Add shader fragment for basic lighting

Simple diffuse lighting for point and direction lights for now.

Not used from anywhere yet.

Change-Id: I20f7ddad9ad5c78f120d47efe8599a2dbe015e65
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/src/render/shaders/light.inc.frag b/src/render/shaders/light.inc.frag
new file mode 100644
index 000000000..4db64100d
--- /dev/null
+++ b/src/render/shaders/light.inc.frag
@@ -0,0 +1,33 @@
+const int MAX_LIGHTS = 8;
+struct Light {
+    vec3 position;
+    vec3 color;
+    float intensity;
+    vec3 direction;
+    vec3 attenuation;
+//    float cutOffAngle;
+};
+uniform Light lights[MAX_LIGHTS];
+uniform int lightCount;
+
+vec3 lightColor(vec3 vpos, vec3 vnormal)
+{
+    vec3 n = normalize( vnormal );
+    vec3 c = vec3( 0.0 );
+    int i;
+    for (i = 0; i < lightCount; ++i) {
+        vec3 lightDir = lights[i].direction;
+        float att = 1.0;
+        if (length( lightDir ) == 0.0) {
+            lightDir = lights[i].position - vpos;
+            if (length( lights[i].attenuation ) != 0.0) {
+                float dist = length(lightDir);
+                att = 1.0 / (lights[i].attenuation.x + lights[i].attenuation.y * dist + lights[i].attenuation.z * dist * dist);
+            }
+        }
+        vec3 s = normalize( lightDir );
+        float diffuse = max( dot( s, n ), 0.0 );
+        c += att * (diffuse * lights[i].color) * lights[i].intensity;
+    }
+    return c;
+}