Move SSAO pass to be before translucent rendering

Fix depth sampling location when not using fullscreen scene

src/gl/renderer/gl_postprocess.cpp

@@ -136,7 +136,6 @@ void FGLRenderer::RenderScreenQuad()
 
 void FGLRenderer::PostProcessScene()
 {
-	AmbientOccludeScene();
 	mBuffers->BlitSceneToTexture();
 	BloomScene();
 	TonemapScene();
@@ -187,6 +186,8 @@ void FGLRenderer::AmbientOccludeScene()
 	mLinearDepthShader->LinearizeDepthB[multisample].Set(MAX(1.0f / GetZNear(), 1.e-8f));
 	mLinearDepthShader->InverseDepthRangeA[multisample].Set(1.0f);
 	mLinearDepthShader->InverseDepthRangeB[multisample].Set(0.0f);
+	mLinearDepthShader->Scale[multisample].Set(mSceneViewport.width / (float)mScreenViewport.width, mSceneViewport.height / (float)mScreenViewport.height);
+	mLinearDepthShader->Offset[multisample].Set(mSceneViewport.left / (float)mScreenViewport.width, mSceneViewport.top / (float)mScreenViewport.height);
 	RenderScreenQuad();
 
 	// Apply ambient occlusion
@@ -246,7 +247,6 @@ void FGLRenderer::AmbientOccludeScene()
 	mSSAOCombineShader->Bind();
 	mSSAOCombineShader->AODepthTexture.Set(0);
 	RenderScreenQuad();
-	glViewport(mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
 
 	FGLDebug::PopGroup();
 }

src/gl/scene/gl_scene.cpp

@@ -503,6 +503,8 @@ void FGLRenderer::DrawScene(int drawmode)
 
 	RenderScene(recursion);
 
+	AmbientOccludeScene();
+
 	// Handle all portals after rendering the opaque objects but before
 	// doing all translucent stuff
 	recursion++;

src/gl/shaders/gl_ambientshader.cpp

@@ -65,6 +65,8 @@ void FLinearDepthShader::Bind(bool multisample)
 		LinearizeDepthB[multisample].Init(shader, "LinearizeDepthB");
 		InverseDepthRangeA[multisample].Init(shader, "InverseDepthRangeA");
 		InverseDepthRangeB[multisample].Init(shader, "InverseDepthRangeB");
+		Scale[multisample].Init(shader, "Scale");
+		Offset[multisample].Init(shader, "Offset");
 	}
 	shader.Bind();
 }

src/gl/shaders/gl_ambientshader.h

@@ -14,6 +14,8 @@ public:
 	FBufferedUniform1f LinearizeDepthB[2];
 	FBufferedUniform1f InverseDepthRangeA[2];
 	FBufferedUniform1f InverseDepthRangeB[2];
+	FBufferedUniform2f Scale[2];
+	FBufferedUniform2f Offset[2];
 
 private:
 	FShaderProgram mShader[2];

wadsrc/static/shaders/glsl/lineardepth.fp

@@ -8,28 +8,34 @@ uniform int SampleCount;
 #else
 uniform sampler2D DepthTexture;
 #endif
+
 uniform float LinearizeDepthA;
 uniform float LinearizeDepthB;
 uniform float InverseDepthRangeA;
 uniform float InverseDepthRangeB;
+uniform vec2 Scale;
+uniform vec2 Offset;
 
 void main()
 {
+	vec2 uv = Offset + TexCoord * Scale;
+
 #if defined(MULTISAMPLE)
 	ivec2 texSize = textureSize(DepthTexture);
-	ivec2 ipos = ivec2(TexCoord * vec2(texSize));
+	ivec2 ipos = ivec2(uv * vec2(texSize));
 	float depth = 0.0;
 	for (int i = 0; i < SampleCount; i++)
 		depth += texelFetch(DepthTexture, ipos, i).x;
 	depth /= float(SampleCount);
 #else
 	/*ivec2 texSize = textureSize(DepthTexture, 0);
-	ivec2 ipos = ivec2(TexCoord * vec2(texSize));
+	ivec2 ipos = ivec2(uv * vec2(texSize));
 	if (ipos.x < 0) ipos.x += texSize.x;
 	if (ipos.y < 0) ipos.y += texSize.y;
 	float depth = texelFetch(DepthTexture, ipos, 0).x;*/
-	float depth = texture(DepthTexture, TexCoord).x;
+	float depth = texture(DepthTexture, uv).x;
 #endif
+
 	float normalizedDepth = clamp(InverseDepthRangeA * depth + InverseDepthRangeB, 0.0, 1.0);
 	FragColor = vec4(1.0 / (normalizedDepth * LinearizeDepthA + LinearizeDepthB), 0.0, 0.0, 1.0);
 }