karts/lighting.frag.glsl
2025-02-16 11:28:18 +13:00

52 lines
1.6 KiB
GLSL

#version 460 core
in vec2 vert_texcoord;
in vec4 vert_pos;
out vec4 frag_color;
uniform sampler2D tex;
uniform sampler2D shadowmap;
float ShadowCalculation(vec4 fragPosLightSpace)
{
// perform perspective divide
vec3 projCoords = fragPosLightSpace.xyz / fragPosLightSpace.w;
// transform to [0,1] range
projCoords = projCoords * 0.5 + 0.5;
// get closest depth value from light's perspective (using [0,1] range fragPosLight as coords)
float closestDepth = texture(shadowmap, projCoords.xy).r;
// get depth of current fragment from light's perspective
float currentDepth = projCoords.z;
// calculate bias (based on depth map resolution and slope)
float bias = 0.005;
// check whether current frag pos is in shadow
// float shadow = currentDepth - bias > closestDepth ? 1.0 : 0.0;
// PCF
float shadow = 0.0;
vec2 texelSize = 1.0 / textureSize(shadowmap, 0);
for(int x = -1; x <= 1; ++x)
{
for(int y = -1; y <= 1; ++y)
{
float pcfDepth = texture(shadowmap, projCoords.xy + vec2(x, y) * texelSize).r;
shadow += currentDepth - bias > pcfDepth ? 1.0 : 0.0;
}
}
shadow /= 9.0;
// keep the shadow at 0.0 when outside the far_plane region of the light's frustum.
if(projCoords.z > 1.0)
shadow = 0.0;
return shadow;
}
void main() {
vec3 lightColor = vec3(1.0);
vec3 ambient = 0.5 * lightColor;
frag_color = texture(tex, vert_texcoord);
float shadow = ShadowCalculation(vert_pos);
if(frag_color.a < 0.1) discard;
frag_color = vec4((ambient + (1.0 - shadow)) * frag_color.xyz, frag_color.a);
}