Updated SSAO tutorial.

src/5.advanced_lighting/9.ssao/ssao.cpp

@@ -22,7 +22,7 @@
 #include <learnopengl/filesystem.h>
 
 // Properties
-const GLuint SCR_WIDTH = 800, SCR_HEIGHT = 600;
+const GLuint SCR_WIDTH = 1280, SCR_HEIGHT = 720;
 
 // Function prototypes
 void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
@@ -87,12 +87,12 @@ int main()
 
     // Set samplers
     shaderLightingPass.Use();
-    glUniform1i(glGetUniformLocation(shaderLightingPass.Program, "gPositionDepth"), 0);
+    glUniform1i(glGetUniformLocation(shaderLightingPass.Program, "gPosition"), 0);
     glUniform1i(glGetUniformLocation(shaderLightingPass.Program, "gNormal"), 1);
     glUniform1i(glGetUniformLocation(shaderLightingPass.Program, "gAlbedo"), 2); 
     glUniform1i(glGetUniformLocation(shaderLightingPass.Program, "ssao"), 3); 
     shaderSSAO.Use();
-    glUniform1i(glGetUniformLocation(shaderSSAO.Program, "gPositionDepth"), 0);
+    glUniform1i(glGetUniformLocation(shaderSSAO.Program, "gPosition"), 0);
     glUniform1i(glGetUniformLocation(shaderSSAO.Program, "gNormal"), 1);
     glUniform1i(glGetUniformLocation(shaderSSAO.Program, "texNoise"), 2);
 
@@ -105,22 +105,22 @@ int main()
 
     // Set up G-Buffer
     // 3 textures:
-    // 1. Positions + depth (RGBA)
+    // 1. Positions (RGB)
     // 2. Color (RGB) 
     // 3. Normals (RGB) 
     GLuint gBuffer;
     glGenFramebuffers(1, &gBuffer);
     glBindFramebuffer(GL_FRAMEBUFFER, gBuffer);
-    GLuint gPositionDepth, gNormal, gAlbedo;
+    GLuint gPosition, gNormal, gAlbedo;
-    // - Position + linear depth color buffer
+    // - Position buffer
-    glGenTextures(1, &gPositionDepth);
+    glGenTextures(1, &gPosition);
-    glBindTexture(GL_TEXTURE_2D, gPositionDepth);
+    glBindTexture(GL_TEXTURE_2D, gPosition);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, SCR_WIDTH, SCR_HEIGHT, 0, GL_RGB, GL_FLOAT, NULL);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB16F, SCR_WIDTH, SCR_HEIGHT, 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_ATTACHMENT0, GL_TEXTURE_2D, gPositionDepth, 0);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, gPosition, 0);
     // - Normal color buffer
     glGenTextures(1, &gNormal);
     glBindTexture(GL_TEXTURE_2D, gNormal);
@@ -221,7 +221,6 @@ int main()
         glfwPollEvents();
         Do_Movement();
 
-
         // 1. Geometry Pass: render scene's geometry/color data into gbuffer
         glBindFramebuffer(GL_FRAMEBUFFER, gBuffer);
             glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
@@ -239,7 +238,7 @@ int main()
             // Nanosuit model on the floor
             model = glm::mat4();
             model = glm::translate(model, glm::vec3(0.0f, 0.0f, 5.0));
-            model = glm::rotate(model, -90.0f, glm::vec3(1.0, 0.0, 0.0));
+            model = glm::rotate(model, glm::radians(-90.0f), glm::vec3(1.0, 0.0, 0.0));
             model = glm::scale(model, glm::vec3(0.5f));
             glUniformMatrix4fv(glGetUniformLocation(shaderGeometryPass.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
             nanosuit.Draw(shaderGeometryPass);
@@ -251,7 +250,7 @@ int main()
             glClear(GL_COLOR_BUFFER_BIT);
             shaderSSAO.Use();
             glActiveTexture(GL_TEXTURE0);
-            glBindTexture(GL_TEXTURE_2D, gPositionDepth);
+            glBindTexture(GL_TEXTURE_2D, gPosition);
             glActiveTexture(GL_TEXTURE1);
             glBindTexture(GL_TEXTURE_2D, gNormal);
             glActiveTexture(GL_TEXTURE2);
@@ -278,7 +277,7 @@ int main()
         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
         shaderLightingPass.Use();
         glActiveTexture(GL_TEXTURE0);
-        glBindTexture(GL_TEXTURE_2D, gPositionDepth);
+        glBindTexture(GL_TEXTURE_2D, gPosition);
         glActiveTexture(GL_TEXTURE1);
         glBindTexture(GL_TEXTURE_2D, gNormal);
         glActiveTexture(GL_TEXTURE2);
@@ -436,8 +435,6 @@ void Do_Movement()
         draw_mode = 3;
     if (keys[GLFW_KEY_4])
         draw_mode = 4;
-    if (keys[GLFW_KEY_5])
-        draw_mode = 5;
 }
 
 GLfloat lastX = 400, lastY = 300;

src/5.advanced_lighting/9.ssao/ssao.frag

@@ -2,7 +2,7 @@
 out float FragColor;
 in vec2 TexCoords;
 
-uniform sampler2D gPositionDepth;
+uniform sampler2D gPosition;
 uniform sampler2D gNormal;
 uniform sampler2D texNoise;
 
@@ -10,17 +10,18 @@ uniform vec3 samples[64];
 
 // parameters (you'd probably want to use them as uniforms to more easily tweak the effect)
 int kernelSize = 64;
-float radius = 1.0;
+float radius = 0.5;
+float bias = 0.025;
 
 // tile noise texture over screen based on screen dimensions divided by noise size
-const vec2 noiseScale = vec2(800.0f/4.0f, 600.0f/4.0f); 
+const vec2 noiseScale = vec2(1280.0/4.0, 720.0/4.0); 
 
 uniform mat4 projection;
 
 void main()
 {
     // Get input for SSAO algorithm
-    vec3 fragPos = texture(gPositionDepth, TexCoords).xyz;
+    vec3 fragPos = texture(gPosition, TexCoords).xyz;
     vec3 normal = texture(gNormal, TexCoords).rgb;
     vec3 randomVec = texture(texNoise, TexCoords * noiseScale).xyz;
     // Create TBN change-of-basis matrix: from tangent-space to view-space
@@ -42,11 +43,11 @@ void main()
         offset.xyz = offset.xyz * 0.5 + 0.5; // transform to range 0.0 - 1.0
         
         // get sample depth
-        float sampleDepth = -texture(gPositionDepth, offset.xy).w; // Get depth value of kernel sample
+        float sampleDepth = texture(gPosition, offset.xy).z; // Get depth value of kernel sample
         
         // range check & accumulate
         float rangeCheck = smoothstep(0.0, 1.0, radius / abs(fragPos.z - sampleDepth));
-        occlusion += (sampleDepth >= sample.z ? 1.0 : 0.0) * rangeCheck;           
+        occlusion += (sampleDepth >= sample.z + bias ? 1.0 : 0.0) * rangeCheck;           
     }
     occlusion = 1.0 - (occlusion / kernelSize);
     

src/5.advanced_lighting/9.ssao/ssao_geometry.frag

@@ -1,5 +1,5 @@
 #version 330 core
-layout (location = 0) out vec4 gPositionDepth;
+layout (location = 0) out vec3 gPosition;
 layout (location = 1) out vec3 gNormal;
 layout (location = 2) out vec4 gAlbedoSpec;
 
@@ -7,20 +7,10 @@ in vec2 TexCoords;
 in vec3 FragPos;
 in vec3 Normal;
 
-const float NEAR = 0.1;
-const float FAR = 50.0f;
-float LinearizeDepth(float depth)
-{
-    float z = depth * 2.0 - 1.0; // Back to NDC 
-    return (2.0 * NEAR * FAR) / (FAR + NEAR - z * (FAR - NEAR));	
-}
-
 void main()
 {    
     // Store the fragment position vector in the first gbuffer texture
-    gPositionDepth.xyz = FragPos;
+    gPosition = FragPos;
-    // And store linear depth into gPositionDepth's alpha component
-    gPositionDepth.a = LinearizeDepth(gl_FragCoord.z); // Divide by far to store depth in range 0.0 - 1.0
     // Also store the per-fragment normals into the gbuffer
     gNormal = normalize(Normal);
     // And the diffuse per-fragment color

src/5.advanced_lighting/9.ssao/ssao_lighting.frag

@@ -2,7 +2,7 @@
 out vec4 FragColor;
 in vec2 TexCoords;
 
-uniform sampler2D gPositionDepth;
+uniform sampler2D gPosition;
 uniform sampler2D gNormal;
 uniform sampler2D gAlbedo;
 uniform sampler2D ssao;
@@ -21,10 +21,9 @@ uniform int draw_mode;
 void main()
 {             
     // Retrieve data from gbuffer
-    vec3 FragPos = texture(gPositionDepth, TexCoords).rgb;
+    vec3 FragPos = texture(gPosition, TexCoords).rgb;
     vec3 Normal = texture(gNormal, TexCoords).rgb;
     vec3 Diffuse = texture(gAlbedo, TexCoords).rgb;
-    float Depth = texture(gPositionDepth, TexCoords).a;
     float AmbientOcclusion = texture(ssao, TexCoords).r;
     
     // Then calculate lighting as usual
@@ -49,11 +48,9 @@ void main()
     if(draw_mode == 1)
         FragColor = vec4(lighting, 1.0);
     else if(draw_mode == 2)
-        FragColor = vec4(vec3(Depth / 50.0), 1.0);
-    else if(draw_mode == 3)
         FragColor = vec4(FragPos, 1.0);
-     else if(draw_mode == 4)
+     else if(draw_mode == 3)
         FragColor = vec4(Normal, 1.0);
-    else if(draw_mode == 5)
+    else if(draw_mode == 4)
         FragColor = vec4(vec3(AmbientOcclusion), 1.0);
 }