From ae745b040cd57e31bf5c64e34cba832f4a16fb12 Mon Sep 17 00:00:00 2001
From: Richard Higgins <richard@relh.net>
Date: Sun, 4 Oct 2026 00:44:44 -0700
Subject: [PATCH 1/2] Release terrain and shadow shader objects after linking

---
 src/polyworld/quadterrain.nim    |  5 ++++
 src/polyworld/shadows.nim        |  5 ++++
 tests/render_shader_lifetime.nim | 51 ++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+)
 create mode 100644 tests/render_shader_lifetime.nim

diff --git a/src/polyworld/quadterrain.nim b/src/polyworld/quadterrain.nim
index bb387aeb..651947f6 100644
--- a/src/polyworld/quadterrain.nim
+++ b/src/polyworld/quadterrain.nim
@@ -817,6 +817,11 @@ proc compileProgram(vertexSource, fragmentSource: string): GLuint =
   glAttachShader(result, vertexShader)
   glAttachShader(result, fragmentShader)
   glLinkProgram(result)
+  # The linked executable owns its code; release the compilation objects.
+  glDetachShader(result, vertexShader)
+  glDetachShader(result, fragmentShader)
+  glDeleteShader(vertexShader)
+  glDeleteShader(fragmentShader)
   var ok: GLint
   glGetProgramiv(result, GL_LINK_STATUS, ok.addr)
   if ok == 0:
diff --git a/src/polyworld/shadows.nim b/src/polyworld/shadows.nim
index 73e5fa66..0badaef2 100644
--- a/src/polyworld/shadows.nim
+++ b/src/polyworld/shadows.nim
@@ -129,6 +129,11 @@ proc compileDepthProgram(vertexSource, fragmentSource: string): GLuint =
   glAttachShader(result, vertexShader)
   glAttachShader(result, fragmentShader)
   glLinkProgram(result)
+  # The linked executable owns its code; release the compilation objects.
+  glDetachShader(result, vertexShader)
+  glDetachShader(result, fragmentShader)
+  glDeleteShader(vertexShader)
+  glDeleteShader(fragmentShader)
   var ok: GLint
   glGetProgramiv(result, GL_LINK_STATUS, ok.addr)
   if ok == 0:
diff --git a/tests/render_shader_lifetime.nim b/tests/render_shader_lifetime.nim
new file mode 100644
index 00000000..b14776fa
--- /dev/null
+++ b/tests/render_shader_lifetime.nim
@@ -0,0 +1,51 @@
+## Run in a GL context; use -d:testSunDepth for the shadow builder.
+import opengl, vmath, windy
+
+when defined(testSunDepth):
+  include ../src/polyworld/shadows
+else:
+  include ../src/polyworld/quadterrain
+
+const
+  vertex = """#version 330 core
+void main() {
+  vec2 vertices[3] = vec2[3](vec2(-1, -1), vec2(3, -1), vec2(-1, 3));
+  gl_Position = vec4(vertices[gl_VertexID], 0, 1);
+}
+"""
+  fragment = """#version 330 core
+out vec4 color;
+void main() { color = vec4(1, 0, 0, 1); }
+"""
+
+let window = newWindow("Linked shader lifetime", ivec2(32), vsync = false)
+window.makeContextCurrent()
+loadExtensions()
+var vao: GLuint
+glGenVertexArrays(1, vao.addr)
+glBindVertexArray(vao)
+glViewport(0, 0, 32, 32)
+
+for cycle in 0 ..< 3:
+  let program =
+    when defined(testSunDepth): compileDepthProgram(vertex, fragment)
+    else: compileProgram(vertex, fragment)
+  var attached, linked: GLint
+  glGetProgramiv(program, GL_ATTACHED_SHADERS, attached.addr)
+  glGetProgramiv(program, GL_LINK_STATUS, linked.addr)
+  doAssert attached == 0, "Compilation objects must not stay attached"
+  doAssert linked == 1
+  glUseProgram(program)
+  glClearColor(0, 0, 0, 1)
+  glClear(GL_COLOR_BUFFER_BIT)
+  glDrawArrays(GL_TRIANGLES, 0, 3)
+  var pixel: array[4, uint8]
+  glReadPixels(16, 16, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixel[0].addr)
+  doAssert pixel == [255'u8, 0, 0, 255], "Linked executable must still draw"
+  glUseProgram(0)
+  glDeleteProgram(program)
+  doAssert glIsProgram(program) == GL_FALSE
+  doAssert glGetError() == GL_NO_ERROR
+
+glDeleteVertexArrays(1, vao.addr)
+echo "Three linked programs drew exact pixels with no attached shader objects"

From 8917ef53c66c3fab9b77de80bcb70311bdaba566 Mon Sep 17 00:00:00 2001
From: Richard Higgins <richard@relh.net>
Date: Mon, 5 Oct 2026 17:51:53 -0700
Subject: [PATCH 2/2] Keep only linked shader object cleanup

---
 tests/render_shader_lifetime.nim | 51 --------------------------------
 1 file changed, 51 deletions(-)
 delete mode 100644 tests/render_shader_lifetime.nim

diff --git a/tests/render_shader_lifetime.nim b/tests/render_shader_lifetime.nim
deleted file mode 100644
index b14776fa..00000000
--- a/tests/render_shader_lifetime.nim
+++ /dev/null
@@ -1,51 +0,0 @@
-## Run in a GL context; use -d:testSunDepth for the shadow builder.
-import opengl, vmath, windy
-
-when defined(testSunDepth):
-  include ../src/polyworld/shadows
-else:
-  include ../src/polyworld/quadterrain
-
-const
-  vertex = """#version 330 core
-void main() {
-  vec2 vertices[3] = vec2[3](vec2(-1, -1), vec2(3, -1), vec2(-1, 3));
-  gl_Position = vec4(vertices[gl_VertexID], 0, 1);
-}
-"""
-  fragment = """#version 330 core
-out vec4 color;
-void main() { color = vec4(1, 0, 0, 1); }
-"""
-
-let window = newWindow("Linked shader lifetime", ivec2(32), vsync = false)
-window.makeContextCurrent()
-loadExtensions()
-var vao: GLuint
-glGenVertexArrays(1, vao.addr)
-glBindVertexArray(vao)
-glViewport(0, 0, 32, 32)
-
-for cycle in 0 ..< 3:
-  let program =
-    when defined(testSunDepth): compileDepthProgram(vertex, fragment)
-    else: compileProgram(vertex, fragment)
-  var attached, linked: GLint
-  glGetProgramiv(program, GL_ATTACHED_SHADERS, attached.addr)
-  glGetProgramiv(program, GL_LINK_STATUS, linked.addr)
-  doAssert attached == 0, "Compilation objects must not stay attached"
-  doAssert linked == 1
-  glUseProgram(program)
-  glClearColor(0, 0, 0, 1)
-  glClear(GL_COLOR_BUFFER_BIT)
-  glDrawArrays(GL_TRIANGLES, 0, 3)
-  var pixel: array[4, uint8]
-  glReadPixels(16, 16, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixel[0].addr)
-  doAssert pixel == [255'u8, 0, 0, 255], "Linked executable must still draw"
-  glUseProgram(0)
-  glDeleteProgram(program)
-  doAssert glIsProgram(program) == GL_FALSE
-  doAssert glGetError() == GL_NO_ERROR
-
-glDeleteVertexArrays(1, vao.addr)
-echo "Three linked programs drew exact pixels with no attached shader objects"