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Screen-space refection: many fixes + optimization (#4575)

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QwertyChouskie 2021-08-30 01:34:02 -07:00 committed by GitHub
parent 25301f9cc6
commit efbd8eb75e
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1 changed files with 51 additions and 54 deletions
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105
data/shaders/IBL.frag
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@ -16,23 +16,15 @@ out vec4 Spec;
#stk_include "utils/SpecularIBL.frag"
vec3 getXcYcZc(int x, int y, float zC)
{
// We use perspective symetric projection matrix hence P(0,2) = P(1, 2) = 0
float xC= (2. * (float(x)) / u_screen.x - 1.) * zC / u_projection_matrix[0][0];
float yC= (2. * (float(y)) / u_screen.y - 1.) * zC / u_projection_matrix[1][1];
return vec3(xC, yC, zC);
}
float makeLinear(float f, float n, float z)
{
return (2.0f * n) / (f + n - z * (f - n));
}
vec3 CalcViewPositionFromDepth(in vec2 TexCoord, in sampler2D DepthMap)
vec3 CalcViewPositionFromDepth(in vec2 TexCoord)
{
// Combine UV & depth into XY & Z (NDC)
float z = makeLinear(1000.0, 1.0, textureLod(DepthMap, TexCoord, 0.).x);
float z = makeLinear(1000.0, 1.0, textureLod(dtex, TexCoord, 0.).x);
vec3 rawPosition = vec3(TexCoord, z);
// Convert from (0, 1) range to (-1, 1)
@ -45,14 +37,18 @@ vec3 CalcViewPositionFromDepth(in vec2 TexCoord, in sampler2D DepthMap)
return ViewPosition.xyz / ViewPosition.w;
}
float GetVignette(float factor)
// Fade out edges of screen buffer tex
// 1 means full render tex, 0 means full IBL tex
float GetEdgeFade(vec2 coords)
{
vec2 inside = (gl_FragCoord.xy / u_screen) - 0.5;
float vignette = 1. - dot(inside, inside) * 5.0;
return clamp(pow(vignette, factor), 0., 1.0);
float gradL = smoothstep(0.0, 0.4, coords.x);
float gradR = 1.0 - smoothstep(0.6, 1.0, coords.x);
float gradT = smoothstep(0.0, 0.4, coords.y);
float gradB = 1.0 - smoothstep(0.6, 1.0, coords.y);
return min(min(gradL, gradR), min(gradT, gradB));
}
vec3 RayCast(vec3 dir, inout vec3 hitCoord, out float dDepth, in sampler2D DepthMap, in vec3 fallback, float spread)
vec2 RayCast(vec3 dir, inout vec3 hitCoord, out float dDepth)
{
dir *= 0.25f;
@ -63,39 +59,24 @@ vec3 RayCast(vec3 dir, inout vec3 hitCoord, out float dDepth, in sampler2D Depth
projectedCoord.xy /= projectedCoord.w;
projectedCoord.xy = projectedCoord.xy * 0.5 + 0.5;
float depth = CalcViewPositionFromDepth(projectedCoord.xy, DepthMap).z;
float depth = CalcViewPositionFromDepth(projectedCoord.xy).z;
dDepth = hitCoord.z - depth;
if(dDepth < 0.0)
if (dDepth < 0.0)
{
// Texture wrapping to extand artifcially the range of the lookup texture
// FIXME can be improved to lessen the distortion
projectedCoord.y = min(.99, projectedCoord.y);
projectedCoord.x = min(.99, projectedCoord.x);
projectedCoord.x = max(.01, projectedCoord.x);
// We want only reflection on nearly horizontal surfaces
float cutout = dot(dir, vec3(0., 0., -1.));
if ((projectedCoord.x > 0.0 && projectedCoord.x < 1.0)
&& (projectedCoord.y > 0.0 && projectedCoord.y < 1.0)
&& (cutout > 10.0)
)
if (projectedCoord.x > 0.0 && projectedCoord.x < 1.0 &&
projectedCoord.y > 0.0 && projectedCoord.y < 1.0)
{
// FIXME We need to generate mipmap to take into account the gloss map
vec3 finalColor = textureLod(albedo, projectedCoord.xy, spread).rgb;
//return finalColor;
return mix(fallback, finalColor, GetVignette(4.));
return projectedCoord.xy;
}
else
{
return fallback;
return vec2(0.f);
}
}
}
return fallback;
return vec2(0.f);
}
// Main ===================================================================
@ -119,30 +100,46 @@ void main(void)
#else
// :::::::: Compute Space Screen Reflection ::::::::::::::::::::::::::::::::::::
float lineardepth = textureLod(dtex, uv, 0.).x;
// Output color
vec3 outColor;
// Fallback (if the ray can't find an intersection we display the sky)
vec3 fallback = .25 * SpecularIBL(normal, eyedir, specval);
float View_Depth = makeLinear(1000.0, 1.0, lineardepth);
vec3 ScreenPos = xpos.xyz;
vec4 View_Pos = u_inverse_projection_matrix * vec4(ScreenPos, 1.0f);
View_Pos /= View_Pos.w;
// Only calculate reflections if the reflectivity value is high enough,
// otherwise just use specular IBL
if (specval > 0.5)
{
vec3 View_Pos = CalcViewPositionFromDepth(uv);
// Reflection vector
vec3 reflected = normalize(reflect(eyedir, normal));
// Reflection vector
vec3 reflected = normalize(reflect(eyedir, normal));
// Ray cast
vec3 hitPos = View_Pos.xyz;
float dDepth;
float minRayStep = 100.0f;
// Ray cast
vec3 hitPos = View_Pos.xyz;
float dDepth;
float minRayStep = 50.0f;
vec2 coords = RayCast(reflected * max(minRayStep, -View_Pos.z),
hitPos, dDepth);
if (coords.x == 0.0 && coords.y == 0.0) {
outColor = fallback;
} else {
// FIXME We need to generate mipmap to take into account the gloss map
outColor = textureLod(albedo, coords, 0.f).rgb;
outColor = mix(fallback, outColor, GetEdgeFade(coords));
// TODO temporary measure the lack of mipmapping for RTT albedo
// Implement it in proper way
// Use (specval - 0.5) * 2.0 to bring specval from 0.5-1.0 range to 0.0-1.0 range
outColor = mix(fallback, outColor, (specval - 0.5) * 2.0);
}
}
else
{
outColor = fallback;
}
vec3 outColor = RayCast(reflected * max(minRayStep, -xpos.z),
hitPos, dDepth, dtex, fallback, 0.0);
// TODO temporary measure the lack of mipmaping for RTT albedo
// Implement it in proper way
outColor = mix(fallback, outColor, specval);
Spec = vec4(outColor.rgb, 1.0);
#endif