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Computer Graphics Panos Trahanias ΗΥ358 Spring 2009.

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Presentation on theme: "Computer Graphics Panos Trahanias ΗΥ358 Spring 2009."— Presentation transcript:

1 Computer Graphics Panos Trahanias e-mail: trahania@csd.uoc.gr ΗΥ358 Spring 2009

2 Panos Trahanias: Computer Graphics Ιστορική Αναδρομή Architecture of a Vector Display

3 Panos Trahanias: Computer Graphics Ιστορική Αναδρομή Architecture of a Raster Display

4 Panos Trahanias: Computer Graphics Ιστορική Αναδρομή Random scan versus raster scan

5 Panos Trahanias: Computer Graphics Conceptual Framework of CG

6 Panos Trahanias: Computer Graphics Line Drawing – Midpoint Algorithm

7 Panos Trahanias: Computer Graphics Line Drawing – Midpoint Algorithm

8 Panos Trahanias: Computer Graphics Line Drawing – Midpoint Algorithm

9 Panos Trahanias: Computer Graphics Line Drawing – Midpoint Algorithm

10 Panos Trahanias: Computer Graphics Line Drawing – Midpoint Algorithm

11 Panos Trahanias: Computer Graphics Line Drawing – Midpoint Algorithm

12 Panos Trahanias: Computer Graphics Line Drawing – Midpoint Algorithm

13 Panos Trahanias: Computer Graphics Circle Drawing – Midpoint Algorithm

14 Panos Trahanias: Computer Graphics Circle Drawing – Midpoint Algorithm

15 Panos Trahanias: Computer Graphics Circle Drawing – Midpoint Algorithm Eight-way symmetry

16 Panos Trahanias: Computer Graphics Circle Drawing – Midpoint Algorithm

17 Panos Trahanias: Computer Graphics Circle Drawing – Midpoint Algorithm

18 Panos Trahanias: Computer Graphics Circle Drawing – Midpoint Algorithm

19 Panos Trahanias: Computer Graphics Circle Drawing – Midpoint Algorithm

20 Panos Trahanias: Computer Graphics Circle Drawing – Midpoint Algorithm

21 Panos Trahanias: Computer Graphics Ellipse Drawing – Midpoint Algorithm

22 Panos Trahanias: Computer Graphics Ellipse Drawing – Midpoint Algorithm

23 Panos Trahanias: Computer Graphics Ellipse Drawing – Midpoint Algorithm

24 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm Increasing Resolution

25 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm Unweighted Area Sampling

26 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm Properties of Unweighted Area Sampling: Intensity of a pixel intersected by a line decreases as the distance between the pixel center and the edge increases. A primitive (e.g. line) does not influence a pixel at all if they are not intersected. Equal areas contribute equal intensity, regardless of the distance between the pixel’s center and the area.

27 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm Unweighted Area Sampling: Box Filter

28 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm Weighted Area Sampling: Cone Filter

29 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm Dramatic Effects of the cone filter.

30 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm

31 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm

32 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm

33 Panos Trahanias: Computer Graphics Antialiasing – Midpoint Line Algorithm

34 Panos Trahanias: Computer Graphics Polygon Filling

35 Panos Trahanias: Computer Graphics Polygon Filling

36 Panos Trahanias: Computer Graphics Polygon Filling Calculation of Span Extrema

37 Panos Trahanias: Computer Graphics Polygon Filling

38 Panos Trahanias: Computer Graphics Polygon Filling

39 Panos Trahanias: Computer Graphics Polygon Filling

40 Panos Trahanias: Computer Graphics Polygon Filling

41 Panos Trahanias: Computer Graphics Polygon Filling Polygon Filling Algorithm

42 Panos Trahanias: Computer Graphics Polygon Filling

43 Panos Trahanias: Computer Graphics Filling Ellipse Arcs

44 Panos Trahanias: Computer Graphics Clipping Lines

45 Panos Trahanias: Computer Graphics Clipping Lines Cohen-Sutherland Line-Clipping Algorithm

46 Panos Trahanias: Computer Graphics Clipping Lines

47 Panos Trahanias: Computer Graphics Clipping Lines

48 Panos Trahanias: Computer Graphics Clipping Lines

49 Panos Trahanias: Computer Graphics Clipping Lines

50 Panos Trahanias: Computer Graphics Clipping Lines Parametric Line-Clipping Algorithm

51 Panos Trahanias: Computer Graphics Clipping Lines

52 Panos Trahanias: Computer Graphics Clipping Lines

53 Panos Trahanias: Computer Graphics Clipping Lines

54 Panos Trahanias: Computer Graphics Geometrical Transformations 2D Transformations - Translation

55 Panos Trahanias: Computer Graphics Geometrical Transformations 2D Transformations - Scaling

56 Panos Trahanias: Computer Graphics Geometrical Transformations 2D Transformations - Rotation

57 Panos Trahanias: Computer Graphics Geometrical Transformations Homogeneous Coordinates The XYW homogeneous coordinate space, with the W=1 plane and point P(X,Y,W) projected onto the W=1 plane.

58 Panos Trahanias: Computer Graphics Geometrical Transformations 2D Transformations – Affine Transformations 45 o rotation and then nonuniform scaling of the unit cube. The result is an affine transformation.

59 Panos Trahanias: Computer Graphics Geometrical Transformations 2D Transformations – Shear Transformations

60 Panos Trahanias: Computer Graphics Geometrical Transformations Composition of 2D Transformations

61 Panos Trahanias: Computer Graphics Geometrical Transformations 2D Transformations – the Window-to-Viewport Transformation

62 Panos Trahanias: Computer Graphics Geometrical Transformations 2D Transformations – the Window-to-Viewport Transformation

63 Panos Trahanias: Computer Graphics Geometrical Transformations 2D Transformations – the Window-to-Viewport Transformation

64 Panos Trahanias: Computer Graphics Geometrical Transformations 3D Transformations – Coordinate Systems Right-handed Coordinate System Left-handed Coordinate System

65 Panos Trahanias: Computer Graphics Geometrical Transformations Composition of 3D Transformations

66 Panos Trahanias: Computer Graphics Geometrical Transformations Composition of 3D Transformations – 1 st Approach

67 Panos Trahanias: Computer Graphics Geometrical Transformations Composition of 3D Transformations – 2 nd Approach

68 Panos Trahanias: Computer Graphics Geometrical Transformations Composition of 3D Transformations

69 Panos Trahanias: Computer Graphics Viewing in 3D Conceptual model of 3D viewing

70 Panos Trahanias: Computer Graphics Viewing in 3D Projections - Projectors

71 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projections – 1-point PP

72 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projections – 2-point PP

73 Panos Trahanias: Computer Graphics Viewing in 3D Parallel Projections

74 Panos Trahanias: Computer Graphics Viewing in 3D Parallel Projections – Isometric Projection

75 Panos Trahanias: Computer Graphics Viewing in 3D Parallel Projections – Oblique Projection

76 Panos Trahanias: Computer Graphics Viewing in 3D

77 Panos Trahanias: Computer Graphics Viewing in 3D Specifying an Arbitrary 3D View

78 Panos Trahanias: Computer Graphics Viewing in 3D Specifying an Arbitrary 3D View

79 Panos Trahanias: Computer Graphics Viewing in 3D

80 Panos Trahanias: Computer Graphics Viewing in 3D

81 Panos Trahanias: Computer Graphics Viewing in 3D

82 Panos Trahanias: Computer Graphics Viewing in 3D

83 Panos Trahanias: Computer Graphics Viewing in 3D The Mathematics of Planar Geometric Projections

84 Panos Trahanias: Computer Graphics Viewing in 3D Alternative Perspective Projection

85 Panos Trahanias: Computer Graphics Viewing in 3D Alternative Perspective Projection

86 Panos Trahanias: Computer Graphics Viewing in 3D Implementation of Planar Geometric Projections

87 Panos Trahanias: Computer Graphics Viewing in 3D Implementation of 3D Viewing

88 Panos Trahanias: Computer Graphics Viewing in 3D Parallel Projection

89 Panos Trahanias: Computer Graphics Viewing in 3D Parallel Projection

90 Panos Trahanias: Computer Graphics Viewing in 3D Parallel Projection

91 Panos Trahanias: Computer Graphics Viewing in 3D Parallel Projection

92 Panos Trahanias: Computer Graphics Viewing in 3D Shearing Matrix

93 Panos Trahanias: Computer Graphics Viewing in 3D Final Translation / Scaling Step

94 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection

95 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection

96 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection

97 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection

98 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection

99 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection Step 4 - Shear

100 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection

101 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection

102 Panos Trahanias: Computer Graphics Viewing in 3D Perspective Projection

103 Panos Trahanias: Computer Graphics Viewing in 3D Implementation Summary

104 Panos Trahanias: Computer Graphics Visible Surface Determination Image Precision ApproachesObject Precision Approaches for (each pixel in the image) { determine the object closest to the viewer that is pierced by the projector through the pixel; draw the pixel in the appropriate color; } for (each object in the world) { determine those parts of the object whose view is unobstructed by other parts of it or any other object; draw those parts in the appropriate color; }

105 Panos Trahanias: Computer Graphics Techniques for Efficient Visible-surface Algorithms Extents and Bounding Volumes

106 Panos Trahanias: Computer Graphics Techniques for Efficient Visible-surface Algorithms Back-face Culling

107 Panos Trahanias: Computer Graphics Z-Buffer Algorithm

108 Panos Trahanias: Computer Graphics Z-Buffer Algorithm

109 Panos Trahanias: Computer Graphics Z-Buffer Algorithm

110 Panos Trahanias: Computer Graphics Scan-Line Algorithms Much like polygon scan- conversion algorithms Each ET entry contains

111 Panos Trahanias: Computer Graphics Scan-Line Algorithms

112 Panos Trahanias: Computer Graphics Scan-Line Algorithms

113 Panos Trahanias: Computer Graphics Scan-Line Algorithms

114 Panos Trahanias: Computer Graphics Scan-Line Algorithms

115 Panos Trahanias: Computer Graphics Scan-Line Algorithms

116 Panos Trahanias: Computer Graphics Scan-Line Algorithms Pseudocode for a general scan-line algorithm

117 Panos Trahanias: Computer Graphics Visible-Surface Ray Tracing

118 Panos Trahanias: Computer Graphics Visible-Surface Ray Tracing Pseudocode for a simple ray tracer

119 Panos Trahanias: Computer Graphics Visible-Surface Ray Tracing

120 Panos Trahanias: Computer Graphics Visible-Surface Ray Tracing Anti-alised ray tracing

121 Panos Trahanias: Computer Graphics List-Priority Algorithms The Depth-Sort Algorithm

122 Panos Trahanias: Computer Graphics List-Priority Algorithms Depth Comparisons

123 Panos Trahanias: Computer Graphics List-Priority Algorithms The Depth-Sort Algorithm – Tests to resolve ambiguities The Depth-Sort Algorithm – Tests with polygons reversed

124 Panos Trahanias: Computer Graphics List-Priority Algorithms The Depth-Sort Algorithm – Results of Tests

125 Panos Trahanias: Computer Graphics List-Priority Algorithms The Depth-Sort Algorithm – Unnecessary polygon split

126 Panos Trahanias: Computer Graphics Illumination and Shading

127 Panos Trahanias: Computer Graphics Illumination and Shading Diffuse Reflection

128 Panos Trahanias: Computer Graphics Illumination and Shading

129 Panos Trahanias: Computer Graphics Illumination and Shading Atmospheric Attenuation

130 Panos Trahanias: Computer Graphics Illumination and Shading Depth Cueing

131 Panos Trahanias: Computer Graphics Illumination and Shading Specular Reflection

132 Panos Trahanias: Computer Graphics Illumination and Shading

133 Panos Trahanias: Computer Graphics Illumination and Shading

134 Panos Trahanias: Computer Graphics Illumination and Shading

135 Panos Trahanias: Computer Graphics Illumination and Shading

136 Panos Trahanias: Computer Graphics Illumination and Shading Surface Normals

137 Panos Trahanias: Computer Graphics Illumination and Shading

138 Panos Trahanias: Computer Graphics Illumination and Shading Normal Vector Interpolation

139 Panos Trahanias: Computer Graphics Illumination and Shading Gouraud Shading – Phong Shading

140 Panos Trahanias: Computer Graphics Illumination and Shading Texture Mapping

141 Panos Trahanias: Computer Graphics Illumination and Shading Scan-line Shadow Algorithm

142 Panos Trahanias: Computer Graphics Illumination and Shading Two-Pass Object Precision Shadow Algorithm

143 Panos Trahanias: Computer Graphics Illumination and Shading Transparency

144 Panos Trahanias: Computer Graphics Illumination and Shading Calculating the refraction vector


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