Add ssao random texture

src/gl/renderer/gl_postprocess.cpp

@@ -108,6 +108,7 @@ 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(Float, gl_ssao_strength, 0.7, 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)
@@ -155,11 +156,13 @@ void FGLRenderer::AmbientOccludeScene()
 	FGLDebug::PushGroup("AmbientOccludeScene");
 
 	FGLPostProcessState savedState;
+	savedState.SaveTextureBinding1();
 
 	float bias = gl_ssao_bias;
 	float aoRadius = gl_ssao_radius;
 	const float blurAmount = gl_ssao_blur_amount;
 	int blurSampleCount = gl_ssao_blur_samples;
+	float aoStrength = gl_ssao_strength;
 
 	//float tanHalfFovy = tan(fovy * (M_PI / 360.0f));
 	float tanHalfFovy = 1.0f / 1.33333302f; //gl_RenderState.mProjectionMatrix.get()[5];
@@ -185,8 +188,14 @@ void FGLRenderer::AmbientOccludeScene()
 	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);
+	glActiveTexture(GL_TEXTURE1);
+	glBindTexture(GL_TEXTURE_2D, mBuffers->AmbientRandomTexture);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glActiveTexture(GL_TEXTURE0);
 	mSSAOShader->Bind();
 	mSSAOShader->DepthTexture.Set(0);
+	mSSAOShader->RandomTexture.Set(1);
 	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);
@@ -194,6 +203,7 @@ void FGLRenderer::AmbientOccludeScene()
 	mSSAOShader->NegInvR2.Set(-1.0f / r2);
 	mSSAOShader->RadiusToScreen.Set(aoRadius * 0.5 / tanHalfFovy * mBuffers->AmbientHeight);
 	mSSAOShader->AOMultiplier.Set(1.0f / (1.0f - nDotVBias));
+	mSSAOShader->AOStrength.Set(aoStrength);
 	RenderScreenQuad();
 
 	// Blur SSAO texture

src/gl/renderer/gl_postprocessstate.cpp

@@ -58,7 +58,7 @@ FGLPostProcessState::FGLPostProcessState()
 {
 	glGetIntegerv(GL_ACTIVE_TEXTURE, &activeTex);
 	glActiveTexture(GL_TEXTURE0);
-	glGetIntegerv(GL_TEXTURE_BINDING_2D, &textureBinding);
+	glGetIntegerv(GL_TEXTURE_BINDING_2D, &textureBinding[0]);
 	glBindTexture(GL_TEXTURE_2D, 0);
 	if (gl.flags & RFL_SAMPLER_OBJECTS)
 	{
@@ -88,6 +88,15 @@ FGLPostProcessState::FGLPostProcessState()
 	glDisable(GL_BLEND);
 }
 
+void FGLPostProcessState::SaveTextureBinding1()
+{
+	glActiveTexture(GL_TEXTURE1);
+	glGetIntegerv(GL_TEXTURE_BINDING_2D, &textureBinding[1]);
+	glBindTexture(GL_TEXTURE_2D, 0);
+	textureBinding1Saved = true;
+	glActiveTexture(GL_TEXTURE0);
+}
+
 //-----------------------------------------------------------------------------
 //
 // Restores state at the end of post processing
@@ -121,6 +130,12 @@ FGLPostProcessState::~FGLPostProcessState()
 
 	glUseProgram(currentProgram);
 
+	if (textureBinding1Saved)
+	{
+		glActiveTexture(GL_TEXTURE1);
+		glBindTexture(GL_TEXTURE_2D, 0);
+	}
+
 	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, 0);
 	if (gl.flags & RFL_SAMPLER_OBJECTS)
@@ -128,6 +143,13 @@ FGLPostProcessState::~FGLPostProcessState()
 		glBindSampler(0, samplerBinding[0]);
 		glBindSampler(1, samplerBinding[1]);
 	}
-	glBindTexture(GL_TEXTURE_2D, textureBinding);
+	glBindTexture(GL_TEXTURE_2D, textureBinding[0]);
+
+	if (textureBinding1Saved)
+	{
+		glActiveTexture(GL_TEXTURE1);
+		glBindTexture(GL_TEXTURE_2D, textureBinding[1]);
+	}
+
 	glActiveTexture(activeTex);
 }

src/gl/renderer/gl_postprocessstate.h

@@ -14,12 +14,14 @@ public:
 	FGLPostProcessState();
 	~FGLPostProcessState();
 
+	void SaveTextureBinding1();
+
 private:
 	FGLPostProcessState(const FGLPostProcessState &) = delete;
 	FGLPostProcessState &operator=(const FGLPostProcessState &) = delete;
 
 	GLint activeTex;
-	GLint textureBinding;
+	GLint textureBinding[2];
 	GLint samplerBinding[2];
 	GLboolean blendEnabled;
 	GLboolean scissorEnabled;
@@ -32,6 +34,7 @@ private:
 	GLint blendSrcAlpha;
 	GLint blendDestRgb;
 	GLint blendDestAlpha;
+	bool textureBinding1Saved = false;
 };
 
 #endif

src/gl/renderer/gl_renderbuffers.cpp

@@ -53,6 +53,7 @@
 #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);
@@ -129,6 +130,7 @@ void FGLRenderBuffers::ClearAmbientOcclusion()
 	DeleteFrameBuffer(AmbientFB1);
 	DeleteTexture(AmbientTexture0);
 	DeleteTexture(AmbientTexture1);
+	DeleteTexture(AmbientRandomTexture);
 }
 
 void FGLRenderBuffers::DeleteTexture(GLuint &handle)
@@ -334,6 +336,26 @@ void FGLRenderBuffers::CreateAmbientOcclusion(int width, int height)
 	AmbientTexture1 = Create2DTexture("AmbientTexture1", GetHdrFormat(), 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 * 32768.0, -32767.0, 32768.0);
+		randomValues[i * 4 + 1] = (int16_t)clamp(y * 32768.0, -32767.0, 32768.0);
+		randomValues[i * 4 + 2] = (int16_t)clamp(z * 32768.0, -32767.0, 32768.0);
+		randomValues[i * 4 + 3] = (int16_t)clamp(w * 32768.0, -32767.0, 32768.0);
+	}
+
+	AmbientRandomTexture = Create2DTexture("AmbientRandomTexture", GL_RGBA16_SNORM, 4, 4, randomValues);
 }
 
 //==========================================================================
@@ -353,7 +375,7 @@ GLuint FGLRenderBuffers::GetHdrFormat()
 //
 //==========================================================================
 
-GLuint FGLRenderBuffers::Create2DTexture(const FString &name, GLuint format, int width, int height)
+GLuint FGLRenderBuffers::Create2DTexture(const FString &name, GLuint format, int width, int height, const void *data)
 {
 	GLuint handle = 0;
 	glGenTextures(1, &handle);
@@ -369,10 +391,11 @@ GLuint FGLRenderBuffers::Create2DTexture(const FString &name, GLuint format, int
 	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, nullptr);
+	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);

src/gl/renderer/gl_renderbuffers.h

@@ -43,6 +43,7 @@ public:
 	GLuint AmbientFB1 = 0;
 	int AmbientWidth = 0;
 	int AmbientHeight = 0;
+	GLuint AmbientRandomTexture = 0;
 
 	static bool IsEnabled();
 
@@ -58,7 +59,7 @@ private:
 	void CreatePipeline(int width, int height);
 	void CreateBloom(int width, int height);
 	void CreateAmbientOcclusion(int width, int height);
-	GLuint Create2DTexture(const FString &name, GLuint format, int width, int height);
+	GLuint Create2DTexture(const FString &name, GLuint format, int width, int height, const void *data = nullptr);
 	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);

src/gl/shaders/gl_ambientshader.cpp

@@ -71,12 +71,20 @@ void FSSAOShader::Bind()
 {
 	if (!mShader)
 	{
+		const char *defines = R"(
+			#define USE_RANDOM_TEXTURE
+			#define RANDOM_TEXTURE_WIDTH 4.0
+			#define NUM_DIRECTIONS 8.0
+			#define NUM_STEPS 4.0
+		)";
+
 		mShader.Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
-		mShader.Compile(FShaderProgram::Fragment, "shaders/glsl/ssao.fp", "", 330);
+		mShader.Compile(FShaderProgram::Fragment, "shaders/glsl/ssao.fp", defines, 330);
 		mShader.SetFragDataLocation(0, "FragColor");
 		mShader.Link("shaders/glsl/ssao");
 		mShader.SetAttribLocation(0, "PositionInProjection");
 		DepthTexture.Init(mShader, "DepthTexture");
+		RandomTexture.Init(mShader, "RandomTexture");
 		UVToViewA.Init(mShader, "UVToViewA");
 		UVToViewB.Init(mShader, "UVToViewB");
 		InvFullResolution.Init(mShader, "InvFullResolution");
@@ -84,6 +92,7 @@ void FSSAOShader::Bind()
 		NegInvR2.Init(mShader, "NegInvR2");
 		RadiusToScreen.Init(mShader, "RadiusToScreen");
 		AOMultiplier.Init(mShader, "AOMultiplier");
+		AOStrength.Init(mShader, "AOStrength");
 	}
 	mShader.Bind();
 }

src/gl/shaders/gl_ambientshader.h

@@ -24,6 +24,7 @@ public:
 	void Bind();
 
 	FBufferedUniformSampler DepthTexture;
+	FBufferedUniformSampler RandomTexture;
 	FBufferedUniform2f UVToViewA;
 	FBufferedUniform2f UVToViewB;
 	FBufferedUniform2f InvFullResolution;
@@ -31,6 +32,7 @@ public:
 	FBufferedUniform1f NegInvR2;
 	FBufferedUniform1f RadiusToScreen;
 	FBufferedUniform1f AOMultiplier;
+	FBufferedUniform1f AOStrength;
 
 private:
 	FShaderProgram mShader;

wadsrc/static/shaders/glsl/ssao.fp

@@ -11,15 +11,14 @@ uniform float NegInvR2;
 uniform float RadiusToScreen;
 uniform float AOMultiplier;
 
+uniform float AOStrength;
+
 uniform sampler2D DepthTexture;
 
-#if USE_RANDOM_TEXTURE
+#if defined(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
@@ -54,13 +53,12 @@ vec2 RotateDirection(vec2 dir, vec2 cossin)
 
 vec4 GetJitter()
 {
-#if !USE_RANDOM_TEXTURE
+#if !defined(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
 }
@@ -109,7 +107,11 @@ void main()
 {
     vec3 viewPosition = FetchViewPos(TexCoord);
     vec3 viewNormal = ReconstructNormal(viewPosition);
-	float occlusion = ComputeAO(viewPosition, viewNormal);
+	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);