asteroidgen/shader/standard.fragment.glsl

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2017-10-29 04:16:22 +00:00
#version 330 core
// Interpolated values from the vertex shaders
in vec2 UV;
in vec3 Position_worldspace;
in vec3 Normal_cameraspace;
in vec3 EyeDirection_cameraspace;
in vec3 LightDirection_cameraspace;
// Ouput data
out vec3 color;
// Values that stay constant for the whole mesh.
uniform sampler2D tAlbedo;
uniform mat4 MV;
uniform vec3 LightPosition_worldspace;
void main(){
// Light emission properties
// You probably want to put them as uniforms
vec3 LightColor = vec3(1,1,1);
float LightPower = 400.0f;
// Material properties
vec3 MaterialDiffuseColor = texture( tAlbedo, UV ).rgb;
vec3 MaterialAmbientColor = vec3(0.1,0.1,0.1) * MaterialDiffuseColor;
vec3 MaterialSpecularColor = vec3(0.03,0.03,0.03);
// Distance to the light
float distance = length( LightPosition_worldspace - Position_worldspace );
// Normal of the computed fragment, in camera space
vec3 n = normalize( Normal_cameraspace );
// Direction of the light (from the fragment to the light)
vec3 l = normalize( LightDirection_cameraspace );
// Cosine of the angle between the normal and the light direction,
// clamped above 0
// - light is at the vertical of the triangle -> 1
// - light is perpendicular to the triangle -> 0
// - light is behind the triangle -> 0
float cosTheta = clamp( dot( n,l ), 0,1 );
// Eye vector (towards the camera)
vec3 E = normalize(EyeDirection_cameraspace);
// Direction in which the triangle reflects the light
vec3 R = reflect(-l,n);
// Cosine of the angle between the Eye vector and the Reflect vector,
// clamped to 0
// - Looking into the reflection -> 1
// - Looking elsewhere -> < 1
float cosAlpha = clamp( dot( E,R ), 0,1 );
color =
// Ambient : simulates indirect lighting
MaterialAmbientColor +
// Diffuse : "color" of the object
MaterialDiffuseColor * LightColor * LightPower * cosTheta / (distance*distance)
+
// Specular : reflective highlight, like a mirror
MaterialSpecularColor * LightColor * LightPower * pow(cosAlpha,5) / (distance*distance);
}