1Name 2 3 EXT_blend_logic_op 4 5Name Strings 6 7 GL_EXT_blend_logic_op 8 9Version 10 11 $Date: 1995/03/31 04:40:24 $ $Revision: 1.4 $ 12 13Number 14 15 39 16 17Dependencies 18 19 EXT_blend_minmax affects the definition of this extension 20 21Overview 22 23 A single additional blending equation is specified using the interface 24 defined by EXT_blend_minmax. This equation is a simple logical 25 combination of the source and destination colors, where the specific 26 logical operation is as specified by LogicOp. While only the XOR 27 operation may find wide application, the generality of full logical 28 operations is allowed. 29 30New Procedures and Functions 31 32 None 33 34New Tokens 35 36 None 37 38Additions to Chapter 2 of the GL Specification (OpenGL Operation) 39 40 None 41 42Additions to Chapter 3 of the GL Specification (Rasterization) 43 44 None 45 46Additions to Chapter 4 of the GL Specification (Per-Fragment Operations 47and the Framebuffer) 48 49 A single additional blending equation is defined. If BlendEquationEXT 50 is called with <mode> set to LOGIC_OP, the blending equation becomes 51 52 C = Cs OP Cd 53 54 where Cs and Cd are the source and destination colors, and OP is the 55 logic operation as specified by LogicOp. 56 57 The value of boolean parameter LOGIC_OP (specified by Enable and 58 Disable, and queried with IsEnabled) has no affect on blending, even 59 when the blend equation is specified as LOGIC_OP. 60 61Additions to Chapter 5 of the GL Specification (Special Functions) 62 63 None 64 65Additions to Chapter 6 of the GL Specification (State and State Requests) 66 67 None 68 69Additions to the GLX Specification 70 71 None 72 73GLX Protocol 74 75 None 76 77Dependencies on EXT_blend_minmax 78 79 If this extension is supported, but EXT_blend_minmax is not, then 80 this extension effectively adds the procedure BlendEquationEXT, its 81 parameter FUNC_ADD_EXT, and the query target BLEND_EQUATION_EXT, as 82 described in EXT_blend_minmax. It is therefore as though 83 EXT_blend_minmax were also supported, except that equations MIN_EXT 84 and MAX_EXT are not supported. 85 86Errors 87 88 INVALID_ENUM is generated by BlendEquationEXT if its single parameter 89 is not FUNC_ADD_EXT, MIN_EXT, MAX_EXT, FUNC_SUBTRACT_EXT, 90 FUNC_REVERSE_SUBTRACT_EXT, or LOGIC_OP. 91 92 INVALID_OPERATION is generated if BlendEquationEXT is executed between 93 the execution of Begin and the corresponding execution to End. 94 95New State 96 97 Get Value Get Command Type Initial Value Attribute 98 --------- ----------- ---- ------------- --------- 99 BLEND_EQUATION_EXT GetIntegerv Z6 FUNC_ADD_EXT color-buffer 100 101New Implementation Dependent State 102 103 None 104