126 lines
3.5 KiB
GLSL
126 lines
3.5 KiB
GLSL
#version 330 core
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uniform mat4 MVP;
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out vec4 FragColor;
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in vec2 texCoord;
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in GS_OUT {
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vec3 tangentLightPos;
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vec3 tangentViewPos;
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vec3 tangentFragPos;
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} from_gs;
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// TODO: make temporary hard coded world/camera pos dynamic
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uniform vec3 CameraPos;
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// Handle multiple textures from the Mesh Object (Might not even be used)
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uniform sampler2D texture_diffuse1;
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uniform sampler2D texture_diffuse2;
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uniform sampler2D texture_rma1;
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uniform sampler2D texture_normal1;
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// PBR functions from learnOpenGL.com
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const float PI = 3.14159265359;
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vec3 fresnelSchlick(float cosTheta, vec3 F0)
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{
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return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
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}
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float DistributionGGX(vec3 N, vec3 H, float roughness)
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{
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float a = roughness*roughness;
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float a2 = a*a;
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float NdotH = max(dot(N, H), 0.0);
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float NdotH2 = NdotH*NdotH;
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float num = a2;
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float denom = (NdotH2 * (a2 - 1.0) + 1.0);
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denom = PI * denom * denom;
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return num / denom;
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}
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float GeometrySchlickGGX(float NdotV, float roughness)
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{
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float r = (roughness + 1.0);
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float k = (r*r) / 8.0;
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float num = NdotV;
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float denom = NdotV * (1.0 - k) + k;
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return num / denom;
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}
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float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
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{
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float NdotV = max(dot(N, V), 0.0);
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float NdotL = max(dot(N, L), 0.0);
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float ggx2 = GeometrySchlickGGX(NdotV, roughness);
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float ggx1 = GeometrySchlickGGX(NdotL, roughness);
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return ggx1 * ggx2;
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}
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vec3 PBR(vec3 albedo, float roughness, float metallic, float ao)
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{
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vec3 lightPosition = from_gs.tangentLightPos;
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vec3 lightColor = vec3(13.47, 11.31, 10.79);
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vec3 camPos = from_gs.tangentViewPos;
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vec3 fragPos = from_gs.tangentFragPos;
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// Thanks to us calculating the tangent space to the triangle and using
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// these values instead of normal space we can just use the plain corrected
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// UV values here.
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vec3 N = normalize((texture(texture_normal1, texCoord).xyz * 2.0 - 1.0)/2);
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vec3 V = normalize(camPos - fragPos);
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vec3 F0 = vec3(0.04);
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F0 = mix(F0, albedo, metallic);
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// reflectance equation
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vec3 Lo = vec3(0.0);
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// calculate per-light radiance
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vec3 L = normalize(lightPosition - fragPos);
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vec3 H = normalize(V + L);
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float distance = length(lightPosition - fragPos);
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float attenuation = 1.0 / (distance * distance);
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vec3 radiance = lightColor * attenuation;
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// cook-torrance brdf
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float NDF = DistributionGGX(N, H, roughness);
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float G = GeometrySmith(N, V, L, roughness);
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vec3 F = fresnelSchlick(max(dot(H, V), 0.0), F0);
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vec3 kS = F;
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vec3 kD = vec3(1.0) - kS;
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kD *= 1.0 - metallic;
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vec3 numerator = NDF * G * F;
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float denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0) + 0.0001;
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vec3 specular = numerator / denominator;
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// add to outgoing radiance Lo
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float NdotL = max(dot(N, L), 0.0);
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Lo += (kD * albedo / PI + specular) * radiance * NdotL;
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vec3 ambient = vec3(0.03) * albedo * ao;
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vec3 color = ambient + Lo;
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color = color / (color + vec3(1.0));
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return pow(color, vec3(1.0/2.2));
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}
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void main()
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{
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vec3 albedo;
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albedo.r = pow(texture(texture_diffuse1, texCoord).r, 2.2);
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albedo.g = pow(texture(texture_diffuse1, texCoord).g, 2.2);
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albedo.b = pow(texture(texture_diffuse1, texCoord).b, 2.2);
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float roughness = texture(texture_rma1, texCoord).r;
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float metallic = texture(texture_rma1, texCoord).g;
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float ao = texture(texture_rma1, texCoord).b;
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FragColor = vec4(PBR(albedo, roughness, metallic, ao), 1.0);
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}
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