fix unfinished example

szabolcsdombi · Jul 5, 2024 · ed0e8db · ed0e8db
1 parent 1db3576
commit ed0e8db
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Showing 2 changed files with 12 additions and 5 deletions.
diff --git a/README.md b/README.md
@@ -186,6 +186,7 @@ pipeline = ctx.pipeline(
 
 ```py
 particle_system = ctx.pipeline(
+    vertex_shader=...,
     fragment_shader='''
         #version 330 core
 
@@ -197,8 +198,11 @@ particle_system = ctx.pipeline(
         layout (location = 1) out vec3 OutputVelocity;
 
         void main() {
-            OutputPosition = Position + Velocity;
-            OutputVelocity = Velocity + Acceleration;
+            ivec2 at = ivec2(gl_FragCoord.xy);
+            vec3 position = texelFetch(Position, at, 0).xyz;
+            vec3 velocity = texelFetch(Velocity, at, 0).xyz;
+            OutputPosition = position + velocity;
+            OutputVelocity = velocity + Acceleration;
         }
     ''',
 )

diff --git a/docs/index.rst b/docs/index.rst
@@ -187,6 +187,7 @@ Postprocessing and Compute can be implemented as rendering a fullscreen quad.
 .. code::
 
     particle_system = ctx.pipeline(
+        vertex_shader=...,
         fragment_shader='''
             #version 330 core
 
@@ -198,10 +199,12 @@ Postprocessing and Compute can be implemented as rendering a fullscreen quad.
             layout (location = 1) out vec3 OutputVelocity;
 
             void main() {
-                OutputPosition = Position + Velocity;
-                OutputVelocity = Velocity + Acceleration;
+                ivec2 at = ivec2(gl_FragCoord.xy);
+                vec3 position = texelFetch(Position, at, 0).xyz;
+                vec3 velocity = texelFetch(Velocity, at, 0).xyz;
+                OutputPosition = position + velocity;
+                OutputVelocity = velocity + Acceleration;
             }
-        ''',
     )
 
 ZenGL intentionally does not support: