Change SSAO blur to be depth aware

src/gl/renderer/gl_postprocess.cpp

@@ -200,8 +200,22 @@ void FGLRenderer::AmbientOccludeScene()
 	RenderScreenQuad();
 
 	// Blur SSAO texture
-	mBlurShader->BlurHorizontal(this, blurAmount, blurSampleCount, mBuffers->AmbientTexture1, mBuffers->AmbientFB0, mBuffers->AmbientWidth, mBuffers->AmbientHeight);
-	mBlurShader->BlurVertical(this, blurAmount, blurSampleCount, mBuffers->AmbientTexture0, mBuffers->AmbientFB1, mBuffers->AmbientWidth, mBuffers->AmbientHeight);
+	glBindFramebuffer(GL_FRAMEBUFFER, mBuffers->AmbientFB0);
+	glBindTexture(GL_TEXTURE_2D, mBuffers->AmbientTexture1);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	mDepthBlurShader->Bind(false);
+	mDepthBlurShader->BlurSharpness[false].Set(blurAmount);
+	mDepthBlurShader->InvFullResolution[false].Set(1.0f / mBuffers->AmbientWidth, 1.0f / mBuffers->AmbientHeight);
+	RenderScreenQuad();
+
+	glBindFramebuffer(GL_FRAMEBUFFER, mBuffers->AmbientFB1);
+	glBindTexture(GL_TEXTURE_2D, mBuffers->AmbientTexture0);
+	mDepthBlurShader->Bind(true);
+	mDepthBlurShader->BlurSharpness[true].Set(blurAmount);
+	mDepthBlurShader->InvFullResolution[true].Set(1.0f / mBuffers->AmbientWidth, 1.0f / mBuffers->AmbientHeight);
+	mDepthBlurShader->PowExponent[true].Set(1.8f);
+	RenderScreenQuad();
 
 	// Add SSAO back to scene texture:
 	mBuffers->BindCurrentFB();
@@ -216,8 +230,8 @@ void FGLRenderer::AmbientOccludeScene()
 	glBindTexture(GL_TEXTURE_2D, mBuffers->AmbientTexture1);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-	mBloomCombineShader->Bind();
-	mBloomCombineShader->BloomTexture.Set(0);
+	mSSAOCombineShader->Bind();
+	mSSAOCombineShader->AODepthTexture.Set(0);
 	RenderScreenQuad();
 	glViewport(mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
 

src/gl/renderer/gl_renderer.cpp

@@ -114,6 +114,10 @@ FGLRenderer::FGLRenderer(OpenGLFrameBuffer *fb)
 	mTonemapPalette = nullptr;
 	mColormapShader = nullptr;
 	mLensShader = nullptr;
+	mLinearDepthShader = nullptr;
+	mDepthBlurShader = nullptr;
+	mSSAOShader = nullptr;
+	mSSAOCombineShader = nullptr;
 }
 
 void gl_LoadModels();
@@ -123,7 +127,9 @@ void FGLRenderer::Initialize(int width, int height)
 {
 	mBuffers = new FGLRenderBuffers();
 	mLinearDepthShader = new FLinearDepthShader();
+	mDepthBlurShader = new FDepthBlurShader();
 	mSSAOShader = new FSSAOShader();
+	mSSAOCombineShader = new FSSAOCombineShader();
 	mBloomExtractShader = new FBloomExtractShader();
 	mBloomCombineShader = new FBloomCombineShader();
 	mExposureExtractShader = new FExposureExtractShader();
@@ -188,7 +194,9 @@ FGLRenderer::~FGLRenderer()
 	if (mBuffers) delete mBuffers;
 	if (mPresentShader) delete mPresentShader;
 	if (mLinearDepthShader) delete mLinearDepthShader;
+	if (mDepthBlurShader) delete mDepthBlurShader;
 	if (mSSAOShader) delete mSSAOShader;
+	if (mSSAOCombineShader) delete mSSAOCombineShader;
 	if (mBloomExtractShader) delete mBloomExtractShader;
 	if (mBloomCombineShader) delete mBloomCombineShader;
 	if (mExposureExtractShader) delete mExposureExtractShader;

src/gl/renderer/gl_renderer.h

@@ -20,7 +20,9 @@ class FSamplerManager;
 class DPSprite;
 class FGLRenderBuffers;
 class FLinearDepthShader;
+class FDepthBlurShader;
 class FSSAOShader;
+class FSSAOCombineShader;
 class FBloomExtractShader;
 class FBloomCombineShader;
 class FExposureExtractShader;
@@ -97,6 +99,8 @@ public:
 	FGLRenderBuffers *mBuffers;
 	FLinearDepthShader *mLinearDepthShader;
 	FSSAOShader *mSSAOShader;
+	FDepthBlurShader *mDepthBlurShader;
+	FSSAOCombineShader *mSSAOCombineShader;
 	FBloomExtractShader *mBloomExtractShader;
 	FBloomCombineShader *mBloomCombineShader;
 	FExposureExtractShader *mExposureExtractShader;

src/gl/shaders/gl_ambientshader.cpp

@@ -96,3 +96,35 @@ void FSSAOShader::Bind()
 	}
 	mShader.Bind();
 }
+
+void FDepthBlurShader::Bind(bool vertical)
+{
+	auto &shader = mShader[vertical];
+	if (!shader)
+	{
+		shader.Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
+		shader.Compile(FShaderProgram::Fragment, "shaders/glsl/depthblur.fp", vertical ? "#define BLUR_VERTICAL\n" : "#define BLUR_HORIZONTAL\n", 330);
+		shader.SetFragDataLocation(0, "FragColor");
+		shader.Link("shaders/glsl/depthblur");
+		shader.SetAttribLocation(0, "PositionInProjection");
+		AODepthTexture[vertical].Init(shader, "AODepthTexture");
+		BlurSharpness[vertical].Init(shader, "BlurSharpness");
+		InvFullResolution[vertical].Init(shader, "InvFullResolution");
+		PowExponent[vertical].Init(shader, "PowExponent");
+	}
+	shader.Bind();
+}
+
+void FSSAOCombineShader::Bind()
+{
+	if (!mShader)
+	{
+		mShader.Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
+		mShader.Compile(FShaderProgram::Fragment, "shaders/glsl/ssaocombine.fp", "", 330);
+		mShader.SetFragDataLocation(0, "FragColor");
+		mShader.Link("shaders/glsl/ssaocombine");
+		mShader.SetAttribLocation(0, "PositionInProjection");
+		AODepthTexture.Init(mShader, "AODepthTexture");
+	}
+	mShader.Bind();
+}

src/gl/shaders/gl_ambientshader.h

@@ -38,4 +38,29 @@ private:
 	FShaderProgram mShader;
 };
 
+class FDepthBlurShader
+{
+public:
+	void Bind(bool vertical);
+
+	FBufferedUniformSampler AODepthTexture[2];
+	FBufferedUniform1f BlurSharpness[2];
+	FBufferedUniform2f InvFullResolution[2];
+	FBufferedUniform1f PowExponent[2];
+
+private:
+	FShaderProgram mShader[2];
+};
+
+class FSSAOCombineShader
+{
+public:
+	void Bind();
+
+	FBufferedUniformSampler AODepthTexture;
+
+private:
+	FShaderProgram mShader;
+};
+
 #endif

wadsrc/static/shaders/glsl/depthblur.fp

@@ -0,0 +1,81 @@
+
+in vec2 TexCoord;
+out vec4 FragColor;
+
+uniform sampler2D AODepthTexture;
+uniform float BlurSharpness;
+uniform vec2 InvFullResolution;
+uniform float PowExponent;
+
+#define KERNEL_RADIUS 3.0
+
+struct CenterPixelData
+{
+	vec2 UV;
+	float Depth;
+	float Sharpness;
+};
+
+float CrossBilateralWeight(float r, float sampleDepth, CenterPixelData center)
+{
+	const float blurSigma = KERNEL_RADIUS * 0.5;
+	const float blurFalloff = 1.0 / (2.0 * blurSigma * blurSigma);
+
+	float deltaZ = (sampleDepth - center.Depth) * center.Sharpness;
+
+	return exp2(-r * r * blurFalloff - deltaZ * deltaZ);
+}
+
+void ProcessSample(float ao, float z, float r, CenterPixelData center, inout float totalAO, inout float totalW)
+{
+	float w = CrossBilateralWeight(r, z, center);
+	totalAO += w * ao;
+	totalW += w;
+}
+
+void ProcessRadius(vec2 deltaUV, CenterPixelData center, inout float totalAO, inout float totalW)
+{
+	for (float r = 1; r <= KERNEL_RADIUS; r += 1.0)
+	{
+		vec2 uv = r * deltaUV + center.UV;
+		vec2 aoZ = texture(AODepthTexture, uv).xy;
+		ProcessSample(aoZ.x, aoZ.y, r, center, totalAO, totalW);
+	}
+}
+
+vec2 ComputeBlur(vec2 deltaUV)
+{
+	vec2 aoZ = texture(AODepthTexture, TexCoord).xy;
+
+	CenterPixelData center;
+	center.UV = TexCoord;
+	center.Depth = aoZ.y;
+	center.Sharpness = BlurSharpness;
+
+	float totalAO = aoZ.x;
+	float totalW = 1.0;
+
+	ProcessRadius(deltaUV, center, totalAO, totalW);
+	ProcessRadius(-deltaUV, center, totalAO, totalW);
+
+	return vec2(totalAO / totalW, aoZ.y);
+}
+
+vec2 BlurX()
+{
+	return ComputeBlur(vec2(InvFullResolution.x, 0.0));
+}
+
+float BlurY()
+{
+	return pow(clamp(ComputeBlur(vec2(0.0, InvFullResolution.y)).x, 0.0, 1.0), PowExponent);
+}
+
+void main()
+{
+#if defined(BLUR_HORIZONTAL)
+	FragColor = vec4(BlurX(), 0.0, 1.0);
+#else
+	FragColor = vec4(BlurY(), 0.0, 0.0, 1.0);
+#endif
+}

wadsrc/static/shaders/glsl/ssao.fp

@@ -108,12 +108,5 @@ void main()
     vec3 viewPosition = FetchViewPos(TexCoord);
     vec3 viewNormal = ReconstructNormal(viewPosition);
 	float occlusion = ComputeAO(viewPosition, viewNormal) * AOStrength + (1.0 - AOStrength);
-
-	// GZDoom does not use linear buffers at the moment, apply some gamma to get it closer to correct
-	occlusion = occlusion * occlusion;
-
-	//FragColor = vec4(viewPosition.x * 0.001 + 0.5, viewPosition.y * 0.001 + 0.5, viewPosition.z * 0.001, 1.0);
-	//FragColor = vec4(viewNormal.x * 0.5 + 0.5, viewNormal.y * 0.5 + 0.5, viewNormal.z * 0.5 + 0.5, 1.0);
-	//FragColor = vec4(occlusion, viewPosition.z, 0.0, 1.0);
-	FragColor = vec4(occlusion, occlusion, occlusion, 1.0);
+	FragColor = vec4(occlusion, viewPosition.z, 0.0, 1.0);
 }

wadsrc/static/shaders/glsl/ssaocombine.fp

@@ -0,0 +1,11 @@
+
+in vec2 TexCoord;
+out vec4 FragColor;
+
+uniform sampler2D AODepthTexture;
+
+void main()
+{
+	float attenutation = texture(AODepthTexture, TexCoord).x;
+	FragColor = vec4(attenutation, attenutation, attenutation, 0.0);
+}