Minor lighting improvements

Shader/bump.fs

@@ -59,6 +59,11 @@ vec2 get_parallax_offset_uv(vec2 uv, vec3 view_direction) {
     return current_uv;
 }
 
+// Return a linear interpolation (0..1) of value between low and high, or 0.0 / 1.0 if value is below / above the bounds
+float linear_step(float low, float high, float value) {
+    return clamp((value - low) / (high - low), 0.0, 1.0);
+}
+
 float get_shadow(vec4 fragPosLightSpace, vec3 normal) {
     // perform perspective divide
     mediump vec3 projCoords = fragPosLightSpace.xyz / fragPosLightSpace.w;
@@ -72,17 +77,20 @@ float get_shadow(vec4 fragPosLightSpace, vec3 normal) {
     vec2 moments = texture(shadowMap, projCoords.xy).rg;
 
     // get closest depth value from light's perspective (using [0,1] range fragPosLight as coords)
-    mediump float closestDepth = texture(shadowMap, projCoords.xy).r; 
+    mediump float closestDepth = moments.r; 
     // get depth of current fragment from light's perspective
     mediump float currentDepth = projCoords.z;
     // check whether current frag pos is in shadow
     float p = step(projCoords.z, moments.x);
+
     // We divide by this later, so make sure it's not exactly 0
     // It seems like it should always be 0.0, but due to interpolation it's not -- it increases with the deviation!
-    float variance = max(moments.y - moments.x * moments.x, 0.00002);
+    // A larger second parameter to max() means more blur (but also more light bleeding)
+    float variance = max(moments.y - moments.x * moments.x, (-0.01 + (currentDepth - closestDepth) * 0.7) * 0.1);
 
-    float d = projCoords.z - moments.x * 1.0; // bias should be "compare", what is that?
-    float p_max = variance / (variance + d * d);
+    float d = projCoords.z - moments.x * 1.0;
+    // Use linear_step to prevent light bleeding
+    float p_max = linear_step(0.2, 1.0, variance / (variance + d * d));
 
     // If this pixel is exactly in the light, p is 1, so make sure we return that in that case
     // min() to make sure that it doesn't get greater than 1.0

Shader/bump.vs

@@ -35,7 +35,7 @@ void main() {
     vec3 N   = normalize(mat3(model) * aNormal);
     mat3 TBN = transpose(mat3(T, B, N));
 
-    vs_out.TangentLightDir = light_direction;
+    vs_out.TangentLightDir = TBN * -light_direction;
     vs_out.TangentViewPos  = TBN * viewPos;
     vs_out.TangentFragPos  = TBN * vs_out.FragPos;
 }   

Shader/shadow.fs

@@ -1,7 +1,9 @@
 #version 430
 
+out vec4 FragColor;
+
 void main()
 {      
     // The mean and the mean squared, which we need to calculate the variance
-    gl_FragColor = vec4(gl_FragCoord.z, gl_FragCoord.z * gl_FragCoord.z, 0.0, 0.0);
+    FragColor = vec4(gl_FragCoord.z, gl_FragCoord.z * gl_FragCoord.z, 0.0, 0.0);
 }

include/Gedeng/DirectionalLight.h

@@ -10,28 +10,6 @@ class DirectionalLight {
   public:
     glm::vec3 direction;
 
-    DirectionalLight() : shadow_shader(Gedeng::Shader("Shader/shadow.vs", "Shader/shadow.fs")) {
-        // Configure depth map
-        glGenFramebuffers(1, &depth_map_fbo);
-
-        // Create depth texture
-        glGenTextures(1, &depth_map);
-        glBindTexture(GL_TEXTURE_2D, depth_map);
-        // R and G with 32 bit floats: stores mean and variance
-        glTexImage2D(GL_TEXTURE_2D, 0, GL_RG32F, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
-
-        // Attach depth texture as FBO's depth buffer
-        glBindFramebuffer(GL_FRAMEBUFFER, depth_map_fbo);
-        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, depth_map, 0);
-        glDrawBuffer(GL_NONE);
-        glReadBuffer(GL_NONE);
-        glBindFramebuffer(GL_FRAMEBUFFER, 0);
-    }
-
     explicit DirectionalLight(glm::vec3 direction)
         // TODO: Avoid all this duplication
         : direction(direction), shadow_shader(Gedeng::Shader("Shader/shadow.vs", "Shader/shadow.fs")) {
@@ -41,8 +19,7 @@ class DirectionalLight {
         // Create depth texture
         glGenTextures(1, &depth_map);
         glBindTexture(GL_TEXTURE_2D, depth_map);
-        glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT,
-                     NULL);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RG32F, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_RGB, GL_FLOAT, NULL);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
@@ -50,9 +27,7 @@ class DirectionalLight {
 
         // Attach depth texture as FBO's depth buffer
         glBindFramebuffer(GL_FRAMEBUFFER, depth_map_fbo);
-        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depth_map, 0);
-        glDrawBuffer(GL_NONE);
-        glReadBuffer(GL_NONE);
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, depth_map, 0);
         glBindFramebuffer(GL_FRAMEBUFFER, 0);
     }
 

test/shadow-demo/main.cpp

@@ -92,10 +92,10 @@ class ShadowDemo : public Gedeng::Application {
     void dynamic_update(double delta) override {
         // Shadows
         light.clear_shadows();
+        light.render_shadow(quad_mesh);
         light.render_shadow(mesh1);
         light.render_shadow(mesh2);
         light.render_shadow(mesh3);
-        light.render_shadow(quad_mesh);
 
         glViewport(0, 0, 1920, 1080);
         glClearColor(0.1, 0.1f, 0.1, 1.0f);