1Name 2 3 INGR_interlace_read 4 5Name Strings 6 7 GL_INGR_interlace_read 8 9Version 10 11 Date: 12/14/98 Revision: 1.0 12 13Number 14 15 175 16 17Dependencies 18 19 None 20 21Overview 22 23 This extension provides a way to skip rows of pixels when reading 24 or copying pixel rectangles. This extension is complementary to 25 the EXT_interlace extension except that it has no affect on getting 26 texture images. 27 28New Procedures and Functions 29 30 None 31 32New Tokens 33 34 Accepted by the <cap> parameter of of Enable, Disable, IsEnabled, and 35 by the <pname> parameter of GetBooleanv, GetIntegerv, GetFloatv, 36 GetDoublev: 37 38 INTERLACE_READ_INGR 0x8568 39 40Additions to Chapter 2 of the 1.2 Specification (OpenGL Operation) 41 42 None 43 44Additions to Chapter 3 of the 1.2 Specification (Rasterization) 45 46 None 47 48Additions to Chapter 4 of the 1.2 Specification (Per-Fragment Operations 49and the Frame Buffer) 50 51 [In section 4.3.2 "Reading Pixels" the specification of an interlace 52 read operation is added to the GL Specification in the sectino on 53 "Obtaining Pixels from the FrameBuffer."] 54 55 Reading interlaced rows of pixels is enabled or disabled with Enable 56 or Disable using the symbolic constant INTERLACE_READ_INGR. If 57 INTERLACE_READ_INGR is disabled, then ReadPixels obtains values from 58 the selected buffer from each pixel with lower left hand corner at 59 (x+i, y+j) for 0 <= i < width and 0 <= j < height; this pixel is said 60 to be the ith pixel in the jth row. 61 62 If INTERLACE_READ_INGR is enabled, then ReadPixels obtains values 63 from the selected buffer from each pixel with lower left hand corner 64 at (x+i, y+(j*2)) for 0 <= i < width and 0 <= j < height; this pixel 65 is said to be the ith pixel in the jth row. 66 67 If any of these pixels lies outside of the window... 68 69Additions to Chapter 5 of the 1.2 Specification (Special Functions) 70 71 None 72 73Additions to Chapter 6 of the 1.2 Specification (State and State Requests) 74 75 None 76 77Additions to the GLX Specification 78 79 None 80 81Errors 82 83 None 84 85New State 86 87 Get Value Get Command Type Initial Value Attribute 88 -------------------- --------------- ----- -------------- ------------- 89 INTERLACE_READ_INGR IsEnabled B False pixel/enable 90 91New Implementation Dependent State 92 93 None 94