The RenderMan Interface - Paul Bourke

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Note that the geometry vector used with the RiHermiteBasis basis matrix must be (point0, vector0, point1, vector1), which is a permutation of the Hermite geometry vector often found in mathematics texts. Using this formulation permits a step value of 2 to correctly increment over data in Hermite patch meshes. RiPatch ( RtToken type, ...parameterlist...) Define a single patch. type can be either ”bilinear” or ”bicubic”. parameterlist is a list of token-array pairs where each token is one of the standard geometric primitive variables or a variable which has been defined with RiDeclare. The parameter list must include at least position (”P”, ”Pw” or ”Pz”) information. Patch arrays are specified such that u varies faster than v. Four points define a bilinear patch, and 16 define a bicubic patch. The order of vertices for a bilinear patch is (0,0),(1,0),(0,1),(1,1). Note that the order of points defining a quadrilateral is different depending on whether it is a bilinear patch or a polygon. The vertices of a polygon would normally be in clockwise (0,0),(0,1),(1,1),(1,0) order. Patch primitive variables that are constant or uniform should supply one value, which is constant over the patch. Primitive variables that are varying should supply four values, one for each parametric corner of the patch (the data will be interpolated bilinearly). Primitive variables that are vertex should supply four values for a bilinear patch, or 16 values for a bicubic patch — that is, the same number of values as control vertices ”P”. A vertex primitive variable will be interpolated across the surface in the same manner as the surface position ”P”. In all cases, the actual size of each array is this number of values times the size of the type associated with the variable. RIB BINDING Patch type ...parameterlist... EXAMPLE Patch ”bilinear” ”P” [ -0.08 0.04 0.05 0 0.04 0.05 -0.08 0.03 0.05 0 0.03 0.05] SEE ALSO RiBasis, RiNuPatch, RiPatchMesh RiPatchMesh ( RtToken type, RtInt nu, RtToken uwrap, RtInt nv, RtInt vwrap, ...parameterlist...) 69
U V 0 1 2 3 12 13 14 15 4 5 6 7 8 9 10 11 8 9 10 11 4 5 6 7 12 13 14 15 0 1 V 2 3 Typical Left-Handed Bezier Bicubic Patch Equivalent Right-Handed Bezier Bicubic Patch Figure 5.1: Bicubic patch vertex ordering This primitive is a compact way of specifying a quadrilateral mesh of patches. Each individual patch behaves as if it had been specified with RiPatch. type can be either ”bilinear” or ”bicubic”. parameterlist is a list of token-array pairs where each token is one of the geometric primitive variables or a variable which has been defined with RiDeclare. The parameter list must include at least position (”P”, ”Pw” or ”Pz”) information. Patch mesh vertex data is supplied in first u and then v order just as for patches. The number of control points in a patch mesh is (nu)*(nv). Meshes can wrap around in the u or v direction, or in both directions. If meshes wrap, they close upon themselves at the ends and the first control points will be automatically repeated. As many as three control points may be repeated, depending on the basis matrix of the mesh. The way in which meshes wrap is indicated by giving a wrap mode value of either ”periodic” or ”nonperiodic”. The actual number of patches produced by this request depends on the type of the patch and the wrap modes specified. For bilinear patches, the number of patches in the u direction, nupatches, is given by nupatches = while for bicubic patches, ⎧ ( ⎪⎨ nupatches = ( ⎪⎩ { nu if uwrap = ”periodic” nu − 1 if uwrap = ”nonperiodic” nu nustep nu−4 nustep ) if uwrap = ”periodic” ) + 1 if uwrap = ”nonperiodic” The same rules hold in the v direction. The total number of patches produced is equal to the product of the number of patches in each direction. 70
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The RenderMan Interface Version 3.2
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TABLE OF CONTENTS List of Figures L
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12.1 Surface Shaders . . . . . . .
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Section I DIFFERENCES BETWEEN VERSI
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LIST OF TABLES 4.1 Camera Options .
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PREFACE This document is version 3.
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Section 1 INTRODUCTION The RenderMa
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created using this language. This l
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Depth of Field The ability to simul
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typedef RtPointer typedef RtPointer
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RiContext (ctx1); ... There is no R
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Section 3 RELATIONSHIP TO THE RENDE
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through the interface. Any place wh
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RtContextHandle RiGetContext ( void
Page 29 and 30: RiWorldBegin (); ... RiColor (...);
Page 31 and 32: Camera Option Type Default Descript
Page 33 and 34: ottom top left right Screen Window
Page 35 and 36: EXAMPLE RiFrameAspectRatio (4.0/3.0
Page 37 and 38: not support the special projection
Page 39 and 40: This procedure sets the times at wh
Page 41 and 42: Output depth values are the camera-
Page 43 and 44: A particular renderer implementatio
Page 45 and 46: Renderers may additionally produce
Page 47 and 48: The number of color components, n,
Page 49 and 50: RiAttributeBegin () RiAttributeEnd
Page 51 and 52: RIB BINDING Color c0 c1... cn Color
Page 53 and 54: An area light source is defined by
Page 55 and 56: The sequencenumber is the integer l
Page 57 and 58: 4.2.5 Displacement shading The grap
Page 59 and 60: SEE ALSO RiExterior RiAtmosphere Ri
Page 61 and 62: Matte onoff EXAMPLE RiMatte (RI TRU
Page 63 and 64: object foo2 will be drawn when the
Page 65 and 66: the exterior is the region adjacent
Page 67 and 68: RiIdentity ( ); SEE ALSO RiTransfor
Page 69 and 70: RiScale ( RtFloat sx, RtFloat sy, R
Page 71 and 72: 4.3.2 Transformation stack Transfor
Page 73 and 74: Section 5 GEOMETRIC PRIMITIVES The
Page 75 and 76: Information Name Type Class Floats
Page 77 and 78: No checking is done by the RenderMa
Page 79: 5.2 Patches Patches can be either u
Page 83 and 84: 10 x 7 Aperiodic Bezier Bicubic Pat
Page 85 and 86: SEE ALSO 2 2 [ 0 0 1 1 ] 0 1 ”Pw
Page 87 and 88: parameterlist is a list of token-ar
Page 89 and 90: Requests a sphere defined by the fo
Page 91 and 92: Hyperboloid 0 0 0 .5 0 0 270 ”Cs
Page 93 and 94: z N z V point2 height U x x y 0 max
Page 95 and 96: particle. If a primitive variable i
Page 97 and 98: The code array is a sequence of mac
Page 99 and 100: is an array of floats that define t
Page 101 and 102: The helper program generates geomet
Page 103 and 104: Procedural ”DynamicLoad” [ ”m
Page 105 and 106: SolidBegin ( ”difference” ); So
Page 107 and 108: Section 6 MOTION Some rendering pro
Page 109 and 110: Transformations Geometry Shading Ri
Page 111 and 112: channels (usually an RGB color) can
Page 113 and 114: Image Forward Axis Up Axis Right Ax
Page 115 and 116: ErrorHandler ”ignore” ErrorHand
Page 117 and 118: Part II The RenderMan Shading Langu
Page 119 and 120: spaces (such as CMYK or pseudocolor
Page 121 and 122: transmit reflect transmit P E light
Page 123 and 124: Section 10 RELATIONSHIP TO THE REND
Page 125 and 126: Section 11 TYPES The Shading Langua
Page 127 and 128: Coordinate System ”shader” ”c
Page 129 and 130: As in C, individual array elements
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Light Source E Vantage Point N L Il
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Surface Element to Illuminate L N I
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Name Type Storage Class Description
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• conditional execution, • loop
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This example integrates over a hemi
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Shader instance variable values can
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} return 2 * (vector noise(p)) - 1;
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These functions compute power and i
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The actual change in a variable is
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Return a unit vector in the directi
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Return surface normal given a point
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diffuse returns the diffuse compone
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prevent aliasing. If one set of tex
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15.7.3 Shadow depth maps Shadow dep
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These functions access the value of
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The standard data names supported b
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} Oi = sum; Ci = Cs * Oi * (Ka + Kd
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path of the ray. The input Ci and O
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A.2.3 Metal surface surface metal(
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distantlight( float intensity = 1;
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A.6 Imager Shaders A.6.1 Background
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variable definitions ; variables va
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triple sixteentuple arrayindex: [ e
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Logical expressions have the value
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typedef RtPointer RtContextHandle;
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RiOptionV(RtToken name, RtInt n, Rt
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RtInt n, RtToken tokens[], RtPointe
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#define RIE_NOTATTRIBS ((RtInt)26)
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Comments Any occurrence of the ’#
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In the following sections the synta
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C.2.2 Error handling There are two
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adhandle badparamlist badripcode ba
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v e r s i o n 212 # version 003 007
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Using RIB File structuring conventi
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Attribute Format PixelFilter Shadin
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##Include filename This entry allow
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D.2.1 RIB Entity File example ##Ren
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Motion Blur Programmable Shading Di
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} E.4 Gaussian Filter RtFloat RiGau
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Appendix G RENDERMAN INTERFACE QUIC
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Function RiOpacity (color) RiOption
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Geometric Primitives (continued) Fu
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Function abs(x) Math Functions Desc
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Function area(P) calculatenormal(P)
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Texture Mapping Functions Function
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RiInterior 47 RiLightSource 42 RiMa
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and uniform variables on an RiNuPat
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Statement About Pixar’s Copyright
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