1 files changed, 138 insertions, 0 deletions
diff --git a/indra/newview/app_settings/shaders/class3/deferred/screenSpaceReflUtil.glsl b/indra/newview/app_settings/shaders/class3/deferred/screenSpaceReflUtil.glsl
new file mode 100644
index 0000000000..5eefd99d00
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+++ b/indra/newview/app_settings/shaders/class3/deferred/screenSpaceReflUtil.glsl
@@ -0,0 +1,138 @@
+/**
+ * @file class3/deferred/screenSpaceReflUtil.glsl
+ *
+ * $LicenseInfo:firstyear=2007&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2007, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+uniform sampler2D depthMap;
+uniform sampler2D normalMap;
+uniform sampler2D sceneMap;
+uniform vec2 screen_res;
+uniform mat4 projection_matrix;
+uniform float zNear;
+uniform float zFar;
+uniform mat4 inv_proj;
+
+vec4 getPositionWithDepth(vec2 pos_screen, float depth);
+float linearDepth(float depth, float near, float far);
+float getDepth(vec2 pos_screen);
+float linearDepth01(float d, float znear, float zfar);
+
+float random (vec2 uv) {
+	return fract(sin(dot(uv, vec2(12.9898, 78.233))) * 43758.5453123); //simple random function
+}
+
+// Based off of https://github.com/RoundedGlint585/ScreenSpaceReflection/
+// A few tweaks here and there to suit our needs.
+
+vec2 generateProjectedPosition(vec3 pos){
+	vec4 samplePosition = projection_matrix * vec4(pos, 1.f);
+	samplePosition.xy = (samplePosition.xy / samplePosition.w) * 0.5 + 0.5;
+	return samplePosition.xy;
+}
+
+bool isBinarySearchEnabled = true;
+bool isAdaptiveStepEnabled = true;
+bool isExponentialStepEnabled = false;
+bool debugDraw = false;
+int iterationCount = 100;
+float rayStep = 0.2;
+float distanceBias = 0.05;
+float depthRejectBias = 0.001;
+float epsilon = 0.1;
+
+bool traceScreenRay(vec3 position, vec3 reflection, out vec3 hitColor, out float hitDepth, float depth, sampler2D textureFrame) {
+	vec3 step = rayStep * reflection;
+	vec3 marchingPosition = position + step;
+	float delta;
+	float depthFromScreen;
+	vec2 screenPosition;
+    bool hit = false;
+    hitColor = vec3(0);
+	
+	int i = 0;
+	if (depth > depthRejectBias) {
+		for (; i < iterationCount && !hit; i++) {
+			screenPosition = generateProjectedPosition(marchingPosition);
+			depthFromScreen = abs(getPositionWithDepth(screenPosition, linearDepth(getDepth(screenPosition), zNear, zFar)).z);
+			delta = abs(marchingPosition.z) - depthFromScreen;
+			
+			if (depth < depthFromScreen + epsilon && depth > depthFromScreen - epsilon) {
+				break;
+			}
+
+			if (abs(delta) < distanceBias) {
+				vec3 color = vec3(1);
+				if(debugDraw)
+					color = vec3( 0.5+ sign(delta)/2,0.3,0.5- sign(delta)/2);
+				hitColor = texture(textureFrame, screenPosition).xyz * color;
+				hitDepth = depthFromScreen;
+				hit = true;
+				break;
+			}
+			if (isBinarySearchEnabled && delta > 0) {
+				break;
+			}
+			if (isAdaptiveStepEnabled){
+				float directionSign = sign(abs(marchingPosition.z) - depthFromScreen);
+				//this is sort of adapting step, should prevent lining reflection by doing sort of iterative converging
+				//some implementation doing it by binary search, but I found this idea more cheaty and way easier to implement
+				step = step * (1.0 - rayStep * max(directionSign, 0.0));
+				marchingPosition += step * (-directionSign);
+			}
+			else {
+				marchingPosition += step;
+			}
+
+			if (isExponentialStepEnabled){
+				step *= 1.05;
+			}
+		}
+		if(isBinarySearchEnabled){
+			for(; i < iterationCount && !hit; i++){
+			
+				step *= 0.5;
+				marchingPosition = marchingPosition - step * sign(delta);
+				
+				screenPosition = generateProjectedPosition(marchingPosition);
+				depthFromScreen = abs(getPositionWithDepth(screenPosition, getDepth(screenPosition)).z);
+				delta = abs(marchingPosition.z) - depthFromScreen;
+
+				if (depth < depthFromScreen + epsilon && depth > depthFromScreen - epsilon) {
+					break;
+				}
+
+				if (abs(delta) < distanceBias && depthFromScreen != (depth - distanceBias)) {
+					vec3 color = vec3(1);
+					if(debugDraw)
+						color = vec3( 0.5+ sign(delta)/2,0.3,0.5- sign(delta)/2);
+					hitColor = texture(textureFrame, screenPosition).xyz * color;
+					hitDepth = depthFromScreen;
+					hit = true;
+					break;
+				}
+			}
+		}
+	}
+	
+    return hit;
+}