refactor(render): unify model and player rendering with single shader pipeline

assets/shaders/model_frag.glsl

@@ -3,13 +3,45 @@
 in vec2 tc;
 in vec3 normal;
 in vec3 vert_pos;
-
+in vec4 FragPosLightSpace;
 out vec4 color;
 
-layout (binding = 0) uniform sampler2D samp;
+layout (binding = 0) uniform sampler2D shadowMap;
+layout (binding = 1) uniform sampler2D samp;
 
+uniform float ambientStrength;
+uniform vec3 sunlightColor;
+uniform vec3 ambientColor;
+uniform vec3 sunlightDir;
+uniform bool shader_on;
+uniform int shadowMode;
+uniform float lightSizeUV; 
+uniform float minRadius;
+uniform float maxRadius;
+
+#include "shadow.glsl"
 
 void main() {
-    color = texture(samp, tc);
+    vec4 objectColor = texture(samp, tc);
 
+    if (!shader_on) {
+        color = objectColor;
+        return;
+    }
+   
+    vec3 lightDir = normalize(-sunlightDir);
+    
+    vec3 norm = normalize(normal);
+
+    vec3 ambient = ambientStrength * ambientColor;
+    
+    float diff = max(dot(norm, lightDir), 0.0);
+    
+    vec3 diffuse = diff * sunlightColor;
+ 
+    float shadow = ShadowCalculation(FragPosLightSpace, norm, lightDir);  
+    //float shadow = 0.0;
+    //color = vec4(vec3(shadow),1);
+    //color = vec4(vec3(diff),1);
+    color = vec4((ambient + (1.0 - shadow) * (diffuse)) * objectColor.rgb, objectColor.a);
 }