95 lines
2.6 KiB
GLSL
95 lines
2.6 KiB
GLSL
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#version 330
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// Color input from Vertex shader
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in vec3 vNormal;
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in vec3 vPosition;
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// Final fragment fColor
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out vec4 fColor;
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// Light object and camera position vectors
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uniform vec3 uCameraPosition;
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struct Light {
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vec3 position;
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// Light colors RGB value
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vec3 ambient;
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vec3 diffuse;
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vec3 specular;
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};
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uniform Light uLight;
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struct Material {
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// Strength ranges 0.0f - 1.0f
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float ambientStrength;
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float diffuseStrength;
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float specularStrength;
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// 32, 64, 128, 256
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float shine;
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// Material color values
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vec3 ambient;
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vec3 diffuse;
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vec3 specular;
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};
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uniform Material uMaterial;
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struct Result {
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vec3 ambient;
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vec3 diffuse;
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vec3 specular;
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vec3 sum;
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};
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void SumResult(inout Result result)
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{
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result.sum = result.ambient + result.diffuse + result.specular;
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}
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void main()
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{
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// A struct to store lighting results as we finish calculating them
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// Valuse stored here will be applied to the final output of our shader
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Result result;
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// Ambient lighting
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result.ambient = (uLight.ambient * uMaterial.ambient) * uMaterial.ambientStrength;
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//
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// Diffuse lighting
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// Normalize the provided normal vector
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// + Creates a vector with length of 1 in the same direction as vNormal
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vec3 norm = normalize(vNormal);
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// Get a vector from this frag to the lightSoruce
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vec3 lightDir = normalize(uLight.position - vPosition);
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// As the normal vector approaches an angle looking at lightDir vector
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// + If this is negative, the frag is on a surface opposite of the lightSource
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float diff = max(dot(norm, lightDir), 0.0f);
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result.diffuse = (uLight.diffuse * diff * uMaterial.diffuse) * uMaterial.diffuseStrength;
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//
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// Specular lighting
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// Get a vector from the camera to the fragment as our viewDir
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vec3 viewDir = normalize(uCameraPosition - vPosition);
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// Since lightDir is already a vector from this frag to the light source
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// reflectionDir is the opposite; A vector from the light to the frag
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vec3 reflectDir = reflect(-lightDir, norm);
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// Use dot product to check if viewDir and reflectDir angles are intersecting
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// -1.0f if they are opposite; 1.0 if they are looking at each other directly
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// + If this is negative, the lightSource is behind the player; Ignore it
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float angleAlpha = max(dot(viewDir, reflectDir), 0.0f);
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// As the angleAlpha approaches 1, raise to the power of uMaterial.shine
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float spec = pow(angleAlpha, uMaterial.shine);
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// Apply specular result to the
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result.specular = (uLight.specular * uMaterial.specular * spec) * uMaterial.specularStrength;
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//
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// Final calculation
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SumResult(result);
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// Final output
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fColor = vec4(result.sum, 1.0f); // Reapply alpha for opacity
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}
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