1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/gles2/shaders/ssao_blur.glsl b/drivers/gles2/shaders/ssao_blur.glsl
new file mode 100644
index 0000000000..f065cd74eb
--- /dev/null
+++ b/drivers/gles2/shaders/ssao_blur.glsl
@@ -0,0 +1,116 @@
+/* clang-format off */
+[vertex]
+
+layout(location = 0) in highp vec4 vertex_attrib;
+/* clang-format on */
+
+void main() {
+	gl_Position = vertex_attrib;
+	gl_Position.z = 1.0;
+}
+
+/* clang-format off */
+[fragment]
+
+uniform sampler2D source_ssao; //texunit:0
+/* clang-format on */
+uniform sampler2D source_depth; //texunit:1
+uniform sampler2D source_normal; //texunit:3
+
+layout(location = 0) out float visibility;
+
+//////////////////////////////////////////////////////////////////////////////////////////////
+// Tunable Parameters:
+
+/** Increase to make depth edges crisper. Decrease to reduce flicker. */
+uniform float edge_sharpness;
+
+/** Step in 2-pixel intervals since we already blurred against neighbors in the
+	first AO pass.  This constant can be increased while R decreases to improve
+	performance at the expense of some dithering artifacts.
+
+	Morgan found that a scale of 3 left a 1-pixel checkerboard grid that was
+	unobjectionable after shading was applied but eliminated most temporal incoherence
+	from using small numbers of sample taps.
+	*/
+
+uniform int filter_scale;
+
+/** Filter radius in pixels. This will be multiplied by SCALE. */
+#define R (4)
+
+//////////////////////////////////////////////////////////////////////////////////////////////
+
+// Gaussian coefficients
+const float gaussian[R + 1] =
+		//float[](0.356642, 0.239400, 0.072410, 0.009869);
+		//float[](0.398943, 0.241971, 0.053991, 0.004432, 0.000134);  // stddev = 1.0
+		float[](0.153170, 0.144893, 0.122649, 0.092902, 0.062970); // stddev = 2.0
+//float[](0.111220, 0.107798, 0.098151, 0.083953, 0.067458, 0.050920, 0.036108); // stddev = 3.0
+
+/** (1, 0) or (0, 1)*/
+uniform ivec2 axis;
+
+uniform float camera_z_far;
+uniform float camera_z_near;
+
+uniform ivec2 screen_size;
+
+void main() {
+	ivec2 ssC = ivec2(gl_FragCoord.xy);
+
+	float depth = texelFetch(source_depth, ssC, 0).r;
+	//vec3 normal = texelFetch(source_normal,ssC,0).rgb * 2.0 - 1.0;
+
+	depth = depth * 2.0 - 1.0;
+	depth = 2.0 * camera_z_near * camera_z_far / (camera_z_far + camera_z_near - depth * (camera_z_far - camera_z_near));
+
+	float depth_divide = 1.0 / camera_z_far;
+
+	//depth *= depth_divide;
+
+	/*
+	if (depth > camera_z_far * 0.999) {
+		discard; //skybox
+	}
+	*/
+
+	float sum = texelFetch(source_ssao, ssC, 0).r;
+
+	// Base weight for depth falloff.  Increase this for more blurriness,
+	// decrease it for better edge discrimination
+	float BASE = gaussian[0];
+	float totalWeight = BASE;
+	sum *= totalWeight;
+
+	ivec2 clamp_limit = screen_size - ivec2(1);
+
+	for (int r = -R; r <= R; ++r) {
+		// We already handled the zero case above.  This loop should be unrolled and the static branch optimized out,
+		// so the IF statement has no runtime cost
+		if (r != 0) {
+			ivec2 ppos = ssC + axis * (r * filter_scale);
+			float value = texelFetch(source_ssao, clamp(ppos, ivec2(0), clamp_limit), 0).r;
+			ivec2 rpos = clamp(ppos, ivec2(0), clamp_limit);
+			float temp_depth = texelFetch(source_depth, rpos, 0).r;
+			//vec3 temp_normal = texelFetch(source_normal, rpos, 0).rgb * 2.0 - 1.0;
+
+			temp_depth = temp_depth * 2.0 - 1.0;
+			temp_depth = 2.0 * camera_z_near * camera_z_far / (camera_z_far + camera_z_near - temp_depth * (camera_z_far - camera_z_near));
+			//			temp_depth *= depth_divide;
+
+			// spatial domain: offset gaussian tap
+			float weight = 0.3 + gaussian[abs(r)];
+			//weight *= max(0.0,dot(temp_normal,normal));
+
+			// range domain (the "bilateral" weight). As depth difference increases, decrease weight.
+			weight *= max(0.0, 1.0 - edge_sharpness * abs(temp_depth - depth));
+
+			sum += value * weight;
+			totalWeight += weight;
+		}
+	}
+
+	const float epsilon = 0.0001;
+	visibility = sum / (totalWeight + epsilon);
+}