添加多模型渲染，添加贴图渲染，添加平行光， 暂时不上传assets

shaders/simple_shader.frag

@@ -1,9 +1,38 @@
 #version 450
 
-layout(location = 0) in vec3 fragColor;
+const int MAX_LIGHTS = 4;
+
+struct Light {
+    vec4 direction;
+    vec4 color;
+};
+
+layout(location = 0) in vec2 fragUV;
+layout(location = 1) in vec3 fragNormal;
+layout(location = 2) in vec3 fragWorldPos;
 
 layout(location = 0) out vec4 outColor;
 
+layout(set = 0, binding = 0) uniform UniformBufferObject {
+    mat4 view;
+    mat4 proj;
+    vec4 ambientColor;
+    Light lights[MAX_LIGHTS];
+} ubo;
+
+layout(set = 1, binding = 0) uniform sampler2D texSampler;
+
 void main() {
-    outColor = vec4(fragColor, 1.0);
+    vec3 albedo = texture(texSampler, fragUV).rgb;
+    vec3 N = normalize(fragNormal);
+
+    vec3 result = ubo.ambientColor.rgb * albedo;
+
+    for (int i = 0; i < MAX_LIGHTS; ++i) {
+        vec3 L = normalize(-ubo.lights[i].direction.xyz);
+        float diff = max(dot(N, L), 0.0);
+        result += ubo.lights[i].color.rgb * ubo.lights[i].color.a * diff * albedo;
+    }
+
+    outColor = vec4(result, 1.0);
 }