mirror of
https://github.com/ZDoom/gzdoom-gles.git
synced 2024-11-29 23:41:56 +00:00
112 lines
3.3 KiB
GLSL
112 lines
3.3 KiB
GLSL
|
|
in vec2 TexCoord;
|
|
out vec4 FragColor;
|
|
|
|
uniform vec2 UVToViewA;
|
|
uniform vec2 UVToViewB;
|
|
uniform vec2 InvFullResolution;
|
|
|
|
uniform float NDotVBias;
|
|
uniform float NegInvR2;
|
|
uniform float RadiusToScreen;
|
|
uniform float AOMultiplier;
|
|
|
|
uniform float AOStrength;
|
|
|
|
uniform sampler2D DepthTexture;
|
|
|
|
#if defined(USE_RANDOM_TEXTURE)
|
|
uniform sampler2D RandomTexture;
|
|
#endif
|
|
|
|
#define PI 3.14159265358979323846
|
|
|
|
// Calculate eye space position for the specified texture coordinate
|
|
vec3 FetchViewPos(vec2 uv)
|
|
{
|
|
float z = texture(DepthTexture, uv).x;
|
|
return vec3((UVToViewA * uv + UVToViewB) * z, z);
|
|
}
|
|
|
|
vec3 MinDiff(vec3 p, vec3 pr, vec3 pl)
|
|
{
|
|
vec3 v1 = pr - p;
|
|
vec3 v2 = p - pl;
|
|
return (dot(v1, v1) < dot(v2, v2)) ? v1 : v2;
|
|
}
|
|
|
|
// Reconstruct eye space normal from nearest neighbors
|
|
vec3 ReconstructNormal(vec3 p)
|
|
{
|
|
vec3 pr = FetchViewPos(TexCoord + vec2(InvFullResolution.x, 0));
|
|
vec3 pl = FetchViewPos(TexCoord + vec2(-InvFullResolution.x, 0));
|
|
vec3 pt = FetchViewPos(TexCoord + vec2(0, InvFullResolution.y));
|
|
vec3 pb = FetchViewPos(TexCoord + vec2(0, -InvFullResolution.y));
|
|
return normalize(cross(MinDiff(p, pr, pl), MinDiff(p, pt, pb)));
|
|
}
|
|
|
|
// Compute normalized 2D direction
|
|
vec2 RotateDirection(vec2 dir, vec2 cossin)
|
|
{
|
|
return vec2(dir.x * cossin.x - dir.y * cossin.y, dir.x * cossin.y + dir.y * cossin.x);
|
|
}
|
|
|
|
vec4 GetJitter()
|
|
{
|
|
#if !defined(USE_RANDOM_TEXTURE)
|
|
return vec4(1,0,1,1);
|
|
//vec3 rand = noise3(TexCoord.x + TexCoord.y);
|
|
//float angle = 2.0 * PI * rand.x / NUM_DIRECTIONS;
|
|
//return vec4(cos(angle), sin(angle), rand.y, rand.z);
|
|
#else
|
|
return texture(RandomTexture, gl_FragCoord.xy / RANDOM_TEXTURE_WIDTH);
|
|
#endif
|
|
}
|
|
|
|
// Calculates the ambient occlusion of a sample
|
|
float ComputeSampleAO(vec3 kernelPos, vec3 normal, vec3 samplePos)
|
|
{
|
|
vec3 v = samplePos - kernelPos;
|
|
float distanceSquare = dot(v, v);
|
|
float nDotV = dot(normal, v) * inversesqrt(distanceSquare);
|
|
return clamp(nDotV - NDotVBias, 0.0, 1.0) * clamp(distanceSquare * NegInvR2 + 1.0, 0.0, 1.0);
|
|
}
|
|
|
|
// Calculates the total ambient occlusion for the entire fragment
|
|
float ComputeAO(vec3 viewPosition, vec3 viewNormal)
|
|
{
|
|
vec4 rand = GetJitter();
|
|
|
|
float radiusPixels = RadiusToScreen / viewPosition.z;
|
|
float stepSizePixels = radiusPixels / (NUM_STEPS + 1.0);
|
|
|
|
const float directionAngleStep = 2.0 * PI / NUM_DIRECTIONS;
|
|
float ao = 0.0;
|
|
|
|
for (float directionIndex = 0.0; directionIndex < NUM_DIRECTIONS; ++directionIndex)
|
|
{
|
|
float angle = directionAngleStep * directionIndex;
|
|
|
|
vec2 direction = RotateDirection(vec2(cos(angle), sin(angle)), rand.xy);
|
|
float rayPixels = (rand.z * stepSizePixels + 1.0);
|
|
|
|
for (float StepIndex = 0.0; StepIndex < NUM_STEPS; ++StepIndex)
|
|
{
|
|
vec2 sampleUV = round(rayPixels * direction) * InvFullResolution + TexCoord;
|
|
vec3 samplePos = FetchViewPos(sampleUV);
|
|
ao += ComputeSampleAO(viewPosition, viewNormal, samplePos);
|
|
rayPixels += stepSizePixels;
|
|
}
|
|
}
|
|
|
|
ao *= AOMultiplier / (NUM_DIRECTIONS * NUM_STEPS);
|
|
return clamp(1.0 - ao * 2.0, 0.0, 1.0);
|
|
}
|
|
|
|
void main()
|
|
{
|
|
vec3 viewPosition = FetchViewPos(TexCoord);
|
|
vec3 viewNormal = ReconstructNormal(viewPosition);
|
|
float occlusion = ComputeAO(viewPosition, viewNormal) * AOStrength + (1.0 - AOStrength);
|
|
FragColor = vec4(occlusion, viewPosition.z, 0.0, 1.0);
|
|
}
|