Textures and colors passed to shader via Uniforms

shaders/flat.frag

@@ -1,9 +1,24 @@
 #version 330 core
 
-uniform vec3 color;
+in vec2 UV;
 
 out vec4 FragColor;
 
+struct Material {
+  vec3 color;
+  bool usesColor;
+  sampler2D tex;
+  bool usesTex;
+};
+
+uniform Material material;
+
 void main() {
-  FragColor = vec4(color, 1.0);  
+  FragColor = vec4(0.0);
+  if (material.usesColor) {
+    FragColor += vec4(material.color, 1.0);
+  }
+  if (material.usesTex) {
+    FragColor += texture(material.tex, UV);
+  }
 }

shaders/flat.vert

@@ -1,11 +1,15 @@
 #version 330 core
 
 layout (location = 0) in vec3 pos;
+layout (location = 1) in vec2 uv;
 
 uniform mat4 MODEL;
 uniform mat4 VIEW;
 uniform mat4 PROJECTION;
 
+out vec2 UV;
+
 void main() {
   gl_Position = PROJECTION * VIEW * MODEL * vec4(pos, 1.0);
+  UV = uv;
 }