Better Shadows

imgui.ini

@@ -9,7 +9,7 @@ Size=894,195
 Collapsed=0
 
 [Window][Debug Utils]
-Pos=14,6
+Pos=13,15
 Size=863,335
 Collapsed=0
 

res/shaders/basic.frag

@@ -78,7 +78,7 @@ void computeShading(
 
 float computeAttenuation(vec3 lightPos, vec3 fragPos, float K_q);
 
-float computeShadows(vec4 fragPosLightSpace);
+float computeShadows(vec4 fragPosLightSpace, vec3 normal, vec3 lightDir);
 
 void main() {
 
@@ -93,10 +93,6 @@ void main() {
         fragmentColor += pointLightContribution(u_pointLight[i], normal, v_fragmentPosition, viewDir);
     }
 
-    // This is not final: ambient lighting should not be affected of shadows.
-    float shadows = computeShadows(v_fragmentPositionLightSpace);
-    fragmentColor *= (1.0f - shadows);
-
     //fragmentColor += spotLightContribution(u_spotLight, normal, v_fragmentPosition, viewDir);
 
     f_color = vec4(fragmentColor, 1.0f);
@@ -114,7 +110,9 @@ vec3 directionalLightContribution(DirectionalLight light, vec3 normal, vec3 view
     vec3 ambient, diffuse, specular;
     computeShading(light.ambient, light.diffuse, light.specular, lightDir, viewDir, normal, ambient, diffuse, specular);
 
-    return (ambient + diffuse + specular) * 1.0f;
+    float shadows = computeShadows(v_fragmentPositionLightSpace, normal, lightDir);
+
+    return (ambient + (1.0f - shadows) * (diffuse + specular)) * 1.0f;
 }
 
 vec3 pointLightContribution(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir) {
@@ -191,7 +189,7 @@ float computeAttenuation(vec3 lightPos, vec3 fragPos, float K_q) {
 
 }
 
-float computeShadows(vec4 fragPosLightSpace) {
+float computeShadows(vec4 fragPosLightSpace, vec3 normal, vec3 lightDir) {
 
     // Perspective divide
     vec3 projCoords = fragPosLightSpace.xyz / fragPosLightSpace.w;
@@ -200,10 +198,25 @@ float computeShadows(vec4 fragPosLightSpace) {
     projCoords *= 0.5f;
     projCoords += 0.5f;
 
+    if(projCoords.z > 1.0f) return 0.0f;
+
     float closestDepth = texture(u_texture_shadowMap, projCoords.xy).r;
     float currentDepth = projCoords.z;
 
-    float shadow = currentDepth > closestDepth  ? 1.0 : 0.0;
+    float bias = max(0.05 * (1.0 - dot(normal, lightDir)), 0.005);
+
+    float shadow = 0.0;
+    vec2 texelSize = 1.0 / textureSize(u_texture_shadowMap, 0);
+    for(int x = -1; x <= 1; ++x)
+    {
+        for(int y = -1; y <= 1; ++y)
+        {
+            float pcfDepth = texture(u_texture_shadowMap, projCoords.xy + vec2(x, y) * texelSize).r; 
+            shadow += currentDepth - bias > pcfDepth ? 1.0 : 0.0;        
+        }    
+    }
+    shadow /= 9.0;
+
 
     return shadow;
 }

res/shaders/shadowDepth.frag

@@ -2,4 +2,6 @@
 
 void main() {
     
+    // Empty as we aren't rendering to any color buffer
+
 }

src/World.cpp

@@ -79,17 +79,22 @@ void World::calculateShadows(ShaderProgram *p_shaderProgram) {
 
     glClear(GL_DEPTH_BUFFER_BIT);
     // ConfigureShaderAndMatrices();
-    float near_plane = 0.1f, far_plane = 7.5f;
+    float near_plane = 1.0f, far_plane = 15.0f;
     glm::mat4 lightProjection = glm::ortho(-10.0f, 10.0f, -10.0f, 10.0f, near_plane, far_plane);
-    glm::mat4 lightView = glm::lookAt(-glm::vec3(-0.2f, -1.0f, -0.3f), glm::vec3( 0.0f, 0.0f,  0.0f), glm::vec3( 0.0f, 1.0f,  0.0f));
+    glm::mat4 lightView = glm::lookAt(-5.0f * glm::vec3(-0.2f, -1.0f, -0.3f), glm::vec3( 0.0f, 0.0f,  0.0f), glm::vec3( 0.0f, 1.0f,  0.0f));
     glm::mat4 lightViewProjectionMatrix = lightProjection * lightView;
 
+    // Switch face culling (Peter panning)
+    glCullFace(GL_BACK);
+
     // Draw scene from light perspective
     // Draw all entities
     for(auto it = entities.begin(); it != entities.end(); it++) {
         it->drawShadows(lightViewProjectionMatrix, p_shaderProgram);
     }
 
+    glCullFace(GL_FRONT);
+
     depthMapFBO.unbind();
 
     // Reset viewport size

src/World.h

@@ -40,7 +40,7 @@ private:
     //SpotLight spotLight;
 
     // Shadows
-    const int SHADOW_RES = 1024;
+    const int SHADOW_RES = 4096;
     DepthMap depthMapFBO;
 
 };