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# need help with shadow mapping

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### #1Yours3!f  Members

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:

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

any idea what is wrong?

best regards,

Yours3lf

### #2Yours3!f  Members

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;

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

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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