refactor shadows.glsl

res/shaders/lib/shadows.glsl

@@ -4,59 +4,36 @@
 uniform sampler2DShadow u_shadows[2];
 uniform mat4 u_shadowsMatrix[2];
 uniform float u_dayTime;
-
 uniform int u_shadowsRes;
 
 float calc_shadow() {
-    float shadow = 1.0;
+    if (!u_enableShadows) {
-    if (u_enableShadows) {
+        return 1.0;
-        vec4 mpos = u_shadowsMatrix[0] * vec4(a_modelpos.xyz + a_realnormal * 0.04, 1.0);
-        vec3 projCoords = mpos.xyz / mpos.w;
-        projCoords = projCoords * 0.5 + 0.5;
-        projCoords.z -= 0.0001;
-
-        vec4 wmpos = u_shadowsMatrix[1] * vec4(a_modelpos.xyz + a_realnormal * 0.2, 1.0);
-        vec3 wprojCoords = wmpos.xyz / wmpos.w;
-        wprojCoords = wprojCoords * 0.5 + 0.5;
-        wprojCoords.z -= 0.0001;
-
-        shadow = 0.0;
-        
-        // TODO: optimize
-        if (dot(a_realnormal, u_sunDir) < 0.0 || true) {
-            if (a_distance > 128) {
-                for (int y = -1; y <= 1; y++) {
-                    for (int x = -1; x <= 1; x++) {
-                        shadow += texture(
-                            u_shadows[1],
-                            wprojCoords.xyz +
-                                vec3(x, y, -(abs(x) + abs(y))) /
-                                    u_shadowsRes
-                        );
-                    }
-                }
-                shadow /= 9;
-            } else {
-                for (int y = -2; y <= 2; y++) {
-                    for (int x = -2; x <= 2; x++) {
-                        shadow += texture(
-                            u_shadows[0],
-                            projCoords.xyz +
-                                vec3(x, y, -(abs(x) + abs(y))) /
-                                    u_shadowsRes * 1.0
-                        );
-                    }
-                }
-                shadow /= 25;
-            }
-            float s = abs(cos(u_dayTime * 3.141592 * 2.0));
-            s = pow(s, 0.7);
-            shadow = mix(0.5, shadow * 0.5 + 0.5, s);
-        } else {
-            shadow = 0.5;
-        }
     }
-    return shadow;
+
+    float step = 1.0 / float(u_shadowsRes);
+    float s = pow(abs(cos(u_dayTime * 6.283185)), 0.7); // 2*PI precomputed
+    vec3 normalOffset = a_realnormal * (a_distance > 128.0 ? 0.2 : 0.04);
+    int shadowIdx = a_distance > 128.0 ? 1 : 0;
+
+    vec4 mpos = u_shadowsMatrix[shadowIdx] * vec4(a_modelpos.xyz + normalOffset, 1.0);
+    vec3 projCoords = mpos.xyz / mpos.w;
+    projCoords = projCoords * 0.5 + 0.5;
+    projCoords.z -= 0.0001;
+
+    float shadow = 0.0;
+    if (dot(a_realnormal, u_sunDir) < 0.0) {
+        for (int y = -1; y <= 1; y++) {
+            for (int x = -1; x <= 1; x++) {
+                vec3 offset = vec3(x, y, -(abs(x) + abs(y))) * step;
+                shadow += texture(u_shadows[shadowIdx], projCoords + offset);
+            }
+        }
+        shadow /= 9.0;
+    } else {
+        shadow = 0.5;
+    }
+    return 0.5 * (1.0 + s * shadow);
 }
 
 #endif // SHADOWS_GLSL_