Initial work to support SSAO: rendering position and normal maps

data/shaders/fs_default.glsl

@@ -20,6 +20,8 @@ smooth in vec4 ioFragColor;
 in vec4 ioFragPosLightSpace;
 
 out vec4 outColor;
+out vec3 outPosition;
+out vec3 outNormal;
 
 float ShadowCalculationPCF(vec4 frag_pos_light_space) {
 	vec3 projected_coordinates = frag_pos_light_space.xyz / frag_pos_light_space.w;
@@ -88,19 +90,9 @@ void main() {
 	vec4 specular = spec * vec4(0.5);
 
 	// shadow
-//	float shadow = ShadowCalculation(ioFragPosLightSpace);
 	float shadow = ShadowCalculationPCF(ioFragPosLightSpace);
 	outColor = ambient + (1.0 - shadow) * (diffuse + specular);
-//
-//
-//	vec3 projected_coordinates = ioFragPosLightSpace.xyz / ioFragPosLightSpace.w;
-//	projected_coordinates = projected_coordinates * 0.5 + 0.5;
-//	float shadow_map_value = texture(uShadowMap, projected_coordinates.xy).r;
-//	outColor = shadow_map_value * vec4(1.0, 1.0, 1.0, 1.0);
-//
-//	outColor = vec4(vec3(1.0f - shadow_map_value), 1.0);
 
-//	outColor = (shadow) * vec4(1.0, 1.0, 1.0, 1.0);
+	outPosition = ioFragPosition.xyz;
-//	outColor = ioFragPosLightSpace / ioFragPosLightSpace.w;
+	outNormal = ioFragNormal;
-//	outColor = ambient + diffuse + specular;
 }

src/modules/RenderModule.cc

@@ -87,6 +87,8 @@ static void module_serialize (
 		Serializer* serializer) {
 	SerializeBool(*serializer, "protot.RenderModule.DrawDepth", sRendererSettings.DrawDepth);
 	SerializeBool(*serializer, "protot.RenderModule.DrawLightDepth", sRendererSettings.DrawLightDepth);
+	SerializeBool(*serializer, "protot.RenderModule.mIsSSAOEnabled", gRenderer->mIsSSAOEnabled);
+
 	SerializeBool(*serializer, "protot.RenderModule.Camera.mIsOrthographic", gRenderer->mCamera.mIsOrthographic);
 	SerializeFloat(*serializer, "protot.RenderModule.Camera.mFov", gRenderer->mCamera.mFov);
 	SerializeVec3(*serializer, "protot.RenderModule.Camera.mEye", gRenderer->mCamera.mEye);
@@ -374,10 +376,16 @@ void Renderer::Initialize(int width, int height) {
 
 	// Render Target
 	gLog("Initializing main render target size: %d,%d", width, height);
-	mRenderTarget.Initialize(width, height, 
+	int render_target_flags = RenderTarget::EnableColor 
-			RenderTarget::EnableColor 
 			| RenderTarget::EnableDepthTexture 
-			| RenderTarget::EnableLinearizedDepthTexture);
+			| RenderTarget::EnableLinearizedDepthTexture;
+
+	if (mIsSSAOEnabled) {
+		render_target_flags = render_target_flags
+			| RenderTarget::EnablePositionTexture
+			| RenderTarget::EnableNormalTexture;
+	}
+	mRenderTarget.Initialize(width, height, render_target_flags);
 
 	mRenderTarget.mVertexArray = &gVertexArray;
 	mRenderTarget.mQuadMesh = &gScreenQuad;
@@ -404,8 +412,22 @@ void Renderer::Shutdown() {
 void Renderer::RenderGl() {
 	mSceneAreaWidth = mSceneAreaWidth < 1 ? 1 : mSceneAreaWidth;
 	mSceneAreaHeight = mSceneAreaHeight < 1 ? 1 : mSceneAreaHeight;
-	if (mSceneAreaWidth != mRenderTarget.mWidth || mSceneAreaHeight != mRenderTarget.mHeight) {
+
-		mRenderTarget.Resize(mSceneAreaWidth, mSceneAreaHeight);
+	// TODO: Refactor enabling/disabling buffers for SSAO
+	int required_render_flags = RenderTarget::EnableColor 
+			| RenderTarget::EnableDepthTexture 
+			| RenderTarget::EnableLinearizedDepthTexture;
+
+	if (mIsSSAOEnabled) {
+		required_render_flags = required_render_flags
+			| RenderTarget::EnablePositionTexture
+			| RenderTarget::EnableNormalTexture;
+	}
+
+	if (mSceneAreaWidth != mRenderTarget.mWidth 
+			|| mSceneAreaHeight != mRenderTarget.mHeight
+			|| mRenderTarget.mFlags != required_render_flags ) {
+		mRenderTarget.Resize(mSceneAreaWidth, mSceneAreaHeight, required_render_flags);
 	}
 
 	if (mCamera.mWidth != mSceneAreaWidth
@@ -488,6 +510,13 @@ void Renderer::RenderGl() {
 		gLog ("Warning: Uniform %s not found!", "uLightSpaceMatrix");
 	}
 
+	if (mIsSSAOEnabled) {
+		GLenum buffers[] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT2, GL_COLOR_ATTACHMENT3 };
+		glDrawBuffers (3, buffers);
+	} else {
+		GLenum buffers[] = { GL_COLOR_ATTACHMENT0};
+		glDrawBuffers (1, buffers);
+	}
 	RenderScene(mDefaultProgram, mCamera);
 
 	if (mSettings->DrawDepth) {
@@ -593,19 +622,32 @@ void Renderer::DrawGui() {
 	ImGui::EndDock();
 
 	if (ImGui::BeginDock("Render Settings")) {
-		ImGui::Text("Scene");
-		ImGui::SliderFloat("Moving Factor", &moving_factor, -10.0f, 10.0f);
-
 		ImGui::Text("Camera");
 		mCamera.DrawGui();
 
-		ImGui::Text("Default Texture");
+		ImGui::Checkbox("Enable SSAO", &mIsSSAOEnabled);
+
+		if (mIsSSAOEnabled) {
+			ImGui::Text("Position Texture");
+			mPositionTextureRef.mTextureIdPtr = &mRenderTarget.mPositionTexture;
+			mPositionTextureRef.magic = (GLuint)0xbadface;
+			float aspect = mRenderTarget.mHeight / mRenderTarget.mWidth;
 			ImVec2 content_avail = ImGui::GetContentRegionAvail();
-		ImGui::Image((void*) mDefaultTexture.mTextureId, 
+			ImGui::Image((void*) &mPositionTextureRef,
-				ImVec2(content_avail.x, content_avail.x),
+					ImVec2(content_avail.x, content_avail.x * aspect),
 					ImVec2(0.0f, 1.0f),
 					ImVec2(1.0f, 0.0f)
 					);
+
+			ImGui::Text("Normal Texture");
+			mNormalTextureRef.mTextureIdPtr = &mRenderTarget.mNormalTexture;
+			mNormalTextureRef.magic = (GLuint)0xbadface;
+			ImGui::Image((void*) &mNormalTextureRef,
+					ImVec2(content_avail.x, content_avail.x * aspect),
+					ImVec2(0.0f, 1.0f),
+					ImVec2(1.0f, 0.0f)
+					);
+		}
 	}
 	ImGui::EndDock();
 

src/modules/RenderModule.h

@@ -55,6 +55,8 @@ struct Renderer {
 	RendererSettings* mSettings = nullptr;
 
 	bool mInitialized = false;
+	bool mIsSSAOEnabled = false;
+
 	uint32_t mWidth = 1;
 	uint32_t mHeight = 1;
 	uint32_t mSceneAreaWidth = 1;
@@ -72,6 +74,8 @@ struct Renderer {
 
 	RenderTarget mRenderTarget;
 	GLTextureRef mRenderTextureRef = { (int)0xbadface };
+	GLTextureRef mPositionTextureRef = { (int)0xbadface };
+	GLTextureRef mNormalTextureRef = { (int)0xbadface };
 
 	Renderer() :
 		mInitialized(false),

src/modules/RenderUtils.cc

@@ -153,6 +153,10 @@ GLuint RenderProgram::LinkProgram(GLuint vertex_shader, GLuint fragment_shader)
 	glBindAttribLocation(ProgramID, 2, "inUV");
 	glBindAttribLocation(ProgramID, 3, "inColor");
 
+	glBindFragDataLocation(ProgramID, 0, "outColor");
+	glBindFragDataLocation(ProgramID, 1, "outPosition");
+	glBindFragDataLocation(ProgramID, 2, "outNormal");
+
 	glLinkProgram(ProgramID);
 
 	GLint Result = GL_FALSE;
@@ -277,14 +281,29 @@ void RenderTarget::Initialize(int width, int height, int flags) {
 
 	mFlags = flags;
 
-	Resize(width, height);
+	Resize(width, height, mFlags);
 }
 
 void RenderTarget::Bind() {
 	assert(glIsFramebuffer(mFrameBufferId));
 	glBindFramebuffer(GL_FRAMEBUFFER, mFrameBufferId);
-	GLenum shadow_map_draw_buffers[] = { GL_COLOR_ATTACHMENT0 };
+
-	glDrawBuffers(1, shadow_map_draw_buffers);
+	GLenum buffers[8];
+	int num_buffers = 0;
+
+	if (mFlags & EnableColor) {
+		buffers[num_buffers++] = GL_COLOR_ATTACHMENT0;
+	}
+
+	if (mFlags & EnablePositionTexture ) {
+		buffers[num_buffers++] = GL_COLOR_ATTACHMENT2;
+	}
+
+	if (mFlags & EnableNormalTexture) {
+		buffers[num_buffers++] = GL_COLOR_ATTACHMENT3;
+	}
+
+	glDrawBuffers(num_buffers, buffers);
 }
 
 void RenderTarget::Cleanup() {
@@ -313,17 +332,30 @@ void RenderTarget::Cleanup() {
 		mLinearizedDepthTexture = -1;
 	}
 
+	if (mPositionTexture != -1) {
+		glDeleteTextures(1, &mPositionTexture);
+		mPositionTexture = -1;
+	}
+
+	if (mNormalTexture != -1) {
+		glDeleteTextures(1, &mNormalTexture);
+		mNormalTexture = -1;
+	}
+
 	mWidth = -1;
 	mHeight = -1;
+	mFlags = 0;
 }
 
-void RenderTarget::Resize(int width, int height) {
+void RenderTarget::Resize(int width, int height, int flags) {
-	if (width == mWidth && height == mHeight)
+	if (width == mWidth && height == mHeight && flags == mFlags)
 		return;
 
 	Cleanup();
 
-	gLog("Resizing RenderTarget to %d,%d", width, height);
+	mFlags = flags;
+
+	gLog("Resizing RenderTarget to %d,%d flags: %d", width, height, flags);
 
 	mWidth = width;
 	mHeight = height;
@@ -360,7 +392,6 @@ void RenderTarget::Resize(int width, int height) {
 		float border_color[] = { 1.0f, 1.0f, 1.0f, 1.0f };
 		glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, border_color);
 
-
 		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, mDepthTexture, 0);
 
 		if (mFlags & EnableLinearizedDepthTexture) {
@@ -383,6 +414,32 @@ void RenderTarget::Resize(int width, int height) {
 		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, mDepthBuffer);
 	}
 
+	if (mFlags & EnablePositionTexture) {
+		glGenTextures(1, &mPositionTexture);
+		glBindTexture(GL_TEXTURE_2D, mPositionTexture);
+
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB16F, mWidth, mHeight, 0, GL_RGB, GL_FLOAT, NULL);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, GL_TEXTURE_2D, mPositionTexture, 0);
+	}
+
+	if (mFlags & EnableNormalTexture) {
+		glGenTextures(1, &mNormalTexture);
+		glBindTexture(GL_TEXTURE_2D, mNormalTexture);
+
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB16F, mWidth, mHeight, 0, GL_RGB, GL_FLOAT, NULL);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT3, GL_TEXTURE_2D, mNormalTexture, 0);
+	}
+
 	GLenum result = glCheckFramebufferStatus(GL_FRAMEBUFFER);
 	if (result != GL_FRAMEBUFFER_COMPLETE) {
 		switch (result) {

src/modules/RenderUtils.h

@@ -254,12 +254,16 @@ struct RenderTarget {
 	GLuint mDepthBuffer = -1;
 	GLuint mDepthTexture = -1;
 	GLuint mLinearizedDepthTexture = -1;
+	GLuint mPositionTexture = -1;
+	GLuint mNormalTexture = -1;
 
 	typedef enum {
 		EnableColor = 1,
 		EnableDepth = 2,
 		EnableDepthTexture = 4,
-		EnableLinearizedDepthTexture = 8
+		EnableLinearizedDepthTexture = 8,
+		EnablePositionTexture = 16,
+		EnableNormalTexture = 32,
 	} Flags;
 
 	int mFlags = 0;
@@ -274,7 +278,7 @@ struct RenderTarget {
 	void Initialize(int width, int height, int flags);
 	void Bind();
 	void Cleanup();
-	void Resize(int width, int height);
+	void Resize(int width, int height, int flags);
 
 	void RenderToLinearizedDepth(const float& near, const float& far, bool is_orthographic);
 };