Add ssao random texture

src/gl/renderer/gl_postprocess.cpp

@@ -100,6 +100,7 @@ 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)
@@ -148,11 +149,13 @@ 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];
@@ -178,8 +181,14 @@ 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);
@@ -187,6 +196,7 @@ 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/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);