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#
# Copyright (C) 2007 Jan Dvorak <jan.dvorak@kraxnet.cz>
#
# This program is distributed under the terms of the MIT license.
# See the included MIT-LICENSE file for the terms of this license.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
#
# Showcase for anisotropic texture filtering
#
require 'opengl'
include Gl,Glu,Glut
# extend Array class with new function
class Array
def rotate!
self << self.shift
end
end
class App
@@filters = [[GL_NEAREST,"None"],[GL_LINEAR_MIPMAP_NEAREST,"Bilinear"],[GL_LINEAR_MIPMAP_LINEAR,"Trilinear"]]
@@anisotropy = [1,2,4,8,16,32]
@@color_tint = ["Off","On"]
def checker_texture(size,divide,color_a,color_b)
strip_a = color_a * (size/divide)
strip_b = color_b * (size/divide)
line_strip_a = (strip_a + strip_b) * (size/2)
line_strip_b = (strip_b + strip_a) * (size/2)
(line_strip_a + line_strip_b) * (divide/2)
end
def printGlutBitmapFont(string, font, x,y, r,g,b)
glDisable(GL_TEXTURE_2D)
glColor3f(r, g, b)
glRasterPos2i(x, y)
string.each_byte do |x|
glutBitmapCharacter(font, x)
end
end
def ortho(w,h)
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
gluOrtho2D(0,w,0,h)
glScalef(1,-1,1)
glTranslatef(0,-h,0)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
end
def persp(w,h)
glMatrixMode(GL_PROJECTION)
glLoadIdentity
gluPerspective(90,w.to_f/h.to_f,1,100)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity
end
def reshape(w,h)
@@w,@@h = w,h
glViewport(0, 0, w, h)
persp(w,h)
end
def initialize
if (not Gl.is_available?("GL_EXT_texture_filter_anisotropic"))
puts "This program needs GL_EXT_texture_filter_anisotropic extension"
exit
end
@@w,@@h = glutGet(GLUT_WINDOW_WIDTH),glutGet(GLUT_WINDOW_HEIGHT)
@t = glGenTextures(2)
# default checkerboard texture
glBindTexture(GL_TEXTURE_2D,@t[0])
data = checker_texture(64,4,[1,1,1],[0,0,0])
gluBuild2DMipmaps(GL_TEXTURE_2D,GL_RGBA,64,64,GL_RGB,GL_FLOAT,data.pack("f*"))
# second texture with color tinted mipmaps
glBindTexture(GL_TEXTURE_2D,@t[1])
data = checker_texture(64,4,[1,1,1],[0,0,0])
glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,64,64,0,GL_RGB,GL_FLOAT,data.pack("f*"))
data = checker_texture(32,4,[1,0,0],[0,0,0])
glTexImage2D(GL_TEXTURE_2D,1,GL_RGBA,32,32,0,GL_RGB,GL_FLOAT,data.pack("f*"))
data = checker_texture(16,4,[0,1,0],[0,0,0])
glTexImage2D(GL_TEXTURE_2D,2,GL_RGBA,16,16,0,GL_RGB,GL_FLOAT,data.pack("f*"))
data = checker_texture(8,4,[0,0,1],[0,0,0])
glTexImage2D(GL_TEXTURE_2D,3,GL_RGBA,8,8,0,GL_RGB,GL_FLOAT,data.pack("f*"))
data = checker_texture(4,4,[1,1,0],[0,0,0])
glTexImage2D(GL_TEXTURE_2D,4,GL_RGBA,4,4,0,GL_RGB,GL_FLOAT,data.pack("f*"))
data = checker_texture(2,2,[1,0,1],[0,0,0])
glTexImage2D(GL_TEXTURE_2D,5,GL_RGBA,2,2,0,GL_RGB,GL_FLOAT,data.pack("f*"))
data = [0.5,0.5,0.5] # single pixel texture, just average it
glTexImage2D(GL_TEXTURE_2D,6,GL_RGBA,1,1,0,GL_RGB,GL_FLOAT,data.pack("f*"))
end
def display_text
ortho(@@w,@@h)
printGlutBitmapFont("Texture Filtering ('f'): #{@@filters[0][1]}", GLUT_BITMAP_9_BY_15, 20, 20, 1.0, 1.0, 1.0)
printGlutBitmapFont("Anisotropy factor ('a'): #{@@anisotropy[0]}x", GLUT_BITMAP_9_BY_15, 20, 40, 1.0, 1.0, 1.0)
printGlutBitmapFont("Colored Mipmaps ('c'): #{@@color_tint[0]}", GLUT_BITMAP_9_BY_15, 20, 60, 1.0, 1.0, 1.0)
persp(@@w,@@h)
end
def display_plane()
glEnable(GL_TEXTURE_2D)
t_repeat = 16
# x,y,z,u,v
quad = [[-4,-1,1, 0,t_repeat],[4,-1,1, t_repeat,t_repeat],[4,1,-8, t_repeat,0],[-4,1,-8, 0,0]]
glBegin(GL_QUADS)
quad.each do |v|
glTexCoord2f(v[3],v[4])
glVertex3f(v[0],v[1],v[2])
end
glEnd()
glDisable(GL_TEXTURE_2D)
end
def display
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
persp(@@w,@@h)
# move back from scene
glTranslatef(0,0,-2)
# set anisotropy
glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAX_ANISOTROPY_EXT,@@anisotropy[0])
# set color tint
if (@@color_tint[0] == "On")
glBindTexture(GL_TEXTURE_2D,@t[1])
else
glBindTexture(GL_TEXTURE_2D,@t[0])
end
# set filters
f = @@filters[0][0]
glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,f)
# draw scene
display_plane()
display_text()
sleep(0.001) # microsleep to avoid consuming all CPU time
glutSwapBuffers()
end
def idle
glutPostRedisplay()
end
def keyboard(key,x,y)
case (key)
when ?f
@@filters.rotate!
when ?a
max_anisotropy = glGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT)
begin @@anisotropy.rotate! end until @@anisotropy[0]<=max_anisotropy
when ?c
@@color_tint.rotate!
when ?\e # Escape
exit(0)
end
glutPostRedisplay()
end
end
# main
glutInit()
glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE )
glutInitWindowPosition(150,50)
glutInitWindowSize(500,500)
glutCreateWindow($0)
app = App.new
glutReshapeFunc(app.method(:reshape).to_proc)
glutDisplayFunc(app.method(:display).to_proc)
glutIdleFunc(app.method(:idle).to_proc)
glutKeyboardFunc(app.method(:keyboard).to_proc)
glutMainLoop()
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