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79 lines
2.2 KiB
Text
79 lines
2.2 KiB
Text
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// From https://gitorious.org/wikibooks-opengl/modern-tutorials/source/mini-portal/phong-shading.f.glsl
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/**
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* This file is in the public domain.
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* Contributors: Martin Kraus, Sylvain Beucler
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*/
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varying vec4 position; // position of the vertex (and fragment) in world space
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varying vec3 varyingNormalDirection; // surface normal vector in world space
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uniform mat4 m, v, p;
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uniform mat4 v_inv;
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struct lightSource
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{
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vec4 position;
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vec4 diffuse;
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vec4 specular;
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float invLinearAttenuation;
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float spotCutoff, spotExponent;
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vec3 spotDirection;
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};
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lightSource light0 = lightSource(
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vec4(0.0, 3.0, 0.0, 1.0),
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vec4(1.0, 1.0, 1.0, 1.0),
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vec4(1.0, 1.0, 1.0, 1.0),
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2.0,
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180.0, 0.0,
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vec3(0.0, 0.0, 0.0)
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);
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vec4 scene_ambient = vec4(0.2, 0.2, 0.2, 1.0);
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struct material
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{
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vec4 ambient;
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vec4 diffuse;
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vec4 specular;
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float shininess;
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};
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material frontMaterial = material(
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vec4(0.2, 0.2, 0.2, 1.0),
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vec4(1.0, 0.8, 0.8, 1.0),
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vec4(1.0, 1.0, 1.0, 1.0),
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5.0
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);
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void main()
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{
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vec3 normalDirection = normalize(varyingNormalDirection);
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vec3 viewDirection = normalize(vec3(v_inv * vec4(0.0, 0.0, 0.0, 1.0) - position));
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vec3 lightDirection;
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float attenuation;
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// initialize total lighting with ambient lighting
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vec3 totalLighting = vec3(scene_ambient) * vec3(frontMaterial.ambient);
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vec3 positionToLightSource = vec3(light0.position - position);
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float distanceSqr = dot(positionToLightSource, positionToLightSource);
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lightDirection = inversesqrt(distanceSqr) * positionToLightSource;
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attenuation = light0.invLinearAttenuation * inversesqrt(distanceSqr);
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vec3 diffuseReflection = attenuation
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* vec3(light0.diffuse) * vec3(frontMaterial.diffuse)
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* max(0.0, dot(normalDirection, lightDirection));
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vec3 specularReflection;
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if (dot(normalDirection, lightDirection) < 0.0) // light source on the wrong side?
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{
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specularReflection = vec3(0.0, 0.0, 0.0); // no specular reflection
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}
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else // light source on the right side
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{
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specularReflection = attenuation * vec3(light0.specular) * vec3(frontMaterial.specular)
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* pow(max(0.0, dot(reflect(-lightDirection, normalDirection), viewDirection)), frontMaterial.shininess);
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}
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totalLighting = totalLighting + diffuseReflection + specularReflection;
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gl_FragColor = vec4(totalLighting, 1.0);
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}
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