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F0rest
07-15-2015, 01:04 PM
When the light source moves away from the object, it creates unnecessary shadow:
1933ok
1934ok
1935problem

creating shadow:

vec3 computeShadow(vec4 vPositionFromLight, sampler2D shadowSampler, float darkness, float bias)
{
vec3 depth = vPositionFromLight.xyz / vPositionFromLight.w;
vec2 uv = depth.xy;

if((depth.x < 0.0)||(depth.x > 1.0) || (depth.y < 0.0) || (depth.y > 1.0) || (depth.z < 0.0) || (depth.z > 1.0))
{
return vec3(1.0);
}else
{
float texelSize = 1.0/1024.0;
vec3 colour = vec3(0.0);int count = 0;float shadow;
for (int y = -2; y <= 2; ++y)
{
for (int x = -2; x <= 2; ++x)
{
vec2 offset = uv + vec2(float(x) * texelSize, float(y) * texelSize);
if((offset.x >= 0.0) && (offset.x <= 1.0) && (offset.y >= -0.0) && (offset.y <= 0.999))
{
shadow = unpack(texture2D(shadowSampler, offset)) + bias;
if ( depth.z > shadow )
{
colour+=vec3(1.0)*0.8;
}
else
{
colour+=vec3(1.0);
}
count++;
}
}
}
colour /= float(count);
return colour;
}
}
How to correct it?
live example (https://webgl-project-toly19.c9.io/index.html)

GClements
07-15-2015, 11:09 PM
Is the shadow map large enough to cover the visible area?

When you render into the shadow map, are you setting the viewport to cover its full extent?

F0rest
07-15-2015, 11:44 PM
shadowmap viewport=1024 px.


the problem is created in a cycle:

vec3 computeShadow(vec4 vPositionFromLight, sampler2D shadowSampler, float darkness, float bias)
{
vec3 depth = vPositionFromLight.xyz / vPositionFromLight.w;
vec2 uv = depth.xy;
if((depth.x < 0.0)||(depth.x > 1.0) || (depth.y < 0.0) || (depth.y > 1.0) || (depth.z < 0.0) || (depth.z > 1.0))
{
return vec3(1.0);
}else
{
float texelSize = 1.0/1024.0;
vec3 colour = vec3(0.0);int count = 0;float shadow;
vec2 offset = uv ;
if((offset.x >= 0.0) && (offset.x <= 1.0) && (offset.y >= -0.0) && (offset.y <= 0.999))
{
shadow = unpack(texture2D(shadowSampler, offset)) + bias;
if(depth.z>shadow)
{
colour+=vec3(1.0)*0.8;
}
else
{
colour+=vec3(1.0);
}
}
return colour;
}
}-Problems aren't present, but shadows aren't smoothed

Dark Photon
07-17-2015, 07:13 AM
That the artifact is not full intensity shadow is a good clue.

Some ideas to help you nail it down. Apply these cumulatively, not just flip each on and off in isolation:
* You can't robustly clip after the perspective divide (with the perspective frustum for your point light). Clip before.
* Are you clearing the shadow map to 1 before you render the scene into it? If not, do so.
* For testing, disable anistropic filtering.
* For testing, set NEAREST on your MIN and MAG filters (i.e. disable PCF)
* What wrap behavior do you have set on your shadow map. Change it to CLAMP_TO_EDGE.
* Are you casting anything besides the human figure (e.g. the ground plane) into the shadow map? Disable that.
* When the light source gets close to the ground plane, how are you computing the bounds of the shadow frustum. Is the size exploding?
* You're sampling textures with implicit LOD inside conditionals. You shouldn't do that. Read this:
** Derivatives I: Derivatives and Discontinuities (http://hacksoflife.blogspot.com/2011/01/derivatives-i-discontinuities-and.html)
** Derivatives II: Conditional Texture Fetches (http://hacksoflife.blogspot.com/2011/01/derivatives-ii-conditional-texture.html)
* In your second shader, if you change (offset.y <= 0.999) to (offset.y <= 1.0 ), does the problem re-appear?
* Is it possible your math to back-project the eye-space vertices of the ground plane back into light (shadow) space isn't right? Try munging the eye-space depth value to 0, 0.5, or 1?