vkdoom_m/wadsrc/static/shaders/lightmap/trace_light.glsl

76 lines
2.3 KiB
GLSL

vec2 getVogelDiskSample(int sampleIndex, int sampleCount, float phi);
vec3 TraceLight(vec3 origin, vec3 normal, LightInfo light, int surfaceIndex)
{
const float minDistance = 0.01;
vec3 incoming = vec3(0.0);
float dist = distance(light.RelativeOrigin, origin);
if (dist > minDistance && dist < light.Radius)
{
vec3 dir = normalize(light.RelativeOrigin - origin);
float distAttenuation = max(1.0 - (dist / light.Radius), 0.0);
float angleAttenuation = 1.0f;
if (surfaceIndex >= 0)
{
angleAttenuation = max(dot(normal, dir), 0.0);
}
float spotAttenuation = 1.0;
if (light.OuterAngleCos > -1.0)
{
float cosDir = dot(dir, light.SpotDir);
spotAttenuation = smoothstep(light.OuterAngleCos, light.InnerAngleCos, cosDir);
spotAttenuation = max(spotAttenuation, 0.0);
}
float attenuation = distAttenuation * angleAttenuation * spotAttenuation;
if (attenuation > 0.0)
{
#if defined(USE_SOFTSHADOWS)
vec3 v = (abs(dir.x) > abs(dir.y)) ? vec3(0.0, 1.0, 0.0) : vec3(1.0, 0.0, 0.0);
vec3 xdir = normalize(cross(dir, v));
vec3 ydir = cross(dir, xdir);
float lightsize = 10;
int step_count = 10;
for (int i = 0; i < step_count; i++)
{
vec2 gridoffset = getVogelDiskSample(i, step_count, gl_FragCoord.x + gl_FragCoord.y * 13.37) * lightsize;
vec3 pos = light.Origin + xdir * gridoffset.x + ydir * gridoffset.y;
rayColor = vec4(light.Color.rgb, 1.0);
if (TracePoint(origin, pos, minDistance, normalize(pos - origin), distance(origin, pos)))
{
incoming.rgb += (rayColor.rgb * rayColor.w) * (attenuation * light.Intensity) / float(step_count);
}
}
#else
rayColor = vec4(light.Color.rgb, 1.0);
if(TracePoint(origin, light.Origin, minDistance, dir, dist))
{
incoming.rgb += (rayColor.rgb * rayColor.w) * (attenuation * light.Intensity);
}
#endif
}
}
return incoming;
}
vec2 getVogelDiskSample(int sampleIndex, int sampleCount, float phi)
{
const float goldenAngle = radians(180.0) * (3.0 - sqrt(5.0));
float sampleIndexF = float(sampleIndex);
float sampleCountF = float(sampleCount);
float r = sqrt((sampleIndexF + 0.5) / sampleCountF); // Assuming index and count are positive
float theta = sampleIndexF * goldenAngle + phi;
float sine = sin(theta);
float cosine = cos(theta);
return vec2(cosine, sine) * r;
}