Specgloss shaders improvements + experimental SSAO (debug only)

shaders/postfx_ssao_blur.frag

@@ -0,0 +1,14 @@
+in vec2 f_coords;
+layout(location = 0) out vec4 out_color;
+
+#texture (ssao_tex, 0, R)
+uniform sampler2D ssao_tex;
+
+void main() {
+    vec2 texel = 1.0 / vec2(textureSize(ssao_tex, 0));
+    float sum = 0.0;
+    for (int x = -2; x < 2; ++x)
+    for (int y = -2; y < 2; ++y)
+        sum += texture(ssao_tex, f_coords + vec2(x, y) * texel).r;
+    out_color = vec4(sum / 16.0);
+}