feat: deferred lighting (WIP)

src/graphics/core/GBuffer.cpp

@@ -84,6 +84,26 @@ void GBuffer::createDepthBuffer() {
     );
 }
 
+void GBuffer::createSSAOBuffer() {
+    glGenTextures(1, &ssaoBuffer);
+    glBindTexture(GL_TEXTURE_2D, ssaoBuffer);
+    glTexImage2D(
+        GL_TEXTURE_2D,
+        0,
+        GL_R16F,
+        width,
+        height,
+        0,
+        GL_RED,
+        GL_FLOAT,
+        nullptr
+    );
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_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);
+}
+
 GBuffer::GBuffer(uint width, uint height) : width(width), height(height) {
     glGenFramebuffers(1, &fbo);
     glBindFramebuffer(GL_FRAMEBUFFER, fbo);
@@ -100,7 +120,20 @@ GBuffer::GBuffer(uint width, uint height) : width(width), height(height) {
     createDepthBuffer();
 
     if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
-        logger.error() << "framebuffer is not complete!";
+        logger.error() << "gbuffer is not complete!";
+    }
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+    glGenFramebuffers(1, &ssaoFbo);
+    glBindFramebuffer(GL_FRAMEBUFFER, ssaoFbo);
+    createSSAOBuffer();
+    glFramebufferTexture2D(
+        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, ssaoBuffer, 0
+    );
+    GLenum ssaoAttachments[1] = {GL_COLOR_ATTACHMENT0};
+    glDrawBuffers(1, ssaoAttachments);
+    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+        logger.error() << "SSAO framebuffer is not complete!";
     }
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
 }
@@ -109,8 +142,10 @@ GBuffer::~GBuffer() {
     glDeleteTextures(1, &colorBuffer);
     glDeleteTextures(1, &positionsBuffer);
     glDeleteTextures(1, &normalsBuffer);
+    glDeleteTextures(1, &ssaoBuffer);
     glDeleteRenderbuffers(1, &depthBuffer);
     glDeleteFramebuffers(1, &fbo);
+    glDeleteFramebuffers(1, &ssaoFbo);
 }
 
 void GBuffer::bind() {
@@ -118,6 +153,11 @@ void GBuffer::bind() {
     glClear(GL_COLOR_BUFFER_BIT);
 }
 
+void GBuffer::bindSSAO() const {
+    glBindFramebuffer(GL_FRAMEBUFFER, ssaoFbo);
+    glClear(GL_COLOR_BUFFER_BIT);
+}
+
 void GBuffer::unbind() {
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
 }
@@ -133,6 +173,10 @@ void GBuffer::bindBuffers() const {
     glBindTexture(GL_TEXTURE_2D, colorBuffer);
 }
 
+void GBuffer::bindSSAOBuffer() const {
+    glBindTexture(GL_TEXTURE_2D, ssaoBuffer);
+}
+
 void GBuffer::resize(uint width, uint height) {
     if (this->width == width && this->height == height) {
         return;
@@ -180,6 +224,17 @@ void GBuffer::resize(uint width, uint height) {
 
     glBindTexture(GL_TEXTURE_2D, 0);
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+    glBindFramebuffer(GL_FRAMEBUFFER, ssaoFbo);
+    glBindTexture(GL_TEXTURE_2D, ssaoBuffer);
+    glTexImage2D(
+        GL_TEXTURE_2D, 0, GL_R16F, width, height, 0, GL_RED, GL_FLOAT, nullptr
+    );
+    glFramebufferTexture2D(
+        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, ssaoBuffer, 0
+    );
+    glBindTexture(GL_TEXTURE_2D, 0);
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
 }
 
 std::unique_ptr<ImageData> GBuffer::toImage() const {

src/graphics/core/GBuffer.hpp

@@ -10,9 +10,11 @@ public:
     ~GBuffer() override;
 
     void bind() override;
+    void bindSSAO() const;
     void unbind() override;
 
     void bindBuffers() const;
+    void bindSSAOBuffer() const;
 
     void resize(uint width, uint height);
 
@@ -29,9 +31,12 @@ private:
     uint positionsBuffer;
     uint normalsBuffer;
     uint depthBuffer;
+    uint ssaoFbo;
+    uint ssaoBuffer;
 
     void createColorBuffer();
     void createPositionsBuffer();
     void createNormalsBuffer();
     void createDepthBuffer();
+    void createSSAOBuffer();
 };

src/graphics/core/PostProcessing.cpp

@@ -88,7 +88,9 @@ void PostProcessing::configureEffect(
         shader.uniform1i("u_position", 1);
         shader.uniform1i("u_normal", 2);
     }
-    shader.uniform1i("u_noise", 3);
+    shader.uniform1i("u_noise", 3); // used in SSAO pass
+    shader.uniform1i("u_ssao", 3);
+
     shader.uniform1i("u_shadows", 4);
     shader.uniform2i("u_screenSize", viewport);
     shader.uniform1f("u_timer", timer);
@@ -126,13 +128,25 @@ void PostProcessing::render(
         glBindTexture(GL_TEXTURE_2D, noiseTexture);
 
         glActiveTexture(GL_TEXTURE0);
+
+        auto& ssaoEffect = assets.require<PostEffect>("ssao");
+        auto& shader = ssaoEffect.use();
+        configureEffect(context, ssaoEffect, shader, timer, camera, shadowMap);
+        gbuffer->bindSSAO();
+        quadMesh->draw();
+        gbuffer->unbind();
+
+        glActiveTexture(GL_TEXTURE3);
+        gbuffer->bindSSAOBuffer();
     } else {
         glActiveTexture(GL_TEXTURE0);
         fbo->getTexture()->bind();
     }
 
     if (totalPasses == 0) {
-        auto& effect = assets.require<PostEffect>("default");
+        auto& effect = assets.require<PostEffect>(
+            gbuffer ? "deferred_lighting" : "default"
+        );
         auto& shader = effect.use();
         configureEffect(context, effect, shader, timer, camera, shadowMap);
         quadMesh->draw();

src/logic/scripting/lua/libs/libposteffects.cpp

@@ -17,7 +17,10 @@ static int l_set_effect(lua::State* L) {
     size_t index = static_cast<size_t>(lua::tointeger(L, 1));
     auto name = lua::require_string(L, 2);
     auto& assets = *engine->getAssets();
-    auto effect = std::make_shared<PostEffect>(assets.require<PostEffect>(name));
+    auto effect = assets.getShared<PostEffect>(name);
+    if (effect == nullptr) {
+        throw std::runtime_error(std::string("post-effect '") + name + "' not found");
+    }
     post_processing->setEffect(index, std::move(effect));
     return 0;
 }