oss/luanti
oss/luanti
1
0
Fork 0
mirror of https://github.com/luanti-org/luanti.git synced 2025-09-15 18:57:08 +00:00
Code Wiki Activity

Implement shadow offsets for the new SM distortion function (#12191)

Browse source 
* Move shadow position calculation to vertex shaders
* Animate entire scene before rendering shadows to prevent lagging of shadows
* Remove unnecessary use of PolygonOffsetFactor
* Apply normal offset to both nodes and objects
* Rename getPerspectiveFactor -> applyPerspectiveDistortion
* Remove perspective distortion from fragment shaders
This commit is contained in:
x2048 2022-04-14 22:49:30 +02:00 • committed by GitHub
parent 9aabd911eb
commit a5d29fa1d4
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
9 changed files with 184 additions and 122 deletions
Download patch file Download diff file Expand all files Collapse all files

70
client/shaders/object_shader/opengl_vertex.glsl
View file

@ -24,10 +24,12 @@ centroid varying vec2 varTexCoord;
uniform float f_shadowfar;
uniform float f_shadow_strength;
uniform float f_timeofday;
uniform vec4 CameraPos;
varying float cosLight;
varying float normalOffsetScale;
varying float adj_shadow_strength;
varying float f_normal_length;
varying vec3 shadow_position;
#endif
varying vec3 eyeVec;
@ -39,8 +41,36 @@ const float e = 2.718281828459;
const float BS = 10.0;
uniform float xyPerspectiveBias0;
uniform float xyPerspectiveBias1;
uniform float zPerspectiveBias;
#ifdef ENABLE_DYNAMIC_SHADOWS
vec4 getRelativePosition(in vec4 position)
{
vec2 l = position.xy - CameraPos.xy;
vec2 s = l / abs(l);
s = (1.0 - s * CameraPos.xy);
l /= s;
return vec4(l, s);
}
float getPerspectiveFactor(in vec4 relativePosition)
{
float pDistance = length(relativePosition.xy);
float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
return pFactor;
}
vec4 applyPerspectiveDistortion(in vec4 position)
{
vec4 l = getRelativePosition(position);
float pFactor = getPerspectiveFactor(l);
l.xy /= pFactor;
position.xy = l.xy * l.zw + CameraPos.xy;
position.z *= zPerspectiveBias;
return position;
}
// custom smoothstep implementation because it's not defined in glsl1.2
// https://docs.gl/sl4/smoothstep
float mtsmoothstep(in float edge0, in float edge1, in float x)
@ -107,20 +137,31 @@ void main(void)
#ifdef ENABLE_DYNAMIC_SHADOWS
if (f_shadow_strength > 0.0) {
vec3 nNormal = normalize(vNormal);
cosLight = dot(nNormal, -v_LightDirection);
f_normal_length = length(vNormal);
// Calculate normal offset scale based on the texel size adjusted for
// curvature of the SM texture. This code must be change together with
// getPerspectiveFactor or any light-space transformation.
vec3 eyeToVertex = worldPosition - eyePosition + cameraOffset;
// Distance from the vertex to the player
float distanceToPlayer = length(eyeToVertex - v_LightDirection * dot(eyeToVertex, v_LightDirection)) / f_shadowfar;
// perspective factor estimation according to the
float perspectiveFactor = distanceToPlayer * xyPerspectiveBias0 + xyPerspectiveBias1;
float texelSize = f_shadowfar * perspectiveFactor * perspectiveFactor /
(f_textureresolution * xyPerspectiveBias1 - perspectiveFactor * xyPerspectiveBias0);
float slopeScale = clamp(pow(1.0 - cosLight*cosLight, 0.5), 0.0, 1.0);
normalOffsetScale = texelSize * slopeScale;
/* normalOffsetScale is in world coordinates (1/10th of a meter)
z_bias is in light space coordinates */
float normalOffsetScale, z_bias;
float pFactor = getPerspectiveFactor(getRelativePosition(m_ShadowViewProj * mWorld * inVertexPosition));
if (f_normal_length > 0.0) {
nNormal = normalize(vNormal);
cosLight = dot(nNormal, -v_LightDirection);
float sinLight = pow(1 - pow(cosLight, 2.0), 0.5);
normalOffsetScale = 0.1 * pFactor * pFactor * sinLight * min(f_shadowfar, 500.0) /
xyPerspectiveBias1 / f_textureresolution;
z_bias = 1e3 * sinLight / cosLight * (0.5 + f_textureresolution / 1024.0);
}
else {
nNormal = vec3(0.0);
cosLight = clamp(dot(v_LightDirection, normalize(vec3(v_LightDirection.x, 0.0, v_LightDirection.z))), 1e-2, 1.0);
float sinLight = pow(1 - pow(cosLight, 2.0), 0.5);
normalOffsetScale = 0.0;
z_bias = 3.6e3 * sinLight / cosLight;
}
z_bias *= pFactor * pFactor / f_textureresolution / f_shadowfar;
shadow_position = applyPerspectiveDistortion(m_ShadowViewProj * mWorld * (inVertexPosition + vec4(normalOffsetScale * nNormal, 0.0))).xyz;
shadow_position.z -= z_bias;
if (f_timeofday < 0.2) {
adj_shadow_strength = f_shadow_strength * 0.5 *
@ -133,7 +174,6 @@ void main(void)
mtsmoothstep(0.20, 0.25, f_timeofday) *
(1.0 - mtsmoothstep(0.7, 0.8, f_timeofday));
}
f_normal_length = length(vNormal);
}
#endif
}