uniform sampler2D randomTexture;
|
uniform sampler2D depthTexture;
|
uniform float intensity;
|
uniform float bias;
|
uniform float lengthCap;
|
uniform float stepSize;
|
uniform float frustumLength;
|
|
varying vec2 v_textureCoordinates;
|
|
vec4 clipToEye(vec2 uv, float depth)
|
{
|
vec2 xy = vec2((uv.x * 2.0 - 1.0), ((1.0 - uv.y) * 2.0 - 1.0));
|
vec4 posEC = czm_inverseProjection * vec4(xy, depth, 1.0);
|
posEC = posEC / posEC.w;
|
return posEC;
|
}
|
|
//Reconstruct Normal Without Edge Removation
|
vec3 getNormalXEdge(vec3 posInCamera, float depthU, float depthD, float depthL, float depthR, vec2 pixelSize)
|
{
|
vec4 posInCameraUp = clipToEye(v_textureCoordinates - vec2(0.0, pixelSize.y), depthU);
|
vec4 posInCameraDown = clipToEye(v_textureCoordinates + vec2(0.0, pixelSize.y), depthD);
|
vec4 posInCameraLeft = clipToEye(v_textureCoordinates - vec2(pixelSize.x, 0.0), depthL);
|
vec4 posInCameraRight = clipToEye(v_textureCoordinates + vec2(pixelSize.x, 0.0), depthR);
|
|
vec3 up = posInCamera.xyz - posInCameraUp.xyz;
|
vec3 down = posInCameraDown.xyz - posInCamera.xyz;
|
vec3 left = posInCamera.xyz - posInCameraLeft.xyz;
|
vec3 right = posInCameraRight.xyz - posInCamera.xyz;
|
|
vec3 DX = length(left) < length(right) ? left : right;
|
vec3 DY = length(up) < length(down) ? up : down;
|
|
return normalize(cross(DY, DX));
|
}
|
|
void main(void)
|
{
|
float depth = czm_readDepth(depthTexture, v_textureCoordinates);
|
vec4 posInCamera = clipToEye(v_textureCoordinates, depth);
|
|
if (posInCamera.z > frustumLength)
|
{
|
gl_FragColor = vec4(1.0);
|
return;
|
}
|
|
vec2 pixelSize = czm_pixelRatio / czm_viewport.zw;
|
float depthU = czm_readDepth(depthTexture, v_textureCoordinates - vec2(0.0, pixelSize.y));
|
float depthD = czm_readDepth(depthTexture, v_textureCoordinates + vec2(0.0, pixelSize.y));
|
float depthL = czm_readDepth(depthTexture, v_textureCoordinates - vec2(pixelSize.x, 0.0));
|
float depthR = czm_readDepth(depthTexture, v_textureCoordinates + vec2(pixelSize.x, 0.0));
|
vec3 normalInCamera = getNormalXEdge(posInCamera.xyz, depthU, depthD, depthL, depthR, pixelSize);
|
|
float ao = 0.0;
|
vec2 sampleDirection = vec2(1.0, 0.0);
|
float gapAngle = 90.0 * czm_radiansPerDegree;
|
|
// RandomNoise
|
float randomVal = texture2D(randomTexture, v_textureCoordinates).x;
|
|
//Loop for each direction
|
for (int i = 0; i < 4; i++)
|
{
|
float newGapAngle = gapAngle * (float(i) + randomVal);
|
float cosVal = cos(newGapAngle);
|
float sinVal = sin(newGapAngle);
|
|
//Rotate Sampling Direction
|
vec2 rotatedSampleDirection = vec2(cosVal * sampleDirection.x - sinVal * sampleDirection.y, sinVal * sampleDirection.x + cosVal * sampleDirection.y);
|
float localAO = 0.0;
|
float localStepSize = stepSize;
|
|
//Loop for each step
|
for (int j = 0; j < 6; j++)
|
{
|
vec2 newCoords = v_textureCoordinates + rotatedSampleDirection * localStepSize * pixelSize;
|
|
//Exception Handling
|
if(newCoords.x > 1.0 || newCoords.y > 1.0 || newCoords.x < 0.0 || newCoords.y < 0.0)
|
{
|
break;
|
}
|
|
float stepDepthInfo = czm_readDepth(depthTexture, newCoords);
|
vec4 stepPosInCamera = clipToEye(newCoords, stepDepthInfo);
|
vec3 diffVec = stepPosInCamera.xyz - posInCamera.xyz;
|
float len = length(diffVec);
|
|
if (len > lengthCap)
|
{
|
break;
|
}
|
|
float dotVal = clamp(dot(normalInCamera, normalize(diffVec)), 0.0, 1.0 );
|
float weight = len / lengthCap;
|
weight = 1.0 - weight * weight;
|
|
if (dotVal < bias)
|
{
|
dotVal = 0.0;
|
}
|
|
localAO = max(localAO, dotVal * weight);
|
localStepSize += stepSize;
|
}
|
ao += localAO;
|
}
|
|
ao /= 4.0;
|
ao = 1.0 - clamp(ao, 0.0, 1.0);
|
ao = pow(ao, intensity);
|
gl_FragColor = vec4(vec3(ao), 1.0);
|
}
|
