNoise (theCoord);\n" " theCoord = theCoord * 3.03; theCoord.y += theTime * 0.06;\n" " aNoise += 0.1250 * smoothNoise (theCoord);\n" " theCoord = theCoord * 3.01;\n" " aNoise += 0.0625 * smoothNoise (theCoord);\n" " theCoord = theCoord * 3.03;\n" " aNoise += 0.03125 * smoothNoise (theCoord);\n" " theCoord = theCoord * 3.02;\n" " aNoise += 0.015625 * smoothNoise (theCoord);\n" " return aNoise;\n" "}\n" "\n" "float clouds (in vec3 theTs, in float theTime)\n" "{\n" " float aCloud = fnoise (theTs * 2e-4, theTime) + uCloudy * 0.1;\n" " aCloud = smoothstep (0.44, 0.64, aCloud);\n" " aCloud *= 70.0;\n" " return aCloud + uFog;\n" "}\n" "\n" "void densities (in vec3 thePos, out float theRayleigh, out float theMie, in float theTime)\n" "{\n" " float aHeight = length (thePos - THE_EARTH_CENTER) - THE_EARTH_RADIUS;\n" " theRayleigh = exp (-aHeight / THE_HR);\n" "\n" " float aCloud = 0.0;\n" " if (aHeight > 5000.0 && aHeight < 8000.0)\n" " {\n" " aCloud = clouds (thePos + vec3 (0.0, 0.,-theTime*3e3), theTime);\n" " aCloud *= sin (M_PI*(aHeight - 5e3) / 5e3) * uCloudy;\n" " }\n" "\n" " float aCloud2 = 0.0;\n" " if (aHeight > 12e3 && aHeight < 15.5e3)\n" " {\n" " aCloud2 = fnoise (thePos * 3e-4, theTime) * clouds (thePos * 32.0, theTime);\n" " aCloud2 *= sin (M_PI * (aHeight - 12e3) / 12e3) * 0.05;\n" " aCloud2 = clamp (aCloud2, 0.0, 1.0);\n" " }\n" "\n" " theMie = exp (-aHeight / THE_HM) + aCloud + uFog;\n" " theMie += aCloud2;\n" "}\n" "\n" "// ray with sphere intersection problem is reduced to solving the equation\n" "// (P - C)^2 = r^2 <--- sphere equation\n" "// where P is P(t) = A + t*B <--- point on ray\n" "// t^2*dot(B, B) + t*2*dot(B, A-C) + dot(A-C, A-C) - r^2 = 0\n" "// [ A ] [ B ] [ C ]\n" "// We just need to solve the above quadratic equation\n" "float raySphereIntersect (in vec3 theOrig, in vec3 theDir, in float theRadius)\n" "{\n" " theOrig = theOrig - THE_EARTH_CENTER;\n" " // A coefficient will be always 1 (theDir is normalized)\n" " float B = dot (theOrig, theDir);\n" " float C = dot (theOrig, theOrig) - theRadius * theRadius;\n" " // optimized version of classic (-b +- sqrt(b^2 - 4ac)) / 2a\n" " float aDet2 = B * B - C;\n" " if (aDet2 < 0.0) { return -1.0; }\n" " float aDet = sqrt (aDet2);\n" " float aT1 = -B - aDet;\n" " float aT2 = -B + aDet;\n" " return aT1 >= 0.0 ? aT1 : aT2;\n" "}\n" "\n" "void scatter (in vec3 theEye, in vec3 theRay, in vec3 theSun,\n" " out vec3 theCol, out float theScat, in float theTime)\n" "{\n" " float aRayLen = raySphereIntersect (theEye, theRay, THE_ATMO_RADIUS);\n" " float aMu = dot (theRay, theSun);\n" " float aMu2 = 1.0 + aMu*aMu;\n" " // The Raleigh phase function looks like this:\n" " float aPhaseR = 3.0/(16.0 * M_PI) * aMu2;\n" " // And the Mie phase function equation is:\n" " float aPhaseM = (3.0 / (8.0 * M_PI) * (1.0 - THE_G2) * aMu2)\n" " / ((2.0 + THE_G2) * pow (1.0 + THE_G2 - 2.0 * THE_G * aMu, 1.5));\n" "\n" " float anOpticalDepthR = 0.0;\n" " float anOpticalDepthM = 0.0;\n" " vec3 aSumR = vec3 (0.0);\n" " vec3 aSumM = vec3 (0.0); // Mie and Rayleigh contribution\n" "\n" " float dl = aRayLen / float (THE_NbSamples);\n" " for (int i = 0; i < THE_NbSamples; ++i)\n" " {\n" " float l = float(i) * dl;\n" " vec3 aSamplePos = theEye + theRay * l;\n" "\n" " float dR, dM;\n" " densities (aSamplePos, dR, dM, theTime);\n" " dR *= dl;\n" " dM *= dl;\n" " anOpticalDepthR += dR;\n" " anOpticalDepthM += dM;\n" "\n" " float aSegmentLengthLight = raySphereIntersect (aSamplePos, theSun, THE_ATMO_RADIUS);\n" " if (aSegmentLengthLight > 0.0)\n" " {\n" " float dls = aSegmentLengthLight / float (THE_NbSamplesLight);\n" " float anOpticalDepthRs = 0.0;\n" " float anOpticalDepthMs = 0.0;\n" " for (int j = 0; j < THE_NbSamplesLight; ++j)\n" " {\n" " float ls = float (j) * dls;\n" " vec3 aSamplePosS = aSamplePos + theSun * ls;\n" " float dRs, dMs;\n" " densities (aSamplePosS, dRs, dMs, theTime);\n" " anOpticalDepthRs += dRs * dls;\n" " anOpticalDepthMs += dMs * dls;\n" " }\n" "\n" " vec3 anAttenuation = exp (-(THE_BETA_R * (anOpticalDepthR + anOpticalDepthRs)\n" " + THE_BETA_M * (anOpticalDepthM + anOpticalDepthMs)));\n" " aSumR += anAttenuation * dR;\n" " aSumM += anAttenuation * dM;\n" " }\n" " }\n" "\n" " theCol = THE_SunPower * (aSumR * THE_BETA_R * aPhaseR + aSumM * THE_BETA_M * aPhaseM);\n" " theScat = 1.0 - clamp (anOpticalDepthM*1e-5, 0.0, 1.0);\n" "}\n" "\n" "// This is where all the magic happens. We first raymarch along the primary ray\n" "// (from the camera origin to the point where the ray exits the atmosphere).\n" "// For each sample along the primary ray,\n" "// we then \"cast\" a light ray and raymarch along that ray as well.\n" "// We basically shoot a ray in the direction of the sun.\n" "vec4 computeIncidentLight (in vec3 theRayDirection, in vec2 theUv, in float theTime)\n" "{\n" " float aSunAttenuation = THE_SunAttenuation;\n" " vec3 aSunDir = uSunDir;\n" " // conversion to moon\n" " float aStarAttenuation = 0.0;\n" " if (aSunDir.y < 0.0)\n" " {\n" " aSunDir *= -1.0;\n" " aSunAttenuation = aSunAttenuation * 0.1;\n" " aStarAttenuation = sqrt (aSunDir.y);\n" " }\n" "\n" " vec3 anEyePosition = vec3(0.0, THE_EyeHeight, 0.0);\n" "\n" " // draw a water surface horizontally symmetrically to the sky\n" " if (theRayDirection.y <= -THE_HorizonWidth / 2.0)\n" " {\n" " theRayDirection.y = -THE_HorizonWidth - theRayDirection.y;\n" " }\n" "\n" " float aScattering = 0.0;\n" " vec3 aColor = vec3 (0.0);\n" "\n" " scatter (anEyePosition, theRayDirection, aSunDir, aColor, aScattering, theTime);\n" " aColor *= aSunAttenuation;\n" " float aStarIntensity = noisyStarField (theUv * 2048.0);\n" " vec3 aStarColor = vec3 (aScattering * aStarIntensity * aStarAttenuation);\n" " aColor += aStarColor;\n" "\n" " return vec4 (1.18 * pow (aColor, vec3(0.7)), 1.0);\n" "}\n" "\n" "uniform int uSide;\n" "\n" "void main()\n" "{\n" " vec2 anUv = vec2 (2.0 * TexCoord.x - 1.0,\n" " 2.0 * TexCoord.y - 1.0);\n" " vec3 aPlanes[6];\n" " aPlanes[0] = vec3 (+1.0, 0.0, 0.0);\n" " aPlanes[1] = vec3 (-1.0, 0.0, 0.0);\n" " aPlanes[2] = vec3 ( 0.0,+1.0, 0.0);\n" " aPlanes[3] = vec3 ( 0.0,-1.0, 0.0);\n" " aPlanes[4] = vec3 ( 0.0, 0.0,+1.0);\n" " aPlanes[5] = vec3 ( 0.0, 0.0,-1.0);\n" " vec3 aRayDirection;\n" " if (uSide == 0)\n" " {\n" " // Positive X side\n" " aRayDirection = aPlanes[0] + vec3 (0.0, +anUv.y, -anUv.x);\n" " }\n" " else if (uSide == 1)\n" " {\n" " // Negative X side\n" " aRayDirection = aPlanes[1] + vec3 (0.0, +anUv.y, +anUv.x);\n" " }\n" " else if (uSide == 2)\n" " {\n" " // Positive Y side\n" " aRayDirection = aPlanes[2] + vec3 (+anUv.x, 0.0, +anUv.y);\n" " }\n" " else if (uSide == 3)\n" " {\n" " // Negative Y side\n" " aRayDirection = aPlanes[3] + vec3 (+anUv.x, 0.0, -anUv.y);\n" " }\n" " else if (uSide == 4)\n" " {\n" " // Positive Z side\n" " aRayDirection = aPlanes[4] + vec3 (+anUv.x, +anUv.y, 0.0);\n" " }\n" " else if (uSide == 5)\n" " {\n" " // Negative Z side\n" " aRayDirection = aPlanes[5] + vec3 (-anUv.x, +anUv.y, 0.0);\n" " }\n" "\n" " occFragColor = computeIncidentLight (normalize (aRayDirection), anUv, uTime);\n" "}\n";