REVIEWED: example: shaders_deferred_render -WIP-

Not working but shader compiles and example runs... not sure if deferred rendering could be supported in OpenGL ES 2.0.

examples/shaders/resources/shaders/glsl100/deferred_shading.fs

@@ -0,0 +1,59 @@
+#version 100
+
+precision mediump float;
+
+// Input vertex attributes (from vertex shader)
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D gPosition;
+uniform sampler2D gNormal;
+uniform sampler2D gAlbedoSpec;
+
+struct Light {
+    int enabled;
+    int type; // Unused in this demo.
+    vec3 position;
+    vec3 target; // Unused in this demo.
+    vec4 color;
+};
+
+const int NR_LIGHTS = 4;
+uniform Light lights[NR_LIGHTS];
+uniform vec3 viewPosition;
+
+const float QUADRATIC = 0.032;
+const float LINEAR = 0.09;
+
+void main()
+{
+    vec3 fragPosition = texture2D(gPosition, fragTexCoord).rgb;
+    vec3 normal = texture2D(gNormal, fragTexCoord).rgb;
+    vec3 albedo = texture2D(gAlbedoSpec, fragTexCoord).rgb;
+    float specular = texture2D(gAlbedoSpec, fragTexCoord).a;
+
+    vec3 ambient = albedo*vec3(0.1);
+    vec3 viewDirection = normalize(viewPosition - fragPosition);
+
+    for (int i = 0; i < NR_LIGHTS; ++i)
+    {
+        if(lights[i].enabled == 0) continue;
+        vec3 lightDirection = lights[i].position - fragPosition;
+        vec3 diffuse = max(dot(normal, lightDirection), 0.0)*albedo*lights[i].color.xyz;
+
+        vec3 halfwayDirection = normalize(lightDirection + viewDirection);
+        float spec = pow(max(dot(normal, halfwayDirection), 0.0), 32.0);
+        vec3 specular = specular*spec*lights[i].color.xyz;
+
+        // Attenuation
+        float distance = length(lights[i].position - fragPosition);
+        float attenuation = 1.0/(1.0 + LINEAR * distance + QUADRATIC*distance*distance);
+        diffuse *= attenuation;
+        specular *= attenuation;
+        ambient += diffuse + specular;
+    }
+
+    gl_FragColor = vec4(ambient, 1.0);
+}
+