Added SSAO pass

src/CMakeLists.txt

@@ -1125,6 +1125,7 @@ set( FASTMATH_SOURCES
 	gl/shaders/gl_shaderprogram.cpp
 	gl/shaders/gl_presentshader.cpp
 	gl/shaders/gl_bloomshader.cpp
+	gl/shaders/gl_ambientshader.cpp
 	gl/shaders/gl_blurshader.cpp
 	gl/shaders/gl_colormapshader.cpp
 	gl/shaders/gl_tonemapshader.cpp

src/gl/renderer/gl_postprocess.cpp

@@ -55,6 +55,7 @@
 #include "gl/renderer/gl_postprocessstate.h"
 #include "gl/data/gl_data.h"
 #include "gl/data/gl_vertexbuffer.h"
+#include "gl/shaders/gl_ambientshader.h"
 #include "gl/shaders/gl_bloomshader.h"
 #include "gl/shaders/gl_blurshader.h"
 #include "gl/shaders/gl_tonemapshader.h"
@@ -98,6 +99,20 @@ CVAR(Float, gl_lens_k, -0.12f, 0)
 CVAR(Float, gl_lens_kcube, 0.1f, 0)
 CVAR(Float, gl_lens_chromatic, 1.12f, 0)
 
+CVAR(Bool, gl_ssao, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
+CVAR(Bool, gl_ssao_debug, false, 0)
+CVAR(Float, gl_ssao_bias, 0.5f, 0)
+CVAR(Float, gl_ssao_radius, 100.0f, 0)
+CUSTOM_CVAR(Float, gl_ssao_blur_amount, 6.0f, 0)
+{
+	if (self < 0.1f) self = 0.1f;
+}
+CUSTOM_CVAR(Int, gl_ssao_blur_samples, 9, 0)
+{
+	if (self < 3 || self > 15 || self % 2 == 0)
+		self = 9;
+}
+
 EXTERN_CVAR(Float, vid_brightness)
 EXTERN_CVAR(Float, vid_contrast)
 
@@ -109,6 +124,96 @@ void FGLRenderer::RenderScreenQuad()
 	GLRenderer->mVBO->RenderArray(GL_TRIANGLE_STRIP, FFlatVertexBuffer::PRESENT_INDEX, 4);
 }
 
+void FGLRenderer::PostProcessScene()
+{
+	if (FGLRenderBuffers::IsEnabled()) mBuffers->BlitSceneToTexture();
+	AmbientOccludeScene();
+	UpdateCameraExposure();
+	BloomScene();
+	TonemapScene();
+	LensDistortScene();
+}
+
+//-----------------------------------------------------------------------------
+//
+// Adds ambient occlusion to the scene
+//
+//-----------------------------------------------------------------------------
+
+void FGLRenderer::AmbientOccludeScene()
+{
+	if (!gl_ssao || !FGLRenderBuffers::IsEnabled())
+		return;
+
+	FGLDebug::PushGroup("AmbientOccludeScene");
+
+	FGLPostProcessState savedState;
+
+	float bias = gl_ssao_bias;
+	float aoRadius = gl_ssao_radius;
+	const float blurAmount = gl_ssao_blur_amount;
+	int blurSampleCount = gl_ssao_blur_samples;
+
+	//float tanHalfFovy = tan(fovy * (M_PI / 360.0f));
+	float tanHalfFovy = 1.0f / 1.33333302f; //gl_RenderState.mProjectionMatrix.get()[5];
+	float invFocalLenX = tanHalfFovy * (mBuffers->AmbientWidth / (float)mBuffers->AmbientHeight);
+	float invFocalLenY = tanHalfFovy;
+	float nDotVBias = clamp(bias, 0.0f, 1.0f);
+	float r2 = aoRadius * aoRadius;
+
+	// Calculate linear depth values
+	glBindFramebuffer(GL_FRAMEBUFFER, mBuffers->AmbientFB0);
+	glViewport(0, 0, mBuffers->AmbientWidth, mBuffers->AmbientHeight);
+	mBuffers->BindSceneDepthTexture(0);
+	mLinearDepthShader->Bind();
+	mLinearDepthShader->DepthTexture.Set(0);
+	mLinearDepthShader->LinearizeDepthA.Set(1.0f / GetZFar() - 1.0f / GetZNear());
+	mLinearDepthShader->LinearizeDepthB.Set(MAX(1.0f / GetZNear(), 1.e-8f));
+	mLinearDepthShader->InverseDepthRangeA.Set(1.0f);
+	mLinearDepthShader->InverseDepthRangeB.Set(0.0f);
+	RenderScreenQuad();
+
+	// Apply ambient occlusion
+	glBindFramebuffer(GL_FRAMEBUFFER, mBuffers->AmbientFB1);
+	glBindTexture(GL_TEXTURE_2D, mBuffers->AmbientTexture0);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	mSSAOShader->Bind();
+	mSSAOShader->DepthTexture.Set(0);
+	mSSAOShader->UVToViewA.Set(2.0f * invFocalLenX, -2.0f * invFocalLenY);
+	mSSAOShader->UVToViewB.Set(-invFocalLenX, invFocalLenY);
+	mSSAOShader->InvFullResolution.Set(1.0f / mBuffers->AmbientWidth, 1.0f / mBuffers->AmbientHeight);
+	mSSAOShader->NDotVBias.Set(nDotVBias);
+	mSSAOShader->NegInvR2.Set(-1.0f / r2);
+	mSSAOShader->RadiusToScreen.Set(aoRadius * 0.5 / tanHalfFovy * mBuffers->AmbientHeight);
+	mSSAOShader->AOMultiplier.Set(1.0f / (1.0f - nDotVBias));
+	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);
+
+	// Add SSAO back to scene texture:
+	mBuffers->BindCurrentFB();
+	glViewport(mSceneViewport.left, mSceneViewport.top, mSceneViewport.width, mSceneViewport.height);
+	glEnable(GL_BLEND);
+	glBlendEquation(GL_FUNC_ADD);
+	if (gl_ssao_debug)
+		glBlendFunc(GL_ONE, GL_ZERO);
+	else
+		glBlendFunc(GL_ZERO, GL_SRC_COLOR);
+	glActiveTexture(GL_TEXTURE0);
+	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);
+	RenderScreenQuad();
+	glViewport(mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
+
+	FGLDebug::PopGroup();
+}
+
 //-----------------------------------------------------------------------------
 //
 // Extracts light average from the scene and updates the camera exposure texture
@@ -190,7 +295,7 @@ void FGLRenderer::UpdateCameraExposure()
 void FGLRenderer::BloomScene()
 {
 	// Only bloom things if enabled and no special fixed light mode is active
-	if (!gl_bloom || gl_fixedcolormap != CM_DEFAULT)
+	if (!gl_bloom || gl_fixedcolormap != CM_DEFAULT || gl_ssao_debug)
 		return;
 
 	FGLDebug::PushGroup("BloomScene");

src/gl/renderer/gl_renderbuffers.cpp

@@ -40,6 +40,7 @@
 #include "w_wad.h"
 #include "i_system.h"
 #include "doomerrors.h"
+#include <random>
 
 CVAR(Int, gl_multisample, 1, CVAR_ARCHIVE|CVAR_GLOBALCONFIG);
 CVAR(Bool, gl_renderbuffers, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_NOINITCALL)
@@ -75,15 +76,16 @@ FGLRenderBuffers::~FGLRenderBuffers()
 	ClearEyeBuffers();
 	ClearBloom();
 	ClearExposureLevels();
+	ClearAmbientOcclusion();
 }
 
 void FGLRenderBuffers::ClearScene()
 {
 	DeleteFrameBuffer(mSceneFB);
-	DeleteRenderBuffer(mSceneMultisample);
+	DeleteFrameBuffer(mSceneDataFB);
-	DeleteRenderBuffer(mSceneDepthStencil);
+	DeleteTexture(mSceneMultisample);
-	DeleteRenderBuffer(mSceneDepth);
+	DeleteTexture(mSceneData);
-	DeleteRenderBuffer(mSceneStencil);
+	DeleteTexture(mSceneDepthStencil);
 }
 
 void FGLRenderBuffers::ClearPipeline()
@@ -132,6 +134,15 @@ void FGLRenderBuffers::ClearEyeBuffers()
 	mEyeFBs.Clear();
 }
 
+void FGLRenderBuffers::ClearAmbientOcclusion()
+{
+	DeleteFrameBuffer(AmbientFB0);
+	DeleteFrameBuffer(AmbientFB1);
+	DeleteTexture(AmbientTexture0);
+	DeleteTexture(AmbientTexture1);
+	DeleteTexture(AmbientRandomTexture);
+}
+
 void FGLRenderBuffers::DeleteTexture(GLuint &handle)
 {
 	if (handle != 0)
@@ -203,6 +214,7 @@ bool FGLRenderBuffers::Setup(int width, int height, int sceneWidth, int sceneHei
 	{
 		CreateBloom(sceneWidth, sceneHeight);
 		CreateExposureLevels(sceneWidth, sceneHeight);
+		CreateAmbientOcclusion(sceneWidth, sceneHeight);
 		mSceneWidth = sceneWidth;
 		mSceneHeight = sceneHeight;
 	}
@@ -240,10 +252,19 @@ void FGLRenderBuffers::CreateScene(int width, int height, int samples)
 	ClearScene();
 
 	if (samples > 1)
-		mSceneMultisample = CreateRenderBuffer("SceneMultisample", GL_RGBA16F, samples, width, height);
+	{
+		mSceneMultisample = Create2DMultisampleTexture("SceneMultisample", GL_RGBA16F, width, height, samples, false);
+		mSceneDepthStencil = Create2DMultisampleTexture("SceneDepthStencil", GL_DEPTH24_STENCIL8, width, height, samples, false);
+		mSceneData = Create2DMultisampleTexture("SceneSSAOData", GL_RGBA8, width, height, samples, false);
+	}
+	else
+	{
+		mSceneDepthStencil = Create2DTexture("SceneDepthStencil", GL_DEPTH24_STENCIL8, width, height);
+		mSceneData = Create2DTexture("SceneSSAOData", GL_RGBA8, width, height);
+	}
 
-	mSceneDepthStencil = CreateRenderBuffer("SceneDepthStencil", GL_DEPTH24_STENCIL8, samples, width, height);
+	mSceneFB = CreateFrameBuffer("SceneFB", samples > 1 ? mSceneMultisample : mPipelineTexture[0], 0, mSceneDepthStencil, samples > 1);
-	mSceneFB = CreateFrameBuffer("SceneFB", samples > 1 ? mSceneMultisample : mPipelineTexture[0], mSceneDepthStencil, samples > 1);
+	mSceneDataFB = CreateFrameBuffer("SSAOSceneFB", samples > 1 ? mSceneMultisample : mPipelineTexture[0], mSceneData, mSceneDepthStencil, samples > 1);
 }
 
 //==========================================================================
@@ -296,6 +317,47 @@ void FGLRenderBuffers::CreateBloom(int width, int height)
 	}
 }
 
+//==========================================================================
+//
+// Creates ambient occlusion working buffers
+//
+//==========================================================================
+
+void FGLRenderBuffers::CreateAmbientOcclusion(int width, int height)
+{
+	ClearAmbientOcclusion();
+
+	if (width <= 0 || height <= 0)
+		return;
+
+	AmbientWidth = width / 2;
+	AmbientHeight = height / 2;
+	AmbientTexture0 = Create2DTexture("AmbientTexture0", GL_RG32F, AmbientWidth, AmbientHeight);
+	AmbientTexture1 = Create2DTexture("AmbientTexture1", GL_RG32F, AmbientWidth, AmbientHeight);
+	AmbientFB0 = CreateFrameBuffer("AmbientFB0", AmbientTexture0);
+	AmbientFB1 = CreateFrameBuffer("AmbientFB1", AmbientTexture1);
+
+	int16_t randomValues[16 * 4];
+	std::mt19937 generator(1337);
+	std::uniform_real_distribution<double> distribution(-1.0, 1.0);
+	for (int i = 0; i < 16; i++)
+	{
+		double num_directions = 8.0; // Must be same as the define in ssao.fp
+		double angle = 2.0 * M_PI * distribution(generator) / num_directions;
+		double x = cos(angle);
+		double y = sin(angle);
+		double z = distribution(generator);
+		double w = distribution(generator);
+
+		randomValues[i * 4 + 0] = (int16_t)clamp(x * 32767.0, -32768.0, 32767.0);
+		randomValues[i * 4 + 1] = (int16_t)clamp(y * 32767.0, -32768.0, 32767.0);
+		randomValues[i * 4 + 2] = (int16_t)clamp(z * 32767.0, -32768.0, 32767.0);
+		randomValues[i * 4 + 3] = (int16_t)clamp(w * 32767.0, -32768.0, 32767.0);
+	}
+
+	AmbientRandomTexture = Create2DTexture("AmbientRandomTexture", GL_RGBA16_SNORM, 4, 4, randomValues);
+}
+
 //==========================================================================
 //
 // Creates camera exposure level buffers
@@ -368,12 +430,28 @@ void FGLRenderBuffers::CreateEyeBuffers(int eye)
 
 GLuint FGLRenderBuffers::Create2DTexture(const FString &name, GLuint format, int width, int height, const void *data)
 {
-	GLuint type = (format == GL_RGBA16F || format == GL_R32F) ? GL_FLOAT : GL_UNSIGNED_BYTE;
 	GLuint handle = 0;
 	glGenTextures(1, &handle);
 	glBindTexture(GL_TEXTURE_2D, handle);
 	FGLDebug::LabelObject(GL_TEXTURE, handle, name);
-	glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format != GL_R32F ? GL_RGBA : GL_RED, type, data);
+
+	GLenum dataformat, datatype;
+	switch (format)
+	{
+	case GL_RGBA8:				dataformat = GL_RGBA; datatype = GL_UNSIGNED_BYTE; break;
+	case GL_RGBA16:				dataformat = GL_RGBA; datatype = GL_UNSIGNED_SHORT; break;
+	case GL_RGBA16F:			dataformat = GL_RGBA; datatype = GL_FLOAT; break;
+	case GL_RGBA32F:			dataformat = GL_RGBA; datatype = GL_FLOAT; break;
+	case GL_R32F:				dataformat = GL_RED; datatype = GL_FLOAT; break;
+	case GL_RG32F:				dataformat = GL_RG; datatype = GL_FLOAT; break;
+	case GL_DEPTH_COMPONENT24:	dataformat = GL_DEPTH_COMPONENT; datatype = GL_FLOAT; break;
+	case GL_STENCIL_INDEX8:		dataformat = GL_STENCIL_INDEX; datatype = GL_INT; break;
+	case GL_DEPTH24_STENCIL8:	dataformat = GL_DEPTH_STENCIL; datatype = GL_UNSIGNED_INT_24_8; break;
+	case GL_RGBA16_SNORM:		dataformat = GL_RGBA; datatype = GL_SHORT; break;
+	default: I_FatalError("Unknown format passed to FGLRenderBuffers.Create2DTexture");
+	}
+
+	glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, dataformat, datatype, data);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
@@ -381,6 +459,17 @@ GLuint FGLRenderBuffers::Create2DTexture(const FString &name, GLuint format, int
 	return handle;
 }
 
+GLuint FGLRenderBuffers::Create2DMultisampleTexture(const FString &name, GLuint format, int width, int height, int samples, bool fixedSampleLocations)
+{
+	GLuint handle = 0;
+	glGenTextures(1, &handle);
+	glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, handle);
+	FGLDebug::LabelObject(GL_TEXTURE, handle, name);
+	glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, samples, format, width, height, fixedSampleLocations);
+	glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, 0);
+	return handle;
+}
+
 //==========================================================================
 //
 // Creates a render buffer
@@ -428,34 +517,26 @@ GLuint FGLRenderBuffers::CreateFrameBuffer(const FString &name, GLuint colorbuff
 	return handle;
 }
 
-GLuint FGLRenderBuffers::CreateFrameBuffer(const FString &name, GLuint colorbuffer, GLuint depthstencil, bool colorIsARenderBuffer)
+GLuint FGLRenderBuffers::CreateFrameBuffer(const FString &name, GLuint colorbuffer0, GLuint colorbuffer1, GLuint depthstencil, bool multisample)
 {
 	GLuint handle = 0;
 	glGenFramebuffers(1, &handle);
 	glBindFramebuffer(GL_FRAMEBUFFER, handle);
 	FGLDebug::LabelObject(GL_FRAMEBUFFER, handle, name);
-	if (colorIsARenderBuffer)
+	if (multisample)
-		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorbuffer);
+	{
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, colorbuffer0, 0);
+		if (colorbuffer1 != 0)
+			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D_MULTISAMPLE, colorbuffer1, 0);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D_MULTISAMPLE, depthstencil, 0);
+	}
 	else
-		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorbuffer, 0);
+	{
-	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, depthstencil);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorbuffer0, 0);
-	if (CheckFrameBufferCompleteness())
+		if (colorbuffer1 != 0)
-		ClearFrameBuffer(true, true);
+			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, colorbuffer1, 0);
-	return handle;
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D, depthstencil, 0);
-}
+	}
-
-GLuint FGLRenderBuffers::CreateFrameBuffer(const FString &name, GLuint colorbuffer, GLuint depth, GLuint stencil, bool colorIsARenderBuffer)
-{
-	GLuint handle = 0;
-	glGenFramebuffers(1, &handle);
-	glBindFramebuffer(GL_FRAMEBUFFER, handle);
-	FGLDebug::LabelObject(GL_FRAMEBUFFER, handle, name);
-	if (colorIsARenderBuffer)
-		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorbuffer);
-	else
-		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorbuffer, 0);
-	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth);
-	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, stencil);
 	if (CheckFrameBufferCompleteness())
 		ClearFrameBuffer(true, true);
 	return handle;
@@ -475,7 +556,8 @@ bool FGLRenderBuffers::CheckFrameBufferCompleteness()
 
 	FailedCreate = true;
 
-#if 0
+	if (gl_debug_level > 0)
+	{
 		FString error = "glCheckFramebufferStatus failed: ";
 		switch (result)
 		{
@@ -489,8 +571,8 @@ bool FGLRenderBuffers::CheckFrameBufferCompleteness()
 		case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE: error << "GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE"; break;
 		case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS: error << "GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS"; break;
 		}
-	I_FatalError(error);
+		Printf("%s\n", error.GetChars());
-#endif
+	}
 
 	return false;
 }
@@ -595,9 +677,54 @@ void FGLRenderBuffers::BindEyeFB(int eye, bool readBuffer)
 //
 //==========================================================================
 
-void FGLRenderBuffers::BindSceneFB()
+void FGLRenderBuffers::BindSceneFB(bool sceneData)
 {
-	glBindFramebuffer(GL_FRAMEBUFFER, mSceneFB);
+	glBindFramebuffer(GL_FRAMEBUFFER, sceneData ? mSceneDataFB : mSceneFB);
+}
+
+//==========================================================================
+//
+// Binds the scene color texture to the specified texture unit
+//
+//==========================================================================
+
+void FGLRenderBuffers::BindSceneColorTexture(int index)
+{
+	glActiveTexture(GL_TEXTURE0 + index);
+	if (mSamples > 1)
+		glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, mSceneMultisample);
+	else
+		glBindTexture(GL_TEXTURE_2D, mPipelineTexture[0]);
+}
+
+//==========================================================================
+//
+// Binds the scene data texture to the specified texture unit
+//
+//==========================================================================
+
+void FGLRenderBuffers::BindSceneDataTexture(int index)
+{
+	glActiveTexture(GL_TEXTURE0 + index);
+	if (mSamples > 1)
+		glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, mSceneData);
+	else
+		glBindTexture(GL_TEXTURE_2D, mSceneData);
+}
+
+//==========================================================================
+//
+// Binds the depth texture to the specified texture unit
+//
+//==========================================================================
+
+void FGLRenderBuffers::BindSceneDepthTexture(int index)
+{
+	glActiveTexture(GL_TEXTURE0 + index);
+	if (mSamples > 1)
+		glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, mSceneDepthStencil);
+	else
+		glBindTexture(GL_TEXTURE_2D, mSceneDepthStencil);
 }
 
 //==========================================================================

src/gl/renderer/gl_renderbuffers.h

@@ -31,7 +31,10 @@ public:
 
 	bool Setup(int width, int height, int sceneWidth, int sceneHeight);
 
-	void BindSceneFB();
+	void BindSceneFB(bool sceneData);
+	void BindSceneColorTexture(int index);
+	void BindSceneDataTexture(int index);
+	void BindSceneDepthTexture(int index);
 	void BlitSceneToTexture();
 
 	void BindCurrentTexture(int index);
@@ -53,6 +56,15 @@ public:
 	GLuint ExposureFB = 0;
 	bool FirstExposureFrame = true;
 
+	// Ambient occlusion buffers
+	GLuint AmbientTexture0 = 0;
+	GLuint AmbientTexture1 = 0;
+	GLuint AmbientFB0 = 0;
+	GLuint AmbientFB1 = 0;
+	int AmbientWidth = 0;
+	int AmbientHeight = 0;
+	GLuint AmbientRandomTexture = 0;
+
 	static bool IsEnabled();
 
 	int GetWidth() const { return mWidth; }
@@ -64,17 +76,19 @@ private:
 	void ClearEyeBuffers();
 	void ClearBloom();
 	void ClearExposureLevels();
+	void ClearAmbientOcclusion();
 	void CreateScene(int width, int height, int samples);
 	void CreatePipeline(int width, int height);
 	void CreateBloom(int width, int height);
 	void CreateExposureLevels(int width, int height);
 	void CreateEyeBuffers(int eye);
+	void CreateAmbientOcclusion(int width, int height);
 	GLuint Create2DTexture(const FString &name, GLuint format, int width, int height, const void *data = nullptr);
+	GLuint Create2DMultisampleTexture(const FString &name, GLuint format, int width, int height, int samples, bool fixedSampleLocations);
 	GLuint CreateRenderBuffer(const FString &name, GLuint format, int width, int height);
 	GLuint CreateRenderBuffer(const FString &name, GLuint format, int samples, int width, int height);
 	GLuint CreateFrameBuffer(const FString &name, GLuint colorbuffer);
-	GLuint CreateFrameBuffer(const FString &name, GLuint colorbuffer, GLuint depthstencil, bool colorIsARenderBuffer);
+	GLuint CreateFrameBuffer(const FString &name, GLuint colorbuffer0, GLuint colorbuffer1, GLuint depthstencil, bool multisample);
-	GLuint CreateFrameBuffer(const FString &name, GLuint colorbuffer, GLuint depth, GLuint stencil, bool colorIsARenderBuffer);
 	bool CheckFrameBufferCompleteness();
 	void ClearFrameBuffer(bool stencil, bool depth);
 	void DeleteTexture(GLuint &handle);
@@ -94,9 +108,9 @@ private:
 	// Buffers for the scene
 	GLuint mSceneMultisample = 0;
 	GLuint mSceneDepthStencil = 0;
-	GLuint mSceneDepth = 0;
+	GLuint mSceneData = 0;
-	GLuint mSceneStencil = 0;
 	GLuint mSceneFB = 0;
+	GLuint mSceneDataFB = 0;
 
 	// Effect/HUD buffers
 	GLuint mPipelineTexture[NumPipelineTextures];

src/gl/renderer/gl_renderer.cpp

@@ -51,6 +51,7 @@
 #include "gl/data/gl_vertexbuffer.h"
 #include "gl/scene/gl_drawinfo.h"
 #include "gl/shaders/gl_shader.h"
+#include "gl/shaders/gl_ambientshader.h"
 #include "gl/shaders/gl_bloomshader.h"
 #include "gl/shaders/gl_blurshader.h"
 #include "gl/shaders/gl_tonemapshader.h"
@@ -121,6 +122,8 @@ void gl_FlushModels();
 void FGLRenderer::Initialize(int width, int height)
 {
 	mBuffers = new FGLRenderBuffers();
+	mLinearDepthShader = new FLinearDepthShader();
+	mSSAOShader = new FSSAOShader();
 	mBloomExtractShader = new FBloomExtractShader();
 	mBloomCombineShader = new FBloomCombineShader();
 	mExposureExtractShader = new FExposureExtractShader();
@@ -184,6 +187,8 @@ FGLRenderer::~FGLRenderer()
 	}
 	if (mBuffers) delete mBuffers;
 	if (mPresentShader) delete mPresentShader;
+	if (mLinearDepthShader) delete mLinearDepthShader;
+	if (mSSAOShader) delete mSSAOShader;
 	if (mBloomExtractShader) delete mBloomExtractShader;
 	if (mBloomCombineShader) delete mBloomCombineShader;
 	if (mExposureExtractShader) delete mExposureExtractShader;

src/gl/renderer/gl_renderer.h

@@ -19,6 +19,8 @@ class FLightBuffer;
 class FSamplerManager;
 class DPSprite;
 class FGLRenderBuffers;
+class FLinearDepthShader;
+class FSSAOShader;
 class FBloomExtractShader;
 class FBloomCombineShader;
 class FExposureExtractShader;
@@ -93,6 +95,8 @@ public:
 	int mOldFBID;
 
 	FGLRenderBuffers *mBuffers;
+	FLinearDepthShader *mLinearDepthShader;
+	FSSAOShader *mSSAOShader;
 	FBloomExtractShader *mBloomExtractShader;
 	FBloomCombineShader *mBloomCombineShader;
 	FExposureExtractShader *mExposureExtractShader;
@@ -172,6 +176,8 @@ public:
 	void WriteSavePic (player_t *player, FileWriter *file, int width, int height);
 	void EndDrawScene(sector_t * viewsector);
 	void UpdateCameraExposure();
+	void PostProcessScene();
+	void AmbientOccludeScene();
 	void BloomScene();
 	void TonemapScene();
 	void ColormapScene();
@@ -198,6 +204,9 @@ public:
 		DAngle rotation, FDynamicColormap *colormap, int lightlevel);
 
 	int PTM_BestColor (const uint32 *pal_in, int r, int g, int b, int first, int num);
+
+	static float GetZNear() { return 5.f; }
+	static float GetZFar() { return 65536.f; }
 };
 
 // Global functions. Make them members of GLRenderer later?

src/gl/scene/gl_scene.cpp

@@ -209,7 +209,7 @@ void FGLRenderer::SetProjection(float fov, float ratio, float fovratio)
 {
 
 	float fovy = 2 * RAD2DEG(atan(tan(DEG2RAD(fov) / 2) / fovratio));
-	gl_RenderState.mProjectionMatrix.perspective(fovy, ratio, 5.f, 65536.f);
+	gl_RenderState.mProjectionMatrix.perspective(fovy, ratio, GetZNear(), GetZFar());
 }
 
 // raw matrix input from stereo 3d modes
@@ -826,12 +826,7 @@ sector_t * FGLRenderer::RenderViewpoint (AActor * camera, GL_IRECT * bounds, flo
 		if (mainview && toscreen) EndDrawScene(lviewsector); // do not call this for camera textures.
 		if (mainview && FGLRenderBuffers::IsEnabled())
 		{
-			mBuffers->BlitSceneToTexture();
+			PostProcessScene();
-			UpdateCameraExposure();
-			BloomScene();
-			TonemapScene();
-			ColormapScene();
-			LensDistortScene();
 
 			// This should be done after postprocessing, not before.
 			mBuffers->BindCurrentFB();

src/gl/shaders/gl_ambientshader.cpp

@@ -0,0 +1,89 @@
+/*
+** gl_bloomshader.cpp
+** Shaders used for screen space ambient occlusion
+**
+**---------------------------------------------------------------------------
+** Copyright 2016 Magnus Norddahl
+** All rights reserved.
+**
+** Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions
+** are met:
+**
+** 1. Redistributions of source code must retain the above copyright
+**    notice, this list of conditions and the following disclaimer.
+** 2. Redistributions in binary form must reproduce the above copyright
+**    notice, this list of conditions and the following disclaimer in the
+**    documentation and/or other materials provided with the distribution.
+** 3. The name of the author may not be used to endorse or promote products
+**    derived from this software without specific prior written permission.
+** 4. When not used as part of GZDoom or a GZDoom derivative, this code will be
+**    covered by the terms of the GNU Lesser General Public License as published
+**    by the Free Software Foundation; either version 2.1 of the License, or (at
+**    your option) any later version.
+** 5. Full disclosure of the entire project's source code, except for third
+**    party libraries is mandatory. (NOTE: This clause is non-negotiable!)
+**
+** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+**---------------------------------------------------------------------------
+**
+*/
+
+#include "gl/system/gl_system.h"
+#include "files.h"
+#include "m_swap.h"
+#include "v_video.h"
+#include "gl/gl_functions.h"
+#include "vectors.h"
+#include "gl/system/gl_interface.h"
+#include "gl/system/gl_framebuffer.h"
+#include "gl/system/gl_cvars.h"
+#include "gl/shaders/gl_ambientshader.h"
+
+void FLinearDepthShader::Bind()
+{
+	if (!mShader)
+	{
+		mShader.Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
+		mShader.Compile(FShaderProgram::Fragment, "shaders/glsl/lineardepth.fp", "", 330);
+		mShader.SetFragDataLocation(0, "FragColor");
+		mShader.Link("shaders/glsl/lineardepth");
+		mShader.SetAttribLocation(0, "PositionInProjection");
+		DepthTexture.Init(mShader, "DepthTexture");
+		LinearizeDepthA.Init(mShader, "LinearizeDepthA");
+		LinearizeDepthB.Init(mShader, "LinearizeDepthB");
+		InverseDepthRangeA.Init(mShader, "InverseDepthRangeA");
+		InverseDepthRangeB.Init(mShader, "InverseDepthRangeB");
+	}
+	mShader.Bind();
+}
+
+void FSSAOShader::Bind()
+{
+	if (!mShader)
+	{
+		mShader.Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
+		mShader.Compile(FShaderProgram::Fragment, "shaders/glsl/ssao.fp", "", 330);
+		mShader.SetFragDataLocation(0, "FragColor");
+		mShader.Link("shaders/glsl/ssao");
+		mShader.SetAttribLocation(0, "PositionInProjection");
+		DepthTexture.Init(mShader, "DepthTexture");
+		UVToViewA.Init(mShader, "UVToViewA");
+		UVToViewB.Init(mShader, "UVToViewB");
+		InvFullResolution.Init(mShader, "InvFullResolution");
+		NDotVBias.Init(mShader, "NDotVBias");
+		NegInvR2.Init(mShader, "NegInvR2");
+		RadiusToScreen.Init(mShader, "RadiusToScreen");
+		AOMultiplier.Init(mShader, "AOMultiplier");
+	}
+	mShader.Bind();
+}

src/gl/shaders/gl_ambientshader.h

@@ -0,0 +1,39 @@
+#ifndef __GL_AMBIENTSHADER_H
+#define __GL_AMBIENTSHADER_H
+
+#include "gl_shaderprogram.h"
+
+class FLinearDepthShader
+{
+public:
+	void Bind();
+
+	FBufferedUniformSampler DepthTexture;
+	FBufferedUniform1f LinearizeDepthA;
+	FBufferedUniform1f LinearizeDepthB;
+	FBufferedUniform1f InverseDepthRangeA;
+	FBufferedUniform1f InverseDepthRangeB;
+
+private:
+	FShaderProgram mShader;
+};
+
+class FSSAOShader
+{
+public:
+	void Bind();
+
+	FBufferedUniformSampler DepthTexture;
+	FBufferedUniform2f UVToViewA;
+	FBufferedUniform2f UVToViewB;
+	FBufferedUniform2f InvFullResolution;
+	FBufferedUniform1f NDotVBias;
+	FBufferedUniform1f NegInvR2;
+	FBufferedUniform1f RadiusToScreen;
+	FBufferedUniform1f AOMultiplier;
+
+private:
+	FShaderProgram mShader;
+};
+
+#endif

src/gl/stereo3d/gl_stereo3d.cpp

@@ -41,7 +41,7 @@ VSMatrix EyePose::GetProjection(float fov, float aspectRatio, float fovRatio) co
 
 	// Lifted from gl_scene.cpp FGLRenderer::SetProjection()
 	float fovy = (float)(2 * RAD2DEG(atan(tan(DEG2RAD(fov) / 2) / fovRatio)));
-	result.perspective(fovy, aspectRatio, 5.f, 65536.f);
+	result.perspective(fovy, aspectRatio, FGLRenderer::GetZNear(), FGLRenderer::GetZFar());
 
 	return result;
 }

wadsrc/static/language.enu

@@ -2633,6 +2633,7 @@ GLPREFMNU_MULTISAMPLE			= "Multisample";
 GLPREFMNU_TONEMAP				= "Tonemap Mode";
 GLPREFMNU_BLOOM					= "Bloom effect";
 GLPREFMNU_LENS					= "Lens distortion effect";
+GLPREFMNU_SSAO					= "Ambient occlusion";
 
 // Option Values
 OPTVAL_SMART 				= "Smart";

wadsrc/static/menudef.zz

@@ -226,4 +226,5 @@ OptionMenu "GLPrefOptions"
 	Option "$GLPREFMNU_TONEMAP", 				gl_tonemap,						"TonemapModes"
 	Option "$GLPREFMNU_BLOOM",		 			gl_bloom,						"OnOff"
 	Option "$GLPREFMNU_LENS",		 			gl_lens,						"OnOff"
+	Option "$GLPREFMNU_SSAO",		 			gl_ssao,						"OnOff"
 }

wadsrc/static/shaders/glsl/lineardepth.fp

@@ -0,0 +1,16 @@
+
+in vec2 TexCoord;
+out vec4 FragColor;
+
+uniform sampler2D DepthTexture;
+uniform float LinearizeDepthA;
+uniform float LinearizeDepthB;
+uniform float InverseDepthRangeA;
+uniform float InverseDepthRangeB;
+
+void main()
+{
+	float depth = texture(DepthTexture, TexCoord).x;
+	float normalizedDepth = clamp(InverseDepthRangeA * depth + InverseDepthRangeB, 0.0, 1.0);
+	FragColor = vec4(1.0 / (normalizedDepth * LinearizeDepthA + LinearizeDepthB), 0.0, 0.0, 1.0);
+}

wadsrc/static/shaders/glsl/ssao.fp

@@ -0,0 +1,117 @@
+
+in vec2 TexCoord;
+out vec4 FragColor;
+
+uniform vec2 UVToViewA;
+uniform vec2 UVToViewB;
+uniform vec2 InvFullResolution;
+
+uniform float NDotVBias;
+uniform float NegInvR2;
+uniform float RadiusToScreen;
+uniform float AOMultiplier;
+
+uniform sampler2D DepthTexture;
+
+#if USE_RANDOM_TEXTURE
+uniform sampler2D RandomTexture;
+#endif
+
+#define NUM_DIRECTIONS 8.0
+#define NUM_STEPS 4.0
+
+#define PI 3.14159265358979323846
+
+// Calculate eye space position for the specified texture coordinate
+vec3 FetchViewPos(vec2 uv)
+{
+    float z = texture(DepthTexture, uv).x;
+    return vec3((UVToViewA * uv + UVToViewB) * z, z);
+}
+
+vec3 MinDiff(vec3 p, vec3 pr, vec3 pl)
+{
+    vec3 v1 = pr - p;
+    vec3 v2 = p - pl;
+    return (dot(v1, v1) < dot(v2, v2)) ? v1 : v2;
+}
+
+// Reconstruct eye space normal from nearest neighbors
+vec3 ReconstructNormal(vec3 p)
+{
+    vec3 pr = FetchViewPos(TexCoord + vec2(InvFullResolution.x, 0));
+    vec3 pl = FetchViewPos(TexCoord + vec2(-InvFullResolution.x, 0));
+    vec3 pt = FetchViewPos(TexCoord + vec2(0, InvFullResolution.y));
+    vec3 pb = FetchViewPos(TexCoord + vec2(0, -InvFullResolution.y));
+    return normalize(cross(MinDiff(p, pr, pl), MinDiff(p, pt, pb)));
+}
+
+// Compute normalized 2D direction
+vec2 RotateDirection(vec2 dir, vec2 cossin)
+{
+    return vec2(dir.x * cossin.x - dir.y * cossin.y, dir.x * cossin.y + dir.y * cossin.x);
+}
+
+vec4 GetJitter()
+{
+#if !USE_RANDOM_TEXTURE
+    return vec4(1,0,1,1);
+	//vec3 rand = noise3(TexCoord.x + TexCoord.y);
+	//float angle = 2.0 * PI * rand.x / NUM_DIRECTIONS;
+	//return vec4(cos(angle), sin(angle), rand.y, rand.z);
+#else
+	#define RANDOM_TEXTURE_WIDTH 4.0
+    return texture(RandomTexture, gl_FragCoord.xy / RANDOM_TEXTURE_WIDTH);
+#endif
+}
+
+// Calculates the ambient occlusion of a sample
+float ComputeSampleAO(vec3 kernelPos, vec3 normal, vec3 samplePos)
+{
+	vec3 v = samplePos - kernelPos;
+	float distanceSquare = dot(v, v);
+	float nDotV = dot(normal, v) * inversesqrt(distanceSquare);
+	return clamp(nDotV - NDotVBias, 0.0, 1.0) * clamp(distanceSquare * NegInvR2 + 1.0, 0.0, 1.0);
+}
+
+// Calculates the total ambient occlusion for the entire fragment
+float ComputeAO(vec3 viewPosition, vec3 viewNormal)
+{
+    vec4 rand = GetJitter();
+
+	float radiusPixels = RadiusToScreen / viewPosition.z;
+	float stepSizePixels = radiusPixels / (NUM_STEPS + 1.0);
+
+	const float directionAngleStep = 2.0 * PI / NUM_DIRECTIONS;
+	float ao = 0.0;
+
+    for (float directionIndex = 0.0; directionIndex < NUM_DIRECTIONS; ++directionIndex)
+    {
+        float angle = directionAngleStep * directionIndex;
+
+        vec2 direction = RotateDirection(vec2(cos(angle), sin(angle)), rand.xy);
+        float rayPixels = (rand.z * stepSizePixels + 1.0);
+
+        for (float StepIndex = 0.0; StepIndex < NUM_STEPS; ++StepIndex)
+        {
+            vec2 sampleUV = round(rayPixels * direction) * InvFullResolution + TexCoord;
+            vec3 samplePos = FetchViewPos(sampleUV);
+            ao += ComputeSampleAO(viewPosition, viewNormal, samplePos);
+            rayPixels += stepSizePixels;
+        }
+    }
+
+    ao *= AOMultiplier / (NUM_DIRECTIONS * NUM_STEPS);
+    return clamp(1.0 - ao * 2.0, 0.0, 1.0);
+}
+
+void main()
+{
+    vec3 viewPosition = FetchViewPos(TexCoord);
+    vec3 viewNormal = ReconstructNormal(viewPosition);
+	float occlusion = ComputeAO(viewPosition, viewNormal);
+	//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);
+}