diff --git a/data/shaders/pbrFragment.glsl b/data/shaders/pbrFragment.glsl new file mode 100644 index 0000000..9984613 --- /dev/null +++ b/data/shaders/pbrFragment.glsl @@ -0,0 +1,117 @@ +#version 330 core +out vec4 FragColor; + +in vec2 ourTexCoord; +in vec3 ourNormCoord; +in vec3 FragPos; +// TODO: make temporary hard coded world/camera pos dynamic +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 = 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_diffuse3; +uniform sampler2D texture_specular1; +uniform sampler2D texture_specular2; + +uniform sampler2D ourTexture; + +// 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; +} + +void main() +{ + albedo = vec3(texture(texture_diffuse1, ourTexCoord)); + // Establish ambient lighting + float ambientStrength = 0.1; + + // Establish a temporary hard coded light position + vec3 lightPosition = vec3(1.0, 1.0, 1.0); + vec3 lightColor = vec3(1.0, 0.9, 1.0); + + // Normal light maths + vec3 N = normalize(ourNormCoord); + vec3 V = normalize(CameraPos - WorldPos); + + vec3 Lo = vec3(0.0f); + //TODO: Loop through this block for the number of lights + 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-Torrence BRDF + vec3 F0 = vec3(0.04); + F0 = mix(F0, albedo, metallic); + vec3 F = fresnelSchlick(max(dot(H, V), 0.0), F0); + + float NDF = DistributionGGX(N, H, roughness); + float G = GeometrySmith(N, V, L, roughness); + + 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; + + //Next bit + vec3 kS = F; + vec3 kD = vec3(1.0) - kS; + + kD *= 1.0 - metallic; + + 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)); + color = pow(color, vec3(1.0/2.2)); + + //FragColor = vec4(color, 1.0); + FragColor = texture(texture_diffuse1, ourTexCoord) * vec4(color, 0.0); +} diff --git a/src/main.cpp b/src/main.cpp index 9c439d2..c45c4d1 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -67,7 +67,7 @@ int main(int argc, char **argv) { SDL_Event input; ShaderLoader shader(ROOT_DIR "data/shaders/vertex.glsl", - ROOT_DIR "data/shaders/fragment.glsl"); + ROOT_DIR "data/shaders/pbrFragment.glsl"); Model backpack(std::string(ROOT_DIR) + std::string("data/models/backpack/backpack.obj"));