From 123a192963fb22f3ad5296aa15f53a37ddd8f0b3 Mon Sep 17 00:00:00 2001
From: Vincent Lejeune <vljn@ovi.com>
Date: Mon, 14 Apr 2014 01:01:36 +0200
Subject: [PATCH] Use half res FBO for SSAO

SSAO is a medium frequency effect, using half res fbo is fine and
improve performance and look by doing an additionnal bilinear filtering.
Also tune up some values.
---
 data/shaders/ssao.frag           | 8 ++++----
 src/graphics/post_processing.cpp | 8 ++------
 src/graphics/render.cpp          | 4 +++-
 src/graphics/rtts.cpp            | 4 +---
 4 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/data/shaders/ssao.frag b/data/shaders/ssao.frag
index e38e75067..e31464efa 100644
--- a/data/shaders/ssao.frag
+++ b/data/shaders/ssao.frag
@@ -13,8 +13,8 @@ varying vec2 uv;
 #define AO gl_FragColor.x
 #endif
 
-const float strengh = 4.;
-const float radius = .4f;
+const float strengh = 3.;
+const float radius = 1.f;
 
 #define SAMPLES 16
 
@@ -22,7 +22,7 @@ const float invSamples = strengh / SAMPLES;
 
 vec3 rand(vec2 co)
 {
-   return texture(noise_texture, co*20.16).xyz;
+   return texture(noise_texture, co * pow(3.14159265359, 2.)).xyz;
 }
 
 vec3 DecodeNormal(vec2 n);
@@ -61,7 +61,7 @@ void main(void)
 		occluderPos /= occluderPos.w;
 
 		bool isOccluded = isInsideTexture && (sampleProj.z > (2. * occluderFragmentDepth - 1.0)) && (distance(FragPos, occluderPos) < radius);
-		bl += isOccluded ? smoothstep(radius, 0, distance(samplePos, FragPos)) : 0.;
+		bl += isOccluded ? samplePoints[i].z * smoothstep(5 * radius, 0, distance(samplePos, FragPos)) : 0.;
 	}
 
 	AO = 1.0 - bl * invSamples;
diff --git a/src/graphics/post_processing.cpp b/src/graphics/post_processing.cpp
index 603e8fef9..4efeccbde 100644
--- a/src/graphics/post_processing.cpp
+++ b/src/graphics/post_processing.cpp
@@ -413,17 +413,13 @@ void PostProcessing::renderSSAO(const core::matrix4 &invprojm, const core::matri
 
     glUseProgram(FullScreenShader::SSAOShader::Program);
     glBindVertexArray(FullScreenShader::SSAOShader::vao);
-    setTexture(0, irr_driver->getRenderTargetTexture(RTT_NORMAL_AND_DEPTH), GL_NEAREST, GL_NEAREST);
+    setTexture(0, irr_driver->getRenderTargetTexture(RTT_NORMAL_AND_DEPTH), GL_LINEAR, GL_LINEAR);
     setTexture(1, irr_driver->getDepthStencilTexture(), GL_LINEAR, GL_LINEAR);
-    setTexture(2, getTextureGLuint(noise_tex), GL_NEAREST, GL_NEAREST);
+    setTexture(2, getTextureGLuint(noise_tex), GL_LINEAR, GL_LINEAR);
 
     FullScreenShader::SSAOShader::setUniforms(projm, invprojm, 0, 1, 2);
 
     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
-    glBindVertexArray(0);
-    glBindBuffer(GL_ARRAY_BUFFER, 0);
-    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
-    glEnable(GL_DEPTH_TEST);
 }
 
 void PostProcessing::renderFog(const core::matrix4 &ipvmat)
diff --git a/src/graphics/render.cpp b/src/graphics/render.cpp
index fa3524975..0ca86da50 100644
--- a/src/graphics/render.cpp
+++ b/src/graphics/render.cpp
@@ -935,10 +935,12 @@ void IrrDriver::renderLights(const core::aabbox3df& cambox,
         glBindFramebuffer(GL_FRAMEBUFFER, m_rtts->getFBO(FBO_SSAO));
         glClearColor(1., 1., 1., 1.);
         glClear(GL_COLOR_BUFFER_BIT);
+        glViewport(0, 0, UserConfigParams::m_width / 2, UserConfigParams::m_height / 2);
         m_post_processing->renderSSAO(irr_driver->getInvProjMatrix(), irr_driver->getProjMatrix());
         // Blur it to reduce noise.
         m_post_processing->renderGaussian6Blur(irr_driver->getFBO(FBO_SSAO), irr_driver->getRenderTargetTexture(RTT_SSAO),
-            irr_driver->getFBO(FBO_TMP4), irr_driver->getRenderTargetTexture(RTT_TMP4), UserConfigParams::m_width, UserConfigParams::m_height);
+            irr_driver->getFBO(FBO_HALF1), irr_driver->getRenderTargetTexture(RTT_HALF1), UserConfigParams::m_width / 2, UserConfigParams::m_height / 2);
+        glViewport(0, 0, UserConfigParams::m_width, UserConfigParams::m_height);
     }
 }
 
diff --git a/src/graphics/rtts.cpp b/src/graphics/rtts.cpp
index 2a3e3359b..598d178e7 100644
--- a/src/graphics/rtts.cpp
+++ b/src/graphics/rtts.cpp
@@ -64,8 +64,6 @@ RTT::RTT()
     const dimension2du eighth = res/8;
     const dimension2du sixteenth = res/16;
 
-    const dimension2du ssaosize = UserConfigParams::m_ssao == 2 ? res : quarter;
-
     const u16 shadowside = 1024;
     const dimension2du shadowsize0(shadowside, shadowside);
     const dimension2du shadowsize1(shadowside / 2, shadowside / 2);
@@ -88,7 +86,7 @@ RTT::RTT()
     RenderTargetTextures[RTT_COLOR] = generateRTT(res, GL_RGBA16F, GL_BGRA, GL_FLOAT);
     RenderTargetTextures[RTT_MLAA_COLORS] = generateRTT(res, GL_RGBA8, GL_BGRA, GL_UNSIGNED_BYTE);
     RenderTargetTextures[RTT_LOG_LUMINANCE] = generateRTT(res, GL_R16F, GL_RED, GL_FLOAT);
-    RenderTargetTextures[RTT_SSAO] = generateRTT(res, GL_R16F, GL_RED, GL_FLOAT);
+    RenderTargetTextures[RTT_SSAO] = generateRTT(half, GL_R16F, GL_RED, GL_FLOAT);
     RenderTargetTextures[RTT_DISPLACE] = generateRTT(res, GL_RGBA16F, GL_BGRA, GL_FLOAT);
 
     RenderTargetTextures[RTT_HALF1] = generateRTT(half, GL_RGBA16F, GL_BGRA, GL_FLOAT);