PyDoc: Fix warnings from out of bounds include statement

doc/python_api/examples/gpu.2.py

@@ -1,19 +1,45 @@
 """
-3D Lines with Single Color
---------------------------
+Triangle with Custom Shader
+---------------------------
 """
 import bpy
 import gpu
 from gpu_extras.batch import batch_for_shader
 
-coords = [(1, 1, 1), (-2, 0, 0), (-2, -1, 3), (0, 1, 1)]
-shader = gpu.shader.from_builtin('3D_UNIFORM_COLOR')
-batch = batch_for_shader(shader, 'LINES', {"pos": coords})
+vertex_shader = '''
+    uniform mat4 viewProjectionMatrix;
+
+    in vec3 position;
+    out vec3 pos;
+
+    void main()
+    {
+        pos = position;
+        gl_Position = viewProjectionMatrix * vec4(position, 1.0f);
+    }
+'''
+
+fragment_shader = '''
+    uniform float brightness;
+
+    in vec3 pos;
+
+    void main()
+    {
+        gl_FragColor = vec4(pos * brightness, 1.0);
+    }
+'''
+
+coords = [(1, 1, 1), (2, 0, 0), (-2, -1, 3)]
+shader = gpu.types.GPUShader(vertex_shader, fragment_shader)
+batch = batch_for_shader(shader, 'TRIS', {"position": coords})
 
 
 def draw():
     shader.bind()
-    shader.uniform_float("color", (1, 1, 0, 1))
+    matrix = bpy.context.region_data.perspective_matrix
+    shader.uniform_float("viewProjectionMatrix", matrix)
+    shader.uniform_float("brightness", 0.5)
     batch.draw(shader)