Source Code for Module glitter.convenience.copying

  1  """Tools for copying a texture to screen through a shader. 
  2   
  3  This is useful for GPGPU. 
  4   
  5  @author: Stephan Wenger 
  6  @date: 2012-03-06 
  7  """ 
  8   
  9  from glitter.arrays import VertexArray 
 10  from glitter.shaders import ShaderProgram 
 11  from glitter.convenience import Pipeline 
 12   
 13  vertex_code = """ 
 14  #version 400 core 
 15   
 16  layout(location=0) in vec4 in_position; 
 17  out vec2 ex_texcoord; 
 18   
 19  void main() { 
 20      gl_Position = in_position; 
 21      ex_texcoord = 0.5 * in_position.xy + 0.5; 
 22  } 
 23  """ 
 24  """Vertex shader for copying a texture onto the screen.""" 
 25   
 26  fragment_code_rectangle = """ 
 27  #version 400 core 
 28  #extension GL_ARB_texture_rectangle : enable 
 29   
 30  uniform sampler2DRect image; 
 31  layout(location=0) out vec4 out_color; 
 32   
 33  void main() { 
 34      out_color = texture(image, gl_FragCoord.xy); 
 35  } 
 36  """ 
 37  """Fragment shader for copying a rectangle texture onto the screen.""" 
 38   
 39  fragment_code_2d = """ 
 40  #version 400 core 
 41   
 42  in vec2 ex_texcoord; 
 43  uniform sampler2D image; 
 44  layout(location=0) out vec4 out_color; 
 45   
 46  void main() { 
 47      out_color = texture(image, ex_texcoord); 
 48  } 
 49  """ 
 50  """Fragment shader for copying a 2D texture onto the screen.""" 
 51   
 52  quad_vertices = ((-1.0, -1.0), (-1.0, 1.0), (1.0, 1.0), (1.0, -1.0)) 
 53  """Vertices of a fullscreen quad.""" 
 54   
 55  quad_indices = ((0, 1, 2), (0, 2, 3)) 
 56  """Indices of a fullscreen quad.""" 
 57   
 58 -def get_fullscreen_quad(context=None): 
 59      """Get a vertex array containing the vertices of a fullscreen quad. 
 60   
 61      @param context: The context to create the program in, or C{None} for the current context. 
 62      @type context: L{Context} 
 63      @rtype: L{VertexArray} 
 64      """ 
 65      return VertexArray(quad_vertices, elements=quad_indices, context=context) 
 66   
 67 -def get_program_rectangle(context=None): 
 68      """Get a shader program for copying a rectangle texture onto the screen. 
 69   
 70      @param context: The context to create the program in, or C{None} for the current context. 
 71      @type context: L{Context} 
 72      @rtype: L{ShaderProgram} 
 73      """ 
 74      return ShaderProgram(fragment=fragment_code_rectangle, context=context) 
 75   
 76 -def get_program_2d(context=None): 
 77      """Get a shader program for copying a 2D texture onto the screen. 
 78   
 79      @param context: The context to create the program in, or C{None} for the current context. 
 80      @type context: L{Context} 
 81      @rtype: L{ShaderProgram} 
 82      """ 
 83      return ShaderProgram(fragment=fragment_code_2d, context=context) 
 84   
 85 -def get_pipeline_rectangle(context=None): 
 86      """Get a pipeline for copying a rectangle texture onto the screen. 
 87   
 88      @param context: The context to create the program in, or C{None} for the current context. 
 89      @type context: L{Context} 
 90      @rtype: L{Pipeline} 
 91      """ 
 92      return Pipeline(get_program_rectangle(context), in_position=quad_vertices, elements=quad_indices) 
 93   
 94 -def get_pipeline_2d(context=None): 
 95      """Get a pipeline for copying a 2D texture onto the screen. 
 96   
 97      @param context: The context to create the program in, or C{None} for the current context. 
 98      @type context: L{Context} 
 99      @rtype: L{Pipeline} 
100      """ 
101      return Pipeline(get_program_2d(context), in_position=quad_vertices, elements=quad_indices) 
102   
103  __all__ = [ 
104      "vertex_code", 
105      "fragment_code_rectangle", 
106      "fragment_code_2d", 
107      "quad_vertices", 
108      "quad_indices", 
109      "get_fullscreen_quad", 
110      "get_program_rectangle", 
111      "get_program_2d", 
112      "get_pipeline_rectangle", 
113      "get_pipeline_2d", 
114  ] 
115