Samsung S5PC100, User Manual, Page: 1311 / 1863

3D-ACCELERATOR S5PC100 USER’S MANUAL (REV1.0)
9.6-84
9.2 PER-FRAGMENT UNIT SPECIAL REGISTERS
9.2.1 Scissor Test Control Register (PF_SCISSOR)
If you want to discard all fragments, please set XMin=0 , XMax=0, YMin=0 and YMax=0. Also if you want to pass
all fragments, please set XMin=0, XMax= Max screen X width, YMin=0, and YMax= Max screen Y height.
y
PF_SCISSOR_X, R/W, Address = 0x0007_0000
y
PF_SCISSOR_Y, R/W, Address = 0x0007_0004
PF_SCISSOR_X Bit Description Reset Value
ScissorTestEnable [31] Scissor test enable bit
0b = disable
1b = enable
0b
Reserved [30:28] Reserved 0
XMax [27:16] Pixel’s X coordinate >= MAX is not written to the frame buffer 0x0
reserved [15:12] Reserved 0
XMin [11:0] Pixel’s X coordinate < MIN is not written to the frame buffer 0x0
PF_SCISSOR_Y Bit Description Reset Value
Reserved [31:28] Reserved 0
YMax [27:16] Pixel’s Y coordinate >= MAX is not written to the frame buffer 0x0
Reserved [15:12] Reserved 0
YMin [11:0] Pixel’s Y coordinate < MIN is not written to the frame buffer 0x0
9.2.2 Alpha Test Control Register (PF_ALPHAT , R/W, Address = 0X0007_0008)
PF_ALPHAT Bit Description Reset Value
Reserved [31:12] Reserved 0
AlphaTestValue [11:4] 8bit alpha test reference value 0x0
AlphaTestMode [3:1] Mode used in alpha test
000b = NEVER 001b = ALWAYS
010b = LESS
011b = LEQUAL( less than or equal to)
100b = EQUAL 101b = GREATER
110b = GEQUAL 111b = NOTEQUAL
000b
AlphaTestEnable [0] Alpha test enable
0b = alpha test disabled
1b = alpha test enabled 0b