feat: water rendering (#13)

* refactor: update water texture

* feat(gameplay): implement transparent block rendering with depth sorting

* fix(world): use camera pos for distance calculations, make water passable

* refactor(player): use ivec3 for block pass check

* feat(camera): add underwater detection

* feat(renderer): add underwater effect with framebuffer post-processing

* feat(block): add gas property and refactor solid block check

* fix(assets): set leaf block transparency to false

* fix(block): set leaf as transparent

assets/shaders/under_water_f_shader.glsl

@@ -0,0 +1,35 @@
+#version 460
+
+in vec2 TexCoord;
+
+out vec4 FragColor;
+
+uniform sampler2D u_sceneTexture;
+uniform float u_time;
+uniform bool u_underwater;
+uniform vec3 u_waterColor;
+uniform float u_fogDensity;
+
+void main() {
+    vec4 original = texture(u_sceneTexture, TexCoord);
+
+    if (!u_underwater) {
+        FragColor = original;
+        return;
+    }
+
+    vec2 distoredUV = TexCoord;
+    float strength = 0.003;
+    distoredUV.x += sin(TexCoord.y * 15.0 + u_time * 5.0) * strength;
+    distoredUV.y += cos(TexCoord.x * 15.0 + u_time * 4.3) * strength;
+    distoredUV = clamp(distoredUV, 0.001, 0.999);
+    vec4 distorted = texture(u_sceneTexture, distoredUV);
+
+    float caustic = 0.9 + 0.1 * sin(TexCoord.x * 20.0 + u_time) * cos(TexCoord.y * 20.0 + u_time * 1.2);
+    vec3 causticLight = vec3(caustic, caustic * 0.95, caustic * 0.9);
+    //vec3 causticLight = vec3(1.0);
+    float fogFactor = clamp(1.0 - (TexCoord.y * u_fogDensity * 10.0), 0.0, 1.0);
+    vec3 mixed = mix(u_waterColor, distorted.rgb * causticLight, fogFactor);
+
+    FragColor = vec4(mixed, 1.0);
+}

assets/shaders/under_water_v_shader.glsl

@@ -0,0 +1,11 @@
+#version 460
+
+layout (location = 0) in vec2 pos;
+layout (location = 1) in vec2 texCoord;
+
+out vec2 TexCoord;
+
+void main() {
+    gl_Position = vec4(pos.x, pos.y, 0.0, 1.0);
+    TexCoord = texCoord;
+}