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need help with shadow mapping


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#1 Yours3!f   Members   -  Reputation: 1299

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Posted 05 January 2013 - 05:19 PM

Hi,

 

I'm trying to do shadow mapping. Unfortunately, I can't get the shadow to be displayed. I checked with gDEbugger, the shadow map is correct, but I'm not sure if I calculate the shadows properly.

 

here's the project:

https://docs.google.com/open?id=0BzHTUfIQ-XD8WjNldzEyZXhjTU0

 

I also attached an image of the shadow map depth texture.

 

any idea what is wrong?

 

best regards,

Yours3lf

Attached Thumbnails

  • depth.png


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#2 Yours3!f   Members   -  Reputation: 1299

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Posted 06 January 2013 - 10:17 AM

ok, I think I got it.

I just needed to transform the clip space shadow coords to ndc, then to tex coords.

 

#version 330 core

layout(binding=0) uniform sampler2D texture0;
uniform vec3 light_pos, spot_dir;
uniform float radius, spot_exponent, spot_cos_cutoff;

in vec3 normal;
in vec3 vs_pos;
in vec4 ls_pos;

out vec4 color;

void main()
{
	vec3 n = normal;
	vec3 l = light_pos - vs_pos;
	float d = length(l);
	l = normalize(l);
	float att = (1 + d / radius);
	att = 1.0 / ( att * att );
	float n_dot_l = dot(n, l);
	
	if(n_dot_l > 0)
	{		
		vec3 h = 0.5 * (l + normalize(-vs_pos));
		float n_dot_h = max(dot(n, h), 0);
		
		float spot_effect = dot(-l, spot_dir);
		if(spot_effect > spot_cos_cutoff)
		{
			spot_effect = pow( spot_effect, spot_exponent );
			att = spot_effect / att + 1;
		}
		att -= 1;
		
		vec4 shadow_coord = ls_pos / ls_pos.w; //convert to ndc
		shadow_coord = shadow_coord * 0.5 + 0.5; //scale, bias to [0...1]
		
		float depth = texture( texture0, shadow_coord.xy ).x;
		
		att *= depth < shadow_coord.z - 0.005 ? 0 : 1; //add bias to get rid of shadow acne
		
		color += vec4(vec3((0.1 + n_dot_l + pow(n_dot_h, 20)) * att), 1);
	}
	
	color.xyz = pow(color.xyz, vec3(1/2.2));
    //color = vec4(1);
}





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