reference/shaderview.py

   1 #!/usr/bin/python
   2 import sys, time
   3 import os
   4 import os.path
   5 import OpenGL
   6 from OpenGL.GL import *
   7 from OpenGL.GLUT import *
   8 from OpenGL.GL import framebufferobjects
   9 import texreader
  10 import shaderreader
  11
  12
  13 BASEDIR = os.path.abspath(os.path.dirname(__file__))
  14
  15
  16 def load_textures(texturePath):
  17         res = []
  18
  19         for name in os.listdir(texturePath):
  20                 if not name.endswith(".ppm"):
  21                         continue
  22
  23                 fullpath = os.path.join(texturePath, name)
  24                 res.append(
  25                                 (name, texreader.textureFromFile(fullpath))
  26                         )
  27
  28         return res
  29
  30
  31 def scale_integer(windowW, windowH, inputW, inputH):
  32         """
  33         Calculates the image as the largest integer multiple of raw frame size.
  34         """
  35         scaleX = windowW / inputW
  36         scaleY = windowH / inputH
  37
  38         if scaleX > 0 and scaleY > 0:
  39                 scale = min(scaleX, scaleY)
  40                 finalW = scale * inputW
  41                 finalH = scale * inputH
  42         else:
  43                 if scaleX == 0:
  44                         finalW = windowW
  45                 else:
  46                         finalW = inputW
  47
  48                 if scaleY == 0:
  49                         finalH = windowH
  50                 else:
  51                         finalH = inputH
  52
  53         return finalW, finalH
  54
  55
  56 def scale_aspect(windowW, windowH, inputW, inputH):
  57         """
  58         Calculates the image as the largest multiple of the raw frame size.
  59         """
  60         scale = min(
  61                         float(windowW) / float(inputW),
  62                         float(windowH) / float(inputH),
  63                 )
  64
  65         return inputW * scale, inputH * scale
  66
  67
  68 def scale_max(windowW, windowH, inputW, inputH):
  69         """
  70         Stretch the image to the largest possible size, regardless of aspect.
  71         """
  72         return windowW, windowH
  73
  74
  75 SCALE_METHODS = [
  76                 ("Integer", scale_integer),
  77                 ("Aspect-correct", scale_aspect),
  78                 ("Maximized", scale_max),
  79         ]
  80
  81
  82 class GLUTDemo(object):
  83
  84         def __init__(self, shaderFile, texturePath):
  85                 self.start = time.clock()
  86                 self.framecount = 0
  87
  88                 glutInitDisplayMode(GLUT_RGBA)
  89
  90                 glutInitWindowSize(640, 480)
  91                 self.window = glutCreateWindow("XML Shader Demo - Esc to exit")
  92                 self.windowW = None
  93                 self.windowH = None
  94
  95                 glutDisplayFunc(self._draw_scene)
  96                 glutIdleFunc(self._handle_idle)
  97                 glutReshapeFunc(self._handle_resize)
  98                 glutKeyboardFunc(self._handle_key)
  99
 100                 glClearColor(0.0, 0.0, 0.0, 0.0)
 101                 glEnable(GL_TEXTURE_2D)
 102
 103                 with open(shaderFile, "r") as handle:
 104                         self.shaderPasses = shaderreader.parse_shader(handle.read())
 105
 106                 self.textures = load_textures(texturePath)
 107                 textureMenu = glutCreateMenu(self._set_texture)
 108                 for index, (filename, _) in enumerate(self.textures):
 109                         glutAddMenuEntry(filename, index)
 110
 111                 self.inputTexture = None
 112                 self._set_texture(0)
 113
 114                 self.framebufferID = framebufferobjects.glGenFramebuffers(1)
 115                 self.framebufferTexture1, self.framebufferTexture2 = \
 116                                 glGenTextures(2)
 117
 118                 scaleMenu = glutCreateMenu(self._set_scale_method)
 119                 for index, (desc, _) in enumerate(SCALE_METHODS):
 120                         glutAddMenuEntry(desc, index)
 121
 122                 self._set_scale_method(0)
 123
 124                 self.masterMenu = glutCreateMenu(lambda _: 0)
 125                 glutAddSubMenu("Test pattern", textureMenu)
 126                 glutAddSubMenu("Scale method", scaleMenu)
 127                 glutAttachMenu(GLUT_RIGHT_BUTTON)
 128
 129         def _set_texture(self, textureIndex):
 130
 131                 _, self.inputTexture = self.textures[textureIndex]
 132
 133                 # According to the OpenGL docs, a glutCreateMenu callback doesn't need
 134                 # to return anything. PyOpenGL seems to think differently.
 135                 return 0
 136
 137         def _set_scale_method(self, index):
 138                 self.scaleMethod = SCALE_METHODS[index][1]
 139
 140                 # According to the OpenGL docs, a glutCreateMenu callback doesn't need
 141                 # to return anything. PyOpenGL seems to think differently.
 142                 return 0
 143
 144         def _setUniform(self, program, name, x, y):
 145                 loc = glGetUniformLocation(program, name)
 146
 147                 if loc < 0:
 148                         return
 149
 150                 glUniform2f(loc, x, y)
 151
 152         def _draw_texture(self, shaderPass, texture, x, y, width, height):
 153                 if shaderPass is not None:
 154                         glUseProgram(shaderPass.programID)
 155
 156                         self._setUniform(shaderPass.programID, 'rubyInputSize',
 157                                         texture.width, texture.height)
 158                         self._setUniform(shaderPass.programID, 'rubyOutputSize',
 159                                         width, height)
 160                         self._setUniform(shaderPass.programID, 'rubyTextureSize',
 161                                         texture.width, texture.height)
 162                         loc = glGetUniformLocation(shaderPass.programID, 'rubyFrameCount')
 163                         if loc >= 0:
 164                                 glUniform1i(loc, self.framecount)
 165
 166                         if shaderPass.filterMethod == shaderreader.ATTR_FILTER_LINEAR:
 167                                 filterID = GL_LINEAR
 168                         else:
 169                                 filterID = GL_NEAREST
 170
 171                 else:
 172                         # There's no shader pass to tell us what to do, so go with a safe
 173                         # default.
 174                         filterID = GL_LINEAR
 175
 176                 glBindTexture(GL_TEXTURE_2D, texture.textureID)
 177
 178                 glTexParameter(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filterID)
 179                 glTexParameter(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filterID)
 180
 181                 glClear(GL_COLOR_BUFFER_BIT)
 182
 183                 glBegin(GL_QUADS)                   # Start drawing a 4 sided polygon
 184
 185                 glTexCoord2f(0,   0  ); glVertex(x,       y,      )
 186                 glTexCoord2f(1.0, 0  ); glVertex(x+width, y,      )
 187                 glTexCoord2f(1.0, 1.0); glVertex(x+width, y+height)
 188                 glTexCoord2f(0,   1.0); glVertex(x,       y+height)
 189
 190                 glEnd()                             # We are done with the polygon
 191
 192                 if shaderPass is not None:
 193                         glUseProgram(0)
 194
 195         def _draw_texture_to_fbo(self, shaderPass, fromTexture, finalW, finalH):
 196
 197                 # How big should the output of this pass be?
 198                 outputW, outputH = shaderPass.calculateFramebufferSize(
 199                                 fromTexture.width, fromTexture.height, finalW, finalH,
 200                         )
 201
 202                 # If this pass doesn't specify a size, default to the input.
 203                 if outputW is None: outputW = fromTexture.width
 204                 if outputH is None: outputH = fromTexture.height
 205
 206                 # Make a texture exactly that big.
 207                 toTexture = texreader.Texture(outputW, outputH)
 208
 209                 # Configure OpenGL to render to the texture.
 210                 framebufferobjects.glBindFramebuffer(
 211                                 framebufferobjects.GL_FRAMEBUFFER,
 212                                 self.framebufferID,
 213                         )
 214                 framebufferobjects.glFramebufferTexture2D(
 215                                 framebufferobjects.GL_FRAMEBUFFER,
 216                                 framebufferobjects.GL_COLOR_ATTACHMENT0,
 217                                 GL_TEXTURE_2D,
 218                                 toTexture.textureID,
 219                                 0,
 220                         )
 221
 222                 # Are we all set?
 223                 framebufferobjects.checkFramebufferStatus()
 224
 225                 glViewport(0, 0, int(outputW), int(outputH))
 226                 glMatrixMode(GL_PROJECTION)
 227                 glLoadIdentity()
 228                 # A framebufferobject will always have the underlying texture's (0,0)
 229                 # at the lower-left, so align our coordinate system to match.
 230                 glOrtho(0, outputW, 0, outputH, -1, 1)
 231
 232                 self._draw_texture(shaderPass, fromTexture, 0, 0, outputW, outputH)
 233
 234                 # Detach all the things we set up.
 235                 framebufferobjects.glBindFramebuffer(
 236                                 framebufferobjects.GL_FRAMEBUFFER,
 237                                 0,
 238                         )
 239
 240                 return toTexture
 241
 242         def _draw_scene(self):
 243                 if None in (self.inputTexture, self.windowW, self.windowH):
 244                         return
 245
 246                 finalW, finalH = self.scaleMethod(
 247                                 self.windowW, self.windowH,
 248                                 self.inputTexture.width, self.inputTexture.height,
 249                         )
 250
 251                 finalX = (self.windowW - finalW) / 2
 252                 finalY = (self.windowH - finalH) / 2
 253
 254                 # Will we need an implicit pass at the end of this?
 255                 requiresImplicitPass = self.shaderPasses[-1].requiresImplicitPass()
 256
 257                 # Render all but the last pass
 258                 fromTexture = self.inputTexture
 259                 for shaderPass in self.shaderPasses[:-1]:
 260                         fromTexture = self._draw_texture_to_fbo(
 261                                         shaderPass, fromTexture, finalW, finalH)
 262
 263                 # If the last pass expects to be rendered at some specific scale, we'd
 264                 # better respect its wishes.
 265                 if requiresImplicitPass:
 266                         fromTexture = self._draw_texture_to_fbo(
 267                                         self.shaderPasses[-1], fromTexture, finalW, finalH)
 268                         lastPass = None
 269                 else:
 270                         lastPass = self.shaderPasses[-1]
 271
 272                 glViewport(0, 0, self.windowW, self.windowH)
 273                 glMatrixMode(GL_PROJECTION)
 274                 glLoadIdentity()
 275                 # After all the shader passes, the (0,0) corner of the resulting
 276                 # texture is supposed to appear at the top-left, so let's set our
 277                 # coordinate system appropriately.
 278                 glOrtho(0, self.windowW, self.windowH, 0, -1, 1)
 279
 280                 self._draw_texture(lastPass, fromTexture,
 281                                 finalX, finalY, finalW, finalH,
 282                         )
 283
 284                 glFlush()
 285
 286         def _handle_key(self, key, x, y):
 287                 if key == '\x1b': # Escape
 288                         self._shutdown()
 289
 290         def _handle_resize(self, width, height):
 291                 self.windowW = max(width, 1)
 292                 self.windowH = max(height, 1)
 293
 294         def _handle_idle(self):
 295                 now = time.clock()
 296                 if now > self.start + 1:
 297                         fps = self.framecount / (now - self.start)
 298                         sys.stdout.write("FPS: %0.1f\r" % fps)
 299                         sys.stdout.flush()
 300                         self.framecount = 0
 301                         self.start = now
 302
 303                 glutPostWindowRedisplay(self.window)
 304                 self.framecount += 1
 305
 306         def _shutdown(self):
 307                 # clean up textures we've allocated.
 308                 for _, texture in self.textures:
 309                         texture.destroy()
 310
 311                 # There's no clean way to kill GLUT.
 312                 sys.exit(0)
 313
 314 if __name__ == "__main__":
 315         argv = glutInit(sys.argv)
 316
 317         if len(argv) != 2:
 318                 print >> sys.stderr, "Usage: %s /path/to/shaderfile" % (argv[0],)
 319                 sys.exit(1)
 320
 321         shaderFile = argv[1]
 322         texturePath = os.path.join(BASEDIR, "test-patterns")
 323         demo = GLUTDemo(shaderFile, texturePath)
 324
 325         glutMainLoop()