From 23ba597a1c61017507a630ec42364bec2acd94b1 Mon Sep 17 00:00:00 2001
From: vlj <vljn@ovi.com>
Date: Mon, 12 May 2014 18:39:33 +0200
Subject: [PATCH] SSAO: Use int rounding

---
 data/shaders/ssao.frag | 164 +++++++++++++++++++++--------------------
 1 file changed, 84 insertions(+), 80 deletions(-)

diff --git a/data/shaders/ssao.frag b/data/shaders/ssao.frag
index 78de29b94..c093802bb 100644
--- a/data/shaders/ssao.frag
+++ b/data/shaders/ssao.frag
@@ -1,80 +1,84 @@
-// From paper http://graphics.cs.williams.edu/papers/AlchemyHPG11/
-// and improvements here http://graphics.cs.williams.edu/papers/SAOHPG12/
-
-uniform sampler2D ntex;
-uniform sampler2D dtex;
-uniform sampler2D noise_texture;
-uniform vec4 samplePoints[16];
-
-#ifdef UBO_DISABLED
-uniform mat4 ViewMatrix;
-uniform mat4 ProjectionMatrix;
-uniform mat4 InverseViewMatrix;
-uniform mat4 InverseProjectionMatrix;
-#else
-layout (std140) uniform MatrixesData
-{
-    mat4 ViewMatrix;
-    mat4 ProjectionMatrix;
-    mat4 InverseViewMatrix;
-    mat4 InverseProjectionMatrix;
-    mat4 ShadowViewProjMatrixes[4];
-};
-#endif
-
-in vec2 uv;
-out float AO;
-
-const float sigma = 1.;
-const float tau = 7.;
-const float beta = 0.0001;
-const float epsilon = .00001;
-const float radius = 2.;
-const float k = 1.5;
-
-#define SAMPLES 16
-
-const float invSamples = 1. / SAMPLES;
-
-vec3 DecodeNormal(vec2 n);
-vec4 getPosFromUVDepth(vec3 uvDepth, mat4 InverseProjectionMatrix);
-
-void main(void)
-{
-    vec4 cur = texture(ntex, uv);
-    float curdepth = texture(dtex, uv).x;
-    vec4 FragPos = getPosFromUVDepth(vec3(uv, curdepth), InverseProjectionMatrix);
-
-    // get the normal of current fragment
-    vec3 ddx = dFdx(FragPos.xyz);
-    vec3 ddy = dFdy(FragPos.xyz);
-    vec3 norm = normalize(cross(ddy, ddx));
-    // Workaround for nvidia and skyboxes
-    float len = dot(vec3(1.0), abs(cur.xyz));
-    if (len < 0.2) discard;
-
-    int x = int(1024. * uv.x), y = int(1024. * uv.y);
-    float r = radius / FragPos.z;
-    float phi = 30. * (x ^ y) + 10. * x * y;
-    float bl = 0.0;
-
-    for(int i = 0; i < SAMPLES; ++i) {
-        float alpha = (i + .5) * invSamples;
-        float theta = 2. * 3.14 * tau * alpha + phi;
-        float h = r * alpha;
-        vec2 occluder_uv = h * vec2(cos(theta), sin(theta));
-        occluder_uv += uv;
-
-        if (occluder_uv.x < 0. || occluder_uv.x > 1. || occluder_uv.y < 0. || occluder_uv.y > 1.) continue;
-
-        float m = round(log2(h)) + 7.;
-
-        float occluderFragmentDepth = textureLod(dtex, occluder_uv, m).x;
-        vec4 OccluderPos = getPosFromUVDepth(vec3(occluder_uv, occluderFragmentDepth), InverseProjectionMatrix);
-
-        vec3 vi = (OccluderPos - FragPos).xyz;
-        bl += max(0, dot(vi, norm) - FragPos.z * beta) / (dot(vi, vi) + epsilon);
-    }
-
-    AO = max(pow(1.0 - 2. * sigma * bl * invSamples, k), 0.);
-}
+// From paper http://graphics.cs.williams.edu/papers/AlchemyHPG11/
+// and improvements here http://graphics.cs.williams.edu/papers/SAOHPG12/
+
+uniform sampler2D ntex;
+uniform sampler2D dtex;
+uniform sampler2D noise_texture;
+uniform vec4 samplePoints[16];
+uniform vec2 screen = vec2(1680, 1050);
+
+#ifdef UBO_DISABLED
+uniform mat4 ViewMatrix;
+uniform mat4 ProjectionMatrix;
+uniform mat4 InverseViewMatrix;
+uniform mat4 InverseProjectionMatrix;
+#else
+layout (std140) uniform MatrixesData
+{
+    mat4 ViewMatrix;
+    mat4 ProjectionMatrix;
+    mat4 InverseViewMatrix;
+    mat4 InverseProjectionMatrix;
+    mat4 ShadowViewProjMatrixes[4];
+};
+#endif
+
+in vec2 uv;
+out float AO;
+
+const float sigma = 1.;
+const float tau = 2.;
+const float beta = 0.0001;
+const float epsilon = .00001;
+const float radius = 1.;
+const float k = 1.;
+
+#define SAMPLES 16
+
+const float invSamples = 1. / SAMPLES;
+
+vec3 DecodeNormal(vec2 n);
+vec4 getPosFromUVDepth(vec3 uvDepth, mat4 InverseProjectionMatrix);
+
+void main(void)
+{
+    vec4 cur = texture(ntex, uv);
+    float curdepth = texture(dtex, uv).x;
+    vec4 FragPos = getPosFromUVDepth(vec3(uv, curdepth), InverseProjectionMatrix);
+
+    // get the normal of current fragment
+    vec3 ddx = dFdx(FragPos.xyz);
+    vec3 ddy = dFdy(FragPos.xyz);
+    vec3 norm = normalize(cross(ddy, ddx));
+    // Workaround for nvidia and skyboxes
+    float len = dot(vec3(1.0), abs(cur.xyz));
+    if (len < 0.2) discard;
+
+    int x = int(gl_FragCoord.x), y = int(gl_FragCoord.y);
+    float r = radius / FragPos.z;
+    float phi = 30. * (x ^ y) + 10. * x * y;
+    float bl = 0.0;
+
+    for(int i = 0; i < SAMPLES; ++i) {
+        float alpha = (i + .5) * invSamples;
+        float theta = 2. * 3.14 * tau * alpha + phi;
+        float h = r * alpha;
+        vec2 occluder_uv = h * vec2(cos(theta), sin(theta)) * screen;
+        occluder_uv += gl_FragCoord.xy;
+
+        float m = round(log2(h)) + 7;
+        ivec2 ioccluder_uv = ivec2(occluder_uv);
+        occluder_uv = (ioccluder_uv >> int(m)) << int(m);
+        occluder_uv /= screen;
+
+        if (occluder_uv.x < 0. || occluder_uv.x > 1. || occluder_uv.y < 0. || occluder_uv.y > 1.) continue;
+
+        float occluderFragmentDepth = textureLod(dtex, occluder_uv, m).x;
+        vec4 OccluderPos = getPosFromUVDepth(vec3(occluder_uv, occluderFragmentDepth), InverseProjectionMatrix);
+
+        vec3 vi = (OccluderPos - FragPos).xyz;
+        bl += max(0, dot(vi, norm) - FragPos.z * beta) / (dot(vi, vi) + epsilon);
+    }
+
+    AO = max(pow(1.0 - 2. * sigma * bl * invSamples, k), 0.);
+}
\ No newline at end of file