gpu_particle_burst_02.py Diff

gpu_particle_burst_02.py

--- /home/docs/checkouts/readthedocs.org/user_builds/arcade-library/checkouts/latest/doc/tutorials/gpu_particle_burst/gpu_particle_burst_01.py
+++ /home/docs/checkouts/readthedocs.org/user_builds/arcade-library/checkouts/latest/doc/tutorials/gpu_particle_burst/gpu_particle_burst_02.py
@@ -1,21 +1,50 @@
 """
 Example showing how to create particle explosions via the GPU.
 """
+from array import array
+from dataclasses import dataclass
+
 import arcade
+import arcade.gl
 
 SCREEN_WIDTH = 1024
 SCREEN_HEIGHT = 768
 SCREEN_TITLE = "GPU Particle Explosion"
 
 
+@dataclass
+class Burst:
+    """ Track for each burst. """
+    buffer: arcade.gl.Buffer
+    vao: arcade.gl.Geometry
+
+
 class MyWindow(arcade.Window):
     """ Main window"""
     def __init__(self):
         super().__init__(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
+        self.burst_list = []
+
+        # Program to visualize the points
+        self.program = self.ctx.load_program(
+            vertex_shader="vertex_shader_v1.glsl",
+            fragment_shader="fragment_shader.glsl",
+        )
+
+        self.ctx.enable_only()
 
     def on_draw(self):
         """ Draw everything """
         self.clear()
+
+        # Set the particle size
+        self.ctx.point_size = 2 * self.get_pixel_ratio()
+
+        # Loop through each burst
+        for burst in self.burst_list:
+
+            # Render the burst
+            burst.vao.render(self.program, mode=self.ctx.POINTS)
 
     def on_update(self, dt):
         """ Update everything """
@@ -23,7 +52,35 @@
 
     def on_mouse_press(self, x: float, y: float, button: int, modifiers: int):
         """ User clicks mouse """
-        pass
+
+        def _gen_initial_data(initial_x, initial_y):
+            """ Generate data for each particle """
+            yield initial_x
+            yield initial_y
+
+        # Recalculate the coordinates from pixels to the OpenGL system with
+        # 0, 0 at the center.
+        x2 = x / self.width * 2. - 1.
+        y2 = y / self.height * 2. - 1.
+
+        # Get initial particle data
+        initial_data = _gen_initial_data(x2, y2)
+
+        # Create a buffer with that data
+        buffer = self.ctx.buffer(data=array('f', initial_data))
+
+        # Create a buffer description specifying the buffer's data format
+        buffer_description = arcade.gl.BufferDescription(
+            buffer,
+            '2f',
+            ['in_pos'])
+
+        # Create our Vertex Attribute Object
+        vao = self.ctx.geometry([buffer_description])
+
+        # Create the Burst object and add it to the list of bursts
+        burst = Burst(buffer=buffer, vao=vao)
+        self.burst_list.append(burst)
 
 
 if __name__ == "__main__":