feat(shaders): Implement FBO capture lifecycle in ShaderManager

src/shader_manager.py

@@ -6,6 +6,38 @@ class ShaderManager:
   self.bg_program = None
   self.pp_program = None
   self.blur_program = None
+  self.capture_fbo = None
+  self.capture_tex = None
+  self.fbo_width = 0
+  self.fbo_height = 0
+
+ def setup_capture_fbo(self, width, height):
+  if self.capture_fbo is not None:
+   gl.glDeleteFramebuffers(1, [self.capture_fbo])
+  if self.capture_tex is not None:
+   gl.glDeleteTextures(1, [self.capture_tex])
+  self.capture_fbo = gl.glGenFramebuffers(1)
+  self.capture_tex = gl.glGenTextures(1)
+  gl.glBindTexture(gl.GL_TEXTURE_2D, self.capture_tex)
+  gl.glTexImage2D(gl.GL_TEXTURE_2D, 0, gl.GL_RGBA, width, height, 0, gl.GL_RGBA, gl.GL_UNSIGNED_BYTE, None)
+  gl.glTexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MIN_FILTER, gl.GL_LINEAR)
+  gl.glTexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MAG_FILTER, gl.GL_LINEAR)
+  gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, self.capture_fbo)
+  gl.glFramebufferTexture2D(gl.GL_FRAMEBUFFER, gl.GL_COLOR_ATTACHMENT0, gl.GL_TEXTURE_2D, self.capture_tex, 0)
+  if gl.glCheckFramebufferStatus(gl.GL_FRAMEBUFFER) != gl.GL_FRAMEBUFFER_COMPLETE:
+   raise RuntimeError("Framebuffer not complete")
+  gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, 0)
+  self.fbo_width = width
+  self.fbo_height = height
+
+ def capture_begin(self, width, height):
+  if self.capture_fbo is None or self.fbo_width != width or self.fbo_height != height:
+   self.setup_capture_fbo(width, height)
+  gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, self.capture_fbo)
+  gl.glViewport(0, 0, width, height)
+
+ def capture_end(self):
+  gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, 0)
 
  def compile_shader(self, vertex_src: str, fragment_src: str) -> int:
   program = gl.glCreateProgram()

tests/test_fbo_capture.py

@@ -0,0 +1,37 @@
+import pytest
+from unittest.mock import patch, MagicMock
+import OpenGL.GL as gl
+
+def test_shader_manager_fbo_initialization():
+ with patch("src.shader_manager.gl") as mock_gl:
+  mock_gl.glGenFramebuffers.return_value = 1
+  mock_gl.glGenTextures.return_value = 2
+  mock_gl.glCheckFramebufferStatus.return_value = mock_gl.GL_FRAMEBUFFER_COMPLETE
+  
+  from src.shader_manager import ShaderManager
+  manager = ShaderManager()
+  
+  manager.setup_capture_fbo(800, 600)
+  
+  assert manager.capture_fbo == 1
+  assert manager.capture_tex == 2
+  assert mock_gl.glGenFramebuffers.called
+  assert mock_gl.glGenTextures.called
+  assert mock_gl.glCheckFramebufferStatus.called
+
+def test_shader_manager_capture_lifecycle():
+ with patch("src.shader_manager.gl") as mock_gl:
+  mock_gl.glCheckFramebufferStatus.return_value = mock_gl.GL_FRAMEBUFFER_COMPLETE
+  from src.shader_manager import ShaderManager
+  manager = ShaderManager()
+  
+  # Ensure setup is called on first capture
+  manager.capture_begin(1024, 768)
+  assert manager.fbo_width == 1024
+  assert manager.fbo_height == 768
+  assert mock_gl.glBindFramebuffer.called
+  
+  mock_gl.glBindFramebuffer.reset_mock()
+  manager.capture_end()
+  # Verify unbind (glBindFramebuffer(..., 0))
+  mock_gl.glBindFramebuffer.assert_called_with(mock_gl.GL_FRAMEBUFFER, 0)