game/data/shaders/pbrFragment.glsl
2022-07-29 13:01:01 +01:00

162 lines
4.7 KiB
GLSL

#version 330 core
out vec4 FragColor;
in vec2 texCoord;
in vec3 normCoord;
in vec3 WorldPos;
in GS_OUT {
mat3 TBN;
vec3 tangentLightPos;
vec3 tangentViewPos;
vec3 tangentFragPos;
} from_gs;
in mat3 TBN;
// TODO: make temporary hard coded world/camera pos dynamic
//uniform vec3 WorldPos ;
uniform vec3 CameraPos;
uniform int tick;
//vec3 WorldPos = vec3(0.0f, 0.0f, 0.0f);
//vec3 CameraPos = vec3(0.0f, 0.0f, -1.0f);
//TODO: make these values rely on associated textures.
//vec3 albedo = vec3(0.8f, 0.8f, 0.8f);
//float metallic = sin(tick / 60 * 0.3f);
//float roughness = sin(tick / 60 * 0.3f);
//float ao = sin(tick / 60 * 0.8f);
//float metallic = 0.3f;
//float roughness = 0.3f;
//float ao = 0.8f;
// Handle multiple textures from the Mesh Object (Might not even be used)
uniform sampler2D texture_diffuse1;
uniform sampler2D texture_diffuse2;
uniform sampler2D texture_rma1;
uniform sampler2D texture_normal1;
// PBR functions from learnOpenGL.com
const float PI = 3.14159265359;
vec3 fresnelSchlick(float cosTheta, vec3 F0)
{
return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
}
float DistributionGGX(vec3 N, vec3 H, float roughness)
{
float a = roughness*roughness;
float a2 = a*a;
float NdotH = max(dot(N, H), 0.0);
float NdotH2 = NdotH*NdotH;
float num = a2;
float denom = (NdotH2 * (a2 - 1.0) + 1.0);
denom = PI * denom * denom;
return num / denom;
}
float GeometrySchlickGGX(float NdotV, float roughness)
{
float r = (roughness + 1.0);
float k = (r*r) / 8.0;
float num = NdotV;
float denom = NdotV * (1.0 - k) + k;
return num / denom;
}
float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
{
float NdotV = max(dot(N, V), 0.0);
float NdotL = max(dot(N, L), 0.0);
float ggx2 = GeometrySchlickGGX(NdotV, roughness);
float ggx1 = GeometrySchlickGGX(NdotL, roughness);
return ggx1 * ggx2;
}
vec3 normalMapNormal(){
// load and invert normal
vec3 normal = normalize(texture(texture_normal1, texCoord).rgb * 2.0 - 1.0);
vec3 lightDir = normalize(from_gs.tangentLightPos - from_gs.tangentFragPos);
vec3 viewDir = normalize(from_gs.tangentViewPos - from_gs.tangentFragPos);
vec3 reflectDir = reflect(-lightDir, normal);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(normal, halfwayDir), 0.0),32.0);
vec3 normMapSpecular = vec3(0.2) * spec;
return normMapSpecular;
}
vec3 PBR(vec3 albedo, float roughness, float metallic, float ao)
{
// Establish a temporary hard coded light position
vec3 lightPosition = vec3(1, 1, 2);
//vec3 lightPosition = vec3( (sin(tick / 1000.0)*2), 1 + sin(tick / 600.0)*2, 2.0);
//vec3 lightColor = vec3(1.0, 1.0, 1.0) - sin(tick / 90);
vec3 lightColor = vec3(13.47, 11.31, 10.79);
vec3 N = normalize(normCoord);
vec3 V = normalize(CameraPos - WorldPos);
//N = (N + normalMapNormal()) / 2;
//N = normalMapNormal(); //For seeing if normal map tracks with light.
vec3 F0 = vec3(0.04);
F0 = mix(F0, albedo, metallic);
// reflectance equation
vec3 Lo = vec3(0.0);
// calculate per-light radiance
vec3 L = normalize(lightPosition - WorldPos);
vec3 H = normalize(V + L);
float distance = length(lightPosition - WorldPos);
float attenuation = 1.0 / (distance * distance);
vec3 radiance = lightColor * attenuation;
// cook-torrance brdf
float NDF = DistributionGGX(N, H, roughness);
float G = GeometrySmith(N, V, L, roughness);
vec3 F = fresnelSchlick(max(dot(H, V), 0.0), F0);
vec3 kS = F;
vec3 kD = vec3(1.0) - kS;
kD *= 1.0 - metallic;
vec3 numerator = NDF * G * F;
float denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0) + 0.0001;
vec3 specular = numerator / denominator;
// add to outgoing radiance Lo
float NdotL = max(dot(N, L), 0.0);
Lo += (kD * albedo / PI + specular) * radiance * NdotL;
vec3 ambient = vec3(0.03) * albedo * ao;
vec3 color = ambient + Lo;
color = color / (color + vec3(1.0));
return pow(color, vec3(1.0/2.2));
}
void main()
{
vec3 albedo;
albedo.r = pow(texture(texture_diffuse1, texCoord).r, 2.2);
albedo.g = pow(texture(texture_diffuse1, texCoord).g, 2.2);
albedo.b = pow(texture(texture_diffuse1, texCoord).b, 2.2);
float roughness = texture(texture_rma1, texCoord).r;
float metallic = texture(texture_rma1, texCoord).g;
float ao = texture(texture_rma1, texCoord).b;
//FragColor = vec4(PBR(albedo, roughness, metallic, ao), 1.0);
FragColor = vec4(PBR(albedo, roughness, metallic, ao) + normalMapNormal(), 1.0);
//FragColor = vec4(normalMapNormal(), 1.0);
//FragColor = vec4(vec3(0.5) + normalMapNormal(), 1.0);
//FragColor = vec4(vec3(0.5), 1.0);
}