Specgloss shaders improvements + experimental SSAO (debug only)

shaders/postfx_ssao_apply.frag

@@ -0,0 +1,22 @@
+in vec2 f_coords;
+layout(location = 0) out vec4 out_color;
+
+#texture (color_tex, 0, RGB)
+uniform sampler2D color_tex;
+
+#texture (ssao_tex, 1, R)
+uniform sampler2D ssao_tex;
+
+const float SSAO_STRENGTH = 0.8;
+const float SSAO_MIN      = 0.3;   // floor on darkening so shadows don't go pitch black
+
+void main() {
+    vec3  c   = texture(color_tex, f_coords).rgb;
+    float occ = texture(ssao_tex, f_coords).r;
+
+    // remap occlusion with strength and a minimum floor
+    occ = pow(clamp(occ, 0.0, 1.0), SSAO_STRENGTH);
+    occ = mix(SSAO_MIN, 1.0, occ);
+
+    out_color = vec4(c * occ, 1.0);
+}