Update/merge examples back into main repo (#192)

Examples/resources/shaders/glsl120/fog.fs

@@ -0,0 +1,92 @@
+#version 120
+
+// Input vertex attributes (from vertex shader)
+varying vec3 fragPosition;
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+varying vec3 fragNormal;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// NOTE: Add here your custom variables
+
+#define     MAX_LIGHTS              4
+#define     LIGHT_DIRECTIONAL       0
+#define     LIGHT_POINT             1
+
+struct MaterialProperty {
+    vec3 color;
+    int useSampler;
+    sampler2D sampler;
+};
+
+struct Light {
+    int enabled;
+    int type;
+    vec3 position;
+    vec3 target;
+    vec4 color;
+};
+
+// Input lighting values
+uniform Light lights[MAX_LIGHTS];
+uniform vec4 ambient;
+uniform vec3 viewPos;
+uniform float fogDensity;
+
+void main()
+{
+    // Texel color fetching from texture sampler
+    vec4 texelColor = texture2D(texture0, fragTexCoord);
+    vec3 lightDot = vec3(0.0);
+    vec3 normal = normalize(fragNormal);
+    vec3 viewD = normalize(viewPos - fragPosition);
+    vec3 specular = vec3(0.0);
+
+    // NOTE: Implement here your fragment shader code
+
+    for (int i = 0; i < MAX_LIGHTS; i++)
+    {
+        if (lights[i].enabled == 1)
+        {
+            vec3 light = vec3(0.0);
+
+            if (lights[i].type == LIGHT_DIRECTIONAL) light = -normalize(lights[i].target - lights[i].position);
+            if (lights[i].type == LIGHT_POINT) light = normalize(lights[i].position - fragPosition);
+
+            float NdotL = max(dot(normal, light), 0.0);
+            lightDot += lights[i].color.rgb*NdotL;
+
+            float specCo = 0.0;
+            if (NdotL > 0.0) specCo = pow(max(0.0, dot(viewD, reflect(-(light), normal))), 16.0); // Shine: 16.0
+            specular += specCo;
+        }
+    }
+
+    vec4 finalColor = (texelColor*((colDiffuse + vec4(specular,1))*vec4(lightDot, 1.0)));
+    finalColor += texelColor*(ambient/10.0);
+
+    // Gamma correction
+    finalColor = pow(finalColor, vec4(1.0/2.2));
+
+    // Fog calculation
+    float dist = length(viewPos - fragPosition);
+
+    // these could be parameters...
+    const vec4 fogColor = vec4(0.5, 0.5, 0.5, 1.0);
+    //const float fogDensity = 0.16;
+
+    // Exponential fog
+    float fogFactor = 1.0/exp((dist*fogDensity)*(dist*fogDensity));
+
+    // Linear fog (less nice)
+    //const float fogStart = 2.0;
+    //const float fogEnd = 10.0;
+    //float fogFactor = (fogEnd - dist)/(fogEnd - fogStart);
+
+    fogFactor = clamp(fogFactor, 0.0, 1.0);
+
+    gl_FragColor = mix(fogColor, finalColor, fogFactor);
+}